Sericea lespedeza is arguably one of the most problematic invasive species of old fields, prairies and other early successional areas managed for wildlife. Sericea lespedeza is a perennial legume native to eastern Asia that was originally promoted for erosion control, cattle forage, cover and food for wildlife. But as with many plant introductions during the early and mid-19th century (e.g., multiflora rose, autumn olive and bush honeysuckle), the original beliefs – while well intentioned – were ill fated and short-sided. Sericea has become invasive, is considered noxious in many states, and can be found from Massachusetts to Nebraska and from Florida to Ontario.
Here are 3 problems with sericea and 3 tools for control.
- Sericea is adapted to a wide variety of conditions: sericea is able to tolerant and thrive in acidic soils with relatively low soil fertility and is also drought tolerant. These factors combined with allopathic chemicals makes sericea extremely competitive causing sericea to quickly invade and overtake early successional areas displacing many native species.
- Sericea produces an abundance of seed: one sericea plant is able to produce more than 1000 seeds and seeds are thought to be viable for up to 20 years in the seedbank. Sericea was initially thought to provide an abundance of seed valuable to wildlife including northern bobwhite. However, the seed cannot be digested by most wildlife, thus it provides no nutritional benefits and bobwhite can actually starve by consuming only sericea seed. Research in Kansas also reported a higher percentage of sericea seed germinated after passing through the digestive system of bobwhite compared to unconsumed seed.
- Sericea responds prolifically following spring fires: fire is the most effective way to manage early successional vegetation. However, fire during the dormant season seems to only anger sericea and exacerbate the problem. Fire scarifies sericea seed and seedling density is increased following spring fires.
- Herbicide: triclopyr (32 oz/acre), triclopyr + fluroxypyr (1.5 pt/acre), or glyphosate (1-2 qt/acre) can be used to effectively control sericea in early successional areas from June through July when sericea is 12-18 inches tall. Metsulfuron methyl (1 oz/ac) provides effective control when applied to sericea during flowering (Aug-Sep).
- Prescribed fire: while prescribed fire during the dormant season enhances sericea germination, fire during the late-growing season (July-Sep) can reduce sericea seed production and can decrease sericea survival. However, fire alone may not be enough to control sericea long term.
- Herbicide + Prescribed Fire: sericea can be controlled with herbicide during the growing season. This can be followed up with a late-growing season fire to consume any sericea not killed by the herbicide and reduce sericea seed production. The following summer herbicide can be used again to kill any new sericea seedlings or plants that have resprouted from rhizomes.
If you find sericea in fields that you manage, working quickly to stop seed production and kill the existing plants will be the most effective way to control an invasion.
Herbicides to control sericea lespedeza, Southeastern Asosciation of Fish & Wildlife Agencies
Effects of Growing-Season Prescribed Burning on Vigor of Sericea Lespedeza in the Kansas Flint Hills: I. Suppression of Seed Production and Canopy Dominance, Kansas Agricultural Experiment Station Research Reports
If Your Native Grasses Look Like This, It’s Time for Management, Got Nature?, Purdue Extension-FNR
Invasive plants: impact on environment and people, The Education Store, Purdue Extension
Jarred Brooke, Extension Wildlife Specialist
Purdue University Department of Forestry and Natural Resources