During the summer months, it is not unusual to have problems with common lespedeza (Kummerowia striata syn. Lespedeza striata) invading your lawn. Lespedeza is an annual legume that can be identified by its woody stem, flowers that range between pink and purple and oval-shaped leaves that are grouped in threes. This weed is often found in the southeastern United States and can begin emerging in the early spring through the late summer. Find ways to control and remove this popular, obnoxious weed with the use of non-chemical and chemical methods below.
Lespedeza Non-Chemical Control
A common cultural tip for weeds in home lawns is to start by mowing them. When lespedeza grows in the home lawn or in landscape beds, however, it can form a dense mat that stays low to the ground and easily avoids the blades of the mower. This can sometimes make it difficult to remove.
Nevertheless, there are many other cultural practices that can be implemented to control existing lespedeza or to lessen the chances that it starts to grow in your lawn. Typically, lespedeza thrives when turfgrass strands are thin and when the soil is dry and compact; therefore, developing and maintaining a healthy lawn can stop this weed before it ever starts. You can read more about this in How to Thicken Your Lawn.
Some practices to implement include watering infrequently and deeply to allow the grass to develop an extensive root system, minimizing or redirecting traffic away from stressed areas to reduce compaction and properly fertilizing and mowing the lawn to create a dense canopy that outcompetes weeds. Here are some of our favorite fertilizer selections:
If your lawn’s soil is compacted, aerification may be needed to increase turf health, which should be done while turfgrass is actively growing so that the voids created are not invaded by weeds.
Pictured above: An aerator punching holes into the lawn to reduce soil compaction.
Before utilizing chemical controls, it may also be possible to hand-pull lespedeza if the infestation is caught early. This may be necessary in landscaping beds if there are plants that will be sensitive to chemical controls. When pulled by hand, it is best to attempt to pull the entire tap root, which can be done by hoeing or digging around the weed to allow for careful removal.
Lespedeza Chemical Control
If cultural practices are not enough and chemical controls are needed, there are both pre- and post-emergent herbicide options. Pre-emergents are designed to prevent weeds from breaking through the surface of the soil. Post-emergents, on the other hand, kill off or control any currently existing weeds.
For a pre-emergent herbicide to be effective, it must be applied before the weed seeds begin to germinate or break through the soil’s surface. For lespedeza, this would need to be applied in the early spring. One pre-emergent option includes Dimension by Dow AgroSciences (active ingredient dithiopyr), which comes as a concentrate and is applied across the entire lawn by using a handheld or backpack sprayer after being mixed into the spray tank. This product controls many common lawn weeds for the entire season. Another pre-emergent option is Crabgrass Control Plus 0-0-7 with 0.37% Prodiamine Herbicide, which is a granular pre-emergent for those who want to avoid the task of tank mixing.
Crabgrass Control Plus 0-0-7 with 0.37% Prodiamine Herbicide$54.95
Dimension 2EW$149.95 – $639.95
A post-emergent option for lespedeza control can be found in Q4 Plus Turf Herbicide (active ingredients 2,4-D, Dicamba, Quinclorac and Sulfentrazone). This product also comes as a concentrate that, when mixed, can be sprayed directly onto stubborn weeds for control down to the roots. This product works best against young weeds that are actively growing. However, it should only be used on cool season grasses or bermuda grass.
An additional post-emergent option that comes in a ready to spray formula is SpeedZone Southern Herbicide (active ingredients 2, 4-D, 2-ethylhexyl ester, Mecoprop-p acid, Dicamba acid Carfentrazone-ethyl). This product features a low-odor formulation and becomes rain-proof between 3–4 hours after application. Spectracide Weed Stop for Lawns Plus Crabgrass Killer is also a great option. This product hooks up to the end of your garden hose for an even spray application.
Spectracide Weed Stop For Lawns + Crabgrass Killer$16.95
Q4 Plus$47.95 – $349.95
SpeedZone Southern Herbicide$99.95
Some of the herbicides listed above should not be used on St. Augustine or centipede grass as these types of turf are sensitive to chemicals like MSMA and 2,4-D. These chemicals have the potential to severely damage these types of grasses. Use an Atrazine-based post-emergent herbicide for both centipede and St. Augustine such as Spectracide Weed Stop for Lawns for St. Augustine and Centipede, Southern Ag Atrazine or Hi-Yield Atrazine Weed Killer.
If chemical controls are necessary for the removal of lespedeza from your lawn, it is important to carefully read the herbicide label to ensure compatibility with your lawn. Chemical products can cause damage if the label is not checked before application.