Watch out for hairy, that winter weed!
Hairy (bittercress, Cardamine hirsuta) spits seeds like players in a baseball dugout spitting sunflower seeds on fast forward. If you have ever touched this plant when the seed pods are ripe, you know just what I mean. Stand back or they will hit you in the eye!
Hairy bittercress and other winter annual weeds are almost finished flowering and beginning to set seed in most of the Miami Valley. In fact, with this past week’s warm weather, many have likely set seed and are ready to disperse.
Winter annuals are those that germinated last fall and hung on through the winter, hugging the ground, loving the cold weather.
In the spring, they resume growth, flower, set seed and die in the heat of summer. Next, we will see summer annual weeds such as purslane, black medic, lambsquarter, spurge and more. These weeds flower, set seed and die with a frost.
Hairy bittercress is easy to spot when it goes to seed. Touch it and the seeds fly everywhere. Learn how to recognize it when it is small, right after it germinates as it is a good time to get it with the hoe (usually in the fall).
The plant emerges and is a rosette with leaves close to the ground, radiating from the center. The leaves are compound with rounded leaflets. In the spring, they send up a flower stalk, bloom with lots of white flowers, and set copious amounts of seed.
All the other winter annuals including spotted dead nettle, henbit, bedstraw, shepherd’s purse, etc. have similar habits. Once it gets hot, these all die out.
Just because they die in the heat doesn’t mean you are rid of them! They left their seeds for the next season.
Control right now is to make every attempt to eliminate them before they go to seed. Pull, hoe, use a herbicide, or whatever method you prefer to get rid of them.
Pre-emergent herbicides are an excellent method to prevent those seeds from germinating this fall. Apply in late summer and early fall. Adding a layer of mulch is even more helpful.
Apply another application of per-emergent herbicides in the spring for those summer annuals. Be sure to read the label any time you apply any pesticides.
If these weeds are in lawns, continual mowing this spring will help prevent them from going to seed. In addition, thicken up the turfgrass with proper fertilization and you eventually prevent these from growing.
They tend to be more of a problem in flower beds and vegetable gardens for the most part. I work especially hard to make sure they don’t get established in plants such as Iris and any groundcovers. They are a challenge to eliminate in these areas.
Keep your eyes open for the next winter annual to bloom, from the mustard family, Cressleaf groundsel with its bright yellow blooms. You will soon see these covering farm fields with bright yellow flowers.