Weeds have been a problem ever since mankind decided to grow one plant instead of another, which is the very definition of a weed: a plant that grows where you don’t want it to grow. There are many reasons a plant can be a weed: it could be interfering with natural waterways, stealing water and sunlight from food crops, or just making our lawn look…weedy. The State of Utah has declared certain plants as noxious weeds--non-native plants that cause a large amount of damage to croplands, pastures, forests, waterways, and even residential yards. Here are three of the most problematic weeds in Utah landscapes and how to control them.
#1 – Field Bindweed (aka Morning Glory)
Convolvulus arvensis
Morning Glory works its way into the plants we love, growing inconspicuously through shrubs, lawns and perennials, twining along branches and stems until its leaves emerge and bloom with pinkish-white flowers, suddenly letting you know you’re in the trouble. When you try to yank it up, you’re rewarded with only the tiniest bit of root for your effort.
As long as there is a piece of Morning Glory root in the ground the weed can regrow. It has evolved brittle roots that break easily to leave as much root as possible in the soil. Controlling bindweed by pulling it is not effective and tilling can make the problem worse. The best approach is to kill the roots. Many systemic broadleaf weed killers are effective, but timing is important. After the first frost when the plant is pulling energy from its leaves down to the roots is the best time to spray. The weed killer chemicals will be pulled down along with the plant nutrients and will cause the greatest damage. Keep your wanted plants and lawn healthy to create competition with the Morning Glory.