close of yellow blossom sweetclover

Yellow Blossom Sweetclover

Melilotus officinalis

This drough-tolerant clover produces beautiful yellow flowers and can be used for forage, cover cropping, and more.

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The origin of the name.

So where does the name “sweetclover” come from? Probably it relates to the fact that when the leaves are crushed, the plant puts out a distinct sweet aroma. In earlier varieties the source of this aroma was identified as coumarin and used to develop the anti-coagulant drug called ‘warfarin’. Since these anti-coagulant properties were found to be detrimental to grazing livestock modern sweetclover varieties have been bred to be low in coumarin.

Really a Clover? No. But a Really Good Legume!

Yellow blossom sweetclover is not a true clover but is probably more closely related to alfalfa. Sweetclover leaves look much like alfalfa, but the margins of alfalfa leaflets are serrated only on the tips. Sweetclover leaflets are serrated around their entire margin. It is typically a biennial, grows 2-6 feet high, and as the name implies, produces yellow flowers. It is used for forage, cover cropping, conservation, and honey making.

When compared to the white flowering types of sweetclover, yellow blossom blooms roughly 2 weeks earlier and also matures earlier, usually grows less upright, possesses finer stems, and is less productive and less winter-hardy. However, yellow blossom sweetclover persists better in pastures and tolerate adverse conditions better than white varieties.

Sweetclover can produce and deposit a high percentage of hard seeds that persist in the soil for many years. This accounts for its consistent volunteering in many areas.

Drought tolerant, winter hardy and so much more.

Yellow blossom is one of the most drought-tolerant of forage legumes, and is quite winter-hardy. In temperate climates with mild summers it can survive and thrive through a second year of production. Sweetclovers grows where alfalfa, red clover and white clover fail, such as on clay pan soils or on sands and tolerates low fertility and wet conditions. Yellow blossom prefers non-acid soil (pH above 6.0).

This plant goes deep.

While not a huge forage producer (under 3 tons/acre), yellow blossom sweet clover has a valuable taproot growth that penetrates deep down in soil - up to five feet. This deep tap root and root branches give sweetclover a greater ability than most other cover crops in extracting potassium, phosphorus and other soil nutrients from insoluble minerals. Root branches take in minerals from seldom-disturbed soil horizons, nutrients that become available as the tops and roots decompose.

Nitrogen producer.

Yellow blossom sweetclover contributes up to 275 lbs. N/A and adding valuable organic matter. In order to achieve optimal nitrogen fixation ability, yellow blossom sweet clover needs to be inoculated with Rhizobium Sinorhizobium meliloti. This is best achieved with Nitro-Coat®.

Yellow Blossom Sweetclover Specifications

Yellow Blossom Sweet Clover Specifications

zonesHumid or irrigated regions of zones 3-8; acts as annual in zone 9
ease of establishmentGood
seeding rate straight8-10 lbs/ac
seeding rate mix6-8 lbs/ac
seeding timeFall (October-November) or late winter to early spring (February-April)
seeding depth1/4-3/8 inch
seeding methodBroadcast or drilled (preferred)
method of killing/suppressionMowing; grazing; chemical
optimal germination temperatureNight temperatures >40 F
seedling emergence/vigorGood
reseeding potentialGood
root typeTap
grazing potentialFair
hay potentialFair
use with wildlifeGood
use in orchardsGood
use with row cropsGood
use with other grasses/legumesExcellent
Bees/beneficial insectsGood
compaction controlGood
erosion controlGood
weed suppression potentialGood
green manure/cover crop useExcellent
spreading capabilityPoor
N contribution potentialGood
DM potentialExcellent
Forage qualityGood
harvest time frame (late/early/year-round)Late
number of harvest/yr1-2/yr
other commentsHard seed so future volunteering is probable; Use only low coumarin varieties for livestock hay or grazing. Better adapted to short rotation pastures.
bloat riskHigh
disease susceptibilityLow
insect/nematode riskModerate; especially susceptible to sweet clover weevil.
cold toleranceHigh
traffic toleranceFair
heat toleranceGood
drought toleranceGood
shade toleranceGood
dry soil toleranceGood
wet soil toleranceGood
pH rangeNeeds high pH (>6.0)
required fertility (P, K, other nutrients)P, K, Ca, Mg needed; minor especially Mo, B also needed