Most flowers go to great lengths to produce nectar, fragrance, and brilliantly colored petals to wantonly attract every passing pollinator. We call this behavior chasmogamy, or “open marriage”.
But some plants are more modest than that. They prefer their own company to that of the masses. These private individuals have evolved a unique method of self-pollination and self-fertilization called cleistogamy [klīˈstäɡəmē]. Cleistogamy is a “closed marriage” type of pollination that occurs inside a flower. These flowers only open after pollination and fertilization have occurred, if at all.
Cleistogamy is believed to have evolved in regions with harsh conditions and fewer resources. Producing petals, fragrances, and nectar is hard work for a plant. Rather than going to all the trouble to create these attractants, cleistogamous plants pollinate themselves in a highly protected process.
Most members of the Viola genus use cleistogamy, but so do barley, beans, peanuts, and peas, to one degree or another. But different plants achieve cleistogamy in different ways. And scientists are still sorting out all the things we are learning about plants.
Using the strictest definition of cleistogamy, we have flowers that pollinate themselves and never open. In this case, the sepals are often partially or completely fused, preventing the flower from opening. Each enclosed flower simply produces its own pollen which falls on the stigma and the plant pollinates and fertilizes itself. Orchids and several grass family plants use complete cleistogamy. This method is different from the normal double-fertilization that most angiosperms use to produce seeds. It is self-sufficient in the extreme, but the downside to this method is reduced genetic diversity. Complete cleistogamy can occur above ground or underground, depending on the plant. When it happens underground, as in the case of peanuts, it is called geocarpy.
Other plants use a combination of cleistogamous (closed) and chasmogamous (open) methods. This group is further divided into three categories: dimorphic, induced, and preanthesis. [The word preanthesis refers to before a flower opens.] If the plant is predetermined to develop into both chasmogamous and cleistogamous flowers, we called it dimorphic cleistogamy. Very often, dimorphic cleistogamous flowers occur at different times or in different locations on the plant. American hog-peanuts (Amphicarpaea bracteata) and Canada violets (Viola canadensis) produce seeds using dimorphic cleistogamy.
If the end result is not predetermined, we call it induced cleistogamy. Flowers in this category are no different from their more open-minded stem-mates except that they do not open. Many fescues and some Impatiens are in this group. They can switch from the normal, social method of seed production to the more protected method, often after being damaged by herbivores.
Preanthesis cleistogamy is a unique reproductive method in which self-pollination occurs first within the closed bud, the bud opens, and then external pollination becomes possible. Monkeyflower (Mimulus nasutus) is one example of preanthesis cleistogamy.
Knowing if a plant is a self-pollinating or cross-pollinating variety can make the difference between having a harvest or not. The difference between cleistogamy and other forms of pollination may not be as important to your crop, but it’s a good reminder about how diverse and amazing plants can be.
It’s still too early for most of us to start planting jalapeño peppers, but thinking about them makes spring and warmer weather feel that much closer. [And knowing they are heavy feeders is a good reminder to incorporate some aged compost into your pepper planting bed now will help them grow better this summer!]
Jalapeño peppers are members of the nightshade family, making them cousins to tomatoes, potatoes, eggplant, and groundcherries. Most commonly seen in stores while green, jalapeños are a type of chili pepper that can mature to yellow, orange, or red, given the opportunity. A favorite of the Aztecs for thousands of years and frequently sliced into Pho, jalapeños can be used raw in salsa, stuffed, smoked, scorched, canned, and baked into countless dishes for added flavor and bite.
Jalapeño pepper heat
Pepper potency is measured using Scoville heat units. Using this tool, jalapeño peppers are relatively mild, ranging from 2,500 to 10,000 heat units. Usually. There have been exceptions. There is also a sweet, heatless jalapeño cultivar. For comparison, bell peppers have zero Scoville heat units, while the Carolina Reaper can incinerate your taste buds with 1.5 to 3 million heat units.
How to grow jalapeño peppers
Being native to southern North American and northern South America, peppers (Capsicum annuum) need lots of heat and sunshine to grow. Optimal germination generally doesn’t occur until temperatures have reached 80°F–85°F, though it can occur as low as 64°F, so there’s no point in starting too early. If you simply can’t wait, you can always invest in or make a seed heating mat. Like other peppers, jalapeños are slow starters. You can plant them indoors as much as 2 months before your last frost date as long as there is sufficient light.
Jalapeño plants are perennials grown as annuals that can reach 2–3’ in height. They grow best in well-drained soil with a pH of 6.0 to 6.8, though they will tolerate 4.5 to 7.0. They need lots of organic matter and they grow well in containers. Seeds should be planted ¼” to ½” deep. Plants should be spaced 12” to 16” apart.
Remember what I said about being heavy feeders? Early in their development, your jalapeños will benefit from a top-dressing of nitrogen (N). As flowers and fruit begin to develop, cut back on the nitrogen and give them potassium (K) and phosphorus (P). Given the right care, each jalapeño plant will produce an average of 25–35 pods, ripening at different times throughout the summer.
Jalapeños need consistent moisture, up to one water-inch a week, but you’ll want to avoid over-watering your jalapeños to prevent fungal disease.
Jalapeño pepper problems
Jalapeños are susceptible to bacterial spot, beet curly top, cucumber mosaic, foliar blight, Fusarium wilt, pepper mottle, phytophthora blight, powdery mildew, ripe rot, root rot, soft rot, southern blight, tobacco mosaic, tomato spotted wilt, and Verticillium wilt. Most of these disease can be avoided with crop rotation and by controlling moisture levels in the surrounding soil. Soaker hoses work well.
Aphids, armyworms, corn earworms, flea beetles, leafrollers, leaf miners, pepper weevils, root-knot nematodes, spider mites, and thrips will all want to take a bite out of your jalapeños, so be on the lookout.
These plants are highly productive and they look lovely in a landscape.
Which types of peppers will you be planting this summer?
You’ve probably heard me say it a hundred times – overhead watering is bad.
But how can overhead watering be bad when plants have been rained on for a very long time? Let’s find out.
In most cases when it rains, the sky is overcast and temperatures are cooler. [Or you’re watering tropical plants that have evolved their own set of built-in protections.] When most gardens get watered with a hose, it’s a sunny afternoon, after you get home from work. Herein lies the problem.
There you are, standing in your garden with a hose in your hand after a long day at the office. You’re sprinkling vegies and other plants with life-giving water. Dust washes away and your plants seem to be refreshed from above and below. But you may be causing more harm than good with overhead watering.
It’s all a matter of timing because when leaves stay wet at night they are far more likely to develop fungal and bacterial diseases.
Overhead watering is a major contributor to fungal and bacterial diseases, such as anthracnose, bacterial spot, black rot, black spot, downy mildews, early blight, halo blight, and leaf spot, just to name a few. Plus, if you have one sick plant, droplets from overhead watering can bounce pathogens onto healthy plants, spreading disease.
These diseases all need three conditions to occur at the same time for your plants to get sick: a susceptible plant, a pathogen, and the right conditions. This is called the disease triangle. Remove any one of the three and your plants stay healthy.
A wasteful practice
Overhead watering is wasteful. On a hot day, as much as 30% of the water ends up running off or evaporating, providing your plants with nothing but disease potential. Some of that evaporation occurs before the water ever reaches the plant. The rest of it happens when the water lands on sun-warmed leaves. Add a little more sunshine and that irrigation water has left the building. Overhead watering also contributes to erosion and groundwater contamination.
What’s in your tap water?
The chemicals found in your tap water also have an impact on plant health. Here, in San Jose, Ca, my soil is alkaline clay, with a pH of 7.7 and our tap water has a pH range of 7.0 to 8.7. I don’t care how often I work on acidifying my soil, irrigating with alkaline water is not going to help. If your tap water is part of your gardening problem, you may want to supplement your irrigation with rainwater collected in rain barrels.
To make the most of your irrigation water, you first need to know your soil texture. Heavy clay can hold on to a surprising amount of water and should be watered less often. Sandy soils need frequent watering. Next, time your irrigation in such a way that leaves can dry out before nightfall.
Besides sprinklers and overhead watering with a garden hose, consider these options:
Conservative watering also reduces weed growth and helps keep nutrients in the soil where your plants can reach them. Mulch helps, too.
There are times when overhead watering can be helpful. Black spot fungal spores take 24 hours to fully attach themselves to leaves. Some growers have found that if spores are washed off of plants every day during peak infection periods, the spores can’t infect plants. A quick afternoon rinse can also get rid of dust, which provides habitat for aphids and spider mites. It can also help cool off plants that are heat or wind stressed. Again, the important thing is making sure the leaves have time to dry out before nightfall.
When you water, water deeply. This encourages roots to grow downward where they are more likely to find their own water and be safely away from various types of surface exposure. And be sure to select plants suited to your microclimate, minimizing the need for irrigation in the first place.
People used to say that watering in the afternoon would cause leaves to burn. That somehow the sun’s rays would use water droplets as magnifying glasses and burn leaves. This isn’t true. Burnt leaves are usually the result of too much fertilizer, chemical overspray, or misapplication of dormant oils.
If you really love watering your garden with a hose the way I do, just do it in the morning. This will give leaves time to dry off during the day.
How do you water your garden?
You can grow a surprising amount of food in your own yard. Ask me how!
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