As the old saying goes, weeds are simply plants that grow where we don’t want them to grow.
Some weeds are harmless, some are harmful, and others are wild medicine. So how do you know which is which? How do you tell the difference between a weed and a vegetable seedling in the spring when everything is pushing its way out of the soil for the first time since the snow melted? To answer those questions, you’ll have to spend a little time getting to know your garden’s weeds.
What are Weeds?
Weeds are prolific plants that can be categorized several different ways. One way is to classify them as either grasses or broadleaf weeds. Grasses are notoriously difficult to control once they establish themselves in your garden. They can be competitive and their large root systems can damage surrounding vegetables if you wait too long to pull them. Broadleaf weeds grow upright and have taproot systems that make them easier to pull, without injuring the surrounding plants.
You can also classify weeds by their lifecycle — annual, biennial, and perennial. Annual weeds produce and spread their seed every year. Biennial weeds produce fruit and disperse seeds in their second year of growth. Perennial weeds lay dormant throughout the winter and come back every spring.
Weeds are often classified as lawn weeds, garden weeds, invasive weeds, and noxious weeds. For example, poison ivy and poison hemlock are considered noxious weeds because they are poisonous to humans. Bindweed is considered invasive because it is nearly impossible to eradicate.
Even though we try to eradicate weeds, many are beneficial to humans and the ecosystem. Dandelions, for example, are an edible food source, attract pollinators, and have medicinal benefits. Milkweed is the only food source for the endangered monarch butterfly. Queen Anne’s Lace attracts beneficial insects, such as predatory wasps and ladybugs, that prey on aphids. (Read: Nine Vegetable-eating Insects that will Kill Your Garden)
How to ID Weeds in Your Garden
If you aren’t familiar with the common weeds in your area, the best thing you can do is mark your garden. This will help you until you are able to ID different weed and vegetable seedlings on your own. After a couple of years in your garden, you’ll be very familiar with the weeds that pop up and will be able to pluck them out of the ground immediately.
Sometimes, even if you’ve labeled your garden, you may still have a difficult time identifying whether a plant is a weed. Although there aren’t any morphological characteristics common to all weeds, there are some clues that may help you. If a plant emerges earlier than other native plants in your region, it is likely a weed. Plants that grow in clusters are also probably weeds. It may also help to let the plant grow a little longer until it is easier to identify. If you’re still having trouble, you can take a picture and send it to your local extension office for help.
One of the best things you can do is to learn about the most common garden weeds so you can easily identify them. Dandelions, plantain, purslane, and Canada thistle are four weeds worth knowing, since they are some of the most common weeds found throughout North America. Once you get to know these plants, you may not consider them weeds at all since every single one has benefits to humans and the environment. As another old saying goes, weeds are just plants whose virtues have not yet been discovered.
You either love them, hate them, or tolerate them for the sake of the bees. One thing is for sure, we all know a dandelion when we see one. They can be found in lawns, gardens, or growing in the cracks of sidewalks. Their sunny flowers become puffballs that disperse their seed when the wind blows. We’ll never get rid of them, and perhaps we shouldn’t.
Not only are dandelion flowers one of the first food sources for pollinators early in the season, but the entire plant is edible and has medicinal benefits. The root can be dried and brewed as a tea that’s rich in antioxidants, vitamins, and minerals. The young, tender leaves can be used in salads. The flowers can be used to make dandelion wine and jelly.
Studies have shown the potential for dandelions to help fight inflammation, control blood sugar, reduce cholesterol, lower blood pressure, promote a healthy liver, fight cancer, aid weight loss, support healthy digestion, boost the immune system, and support healthy bones. We should probably be harvesting dandelions instead of trying to remove them.
If you still want to rid your garden or lawn of dandelions, your only hope is to manage them. You need to pull them out by the entire root. If you leave even the smallest bit of root in the soil, it will regrow. Your best chance is to use a weeding tool specific to dandelions when the soil is moist. If you choose to use herbicides in your garden, the best time of year to treat dandelions is in early fall. (Read: Cooking with Cannabis: Country Fried Dandelions with Smoky Ranch Dip)
Plantain can be identified by its basal rosette of oval shaped leaves with a flower spike emerging from the center. It usually only reaches about six inches in height and doesn’t generally get larger than 12 inches across. One plant can produce 20,000 seeds, which ensures its survival regardless of the work you put in to purge it. The roots are shallow and they are generally easy to pull. You’ll find plantain growing anywhere the ground has been disturbed. It grows well in poor, compacted soil.
It is found in temperate climates and was one of the first plants brought to North America by the Puritans because it was prized for its culinary and medicinal benefits. It has anti-inflammatory, analgesic, antioxidant, antibiotic, and astringent properties. The leaves are loaded with vitamins A, K, C, and calcium, and it makes a great addition to salads or livestock feed. This is another weed you may want to harvest instead of poison.
The best method for clearing these weeds is hand pulling. Deep mulching is another effective way to control their spread in your garden.
While some people work to rid their gardens of purslane, other gardeners buy purslane seeds to grow on purpose. This plant may be considered a weed, but it is actually an edible addition to your garden that tastes great in a salad. It has a spinach-like flavor and is full of vitamins, antioxidants, and omega-3 fatty acids. It has diuretic and anti-inflammatory properties and can be used to soothe skin and treat wounds.
Purslane is an annual succulent that displays fleshy, flat, reddish-green leaves. You’ll find it growing in the cracks of sidewalks and throughout your garden. It has a sprawling growth habit and does well in dry soil and hot weather. Each plant has the capacity to produce 200,000 seeds, which remain viable in the soil for 20-40 years.
If you want to get rid of purslane in your garden, you need to be sure to pull the entire plant and root system. If you leave any part of the plant behind, it can regenerate. Mulching with black plastic or straw on top of newspaper are effective ways to control this weed. (Read: Floral Feasts: Edible Flowers)
Canada thistle, also known as creeping thistle or field thistle, is a noxious weed that spreads through wind-dispersed seeds and a prolific underground root system. You’ll recognize thistle seedlings by their long, thin, spiny leaves. When it grows to about four to five feet tall, beautiful purple flowers will bloom, creating a rich source of pollen for many different pollinators. The bees love them.
Even though thistle has benefits to the ecosystem, along with many medicinal properties, it can be a true pain to the gardener — literally. Those spiny leaves hurt! You’ll want to be sure to wear gloves when you pull these weeds. You also need to be sure to pull the entire root system or they will multiply when they pop up again... and again, and again. Tilling or disturbing the soil in any way can exacerbate the problem by breaking up the root system, which creates more weeds. If left unchecked, thistles will completely overtake a field.
In order to control thistle, you need to be diligent about pulling them and their complete root system consistently for two to five years. Do not under any circumstances let them go to seed. If you choose to use a systemic herbicide, the best times to apply it is in the early bloom stage (mid-May to early June) or in the fall. Multiple applications will probably be necessary.
As a gardener, it’s important to understand the weeds that invade our gardens. While some have benefits, others are purely a nuisance. Learning how to identify and deal with each one is an important skill for all gardeners to cultivate.