Organic Treatment Options for Controlling Sericea lespedeza.

Multiple folks have been reaching out lately about Sericea lespedeza and how to control it. It's a widespread, non-native, shrubby invasive species common in fields and roadsides. It takes over fields and pastures by forming a dense shrubby monoculture that spreads outwards. I've dealt with it indirectly since college research projects and ongoing landowner site visits. It's common and a nuisance for many.

The way I pronounce it is with a bit of a melody, "Sarah-See-a". I've also heard and used "Suh-Ree-See-a". The final 'a' is soft like in the words 'orca' or 'taxa'.

Inquiring minds have been looking for alternatives to the standard recommendation of multiple applications of herbicides. For various reasons, these folks are concerned with spraying chemicals at the recommended rates on their properties.

A simple organic solution is shade. It's free and can be abundant when given the opportunity. It's as simple as leaving it alone and allowing the site to advance in succession. Stop mowing, burning, discing, spraying, etc.

Allow the site to reforest. Sericea doesn't do well in shade. Eventually, within 10 years in most places, it will go away. Some sources have stated that it tolerates deep shade. Personal experience sees it stop at the edge of the field in all cases, except severely depleted soils.

However, nobody seems to want to lose their fields and so it's an unpopular option.

Successfully dealing with the Sericea becomes a dealing with the soil issue. Those fields have a working history that is evident in the soil. The soil biology and soil structure have been altered and degraded. We could say the ecosystem has an upset tummy, being that the soil is the ecosystem digester.

The Sericea is here to provide some services so the soil can regenerate back to health. We may think of sericea as nature's tummy ache medicine. In this way, the sericea is a temporary solution arriving on site in order to help regenerate the soils and provide for some wildlife. When the soil is healthy, the sericea can't compete.

Ecologists have labeled Sericea as an ecosystem driver as a result, meaning it directly alters soil conditions so the ecosystem can progress into a new state. Sericea tolerates poor soil nutrition and acid soils when few natives can. Many of the old-field species commonly seen, such as cedar and honey locust, are ecosystem drivers. We could call these folks an enzyme, creating transformations on site, in the digestive system, so more productivity can occur. They come and go as needed in service to the ecosystem.

Sericea has a deep woody taproot extending outward and going up to three feet below the soil surface. This allows it to harvest nutrients from deep in the soil and deposit some on the soil surface as leaf litter, and elsewhere in the soil profile as root exudation. Sericea is moving some macro-nutrients such as nitrogen, potassium, calcium, magnesium, phosphorus, and the micro-nutrients iron, boron, manganese, zinc, copper, and molybdenum, around, in and on the soil. It's a legume which harvests nitrogen from the atmosphere and gives it to the soil.

This tummy ache medicine is re-establishing nutrients in the soil profile.

Deep woody roots are excellent at breaking up old compacted agriculture soils. The perennial woody roots create structure and stability allowing the soil profile to become more complex and diverse, closer to it's natural state. The agriculturally compacted soils have lost their structure which prevents many native species from thriving. We might say this tummy ache medicine provides fiber to get things moving again.

The bacterial and fungal communities are altered by Sericea. This tummy medicine is also providing probiotics so more of the nutrients that are in the soil are pre-digested and become available for the plants to digest.

These are some reasons Sericea is implicated as a driver that deserves our attention. Depleted agricultural soils have wonky soil biology profiles.

Sericea flowers are also attracting a large diversity of pollinators, filling in the gaps where the natives are now missing. If doing ecological restoration the flowers may be hurting natives by stealing the pollinators away, in which case we'd want to lose the Sericea flowers.

If it's a depleted site with few or no natives, which is common, Sericea flowers are nurturing native pollinators by allowing them to survive. In this way the Sericea is supporting native pollinators.

The flowers then create an abundance of seeds that feeds various small critters and winged ones. In this way the Sericea is inviting life back to the site who themselves provide ecosystem services.

The seeds that fail to germinate and don't get eaten contribute to soil organic matter and health.

The Sericea is providing us with alot of information about the site. If we can provide some of the same ecosystem services that the sericea is providing, it seems to go away. No chemicals needed. We can replicate these enzymes and provide the site with what it needs to be healthy. If you'd like help to understand organic non-chemical treatment options send a message or call...links at the top of this page.