Read more about Poa annua on golf courses: Controlling Poa annua With The Right Tools
Photo: OSU Bugwood
1. Annual bluegrass
Photo: OSU Bugwood
Photo: Dr. Aaron Patton
The best defense against henbit is to properly maintain turfgrass. This includes selecting the right species for the location and usage, plus proper cultural practices including mowing, fertility, irrigation and aeration.
Prevention/Treatment: To prevent this weed in a residential lawn, cultural practices to develop a dense, aggressive turf may help to hinder its invasive qualities. This includes proper mowing and watering,
Time of year: Poa Annua is a cool-season grass weed that starts germinating in late summer or fall as soil temperatures fall below 70 degrees Fahrenheit. It continues to germinate throughout winter, allowing several flushes of germination at any one site throughout the season.
Prevention/Treatment: Encouraging good grass growth is important to preventing hairy bittercress invasions. Pulling out hairy bittercress can often leave the roots behind and is usually most effective with young plants. It’s best to use a weeding tool to dig down and around the taproot to get all the plant material out of the ground. Post-emergent weed control is the most effective and long-term solution.
The seeds that they spread can germinate if brought to the surface within a couple of years. There are even cases where seeds were found in archaeological excavations that were 100’s of years old and still germinating when planted.
A weed is a plant that is not only in the wrong place, but intends to stay.
– Sara Stein
Many of the weeds we deal with in our lawns and landscapes are not native to North America and originated in Europe or Asia. To farmers, weeds cause more loss and add more costs than dealing with insects, diseases, rodents, birds, deer and other grazers. In fact the number one complaint from customers of lawn care companies involve weeds growing in their lawn.
Weeds are amazing plants. In some cases, they are beneficial as they will quickly cover bare ground to keep it from eroding away.
According to the Weed Science Society of America, more than 200 weeds have developed resistance to common weed control products. They also stated that more than 240 weed species are reported to be “allelopathic” and produce chemicals from their roots that inhibit the growth of nearby plants.
The problem comes from the difficulty in removing them when trying to plant more desirable plants in their place. Weeds will germinate, grow and reproduce through various means much faster than plants that we prefer to grow.
Of the almost 250,000 plant species found worldwide, about 3% or 8,000 plants are considered weeds. They are especially designed to spread quickly, either by wind currents, movement by water, carried in by animals, carried unseen in bales of hay, straw or even on the tires of cars.
As I was walking my dog during the morning of New Year’s Day, I spotted a dandelion seed head poking through the snow. I found it interesting that this dandelion actually produced a flower in December, but it’s most likely due to some unseasonably warm weather. I think it shows just how opportunistic a weed can be when the weather is suitable for flower production.