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.
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
|zones||Humid or irrigated regions of zones 3-8; acts as annual in zone 9|
|ease of establishment||Good|
|seeding rate straight||8-10 lbs/ac|
|seeding rate mix||6-8 lbs/ac|
|seeding time||Fall (October-November) or late winter to early spring (February-April)|
|seeding depth||1/4-3/8 inch|
|seeding method||Broadcast or drilled (preferred)|
|method of killing/suppression||Mowing; grazing; chemical|
|optimal germination temperature||Night temperatures >40 F|
|use with wildlife||Good|
|use in orchards||Good|
|use with row crops||Good|
|use with other grasses/legumes||Excellent|
|weed suppression potential||Good|
|green manure/cover crop use||Excellent|
|N contribition potential||Good|
|harvest time frame (late/early/year round)||Late|
|number of harvest/yr||1-2/yr|
|other comments||Hard seed so future volunteering is probable; Use only low coumarin varieties for livestock hay or grazing. Better adapted to short rotation pastures.|
|insect/nematode risk||Moderate; especially susceptible to sweet clover weevil.|
|dry soil tolerance||Good|
|wet soil tolerance||Good|
|pH range||Needs high pH (>6.0)|
|required fertility (P,K, other nutrients)||P, K, Ca, Mg needed; minor especially Mo, B also needed|