Synonym(s): Melilotus alba, Melilotus arvensis, Melilotus leucanthus, Melilotus lutea, Melilotus officinalis
Family: Fabaceae (Pea Family)
Duration and Habit: Annual, Biennial, Perennial Herb
Plants can grow to approximately 6 1/2 ft. (2 m) in height and can sometimes be woody at the base. Leaves are ovate to oblong, entire, stipulate and 0.4-1 in. (1-2.5 cm) long. Flowering occurs from April to September, when yellow, pea-like flowers develop in a branched inflorescence at the tips of the flowering stems. Flowers are less than 1/4 in. (7 mm) long. Fruits are small, circular, wrinkled and light brown pods that contain one seed (rarely 2)
Ecological Threat: It is a threat to recovering prairies because it easily invades open areas and may compete for resources with native species. It is similarly an unwanted invader of rocky, open, calcareous glades and woodlands. It can degrade natural communities by overtopping and shading native sun-loving species.
Biology & Spread: Seeds are dispersed by water and wind
History: Yellow sweet clover was introduced into North America as a forage crop in the 1900s.
U.S. Habitat: Plants occur along roadsides, in open fields, pastures and other disturbed areas.
U.S. Nativity: Introduced to U.S.
Native Origin: Eurasia.
U.S. Present: AK, AL, AR, AZ, CA, CO, CT, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, PR, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY
List All Observations of Melilotus officinalis reported by Citizen Scientists
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Manual- Manual methods include hand pulling before seeds are set, cutting to ground level when plants are in full bloom, mowing close to the ground when seedlings are 6-8 inches tall. For very dense small patches, cutting with a power brush-cutter using a heavy duty saw blade is effective. The stand should be cut just before flowering, and checked a week later for missed or partly cut plants.
Prescribed Burns- Sweetclover response to carefully timed seasonal burns using good management practices. A burn schedule such as a dormant season burn (late fall or early spring) to stimulate germination in the subsequent growing season, followed by a later spring burn the next season to eliminate the second year plants before they set seed has been effective.
Chemical- Spray with 2, 4-D in early spring when seedlings are very small.
U.S. Forest Service. Weed of the Week: Yellow Sweetclover. Accessed February 2009: http://www.na.fs.fed.us/fhp/invasive_plants/weeds/yellow_sweetclover.pdf.
Bugwood Network. Bugwood.com
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Invasive Plant Atlas of the United States: Melilotus officinalis
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