Photo: Used with permission of Walter Reeves, walterreeves.com | Dichondra, Creeping Charlie, and Dollarweed (similar but different)

By Nancy Adams, Mobile County Master Gardener | CoastalAlabamaGardening@gmail.com

Q: We recently moved to the Gulf Coast from the Midwest, and among the landscape differences I have noticed are several unfamiliar plants growing in our centipede grass. Can you tell me about some of the more prevalent landscape weeds that grow in South Alabama and suggest ways to eliminate or control them?

A: In response to your question, I talked with an agent from the Alabama Cooperative Extension System in Mobile, and he named five of the most prevalent weeds in South Alabama landscapes. Following are results of my research on them.


Crabgrass (Digitaria)

Where does crabgrass not grow? Actually, crabgrass is native to tropical, subtropical and warm temperate regions. These plants are distinguished by long, fingerlike inflorescences (the complete flower head, including stems, stalks and flowers). This annual plant, one of which is capable of producing 150,000 seeds per season, thrives in thin lawns that are improperly watered, improperly fertilized and poorly drained.

Rather than relying on herbicides, you can best control crabgrass by mulching and keeping the lawn itself strong and healthy.


Cogongrass (imperata cylindrica)

According to reports of the Alabama Forestry Commission, cogongrass, a highly invasive perennial, is one of the 10 most destructive weeds in the world. It is highly invasive, grows to 5 feet tall and has yellow-green blades and silver plumed flowers. In Alabama it flowers from February to May; brown seeds appear in early spring and are dispersed by wind. It has destroyed entire landscapes and wildlife food supplies, along with corn and cotton crops.

Numerous herbicides for treating cogongrass are now on the market. For more information about cogongrass, go to www.cogongrass.org/cogongrassid.pdf and download the field guide.


Florida betony (Stachys floridana)

Florida betony is also known as rattlesnake weed because of its underground tuber resembling the rattle of a rattlesnake. The tubers begin to grow in late spring and usually grow from 1 to 4 inches long, but can grow much longer before going nearly dormant in the summer heat. The trumpet-shaped white and pink flowers then emerge in early fall and will stay green until winter cold. Florida betony will grow in part shade to full sun and can tolerate wet or dry soil as well as a variety of other soil conditions.

You can reduce the chance of Florida betony becoming established in your lawn by keeping the lawn mown at the recommended height and by fertilizing and adding lime to the grass based on soil test results. For information about treating with herbicides, contact your Mobile or Baldwin County extension system.


Dollarweed (Hydrocotyle spp)

Also known as pennywort, this perennial weed has green, shiny leaves that grow approximately 1 inch in diameter (some larger) and have scalloped edges. It reproduces by seeds, rhizomes and tubers and thrives in moist to wet conditions.

Although it is impractical to expect to eradicate dollarweed — or any weed — from the landscape, there are ways to limit its spread. Simply controlling moisture levels by reducing irrigation frequency can be the first step. One inch of water once per week is recommended for best results with most landscape plants. So this, along with proper mowing, fertilizing and mulching, can go a long way toward controlling dollarweed and other weeds in your landscape.


Dichondra

Also known as ponysfoot, dichondra is a broadleaf perennial herbaceous (meaning no woody stems above ground) plant in the morning glory family with flowers that appear white, green and yellow. Its creeping stems root at the leaf nodes and form mats that are 1.5 to 3 inches tall. Its ability to spread and take over other plants causes many homeowners to see it as an undesirable weed. However, it is cultivated in some states as a ground cover or decorative grass.

Dichondra is often mistaken for dollarweed because of their similarity; they both have round leaves that grow parallel to the ground and grow in groups. However, dichondra is smaller and prefers shady and moist soil.

Again, keeping a healthy lawn with nutrient-rich soil that deters weeds from germinating is one of the best methods for controlling dichondra and various other weeds.

You’ll find many combination products that promise to both kill weeds and feed your lawn, but they are generally not useful for our climate as the best times to kill weeds and to fertilize don’t coincide. Carefully choose products to add to your lawn by reading labels and consulting your county extension service or aces.edu for more information.

YOU ARE INVITED TO THESE UPCOMING GARDENING EVENTS

What: Mobile Master Gardeners monthly meeting (free)
When: Thursday, May 10, 10:30-11:45 a.m.
Where: Jon Archer Ag Center, 1070 Schillinger Road N., Mobile
Topic: Keep Mobile Beautiful — Phyllis Wingard

What: Fire Ant Control in Home Lawns, Gardens and Pastures (free)
When: Tuesday, May 15, 6-8 p.m. (dinner provided)
Where: Jon Archer Ag Center, 1070 Schillinger Road N., Mobile
Register: RSVP to Kelly Palmer, ridleka@auburn.edu or 251-937-7176

What: Alabama Cooperative Extension: Wildflower Workshop (free)
When: Tuesday, May 22, 9-11 a.m.
Where: Jon Archer Ag Center, 1070 Schillinger Road N., Mobile
Register: 251-574-8445 or jda0002@aces.edu

Master Gardener Helpline: 1-877-252-4769, or send gardening questions to coastalalabamagardening@gmail.com