Identification

Medicago Lupulina, often referred to as Black Medic, is a common but invasive weed in North America. Like many other prostrate plants that grow low to the ground, Black Medic can survive in harsh climates due to a large taproot that grows deeper than most grasses. It thrives in full sun and is frequently found in the summer growing in areas turf grasses find difficult to inhabit. If Black Medic is found growing within your lawn, there’s a good chance your lawn is weakening (possibly due to low levels of nitrogen).

Prolific Plant

If you’ve ever seen clover grow, you’ll have an idea of just how prolific and easily spread Black Medic weeds can be. While they’re considered annuals, Black Medics plants are able to survive into cooler winters and can sometimes return as perennials the next spring.

Black Medic Uses

In Europe and Asia, Black Medic is often treated like a salad green. If you’ve identified your Black Medic weed with 100% accuracy, you may be interested in hand-pulling it when young (before you risk leaving a root in the soil) and sampling it for yourself. While it has a redeeming feature, we strongly recommend ridding yourself of this particular weed before it gets the better of your lawn. The negatives to your yard greatly outweigh any Black Medic plant uses.

As a member of the legume family, Black Medic boasts long, thin, slightly hairy stems that spread out along the grass or pavement from a central, deeply rooted stem. Summer heat brings out tiny, yellow flowers that look similar in appearance to the domed flowers you’ve probably seen on clover. Each “petal” is actually its own flower and a single Black Medic flower dome usually contains between 10-50 miniature buds.

Look for Black Seed Pods

With green leaves and yellow flowers, you may be wondering where Black Clover gets its name! When the coiled seed pods of a Black Clover plant become ripe, they turn a deep, black color before releasing single seeds (often gold or brown in color). Recognizing this characteristic can help you know when Black Clover is about to do serious damage to your lawn.

Medic vs Clover

While similar in many ways, yellow flowers are the first indicator you’re dealing with Black Medic and not Clover. Clover will often form nodules on secondary roots to help it gain nourishment and grow from more areas. Black Medic grows from a single taproot and won’t root from additional stems.

You can absolutely prevent Black Medic in your lawn! Weed suppressants, slow release nitrogen fertilizers, and herbicides applied in late winter or early spring all help to prevent unwanted weed seeds from germinating and taking root where they’re not welcome. Mowing your lawn down to 3” at the lowest will help keep your lawn out of shock and prevent sun from reaching thinner areas where weeds are known to sprout.

Lawn aeration and frequent raking is key to keeping your grass’ roots healthy and thriving. Provided with the right oxygenation, nutrients, and watering schedule, your own lawn can play  a part in preventing Black Medic’s yellow flowers from making an appearance.

If a Black Medic plant is still very small, you might find it helpful to get your gloves out and pull the main stem upward from as close to the soil as you can. If you’re seeing weeds that look like clover with yellow flowers in your lawn, the plant has probably already developed an extensive taproot that, upon pulling, can break off – only to regrow and spread again.