Getting to know your weeds

Paul McKenzie, N.C. Cooperative Extension
Jan. 26, 2014 @ 08:18 AM

You know you’re a garden nerd when someone makes a joke about aphids and you’re the only one laughing. Fact is, those of us “in the business” spend a lot of time studying insects, soil, fungi and other obscure subjects and, at some point, begin to find it all fascinating. “What do you want to be when you grow up?” has likely never been answered with “A scientists who studies weeds!” So my task is to show you how fascinating the world of weeds can actually be!

It’s oft been said that a weed is simply a “plant out of place,” the classic example being the corn plant in a soybean field. However, to really stand out, a plant needs to do more than just grow a bit taller than the rest.

One way to do that is to produce prolific seed. Many weeds excel at that. With some, a single plant can produce dozens, scores or even hundreds of seeds. You’ve probably heard me tell of the importance of getting rid of weeds before the seed is mature. Now you know why.

Another way plants can excel at being weedy is by having alternate ways to spread. Many have above and/or below ground stems that can spread laterally (known as stolons and rhizomes, respectively, in case you want to impress your friends). A single plant, even if it never flowers, can become a modest clump of plants in a little while and cover a large area given enough time.

Other weeds are able to survive (or even thrive) in poor soil conditions. These tough weedy plants laugh at the acidic, compacted, droughty soils that many plants fear, and just keep on growing and spreading.

Finally, different species of weeds vary in their life cycle, so something is almost always growing. Cool-season weeds, for example, germinate in the late fall or through the winter. They lay low during the coldest months, but grow fast once the temperatures warm just a bit (as early as March and April).

So what does all this mean for weed management in your own garden, lawn and landscape? Plenty.

First, a very effective tool for weed management is to improve poor soil conditions. Improving soil pH, nutrient levels, organic matter and tillage depth all help to make the site less hospitable to many weeds, and more so for the plants you love.

Second, effective weed control requires ongoing diligence. Lawns, flower beds and vegetable gardens should be scouted frequently. When you do so, be prepared to pull a few, or squirt them with a bit of herbicide (the products that come in hand-held spray bottles are quite convenient). If you are using one of the “kills everything green” herbicides, make sure your squirts are accurately targeted. And follow the instructions, of course.

Third, understanding weed life cycles, and timing your efforts accordingly, can greatly improve results. Those aforementioned cool season weeds, for example, must generally be dealt with in late February or early March.

If I haven’t convinced you that weeds are a fascinating topic, hopefully I’ve at least given you some tips for success. Or perhaps confirmed your suspicion that the weeds are going to win in the end. Dandelion salad, anyone? They say the tender young leaves are tasty!