Donaldson, S. and Hanson Mazet, W. 2013, A Northern Nevada Homeowner’s Guide to Identifying and Managing Black Medic, Extension | University of Nevada, Reno, FS-13-13

Other common names

Black medick, yellow trefoil, black clover, hop clover, black hay, etc.

Scientific name

Medicago lupulina

Family

Fabaceae

Description

A low-growing spreading weed commonly found in lawns or pastures, black medic can be differentiated from other common lawn clovers by its yellow flowers. It grows well in dry soil low in nitrogen or compacted soil.

Black medic growth

Typical plant growing in disturbed site. Photo by S. Donaldson.

Leaves

Compound, with three oval leaflets with visible teeth at the tips. The central tooth on each leaflet is a bit longer than the others. The center leaflet has a longer stalk. Leaves have soft hairs.

Black medic leaves

This photo shows two compound leaves, each made of three leaflets. Note the tooth at the tip of each leaflet. Photo by W. Hanson Mazet.

Stems

Grow flat to the ground, branch, and may be more than a foot long. Stems are softly hairy.

Flowers

Yellow flowers are tiny and group together in clusters of as many as 50 individual flowers. Blooms from spring to mid-summer. Seedpods turn black at maturity.

Black madic flowers

The tiny individual yellow flowers are arranged in clusters to form the flower heads. Photo by S. Donaldson.

Roots

Grows a thin taproot with many fine, spreading roots.

Native to

Eastern Europe and Asia

Where it grows

Lawns, pastures, gardens, roadsides, crops and forests

Life cycle

Annual (sprouts, flowers and dies in a single year); sometimes lives longer

Reproduction

Reproduces by seed

Black medic seedlings

Seedlings leaves are pale on the underside. Photo courtesy of J. DiTomaso, UCCE.

Control methods

Control relies on preventing production of seed. Each plant can produce thousands of seeds, which live for several years.

Mechanical

Dig, hoe or pull small patches. It’s easiest to pull them when the soil is moist. Mowing alone does not provide control.

Cultural

Encourage thick, competitive vegetation. In turf, mow high (to 3½ inches) so the grass will shade the black medic, and aerate to relieve compaction. Use thick mulches in garden settings.

Biological

Can be grazed when young, but contains substances toxic to livestock, so grazing must be carefully managed.

Chemical

Apply broadleaf-selective herbicides such as 2,4-D+dicamba on young plants. Glyphosate may also be effective but is nonselective and can kill or damage other plants, including lawn grasses. Preemergence herbicides are available.

References

DiTomaso, J.M. and E.A. Healy. 2007. Weeds of California and Other Western States. University of California Publication 3488.

UC IPM. No date. Black medic, IPM.

UC Berkeley Jepson Manual. 2012. Medicago lupulina L., UC/JEPS.

Whitson, Tom D. (editor). 2009. Weeds of the West. University of Wyoming, Jackson, Wyoming.

Learn more about the author(s)

A Northern Nevada Homeowner’s Guide to Identifying and Managing Black Medic

Other common names

Black medick, yellow trefoil, black clover, hop clover, black hay, etc.

Scientific name

Medicago lupulina

Family

Fabaceae

Description

A low-growing spreading weed commonly found in lawns or pastures, black medic can be differentiated from other common lawn clovers by its yellow flowers. It grows well in dry soil low in nitrogen or compacted soil.

Black medic growth

Typical plant growing in disturbed site. Photo by S. Donaldson.

Leaves

Compound, with three oval leaflets with visible teeth at the tips. The central tooth on each leaflet is a bit longer than the others. The center leaflet has a longer stalk. Leaves have soft hairs.

Black medic leaves

This photo shows two compound leaves, each made of three leaflets. Note the tooth at the tip of each leaflet. Photo by W. Hanson Mazet.

Stems

Grow flat to the ground, branch, and may be more than a foot long. Stems are softly hairy.

Flowers

Yellow flowers are tiny and group together in clusters of as many as 50 individual flowers. Blooms from spring to mid-summer. Seedpods turn black at maturity.

Black madic flowers

The tiny individual yellow flowers are arranged in clusters to form the flower heads. Photo by S. Donaldson.

Roots

Grows a thin taproot with many fine, spreading roots.

Native to

Eastern Europe and Asia

Where it grows

Lawns, pastures, gardens, roadsides, crops and forests

Life cycle

Annual (sprouts, flowers and dies in a single year); sometimes lives longer

Reproduction

Reproduces by seed

Black medic seedlings

Seedlings leaves are pale on the underside. Photo courtesy of J. DiTomaso, UCCE.

Control methods

Control relies on preventing production of seed. Each plant can produce thousands of seeds, which live for several years.

Mechanical

Dig, hoe or pull small patches. It’s easiest to pull them when the soil is moist. Mowing alone does not provide control.

Cultural

Encourage thick, competitive vegetation. In turf, mow high (to 3½ inches) so the grass will shade the black medic, and aerate to relieve compaction. Use thick mulches in garden settings.

Biological

Can be grazed when young, but contains substances toxic to livestock, so grazing must be carefully managed.

Chemical

Apply broadleaf-selective herbicides such as 2,4-D+dicamba on young plants. Glyphosate may also be effective but is nonselective and can kill or damage other plants, including lawn grasses. Preemergence herbicides are available.

References

DiTomaso, J.M. and E.A. Healy. 2007. Weeds of California and Other Western States. University of California Publication 3488.

UC IPM. No date. Black medic, IPM.

UC Berkeley Jepson Manual. 2012. Medicago lupulina L., UC/JEPS.

Whitson, Tom D. (editor). 2009. Weeds of the West. University of Wyoming, Jackson, Wyoming.

Published by: Donaldson, S. and Hanson Mazet, W., 2013, A Northern Nevada Homeowner’s Guide to Identifying and Managing Black Medic, Extension | University of Nevada, Reno, FS-13-13