|
|
Garden Word of the Day
Take $5 off planting calendars from Forging Time with the code DAILYGARDEN841. This is an excellent resource with some amazing photos.
|
We’ve all heard social networks help us to be healthy and successful. It ends up that trees have been networking quite intimately for a very long time. Tree networking takes two forms. They frequently share nutrients indirectly, using soil microorganisms as go-betweens. And they fuse their root systems in natural root grafts, called anastomoses.  Exposed tree roots (Jennifer Boyer) CC BY 2.0 How do roots graft? Natural root grafts occur when relatively small roots of two different trees come into contact with each other. As they grow, they fuse, creating mutually accessible cambium layers and vascular bundles that allow them to share water, nutrients, and the products of photosynthesis. Why does this happen? More than 150 plant species exhibit natural root grafts, according to researchers. There is debate about whether this occurs due to overcrowding or if plants purposefully graft their roots onto neighboring roots. There is also debate whether this action is beneficial or verging on parasitism. Most researchers lean toward the mutually beneficial explanation. Potatoes and strawberries frequently graft their roots onto neighboring plants of the same species. Surprisingly, some natural root grafts are between different species.  Mature roots from two trees naturally grafted together to share water and nutrients (Wood Geek) CC BY-SA 4.0 Benefits of natural root grafting
Natural root grafting provides several benefits to all parties involved. Those benefits include improved stability and water and nutrient sharing. These benefits help keep neighboring trees healthy, making them more resistant to wind and herbivore damage. In one study, trees with natural root grafts were found better able to recover from a spruce budworm attack. Tree root grafting allows groups of trees to share water and nutrients. It also forces them to share soil-borne pests and diseases, such as Dutch elm disease and apple proliferation. For me, this is yet another example of the amazing processes going on underground. I was stunned to learn that plants can hear. I wonder what will be discovered next.
0 Comments
Summer BBQs often involve a spilled beer or two, but did you know that might be helping your drought-impacted plants? Read on!  Beer bottle on lawn (PxHere) Public Domain Climate change and food production Climate change is having a growing impact on food production worldwide. [Sorry, I couldn’t resist.] Not all of our groceries grow well in these rising temperatures. And drought is reducing crop yields all over the place. Scientists estimate that corn and wheat crops will be seriously affected by 2030, so a lot of research is being done to see if bigger root systems or other modifications can help plants grow with less water and in higher temperatures.  Corn growing in cracked, dry soil (PxHere) Public Domain Plants respond to heat
When plants are hot and dry, they protect themselves by closing pores found on the underside of leaves. These stomata control the rate of gas exchanges used by plants in photosynthesis. This respiration can be slowed by as much as 50% during periods of extreme heat. Unless your plants are drunk. Pints and plants Recent research has found that many plants can thrive during drought if they are given ethanol. Ethanol is alcohol. It ends up that plants produce alcohol when they don’t have enough water. This fact led some researchers at the RIKEN Centre for Sustainable Resources Science to wonder if the same processes could be used to protect plants. Alcohol abundant and cheap to make. Did you know that U.S. bars mark up their alcohol by an average of 400-500%? But back to the plants. Researchers compared wheat and rice plants that had been treated with alcohol to those without. The plants were deprived of water for a couple of weeks in summer. Only 5% of the untreated plants recovered, while 75% of the alcohol-treated plants were able to resume growing once watered. Those are some significant numbers! The scientists radio-tagged the alcohol so that they could see where it went within the plants. Plants that were given alcohol started behaving like they were in a drought even before the water was cut off. This helped them to be better prepared than their teetotaling brethren. Not only did they make better use of the water they had, but they also used the alcohol to create sugars to provide themselves with energy and perform more photosynthesis, even though their stomata were closed. Now, this doesn’t mean you should go around giving your pumpkin plants shots of tequila. That would be a bad idea. What it does mean is that an occasional spilled beer might not be such a bad thing and we should all be on the lookout for more specific instructions as the research continues. Bacterial soft rot destroys more crops than any other bacterial disease. Commonly occurring in cruciferous, cucurbit, nightshade, and onion families, bacterial soft rot also causes severe pitting in carrots.  Potato with bacterial soft rot (Scot Nelson) Public Domain Rather than a single disease with a simple cause, bacterial soft rot refers to a collective of bacterial rots caused by Dickeya dadantii (previously known as Erwinia chrysanthemi), Pectobacterium carotovorum, and various Bacillus, Clostridium, and Pseudomonas bacteria. Whichever critter starts this problem, the soft tissues of buds, bulbs, corms, petioles, rhizomes, stems, and tubers are liquified and your crop turns to mush.  Onion infected with bacterial soft rot (Scot Nelson) Public Domain Symptoms of bacterial soft rot
Like other bacterial diseases, bacterial soft rot is easily overlooked at first. As the disease progresses, water spots start to form on soft tissues. Unlike the whitish splash marks left on old wooden furniture, these spots grow larger, softer, and start to sink. As interior tissues break down, these damaged areas may ooze and start changing color. Discolorations can range from cream to black. And they smell bad. Bacterial soft rot management Poor drainage, waterlogged soil, and insufficient airflow all set the stage for bacterial soft rot. Infected plants must be destroyed and removed. Prevention is worth the effort. The following good cultural practices can significantly reduce the likelihood of bacterial soft rot affecting your plants: • Use certified clean seeds and seedlings. • Quarantine and harden off new plants. • Install resistant varieties. • Plant at the appropriate times and correct depths. • Use recommended plant density. • Monitor plants regularly for signs of infection. • Provide adequate airflow through proper pruning. • Irrigate properly, allowing the soil to dry out between waterings. • Employ crop rotation to reduce overwintering bacteria. • Remove weeds. • Avoid working crops when they are wet. • Remove infected plants and dispose of them in the trash. • Clean and disinfect tools regularly. If bacterial soft rot continues to be a problem in specific areas of your garden, use that space for plants that are generally not susceptible. That list includes beets, corn, and snap beans. It’s a wonder I haven’t written about aloe vera before. It’s such a useful and easy plant to have around. It took the gift of an aloe plant from a dear friend that sparked this post. [Thank you, Sandy!]  Sandy's aloe vera and Brad's lipstick plant (Kate Russell) Aloe vera (Aloe barbadensis miller) is the cousin of over 500 flowering succulent plants. It has been used medicinally for countless centuries. Cuts and burns heal much faster when gel from the aloe vera plant is applied, making it an excellent plant to have around the kitchen. Native to Africa, the Arabian Peninsula, Jordan, and Madagascar, aloe vera thrives in hot, dry climates and on window sills. Aloe vera description Aloe vera plants have triangular, fleshy, often spiked leaves that grow from a central rosette. They vary in color from bright green to nearly gray and can be mottled or striped. The flowers are yellow to orangish-red and tubular. Oblong fruits contain many seeds. These perennial evergreens can hold their own in hot, dry landscapes without any help from homeowners.
Aloe vera as medicine
There are more claims about the medicinal uses for aloe vera than I have room to list. As is usually the case, most of those claims are false. While we would all love simple answers to common problems, life rarely works that way. Claims that sound too good to be true generally end up being false. The compounds found in aloe vera provide conflicting results. For example, one compound found in aloe vera, alprogen, reduces inflammation and allergic responses, while another component, acemannan, does the opposite. In 2002 aloe vera sap was banned as an OTC laxative by the US FDA. However, reports from the U.S. Department of Health and Human Services tell us that topical applications of aloe vera do provide the following benefits:
As for all the other claims, research is still ongoing. We will have to wait. While we wait, there’s no reason we can’t grow and enjoy these lovely burn treatments. How to grow aloe vera Aloe vera plants are easily grown from leaves taken from parent plants. Just pull off a leaf and stick it in moist soil. These plants take well to containers. Just be sure to allow the soil to dry out between waterings. Overwatering can kill an aloe vera. It can also attract fungus gnats. If you start seeing gnats, sprinkle crumbled mosquito dunk on top of the soil and water it in. The Bacillus thuringiensis bacteria found in these dunks kill fungus gnat larvae, along with mosquitoes. Aside from the numerous false claims about what aloe vera can do, overwatering and poor drainage can result in several diseases, including aloe rust, anthracnose, bacterial soft rot, basal stem rot, fungal stem rot, leaf rot, and root rot. As always, aphids can turn up in your aloe plants. Even though aloe vera can’t do all the things claimed in popular media, they are still attractive, useful, and easy plants. Every home should have one. And once you do, you can start taking leaves off and creating gifts for family and friends. Papaya trees are some odd critters. Besides being delicious, they have three genders.  Papaya (Ivar Leidus) CC BY-SA 4.0 In a complex reproductive arrangement similar to avocados, papaya flowers can be male, female, or hermaphroditic. Male flowers only produce pollen. Female flowers always produce fruit, but it’s only edible if the flower was pollinated. Most commercially grown papayas are from hermaphroditic trees. What’s in a name? Also known as pawpaws, there’s more to papaya than the fruits seen in grocery stores. Those are tropical papayas. There are also mountain papayas and Eastern North American pawpaws. Each of these plants comes from a completely different family. Tropical and mountain papayas are distantly related to Brussels sprouts and they grow best in USDA Hardiness Zones 9–11. North American pawpaws are cousins to the cherimoya. Let’s see what each has to offer the home gardener. Tropical papayas Tropical papayas (Carica papaya) originated in Mesoamerica and southern Florida. India now produces nearly half of the world’s papaya supply. These trees are tall (15 to 30 feet) and narrow, with the fruit growing in clusters just under the canopy. Fruits are initially green and then turn yellow or red, depending on the cultivar.
Mountain papayas Mountain papayas (Vasconcellea pubescens, aka Carica pubescens) are native to the Andes. They love higher elevations. These evergreen shrubs rarely grow more than 15 feet tall, though they can reach twice that height. These shrubs grow so quickly that they are considered invasive in some areas. Fall armyworms can be a problem for mountain papayas.
Eastern North American papayas Eastern North American pawpaws (Asimina triloba), also known as wild bananas, tolerate colder temperatures than their fruity cousins. They occur naturally in USDA Hardiness Zones 5–9. But you don’t see them in stores because they start to ferment as soon as they ripen.  Pawpaw tree and fruit (USDA) Public Domain These clonal understory trees produce fruits with a custard-like flavor said to be something like a tropical milkshake. The beautiful purple flowers are perfect, which means they are both male and female. They are imperfect because they stink. More on that in a minute. And you will need two trees to get a good harvest.  Pawpaw flowers begin female (left), then turn male and produce pollen (right). (Cbarlow) CC BY-SA 4.0
The fruit is a botanical berry and can become heavy enough to break branches, so supporting poles may be needed. The bark, leaves, and twigs of pawpaws contain natural insecticides (acetogenins) that keep most pests away. Fruit flies and whiteflies may still show up. Zebra swallowtail caterpillars love to feed on these trees, but this is generally not a problem for the trees or the caterpillars, and the toxins consumed provide natural protection against predators for the adult butterflies.
Caring for a papaya tree Common diseases associated with papaya trees include anthracnose, black leafspot, papaya mosaic virus, phytophthora blight, and powdery mildew, along with the dreaded papaya ringspot virus. Before you start working with a papaya tree, you need to know that the latex from unripe fruits can be extremely irritating. Many people learn the hard way that they are allergic. Sadly for those individuals, this latex is commonly used as a meat tenderizer. Did you know that you can use papaya seeds as a pepper replacement? Now you know. Apple proliferation might sound like a bumper crop of Granny Smiths, but it’s far more sinister than that. Sadly, I couldn’t find any images I could use.
Apple proliferation (AP) is a devastating plant disease that can result in crop losses of up to 80%. It is spread by apple proliferation phytoplasmas (Candidatus Phytoplasma mali). There are quarantines for this pest in Canada and the U.S. While AP mainly attacks apple trees, it also occurs on Asian and European pear, hazelnut, and plum trees, along with dahlias, hawthorns, magnolias, and roses. What are phytoplasmas? Phytoplasmas are a type of bacteria known as mollicutes. Mollicutes are unique in that they do not have cell walls. Instead, they have a multi-layered membrane. Phytoplasmas were discovered in 1967. Most phytoplasmas contain a single mysterious protein. Studying these 1 μm life forms has been difficult since no one has been able to grow them in a lab to date. For reference, the plastic wrap in your kitchen drawer is probably 10 μm thick. How the disease spreads Phloem-feeding insects such as cherry leafhoppers, planthoppers, and psyllids are responsible for spreading apple proliferation. AP can also spread through natural root grafting. Natural root grafting occurs when the roots of different trees end up pressed against each other. Over time, the vascular tissues of both root systems come into contact with each other and begin sharing nutrients. There is debate about whether or not this is a survival mechanism. We may explore that another time. For this discussion, those natural root grafts can spread disease. Research has also demonstrated that infected trees emit unusually high amounts of a chemical that actively attracts psyllids, increasing the spread of disease to neighboring trees and shrubs. Apple proliferation symptoms Symptoms of apple proliferation change with the seasons because the phytoplasmas migrate within the tree. In the winter, they head south into the root system. As temperatures rise and the sap moves upward into twigs and leaves, so do the phytoplasmas. Symptoms also vary depending on the species infected and how long the infection has been present. This condition may appear in only some branches. It may disappear altogether for a couple of years before returning. No one knows why, but it may be related to the fact that there are more and less virulent strains of this particular phytoplasma. The most common symptoms of apple proliferation are small tasteless fruits with longer stems, witches’ broom, leaf rosettes, enlarged leaf stipules, shortened petioles, and dwarfism. Other, less common symptoms include increased suckering around the tree base, chlorosis, and downward leaf cupping. Leaves may also be smaller than normal and brittle. In autumn, the leaves of infected apple trees will turn red rather than yellow. AP Management There is no known cure for apple proliferation, so prevention is the only option. Infected trees must be removed and destroyed. Luckily, there are APP-resistant rootstocks, so look for that when tree shopping. And if apple proliferation is occurring in your region, do your best to control those psyllids and leafhoppers. The adventure never ends. Living in a Seattle high rise, I’ve been delighted at how well my balcony strawberries are growing. But we’re moving again, so I brought all my plants inside as a form of quarantine. There’s no sense bringing pests with me to a new location, is there? Especially when there is no balcony at the new location and all of my plants will be indoors. Good thing, too, because aphids had found my strawberries. How they found us on the 7th floor, I’ll never know.  Aphids on strawberry stems (Kate Russell) Aphids are insidious sapsuckers and extremely prolific. I’ve been squishing them as soon as I see them, but there always seems to be more. While out walking my dogs, I kept an eye out for ladybugs, but no luck. What surprised me was to see that something was helping me kill off the aphids. I’m still not sure what it is. What I can see are white aphid husks, dried-up little mummies. These are aphids drained of all their bodily fluids by parasites.  Aphid mummy on strawberry stem (Kate Russell) Parasitism refers to one-sided relationships in which one organism lives on or in a host, inflicting harm. In his book The Meaning of Human Existence, Edward Wilson describes parasitism as “predators that eat prey in units of less than one.” Parasitism isn’t the same thing as the benign hitchhikers of phoresy. Parasites are like vampires. They cause damage. In the case of my strawberries, the aphids are bad parasites. Whatever is killing the aphids are good parasites. Once again, it depends on how you look at things. Types of parasitism Ectoparasites occur on the outside of their hosts. Endoparasites are found inside. Parasites don’t kill their host outright, with parasitoids being the exception, but they sure can make your plants less productive. The difference between parasites and parasitoids is that parasitoids kill their hosts while parasites just keep draining theirs. Parasites can be insects, fungi, nematodes, or bacteria. Insect parasites Most sap-sucking insects qualify as parasites. This large group includes aphids, cicadas, leafhoppers, mealybugs, planthoppers, psyllids, scale insects, squash bugs, stink bugs, tarnished plant bugs, and whiteflies. As these pests suck sap from your beloved garden plants, they may also spread diseases, making them pathogens and well as parasites. At the same time, several parasitoid insects kill our plant pests. Braconid wasps, chalcid wasps, Goniozus navel orangeworm wasps, ichneumon wasps, and tachinid flies are all happy to suck the life from more bothersome visitors.
Fungal parasites It is estimated that fungi cause 85% of all plant diseases. Parasitic fungi attack living organisms. Their more peaceable relatives, the saprotrophic fungi, feed on dead and decaying plant materials. Parasitic fungi are responsible for apple scab, black spot, blights, brown rot, downy mildews, powdery mildew, rusts, smuts, and wilts. These microscopic predators travel on the wind, landing on damp leaves and stems. Each spore produces a germ cell that burrows into the plant and starts feeding and reproducing. On the other hand, some fungal parasites prefer feeding on scale insects.  Soybean cyst nematode and egg (Agricultural Research Service) Public Domain Nematodes as parasites Nematodes cause an estimated $100 billion in economic losses each year. Some nematodes are root grazers, but others are parasites. Parasitic nematodes burrow into root systems to access a continuous food supply. These pests can also carry diseases. Or, they may be beneficial nematodes that feed on cutworms and corn earworm larvae. I know, it gets confusing.  Plant cell containing multiple Rhizobacteria (Louisa Howard, Dartmouth) Public Domain Bacterial parasites Splashing water from rain, sprinklers, and irrigation is how bacteria get around. Luckily, most bacterial parasites are beneficial to their plant hosts. These are the nitrogen-fixing Rhizobacteria of the legume world. Rhizobacteria live in and around the roots, converting atmospheric nitrogen into a form usable by plants, making them part of the Nitrogen Cycle. These beneficial parasites also help plants fight diseases.
Parasites make up more than half of Earth’s biodiversity. Like them or not, parasites serve important functions. Without them, evolutionary change would be reduced, and we would all be more vulnerable.
And I’m grateful to whatever is parasitizing the aphids in my strawberry pots. Anemophily [ani-MA-filly] describes plants that are pollinated by wind. Most plants are pollinated by bees, butterflies, and wasps, along with occasional bats, beetles, and birds. These pollinators are responsible for the lion’s share of our harvests by carrying sticky pollen from one flower to another. In one out of ten cases, the wind carries pollen from plant to plant.  Corn tassels send pollen flying (lglglglg75) Pixabay Very often, wind pollination augments pollination by pollinators. This is important information if you grow any of these anemophilous plants and want a harvest.
 Oats and wheat are wind-pollinated (Kate Russell) Characteristics of wind-pollinated plants
This is one of those cases where you don’t know what you have until it’s gone. Most plants invest a lot of energy and resources into attracting pollinators. They produce chemicals with enticing aromas, construct flashy, intricate flowers, and crank out sugary nectar. Anemophilous plants don’t need to go to all that trouble. Even the size and stickiness of pollen grains are reduced in wind-pollinated plants. The pollen of these plants is so small that it can be captured by a bee’s electrostatic field. [There’s a lot of it flying around at certain times of the year.] That is why honey can contain ragweed pollen even though honey bees generally do not visit ragweed flowers. Bees do visit corn tassels and other grains. Structurally, these plants tend to have long, exposed stamens and feathery stigmas. These are used to dispense and collect pollen, respectively. If you are allergic to pollen, it’s most likely pollen from anemophilous plants. Researching yesterday’s post on bacterial blight, I was astounded at the number of diseases caused by Pseudomonas. Pseudomonas [soo-doh-MO-nas] is a genus of bacteria that most of us gardeners end up fighting. These bacteria are commonly found in plant debris, soil, and water. They also hide out in many dicot seeds. But don’t worry, Pseudomonas only infects plants with leaves and stems. The rest of your garden is safe. *wink*  Tomato leaf infected with bacterial speck (Alan Collmer, Cornell University) Public Domain Pseudomonas plant pathogens To date, more than 500 strains of Pseudomonas have been sequenced. Here is a list of the most common bacterial diseases caused by Pseudomonas:
In nearly all of these diseases, small dark spots appear and expand into odd-shaped dead areas. It’s all downhill from there.  Bacterial leaf spot on a beet leaf (Howard F. Schwartz, Colorado State University, Bugwood.org) CC BY 3.0 US Managing Pseudomonas These are some tough SOBs. These bacteria have evolved to survive rugged conditions. Their cell walls are equipped with pumps that eject antibiotics and other unwanted materials before they can do anything, so chemicals are often ineffective. Because of this, prevention is your best management tool. Most importantly, be sure to space plants far enough apart so they dry off rapidly. And avoid overhead watering.  Bean leaves with bacterial brown spot (Nancy Gregory, University of Delaware, Bugwood.org) CC BY 3.0 US Pseudomonas isn’t all bad
As handy as it would be to say that all Pseudomonas are bad, it ends up that some of these soil bacteria help plants stay healthy. In fact, they practically make life possible on Earth. Life sure is messy, isn’t it? Some Pseudomonas protect plant roots against disease-causing Fusarium fungi and Pythium oomycetes. They also protect against plant-eating nematodes. And other strains help activate disease resistance within wheat and other cereal crops. Some Pseudomonas can metabolize pollutants and are used in bioremediation. Finally, Pseudomonas is also responsible for the formation of most of the snowflakes and raindrops that fall on Earth. Now you know. If you grow apples, cherries, kiwifruit, mulberries, nectarines, peaches, pears, plums, or walnuts, you need to know about bacterial blight.  Early symptoms of bacterial blight on mulberry leaf (William M. Brown Jr., Bugwood.org) CC BY 3.0 US Bacterial blight is not the same thing as common bacterial blight, which attacks legumes. To make matters worse, many people call another bean variety of blight ‘bacterial blight’. I know, it gets confusing. Let’s see if we can clarify some of this.
The cause of bacterial blight Bacterial blight, also known as blossom blight or shoot blight, is caused by a bacterium called Pseudomonas syringae. There are over 50 different strains of this bacteria that cause plant disease. Common examples include bacterial canker, bacterial speck, citrus blast, and halo blight. Pseudomonas syringae is commonly found on the exterior surfaces of healthy plants. It is only when bacteria get inside, through wounds or natural openings, that the trouble starts. Bacterial blight symptoms Like the other diseases caused by this pathogen, the first symptom is water-soaked areas on leaves. These areas turn brown and mushy and often have yellow halos. If these spots occur early in a leaf’s development, leaf curling and twisting may also occur. Leaves may also start dying from the outer edge, with the infection moving inward toward the center. Twigs may exhibit black streaks, and it is common for infected blossoms, branch tips, and leaves to die. If infected twigs develop a shepherd’s crook shape, it’s probably fireblight. Managing bacterial blight Pseudomonas syringae is most commonly spread by wind and rain. Insects and your garden tools can also be part of the problem. You have to assume that the disease is present. These bacteria can survive in diseased plants, infected plant debris, and soil. Once a plant is infected, you can try to save it by trimming 10 to 12 inches below infected areas, making sure to disinfect your pruners between each cut. You can dip them in a 10% bleach solution for 30 seconds, though bleach is hard on tools. You can also use bathroom cleaner or other spray disinfectants that contain at least 70% alcohol. Just be sure to give it a few minutes to work before making another cut. Infected plant material should be bagged and thrown in the trash right away. Prevention is easier. To prevent bacterial blight from taking hold in your landscape, use these tips:
Fixed copper sprays may also help. Now that I live in an apartment, I find myself missing the fresh figs and nectarines, abundant almonds, and deluge of citrus from my old trees. And that got me thinking about putting a small fruit tree on my balcony. It ends up that you can grow a surprising number of fruit and nut trees in containers.  Even this bonsai Chinese quince can produce fruit! (Sage Ross) CC BY-SA 3.0 Following the same advice I gave in my post on container gardening, we’ll need to select a food-safe container with good drainage, fill the container with potting soil, and make sure the tree gets enough sunlight. But which trees can be grown in containers? And how big do the containers need to be? Let’s find out. Tree containers and soil Back in California, I had a friend who was growing an orange tree in a two-foot wooden planter box. The tree was 20 years old, less than three feet tall, and very productive. It can be done. The most important things to keep in mind when selecting a container for your tree are drainage, durability, and food safety. Too many planters out there are made of toxic materials. Make sure your tree’s home is made of food-grade materials and that there are drainage holes in the bottom of the pot. You’ll need a 10- to 15-gallon pot. Tree roots can be surprisingly strong. I’m sure you’ve seen sidewalks that can attest to that. Your tree’s container needs to be durable enough to withstand tree roots and temperature extremes. Lightweight plastic may be easier to move around, but it probably won’t last as long as your tree. Once you have a container, you’ll want to fill it with potting soil, not planting soil or topsoil. Topsoil may contain pests or diseases that may cause years of headaches and it won’t drain properly in a container. Planting soil is meant for the ground and doesn’t drain the way your potted tree will need. Potting soil is specifically engineered to help plants thrive in containers. And please don’t put rocks in the bottom of planting containers. All they do is take up space better allocated to soil and roots. When you fill your container with potting soil, create a mound in the center of the pot. You will arrange the roots of your tree over that mound and then cover them with soil. Do not tamp down the soil. Instead, mud in your new tree to prevent damaging tender roots, making sure that the graft union is visible above the soil line. Remember that improper tree planting depth is one of the worst things you can do to your tree. Be sure to install a tree support until your baby tree has had a chance to send out supporting roots, then remove the support. Which trees can be grown in pots? Preparing for my trek across Spain, I saw this olive tree in Paris. Based on the trunk, I’d say it was a very old tree living in a rather small container. But it looks healthy, so you can certainly put olives on your list of possibilities.  Olive tree growing in Paris (Kate Russell) Generally speaking, you will want to choose a dwarf variety tree. These are trees grafted onto M-9, M-26, M-27, or P-22 rootstock. Larger varieties will be okay in a container for a while, but they will need to go into the ground eventually. And transplanting a tree is no small feat. Which reminds me, containerized trees can live for 20 years or more. Because of this, it’s a good idea to have a plan in place for up-potting your tree, should that ever become necessary. Personally, I’m going to start with a full-sized container so that I can avoid that Herculean task.
To get the most out of your containerized fruit tree, you may want to get a fruit cocktail tree. These are trees that have different types of fruit grafted onto the branches. For example, a fruit cocktail stone fruit tree can produce apricots, nectarines, and peaches on the same tree. Or, you may select a 4-in-1 cherry tree with four different varieties of cherries growing on the same tree. It really helps make the most out of small spaces.
When shopping for rootstock, look for self-fruiting varieties, or you’ll need more than one tree to get fruit. Whichever tree you select, make sure that it is suited to your USDA Hardiness Zone. If you absolutely must have that dwarf lime (Zones 9-10) and you live in Grand Rapids, Minnesota (Zone 3a), you’ll have to bring it indoors for the winter, so make sure you have a plant stand with sturdy wheels. Or, you can keep it indoors and hand-pollinate. In either case, your potted fruit or nut tree will need at least 6 hours of sunlight each day. Other factors to consider when selecting your potted tree are chill hours and local pests and diseases. One of the first things I noticed about Seattle when I arrived last summer was the number of plants affected by powdery mildew. And the few plants I put on my balcony were soon populated with stink bugs. (And I’m on the 7th floor!). Fruiting trees need a certain number of chill hours each winter to trigger fruit production in spring. As always, be sure to buy certified pest- and disease-free rootstock. Caring for potted trees Containerized plants need to be monitored regularly to make sure they don’t dry out too much in summer. You can encourage root growth by watering your potted tree from the bottom, rather than the top. Simply add water to the tray under your pot. The soil will absorb the water and the tree roots will extend downward to access that water. You will also need to feed your tree regularly. So which tree am I going to get? My balcony faces north and I live in Hardiness Zone 8b. Luckily, my balcony gets lots of sunlight and Seattle usually gets 3,000 chill hours each winter. My next step is to figure out which tree is least likely to attract or be affected by powdery mildew or stink bugs. I found a website dedicated to thwarting invasive brown marmorated stink bugs (Stop BMSB) and learned that these pests love almond, apple, apricot, black walnut, cherry, fig, hazelnut, olive, peach, pear, pecan, and pistachio trees. They also feed on beans, cabbage, cayenne peppers, collards, cucumbers, horseradish, persimmons, soybeans, summer squash, sunflowers, and Swiss chard. Darn! It looks like my balcony garden is going to have a stink bug problem no matter what I grow! Luckily, fruit trees are mostly resistant to powdery mildew. Based on where I live, the amount of sun exposure available, and all the rest, I think I am going to opt for a dwarf multi-variety cherry or plum tree for my balcony. Now if I could only find one that isn’t already sold out! Which tree are you going to plant? Planthoppers are not leafhoppers, though they have much in common. Most important, both spread disease as they siphon sap from plants.  Green coneheaded planthopper (xpda) CC BY-SA 4.0 Planthoppers as disease vectors Planthoppers are responsible for transmitting several diseases, especially those caused by phytoplasmas and viruses. One planthopper species nearly wiped out Jamaican Tall coconuts by infecting trees with lethal yellowing. Planthoppers often transmit X disease to cherries and other stone fruits. They are also responsible for spreading cereal tillering disease, maize mosaic, and several other diseases. Planthopper description There are more than 12,500 planthopper species (Fulgoroidea), and they occur worldwide. With so many species, it’s no surprise that they come in several shapes, sizes, and colors. Spotted lanternflies and buffalo treehoppers are types of planthoppers. Snowy planthoppers look like whiteflies.
As their name indicates, these insects can launch themselves from one place to another. They do this the same way grasshoppers do. More often, however, they walk very slowly. But that’s not what makes them so hard to see. Planthoppers often look like leaves or other plant parts. You can look right at one and not see it. Generally speaking, planthoppers hold their wings vertically, like butterflies, and their bodies are flattened. Nymphs produce a waxy substance that protects them from water and predators. Adult females also produce this wax and use it to protect their eggs.  Planthopper larvae (Richard Bartz) CC BY-SA 2.5 Planthopper diet
Planthoppers are sap suckers. As they feed on practically all of your garden plants, they produce a sugary poop called honeydew. Sooty mold thrives on honeydew. So do ants. In fact, ants are known to tend planthopper larvae, protecting them from predators. The larvae of some planthopper species live underground and feed on plant roots or fungi. Planthopper management Planthoppers can be difficult to control because of their mobility. Many people recommend spraying them with a blast from the hose. I imagine this would take care of the nymphs who would be unable to return to their food supply, but I can’t imagine it would be very effective against adults. I could be wrong. Luckily, they are attracted to yellow sticky sheets. And predatory stink bugs feed on planthopper larvae. Did you know that some planthopper species communicate with their neighbors through vibrations in plant stems? I didn’t either. Also known as cherry X disease, peach X disease, and cherry buckskin disease, X disease makes fruit small, pale, and bitter. It can affect stone fruits, such as apricots and cherries. Once a tree is infected with X disease, it must be removed to prevent the infection from spreading to other trees.  Cherries on the left infected with X disease (Plantpathfinder) CC BY-SA 3.0 What causes X disease? X disease is caused by phytoplasma. Phytoplasmas are microscopic, one-celled bacteria that have no cell walls or nuclei. To me, that’s just weird. Animal and plant cells and most bacteria have clearly defined cell walls that hold their insides in and a central nucleus that runs the show. I have a hard time wrapping my brain around these phytoplasmas. Maybe they are like parasitic amoebas, even though amoebas are animals. But I digress. So how does a cell with no wings, legs, feet (or brain) find its way to our fruit trees? The answer is phoresy. Phoresy describes the relationship between two organisms in which one is a hitchhiker, but not a parasite. There are some pretty bizarre examples of phoresy in my post on the subject. You may want to check it out. Anyway, phytoplasmas catch rides inside sap-sucking leafhoppers, planthoppers, and psyllids without harming their hosts. When a cherry leafhopper feeds on an infected plant, the phytoplasma responsible for X disease is sucked into the insect’s gut along with the sugary sap. When that vector moves to an uninfected plant and begins feeding, the pathogen is transferred to the new plant, causing infection. What does X disease look like? This disease can take up to 9 months to appear after infection occurs. Eventually, trees infected with X disease produce pale fruit that is small and leathery. Symptoms are commonly seen on only one branch, at first. The leaves on infected branches may appear bronzed and small. Older leaves tend to fall off. Beyond that, symptoms can vary, depending on the tree species.  Cherry tree infected with X disease (H.J. Larsen, Bugwood.org) CC BY 3.0 US X disease is often mistaken for root rot. To figure out which it is, look closely at the graft union. That’s where the rootstock was grafted onto the fruiting stock. If it is X disease, you will see pits and grooves near the graft union. If you cut into the wood, you will see brown areas in the phloem. These other symptoms are also common:
The fruit from infected trees tends to be pale, pointed, small, and nasty tasting. X disease hosts There are two types of X disease hosts: those that don’t mind the infection (reservoir hosts) and those who succumb to the disease (non-reservoir hosts). Reservoir hosts are a problem because they look perfectly healthy, but they provide a source of infection to many important fruit and nut trees in our landscapes. Almonds, chokecherries, sweet and sour cherries, Japanese plums, clovers, and dandelions are all reservoir hosts. [Dandelions?!!? Yes, dandelions.] Nectarines and peaches can also become infected with X disease, but they are non-reservoir hosts. This means that they can catch the disease but not spread it. Scientists don’t yet understand why that is, but they’re working on it. X disease management Since scientists have been unable to reproduce the phytoplasmas responsible for X disease in the lab, there are currently no treatments for this fatal disease. To reduce the likelihood of X disease occurring in your landscape, do your best to manage the insect pests responsible for carrying the pathogen. The insects responsible for spreading X disease are often found on beets, burclover, ceanothus, curly dock, hawthorn, and pyracantha. Because of this, it is a good idea to maintain some distance between these plants and vulnerable trees. If you suspect X disease has infected one of your trees, it’s a good idea to get help. Contact your local Master Gardeners or Department of Agriculture for verification. They can also help you figure out the safe removal and disposal of any infected trees. Cherry leafhoppers are easy to miss, but they can cause big problems. I can’t deny that leafhoppers are fascinating creatures because they are. I just don’t want them anywhere near my plants.  Cherry leafhopper (Slimguy) CC BY-SA 4.0
Cherry leafhoppers (Fieberiella florii Stål) are ¼” long and wedge-shaped. They have wide, flattened heads and narrow, upright rear ends. Depending on what they eat, where they are, and their developmental stage, they may be grayish-brown, green, orange, or tan.  Brown cherry leafhopper (gbohne) CC BY-SA 2.0
Here is a list of the many diseases that can be spread by cherry leafhoppers:
They also leave collections of white crystalline frass on apples, pomegranates, and stone fruits. Cherry leafhopper lifecycle Leafhoppers lay their eggs in soft plant tissue where they are protected through the winter. Nymphs may also overwinter in tiny hideaways. Come spring, the eggs hatch, and nymphs go through several molts before reaching adulthood. These pests are most active during the hottest months of summer. Leafhoppers are best managed with insecticidal soap. No, we’re not discussing those yummy chocolate cherry cookies, though I may have to try baking a batch after researching this post! The cherry crinkle we are exploring today is a condition that occurs in cherry trees. Cherry crinkle looks like a viral disease, but it’s not. Also known as cherry vein clearing, this condition is believed to be a genetic mutation that may or may not be related to a boron deficiency.  Healthy cherry trees are a garden treat (Couleur) Pixabay Cherry crinkle symptoms
Vein clearing, especially in the margins, is the most common symptom of cherry crinkle. Vein clearing refers to the way veins look lighter or more yellow than normal. I wasn’t able to find a photo that I could use, but these other symptoms may also occur:
Cherry crinkle management If you suspect cherry crinkle, send a sample of soil to a lab for testing. This will tell you if your boron levels are low. It’s not a good idea to add nutrients without a soil test because too much of a nutrient can cause just as many if not more, problems as a nutrient deficiency. If boron isn’t the problem, the tree is probably a mutant and should be replaced. Cherry crinkle can be spread to unaffected trees by grafting mutated scions onto healthy wood. When shopping for a cherry tree, try to find one listed as unlikely to crinkle. Parasites feed on other organisms. Aphid parasites feed on aphids. Let’s see what we can find out about these tiny garden helpers.  Aphid parasite with Russian wheat aphids (Frank Peairs, Colorado State University, Bugwood.org) CC BY 3.0 US Aphid parasites (Aphidius colemani) and greenhouse aphid parasites (A. ervi) are parasitic wasps, but you don’t have to worry about getting stung. These native North American braconid wasps are more interested in aphids, honeydew, and nectar. Aphid parasite description Aphid parasite adults are black or brown with a narrow waist. They have yellow legs and long antennae. These tiny predators are only 1/10” long, which means you could put 7 or 8 of them in a line across the top of an American dime. You’ll probably never see aphid parasite larvae. They are very tiny and white, grub-like creatures.  Greenhouse aphid parasite (Matt Bowser, U.S. Fish and Wildlife Service) Public Domain Aphid parasite lifecycle Females only mate once. After mating, they fly in search of aphid hosts for their young. Aphid parasites insert single eggs inside 100 aphids, and their greenhouse cousins lay up to 300 eggs. When those eggs hatch, the larvae eat their host aphids from the inside out. Ouch! Aphid parasites often cut holes in the underside of their hosts to attach anchoring threads to a leaf. After about a week, these parasitized aphids swell up like balloons and turn beige to brown. These puffed-up aphids are called mummies. The larvae pupate inside the aphid and emerge as adults, ready to continue the cycle.  Parasitized aphid (Katja Schulz) CC BY 2.0 Surviving aphids frequently emit “alarm” pheromones that cause neighboring aphids to jump ship, abandoning the host plant and falling to the ground where they often die of starvation. Just as well. Adult aphid parasites only live for 2 or 3 weeks, feeding on aphid honeydew and nectar from small flowers, such as anise, dill, mustard, and parsley. Their offspring can parasitize a large number of aphids. Aphid parasites are most active when temperatures are between 64°F and 77°F. They prefer green peach aphids and melon aphids for their supper but eat other aphid species, too.  Aphids and parasitized "mummies" hosting aphid parasites (Whitney Cranshaw, CSU, Bugwood.org) CC BY 3.0 US Aphid parasites are available commercially and are frequently used to control aphids in greenhouse environments. You can attract and maintain habitat for aphid parasites by planting clumps of rye or barley. These plants attract aphids, providing a long-term food source for your aphid parasites. You can also add the flowers mentioned earlier. Because aphid parasites can fly, they will regularly scan your garden for all sorts of aphids. You should start seeing aphid mummies 10 to 14 days after releasing these hunters into your garden.
A midge is a small fly. Most midges are food for frogs and swallows. Many of them eat debris and help with nutrient cycling. Two of them, sand flies and black flies, bite and are vectors for disease. But, aphid midges deserve our notice and appreciation. They eat aphids. They eat a lot of aphids. Once you see how tiny these predators are, you may wonder how they do it. Let’s find out.  A midge feeding on the knee of a mantis, while the mantis eats a bee (JonRichfield) CC BY-SA 3.0.jpeg Aphid midge description Adult aphid midges (Aphidoletes aphidimyza) are only 1/8 inch long. This means that you could line up half a dozen of them across the face of an American dime. Aphid midges can be mistaken for large fungus gnats or small mosquitoes. This is understandable since they are all members of the Diptera (two-winged) order, but mosquito wings are thinner than aphid midge wings.  Aphid midge (James Lindsey at Ecology of Commanster) CC BY-SA 3.0
Aphid midge larvae look like tiny orange slugs. Aphid midge diet Aphid midges feed on more than 70 different aphid species, including the dreaded green peach aphid. And it is the larvae who eat the most. They do this by injecting a paralyzing toxin into the leg of their prey. Then they suck the life juices out through a hole they have chewed in their prey’s thorax, the middle portion. Because their prey is paralyzed, aphid midge larvae can kill insects much larger than themselves. In fact, aphid midges are known to kill more prey than they can eat, but we won’t hold that against them. Aphid midge larvae kill up to 65 aphids each day.  Orange predatory midge larvae among pea aphids (Whitney Cranshaw, Colorado State University) CC BY 3.0 US Working with aphid midges
February may feel too early to consider aphids (unless you live in the Southern hemisphere). But it’s never too soon to learn how to help your garden plants stay healthy. As temperatures rise, you may want to buy aphid midge pupae to help in your fight against aphids. Pupae arrive in the mail in containers filled with moist vermiculite or peat. Depending on the temperature, pupae emerge as adults in 3–7 days. This is important. You’ll want to time your aphid midge release to coincide with newly emerging aphid populations. If you release them too early in the season, they’ll run low on food. Before you squish another cluster of aphids, you may want to take a closer look to see if aphid midges aren’t already at work. Blackheart is a disorder caused by environmental conditions. It occurs in a diverse collection of garden crops. Celery, potatoes, sweet potatoes, and tomatoes are all susceptible to blackheart. Wherever it occurs, the causes of blackheart are the same. Unless it is seen in almonds. Then it’s a fungal disease called Verticillium wilt. Causes of blackheart Blackheart is caused by a lack of oxygen or too much CO2. How can you control those levels, you might ask. It’s easy. Picture this: it’s a hot day. Your plants are wilting. You add water. A lot of water. Your intentions are good, but now the ground is saturated. This miniature flood pushes oxygen out of the soil’s macropores and micropores. Blackheart takes hold. Blackheart is also caused by extended periods of cold temperatures, like those in your refrigerator. You may be surprised to learn, as I was, that blossom end rot and blackheart result from similar conditions and may appear in tandem. Before adding calcium to your soil, be sure to have it tested first. Too much of a good thing can be a bad thing. Blackheart of celery If young tissues in the middle of your celery plants turn black, it may be blackheart. Much like blossom end rot of tomatoes and tip burn of lettuce, this condition is directly related to calcium uptake problems. That doesn’t mean your soil needs calcium. It means they can’t access enough of it. The only way to know how much calcium is in your soil is with a lab-based soil test. In many cases, the problem is irregular watering, soil salinity, and excessive fertilizer, specifically magnesium, nitrogen, or potassium.  Celery blackheart (PlantVillage) CC BY 3.0 Blackheart of tomatoes and potatoes (sweet and otherwise) Commonly affecting potatoes and tomatoes, blackheart causes them to turn black in the middle. [Unfortunately, I was unable to find licensable photos.] Fruit suffering from blackheart looks perfectly normal on the outside. Like hollow heart, which creates cavities within tubers, blackheart is seen as dark areas with distinct edges inside the fruit. These darkened areas start out as random spots that can expand. There may be small cavities, but they are mostly absent. These symptoms are similar to soft rot and Phytophthora root and stem rot, except that the interior stays firm. Eventually, these darkened areas will rot. If your seed potatoes have blackheart, they will grow into weak plants, if they grow at all.
Preventing blackheart
To prevent blackheart from occurring, use these tips:
I hope the only blackhearts you have to deal with are the ones found in comic books. Sometimes things look fine on the outside when the inside is damaged. This can happen to people. And it happens in beets, potatoes, seeds, and watermelons. If you cut a beet, potato, seed, or watermelon in half and find the empty space in the center, it has hollow heart. Also known as hallowheart, this condition indicates that the plant faced more stress than it could handle. [The same might be said for people, but I digress.]  Watermelon with early-stage hollow heart (utroja0) Pixabay Sadly, this was the only licensable photo of hollow heart I could find. Hollow heart of beets If you cut into a beet and find an empty center, it’s time to get your soil tested. Hollow heart in beets is most commonly caused by a boron deficiency. If you look closely at the petioles, you will see that they are cracked, deformed, or smaller than normal. If the cavity is rotting, it may be black heart. Hollow heart of potatoes Hollow heart in potatoes is related to the water supply. And hollow heart is only one potato problem caused by irregular watering. Splitting and spraing (brown lines) are also water-related. Cold injury can also cause hollow heart in potatoes.
Hollow heart in seeds
Garden peas and other seeds can also develop hollow heart. This occurs when unusually high temperatures occur right after germination begins. Because this disorder happens so early in the plants’ development, it leaves plants vulnerable to several fungal diseases. The best way to avoid hollow heart in peas and other seeds is to plant at the optimal time of year for each species. Hallowheart of watermelons Hollow heart in watermelons is mostly caused by insufficient pollen transfer. Poor pollination occurs when temperatures are low or when there are not enough pollinators in the area. Somehow, poor pollination causes the interior of a watermelon to develop triangular, often symmetrical gaps in the fruit. Seedless watermelons are more likely to develop hollow heart than seeded varieties, and orange and yellow-fleshed watermelons are the most likely to develop this condition. I have no idea why. What I do know is that you can attract more pollinators to your watermelon patch by adding flowers that appeal to both honey bees and bumblebees. You can offset low temperatures with row covers. Hollow heart in watermelons can also occur when they are hit with too much fertilizer combined with not enough water, making the cells responsible for producing fruit unable to keep up with the cells producing rind. Bottom line: a steady supply of water, planting at the appropriate time, and the right amount of nutrients can help prevent hollow heart from occurring in your garden. Walking a garden path has long been known to soothe the soul. Today, we are exploring that idea in more depth. Can a garden be designed with healing in mind? I think so.  Healing Garden at AdventHealth Celebration CC BY-SA 3.0 We’ve already looked at several garden designs and themes. We’ve learned about scent gardens, sensory gardens, and tranquil gardens. Each of these can help us deal with emotional hurt and trauma. But how do they help us? How can we create a garden space that helps us deal with life’s difficulties? Let’s find out. How gardens help us heal Traumatic events can take many forms. Assault, betrayal, death, illness, and the mind-numbing exhaustion that comes from dealing with a global pandemic all have one thing in common: they create a sense of helplessness. According to trauma expert Robert Stolorow, trauma creates a “dreadful sense of estrangement and isolation” that leaves us feeling disconnected and out of control.  Dark path (Tama66) Pixabay Gardening helps us deal with that sense of helplessness because we have some level of control. There is little risk. Like a beloved pet, our garden plants accept us exactly as we are, without judgment. They don’t hurt us. Gardens offer the possibility of a better future, even if that future is nothing more than a germinating seed.  Seedlings in hand (Conger Design) Pixabay Spending time in a garden brings us back in touch with natural cycles. No matter what we have gone through, spring bulbs bloom, summer squash grows, and the seasons advance as they always do. This helps ease our natural fight/flight/freeze response. The sights, smells, textures, and sounds of a garden reassure us on a lizard-brain level. The act of gardening resets us physically. Bending, pulling, breathing, reaching—blood flows to our brains, our muscles, helping us think more clearly and sleep more deeply. We are more in the moment when gardening. Time passes unnoticed. We are in the zone, in a flow state, fully engaged in the right now, experiencing ourselves doing something positive instead of experiencing pain and loss. And these claims are not just my opinion. Recent research has demonstrated that gardening has powerful therapeutic effects. Known in the psychology world as horticulture therapy, caring for plants reconnects us with ourselves, our communities, and nature. It is believed that planting seeds and caring for plants parallels our healing. There is even a professional association dedicated to this type of therapy. According to the American Horticultural Therapy Association, “horticultural therapy helps improve memory, cognitive abilities, task initiation, language skills, and socialization. In physical rehabilitation, horticultural therapy can help strengthen muscles and improve coordination, balance, and endurance. In vocational horticultural therapy settings, people learn to work independently, problem solve, and follow directions.” Horticultural therapy is frequently used in prisons, mental hospitals, rehabilitation facilities and retirement homes to improve healing and recovery. Building a healing garden You may have nothing more than a window sill or balcony, like me. You may have a huge yard. Odds are, you’re probably somewhere in between. Whatever your starting point, how can you create a space that will help you through difficult times? First, any act of gardening will be a step in the right direction. Second, there is no Right Answer when designing a garden to help you heal emotionally. Whatever helps you is the best design. My healing garden design This post was inspired by a garden design that popped into my head while writing my gardening as therapy post. Let me share it with you, if I may. Imagine standing on the edge of a space in a rage, distraught and exhausted. Ready to lash out or give up, your feelings are mirrored by the plants closest to you: sharp thorns, ominous colors, looming trees, darkly shaded nooks and crannies. And a hard, rigid path. A few steps down that path, things begin to change. It's a little brighter, the colors are somewhat softer, and you hear a gentle rustle. The path becomes less rigid, and it beckons.  Garden path (James DeMers) Pixabay The crunch of gravel under your feet is echoed by a gentle wind chime. A few shade-loving flowers brighten the way. A sweet aroma is carried on the breeze. A soft leaf brushes your hand, and you come around a bend. The path is now soft and mossy. The view in front of you is a small woodland clearing with a patch of blue sky overhead. A bench invites you to set a spell. Birds flutter and splash in a nearby birdbath. Cascading flowers and fragrant herbs remind you that life isn’t always bad.  Garden bench (Mammiya) Pixabay Don’t you feel better? I know I do.
|
Welcome!You can grow a surprising amount of food in your own yard. Ask me how! To help The Daily Garden grow, you may see affiliate ads sprouting up in various places. These are not weeds. Pluck one of these offers and, at no extra cost to you, I get a small commission. As an Amazon Associate I earn from these qualifying purchases. You can also get my book, Stop Wasting Your Yard!
 Index
All
Archives
September 2022
|
.jpg)
,fr(wh,TS)_Naivasha-Gilgil(Rift_Valley_Prov.),KE_tue13sep2011-1230h.jpg)
_(Unidentified_Dark-winged_fungus_gnat)_-_(imago),_Arnhem,_the_Netherlands.jpg)
RSS Feed