Understanding Weeds – How to Kill them
Weeds – those pesky, unwanted plants that invade our gardens, our lawns, and any other area we’d rather keep free from uninvited guests. They seem to grow faster and stronger than anything we actually want to keep, and can quickly take over whole areas if left unchecked. Even worse, some weeds can cause harm to people and pets with their thorns, toxins, or allergic reactions.
But before you start spraying every weed in sight with chemical herbicides, it’s important to understand a few things about weeds and the best ways to get rid of them safely and effectively.
What Are Weeds?
While the term “weed” is often used to refer to any unwanted plant, a more scientific definition would be any plant that grows where it is not wanted, or any plant that has economic or ecological importance. So while dandelions and clover may be considered weeds in a perfectly manicured lawn, they actually have ecological value as food sources for pollinators and other wildlife.
Understanding the different types of weeds and why they grow where they do can help you determine the best approach to getting rid of them.
Annual weeds complete their entire life cycle in one year or season, going from seed to mature plant to seed production in a matter of months. Examples include crabgrass, chickweed, and pigweed.
Perennial weeds live for more than one year, often reproducing from underground roots or rhizomes in addition to seeds. Examples include dandelions, thistles, and bindweed.
Understanding the life cycle of a weed can help guide your management strategy. For example, pulling annual weeds before they can produce seeds can help prevent them from returning the following year, while using systemic herbicides on perennial weeds can help kill them at the root and prevent regrowth.
Why Do Weeds Grow?
Weeds grow for a variety of reasons, including:
Poor soil conditions: Weeds often thrive in soil that is compacted, lacking in nutrients or organic matter, or acidic.
Sunlight and water exposure: Some weeds, such as crabgrass, thrive in areas of full sun and high water availability, while others, such as oxalis, do better in shady, moist areas.
Disturbances and damage: When soil is disturbed, such as during construction or tilling, it creates opportunities for weed seeds to take root. Damage to the soil from overuse or erosion can also create conditions that favor weed growth.
Lack of competition: Weeds can often outcompete other plants for resources, especially in areas where native plant populations have been disrupted.
How to Kill Weeds
Once you understand why weeds grow, you can start to develop a plan to kill them. Here are some options:
1. Pulling
The most obvious method for getting rid of weeds is simply pulling them out by the roots. This works best for annual weeds or younger perennial weeds that haven’t yet developed extensive root systems. It’s important to get the entire root system, as any remaining roots can quickly regrow.
2. Organic Herbicides
Organic herbicides are made from natural ingredients such as vinegar, boiling water, salt, or essential oils. They work by burning the plant’s foliage and roots, but they are not always as effective on more established perennial weeds. Be careful when using organic herbicides, as they can also damage surrounding plants or soil microbiota.
3. Chemical Herbicides
Chemical herbicides work by interfering with the metabolism of the weed, ultimately killing it. They can be selective, targeting specific types of weeds while leaving desirable plants unharmed, or non-selective, killing any plant they come into contact with.
If you choose to use chemical herbicides, be sure to carefully read and follow the label instructions, as improper use can be harmful to people, pets, and the environment. Also, be aware that some herbicides can persist in the soil for long periods and may harm beneficial insects, birds, and other wildlife.
4. Mulching and Cover Crops
Mulching with organic matter like straw or leaves can help suppress weed growth by reducing sunlight exposure and keeping the soil moist. Cover cropping with legumes like clover or vetch can also help by adding nitrogen back into the soil and outcompeting weeds for resources.
Conclusion
Understanding weeds is the first step to effectively managing them in your garden or landscape. With a little bit of knowledge and careful planning, you can get rid of weeds safely and effectively, without harming the rest of your plants or the environment.