Weeds

Warm temperatures and moist soil are all it takes to help weeds invade your garden, lawn, and landscape. Fighting weeds is a constant battle, but it is much easier while they are young and vulnerable.

Dandelion (Greg Hume) CC BY-SA 3.0

So many weed seeds!

Shakespeare gave us some excellent gardening advice in his play Richard II, when he told us, "One year's seeds is seven year's weeds." Once a weed takes hold and start reproducing, your work level will compound exponentially! 

The dandelion is a perfect example. Each seed head holds 54 to 172 seeds. But each dandelion plant can produce over 2,000 seeds in a single growing season. A single creeping woodsorrel plant produces 5,000 seeds each year. That’s a lot of weed seed!

Creeping woodsorrel (Kate Russell)

Why get rid of weeds?

Getting ride of weeds is work, so why bother? There are many reasons for getting rid of weeds:

• weeds take up valuable real estate, nutrients, and water
• weeds can block sunlight
• weeds can carry plant diseases
• weeds can provide food and shelter for common plant pests
• weeds may release chemicals that slow the growth of nearby plants (allelopathy)
• climbing vines, such as bindweed, can choke out other plants
• some weeds, such as dodder, parasitize host plants
• some weeds, such as foxtail, can harm pets
• invasive weeds can push native plants, insects, birds, and animals to extinction

​So, getting rid of weeds helps your plants stay healthy. Most of the time. 

Benefits provided by weeds

Before trying to rip out every weed on your property, you may be surprised (and relieved) to learn, as I was, that some weeds actually provide benefits. Because they grow and go to seed so fast, weeds reduce erosion and the loss of top soil. Weeds can also be used to support soil microorganisms and to add organic material back into the soil. Weeds absorb carbon, keeping it out of the atmosphere, increase biodiversity, and provide food and shelter for native insects and animals. In some cases, weeds act as trap crops, luring pests away from favorite plants.

Looking at the sunny dandelion in this new light, we see it has a taproot that grows in even the most compacted soil, provides nectar and pollen for beneficial insects, new greens can be used in a salad, and flowers can be used to make wine! So, not all weeds are bad. But most of them are not what we want in our gardens.

What is a weed?

Before we start learning about some of the more common weeds, let’s be clear about what a weed is and what it isn’t. According to ​Gallagher, “If you pull it out and it grows back, it’s a weed.”  I’ve always said, "A weed is a plant that grows after you try to kill it.” So, how do we get rid of unwanted weeds?

​Weed control

​Weeds are some tenacious opponents. They have evolved to go to seed only days after emerging from the soil. Their stems and roots tend to be brittle, so part of them is left behind to continue after you try to pull them out. There are only two ways to get rid of weeds: the Hard Way and the Hard Way.

Garden sprayer

​Common weeds

Each region has its own collection of common weeds. The more you learn about weeds in your garden, the better you will be at getting rid of them!


​All too often, we opt for the quick fix. Spray some herbicides on it and its gone, right? Well, that’s mostly true. The Hard Truth about this method is that it can also mean those sprays leave behind a residue that can take years to go away. These chemicals may end up in your food and the water supply. Bad plan.


The other Hard Way simply means taking the time to remove every bit of each weed you come across and to check for weeds every single day. The only way to do that is to spend time in the garden and to learn about the most common weeds in your area.

Which of these weeds cause problems in your garden?

Annual sowthistle (Sonchus oleraceus) Like dandelions, sowthistle seeds travel on the wind, so they will always be back. Learn to recognize these weeds while they are young, before they go to seed.

​Burning nettle (Urtica urens) and stinging nettle (U. dioica), have tiny hairs along the stem that sting for several minutes and can itch for hours. ​
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Common lambsquarters (Chenopodium album) may be edible, but these weeds can also carry beet curly top, potato viruses M, S, and X, tomato ringspot, and several mosaic diseases of alfalfa, barley, beans, beets, cucumber, eggplant, hops, lettuce, squash, and watermelons. ​​

​Field bindweed (Convolvulus arvensis) may have pretty flowers, but that root system can down 20 feet or more! Also, bindweed frequently plays host to viruses that impact beans, potatoes and cereals, such as tomato spotted wilt, vaccinium false bottom, and potato X disease. If you discover bindweed in the garden, your best bet is to monitor the area frequently and pull new growth as soon as it is seen. You can also use sheet mulching.

Pigweeds (Amaranthus spp.) provide overwintering sites for disease-ridden green peach aphids and beet armyworms, which negatively impact beans, buckwheat, celery, cilantro, citrus, cole crops, cucurbits, lettuces, parsley, peppers, strawberries, and tomatoes. ​​​

​Spotted spurge (Euphorbia maculata) is a common weed that can reach a surprisingly large size. Mature plants can be several feet in diameter!

​Of course, poison ivy, poison hemlock, and crabgrasses are commonly referred to as weeds, as are the many invasive plants being installed haphazardly. Kudzu, ice plant, purple nutsedge, and English ivy are wreaking havoc on local environments wherever they occur. Once established, it is very difficult to get rid of them.

If you are unsure about a potential weed in your garden, post pictures in the Comments section and we can work together to identify it.