While some weeds are invasive and steal nutrients from intentionally planted flowers or edibles, there are other “weeds” that may actually help your garden or lawn. Before declaring war on those dandelions, read on to learn about some of the beneficial volunteer plants. You might find some new helpers and save yourself some work.
1. Nitrogen Fixers
Plants require nitrogen to survive. The problem is most nitrogen naturally occurs as a gas in our atmosphere and is unavailable to plants.
Nitrogen fixing plants solve this issue with specialized root nodules that can take nitrogen from the air and store it in their roots. The nitrogen becomes available to other plants once the nitrogen fixers die and the roots start to decompose.
The legume family of plants are excellent nitrogen fixers, including clover, vetch, peas, beans, lupines, false indigo, and alfalfa. Leave these plants to die at the end of the season or till in perennial varieties to allow the nitrogen to be released.
Even some potentially weedy trees and shrubs are great for fixing nitrogen, such as sea buckthorn, broom, alder, locust trees, and Russian olives. The older roots that die off naturally will release nitrogen into the surrounding soil.
2. Deeply-Rooted Weeds
Plants with deep root systems, like docks, dandelion, pigweed, or thistles, will draw hidden nutrients to the soil surface. This often includes trace minerals that many of your shallow-rooted ornamental plants would have a hard time accessing. The deep roots also break up compacted soil to improve water permeability and texture.
These weeds are excellent to add to your compost. Try leaving some in place throughout the growing season to harvest and compost the leaves regularly before they start to flower or seed.
You can also dig up the roots at the end of the season. But make sure they don’t survive in your finished compost. Try putting the harvested roots in the sun for at least a week to thoroughly dry out. Soaking the roots in a bucket of water until they ferment will also finish them off before adding to your compost.
3. Ground Covers
Ground cover plants in any form, including weeds, can help your garden in many ways.
Their roots will stabilize soil, preventing erosion and the loss of nutrient-rich top soil. The stems and leaves will provide shade to keep your ground moist and reduce irrigation needs.
Although it may sound contradictory, a good ground cover of weeds will also help with weed control. Weeds that make a tight mat of vegetation over the ground, such aspurslane or dead-nettle, will prevent more invasive weeds from taking hold.
4. Edible Weeds
Many of our modern-day weeds were once sought-after food crops. The flavor of wild greens is often stronger than our cultivated varieties, but this is no reason to disregard them.
In fact, weeds such as lamb’s quarters, yellow dock, dandelion leaves, purslane, chickweed, and sorrel have two or three times the nutritional value of spinach or Swiss chard.
If you steam or sauté the greens, it will remove any bitter aftertaste they may have when raw. Then you can use them as you would any other green vegetable in soups, stews, sauces, or as a simple side dish.
These are some tasty edible weeds you can try:
- Dandelion (Taraxacum officinale) – eat the fresh leaves or dry the roots in small pieces and use in tea.
- Clover (Trifolium pretense) – leaves and blossoms are good fresh, blossoms can be steeped in tea.
- Plantain (Plantago major) – leaves are excellent steamed.
- Sorrel (Rumex acetosella) – lemon-flavored leaves are tasty raw when young, or steamed when older.
- Watercress (Nasturtium officinale) – tangy leaves are good fresh or steamed.
- Chickweed (Stellaria media) – fresh leaves are great in salad.
- Lamb’s quarters (Chenopodium album) – young leaves are good raw or steamed, and the seeds are also very nutritious.
5. Cover Crops
The main purpose of a cover crop is to provide more nutrients and organic matter for your soil. Many farmers and gardeners will purposely sow certain plants as cover crops, but you can also use your existing weed species.
It’s recommended to regularly cut off the greens of a cover crop and leave them as a mulch to decompose on the soil, or take them to your compost. The plants can be tilled into the ground at the end of the season.
You can leave lush weeds you already have in place, such as clover, burdock, thistles, chickweed, or pigweed. Just make sure to keep cutting them down before they flower and make seeds.
6. Insect Attractants and Repellants
You can help support pollinating insects by keeping some wild, flowering weeds around to provide food. Some of their favorites include dandelions, clover, thistles, evening primrose, borage, and Queen Anne’s lace. Allowing weedy shrubs, such as wild cherries or roses, to grow in unused corners of your yard is also useful.
These weeds can attract beneficial predatory insects to your garden as well, such as ladybugs, parasitic wasps and lacewings, which control your bad bugs.
On the other hand, some weeds can keep unwanted bugs away. A study in Florida found there was less armyworm damage in cornfields with weeds like dandelion, cockleburs and goldenrod. Plants like pennyroyal, feverfew and peppermint are known to repel mosquitos.
Weeds can also lure harmful insects away from your desired plants. For example, lamb’s quarters often attracts leafminers, which could attack your spinach or other greens instead.
7. Soil Indicators
Certain weeds grow best under specific soil and climate conditions. If you see them growing in an area, you’ll have a good idea of what’s going on in that soil.
For instance, knotweed, sow thistle and plantain are all indicators of an acidic soil. Whereas sheep sorrel and yellow toadflax will often grow in poor soils low in organic matter.
If you see a lot of one or two types of weeds in a location, look into what they’re telling you before you make any further plans for the area.