Another weed with a pretty flower is henbit. But you might need a magnifying lens to fully appreciate these tiny flowers. Henbit can be an important early source of nectar and pollen for bees.
Henbit is a winter annual weed in the plant family, mint family. How can you tell? Mints have square stems. Roll a stem between your fingers and you will know what I mean. Where did its name come from? It came from the observation that chickens like to eat it. And it is even edible for us. Leaves, stems and flowers eaten raw in salads gives them a slight sweet peppery flavor. It can be eaten cooked or made into a tea as well.
The Latin name for this weed is lamium amplexicaule. It also goes by another less common name, purple dead-nettle, even though it is not a nettle. It has a weak, erect or sprawling growth habit, growing 4-10 inches tall. Leaves are more or less round with coarsely lobed margins. Upper leaves grow opposite each other and tightly against their stems.
The tiny flowers are quite pretty, generally pink to purple and are two-lipped. They are borne in the upper leaf whorls in the leaf axils. Each flower produces four seeds. A single plant has the potential of producing as many as 2,000 seeds in a season. As a winter annual, generally seeds germinate in the fall. But you probably won't notice this weed until early spring when their growth accelerates and flowers begin to appear in March.
This can be a problem weed in cropland, gardens, or especially in newly seeded or weak lawns. Bare ground is also a potential infestation site. While problems usually involve individual plants, sometimes whole large areas can be infested. While not a native of North America, it is now found across the area since being accidentally introduced from Eurasia or North Africa.
The best time to control this weed is in the fall by preventing seed germination. An application of a pre-emergent herbicide such as Treflan® or Preen® around Labor Day often does the job but a follow up application in late October might be needed. Casoron® is another good pre-emergent herbicide, to be used near sensitive plants. However it is very expensive. For you organic gardeners, corn gluten herbicides can work but with lesser results.
If there are any escapes in the spring, a post-emergent herbicide before flowers appear, such as glysophate or a combination of 2,4-D and either dicamba or MCPP will also be effective. Be careful of herbicides containing dicamba. This chemical has some soil activity and might hurt trees, bushes and other woody perennials whose roots are under the target area.
You can always hoe or hand pull if there are not many henbit weeds. Mulching bare areas also discourages weed emergence.
So for all of you out there not feeling so tickled pink about this purple-flowering weed visiting your yard, fight back at this sometimes nuisance weed by following one of these strategies to get square with this garden pest. Or you can just chill out and accept a few weeds in your garden, especially one with a pretty flower!
Jim Leser retired to Cedaredge in 2007 after a career with Texas A&M University Extension in entomology. He is a member of the Cedaredge Tree Board and a Colorado Master Gardener.