This unusually warm weather has had many homeowners getting out and working in their gardens. As I look at my garden, I see numerous things that need to be done to prepare for this spring.
But there is one glaring thing that needs to be done – taking care of winter weeds. The older the weeds get, the harder they are to control.
The No. 1 weed in Bermuda and zoysia lawns in the winter is annual bluegrass (Poa annua). This is a grassy weed that is a yellow-green color and has a silvery seed head in the spring. They seem to appear overnight. However, they have been present since late September or early October, and some of the seeds will germinate in March as well.
Annual bluegrass likes areas that have wet, compacted soils, and areas where high amounts of nitrogen fertilizer were applied.
One way this weed can be controlled is through proper management. The first practice is to aerate the soil to reduce compaction. Another way to reduce the excess moisture is to water the grass only when needed. This means watering deep once each week; not applying smaller amounts of water more often. It also helps to apply the proper amount of nitrogen to the turf.
There are herbicide options that can be used. For annual bluegrass control, one of the best herbicides is atrazine, which will give post-emergent control of this weed and provide pre-emergent control for 30 to 45 days.
Atrazine is labeled for use on centipede, St. Augustine and zoysia grasses. Some products that contain atrazine have dormant Bermuda grass on the label. The Bermuda needs to be fully dormant if this product is used. The best way to determine this is to part the grass and look from the top of the grass to where it enters the soil. If green is present, the Bermuda could be damaged from the herbicide.
There are four other common weeds that will show up this time of the year – henbit, chickweed, dandelions, or wild onion and garlic.
Henbit is the weed that has a purple flower in late winter and early spring. The stem of the plant is square or four-sided. It has a slight odor when crushed. Henbit likes areas of the lawn where the grass is thin or open, and areas that have been disturbed.
Chickweed is a mat-forming weed that has small oval leaves arranged opposite of each other on the stem. Chickweed flowers are small, white clusters on the end of the stem. Most of the chickweeds are annuals, but mouse-ear chickweed is a perennial. Mouse-ear gets its name from the hairy, gray-green leaves. Chickweed, like henbit, likes areas where the turf is thin and the soil has been disturbed.
Dandelion is one of the harder weeds to control in centipede and St. Augustine lawns. It has a deep taproot. The leaves form a rosette close to the ground. One way to remove this weed is to dig it up. The leaves and stalk of the plant will exude a milky substance when broken. When the puff-ball breaks up and floats away, each of these parts that float away are seeds.
The next group of hard-to-control weeds is wild garlic and onion. Wild garlic (Allium vineale) and wild onion (Allium canadense) are winter perennials. These weeds emerge in late fall from underground bulbs and grow through the winter and spring. In late spring, they form aerial bulblets and the plants die back in early summer. While both have thin, green, waxy leaves, those of wild garlic are round and hollow, while those of wild onion are flat and solid.
The best way to control these weeds is to use a herbicide. There are a couple that will do a good job. The first is atrazine. The second is one that contains 2,4-D, which can be found in products such as Weed B Gon. Be careful when using 2,4-D on centipede or St. Augustine. Damage can occur if used at the full rate.