Crops, Horticulture, Uncategorized

Pesky Purple Weed

People have asked me about the purple weed that has emerged in fields and lawns. Most likely that flower is henbit that is an annual forb in Nebraska and a member of the mint family, which means it has a square stem. It has distinctive leaves with crenate and lobed leaf margins and purple to pink flowers. For control, this weed is a winter annual, which means the seed germinates in the fall and the small plants overwinter before growing aggressively in early spring. It flowers in April and May and dies in the hot, dry summer weather. Flowers can produce a lot of seed, which is one reason henbit infestations can increase each year.Henbit

Control of henbit this time of year is not recommended because the plant will die shortly. The best option for control is to hand pull the weed in lawns. This has the advantage of minimizing the amount of seed production for next fall. If henbit infestation becomes unacceptable, then apply a PRE herbicide in late summer to early fall. Finally, henbit that does germinate in the fall will be killed with the same POST herbicides that are used to control other pesky weeds like dandelions and creeping Charlie. Other management options for henbit control include, 1) maintaining a healthy and vigorously growing lawn or 2) adding a deep layer of mulch to landscape beds.


Lawn & Tree Tips

Nebraska Extension offers excellent resources on varying horticultural topics. One of those sources is an online, Horticultural Update newsletter at The most recent articles had lots of great information, so I’ve highlighted two of those in this week’s column.

First, I’m sure you’ve noticed this has been perfect condition for weeds to take over landscapes and gardens in a hurry. The wet weather has also encouraged an increase in broadleaf weeds in turf. Control involves good management to promote a dense, vigorous turf that competes with weeds. Use a tall mowing height of three inches to reduce seed germination and to shade out weed seedlings.

September is the best month to control broadleaf perennial weeds with herbicides. If herbicides are used during summer, read label directions for temperature ranges within which to apply. Hot temperatures will increase damage potential to nontarget plants. Whenever used, spot applications are best as they result in the smallest amount of herbicide being used; saving money and protecting the environment. Read and follow label directions. Labels are the law and herbicides should not be used outside of recommended temperature ranges.

Another thing to watch for is bagworms hatching on evergreens trees. Monitor evergreens for young bagworms. At this time of year, they can be as small as one-fourth inch long. Bagworms are small, brown, triangular-shaped and covered with needles for camouflage.  At this size is the time when products like Bacillus thuringiensis will be most effective in controlling bagworms.

Finally, mosquitoes are awful this year! Public Health Solutions has brought us some mosquito dunks, which can reduce mosquito number by putting them in landscape ponds, livestock tanks and other sources of standing water. Standing water areas can be treated with a biological larvicide. Bacillus thruingiensis israelensis (Bti) or Bacillus sphaericus (Bs) are naturally occurring soil bacterium that control mosquito larvae by disrupting the gut receptors and causes the larvae to stop eating anddie. Biological larvicides are safe to use in water of livestock troughs. Stop in to pick up your free sample of mosquito dunk!

(Source: NE Extension HortUpdate, 2015)