Weeds are misunderstood. A weed is simply a plant that is in the wrong place. This is not to say that all weeds are good. There are many plants – let’s call them weeds – that are a nuisance. However, the occasional stray plant in your garden should not be cause for alarm. In fact, it may be doing something useful.
Which Weeds are Bad?
Some weeds are invasive species; they are difficult to control and cause problems for agricultural production and the maintenance of natural areas. Some very attractive plants such as purple loosestrife cause extensive damage to the ecosystem. Fortunately, most plants are not too troublesome for homeowners, but it does make sense to find out about a plant’s growing habits before you plant it in your yard.
The US Department of Agriculture has lists of invasive and noxious weeds for each state.
How Did Weeds Get in My Garden?
Weeds distribute themselves in several different ways. Depending on the species, their seeds may float through the air, hitch a ride on a lawn mower, or pass through an animal’s digestive tract to be deposited in your yard.
Usually, there are lots of weed seeds present in the soil waiting for the right conditions to germinate. Many seeds stay buried in the soil and never sprout. Simply digging or turning over the soil to expand a planting bed or start a new garden is all that it takes – along with a little water – for some weeds to start growing.
The Good Weeds
There are times when having a few weeds around may be beneficial. Some weeds act as a temporary cover crop that keeps soil in place for areas that have not been mulched or planted. Tilling them into the soil will increase the amount of organic matter present, adding nutrients and improving soil structure. Many weeds have deep roots that can help to break up hard and compacted soil.
Some weeds help with insect problems. Allowed to grow in the right location, they can attract insect pests away from your garden. There are also weeds that attract beneficial insects. Knowing which is which is the the tough part. Your local native plant society is a good place to start.
How Do I Know if a Weed is Good?
There are several sources of information about weeds. You can look online, but make sure you are getting information for the right region. Plants behave differently in Maine than in California. Local universities and organizations with plant-focused missions are often helpful. You can also take a picture or sample of a weed to your local landscape supplier or nursery. They can advise you on whether a particular weed is a pest and recommend the safest and most effective way to control weed infestations.
Getting to know your weeds a little bit better is a good idea. You might discover some new garden friends while learning to understand your enemies, if only to do a better job of keeping them away.