| Scientific name: | Melilotus officinalis (biennnial yellow flowers; M. alba (annual & biennial white flo) |
| Cultivars: | Annual: Hubam (white flowered); Golden (yellow flowered)
Biennial: Most yellow flowered: Goldtop (early release from WI), Madrid, Norgold, Polara, Denta, Yukon (improved from cultivar Madrid)
Very cold tolerant: Polara, Arctic, Madrid
Low coumarin: Denta, Polara, Norgold |
| Origin: | Europe (Spain) |
| Growth Habit: | Upright, one stem produced during seedling yr, several stems come in 2nd yr |
| Life Cycle: | Annual or biennial |
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| Use |
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| Production: | Yellow sweetclover can produce up to 24 inches of vegetative growth and 2.5 tons dry matter/acre in establishment year. Can produce up to 9,000 lb DM/acre over a summer after being oversown into a grain crop or direct seeded with a spring grain |
| Nutritive Value: | High but drops past bud stage because stems become lignified (woody) |
| Herbaria Image: | Click this link |
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| Identification |
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| Seed Head: | Raceme, yellow flowers (biennial); white flowers (annual) |
| Seed: | Has high percentage of hard seeds (those whose hard coats don't allow water absorption; this allows the plant to establish new plants after the seedling yearMitten shaped (3-5 mm) Bushel of hulled seed= 60 lb; bushel of unhulled seed= 32 |
| Shoot: | Stems become woody with maturity. Harvest at bud stage to avoid coarse stems |
| Leaf: | Trifoliolated (three leaflets) with Petiolule present much like alfalfa, but leaflet is serrated all around the margin instead of the top 1/3 as in alfalfa |
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| Adaptation |
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| Soil: | Loam soils |
| pH: | 6.5 to 7.5; tolerates soil that are too alkaline for alfalfa |
| Moisture: | Grows best where rainfall is > 17 inches. It is very drought tolerant due to deep tap root; and also tolerates poorly drained soils |
| Temperature: | Tolerant of frost and cold temperature |
| Other: | Bloat can occur but is less common than in alfalfaSoil structure builder, controbutes organic matter, looser structure due to deep root growth |
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| Establishment - Management |
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| Seeding rate: | 10-15 lb/acre of scarified, hulled seed. Use lower rate where moisture is limited.20-30 lb/acre for unhulled seed.
2-6 lb/acre in mixes |
| Seed cost: | $2 to 3.16/lb; $20 to 45/acre (alone) $4-16/acre (in mixes) |
| Planting date: | spring with small-grain companion crop early summer without a companion crop. Later summer plantings are likely to be injured by grasshoppers, or by winter if severe; if planting hulled seed plant in late fall (freezeing-thawing will soft |
| Planting depth: | 1/4 to 1/2 inch (for heavy fine textured soils); 1 inch or 1 and half inch (for sandy, coarse-textured soils) |
| Frost seeding: | Can be done, but seeding rate needs to be increased to consider the amount of hard seed. |
| Fertilization: | Usually produces about 100 lb. N/A, but can produce up to 200 lb. N/A with good fertility and rainfall. |
| Grazing: | Should not be grazed low (to protect live buds & reserves
Light grazing when plants are 12-14 inches and rest the stand during early fall (to allow carbohydrate storage)
Start pring grazing when plants are greater than 6 inches; do not graze lower than 8 to 12 inches for good regrowth.
If underglaze, plants will become coarse and hard.
In Spring and early summer, good soil and management may support 2-3 heads of cattle/acre |
| Hay: | If planted with companion crop (the harvested or combine should be set high (>8 inches) to allow for leaves growth.
Cut at bud stage; harvesting past bud stage results in coarse and woody stems that lower the nutritive valueCut to a 8-12 inch stubble to allow for second crop in the 2nd year At 1 to 1 1/2 ft tall no viable/live buds remain, and cutting results in no regrowthIf heating or spoilage of the hay occurs, the coumarin compound turns into toxic dicoumarol (with anticoagulant properties causing internal hemorrhage in animals) Use hay conditioning if possible to aid drying and avoid leaf shatteringHay production is challenging because of high moisture stems, and the tendency to mold, which causes problems with coumarin production. |
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| Notes |
Excellent source of nectar and pollen for bees
Used for soil improvement due to good N fixing and DM yield
Coumarin (anticoagulant) gives the sweet odor
Alternate feeding with other forage at 2-3 week intervals helps reduce the risk.
The bacteria Inoculant used for alfalfa also works for sweet clover. Can be planted where alfalfa has been planted.
Resistance to grasshoppers better than small seeded legumes
Sweetclover weevil is the most damaging pest
Black stem and root rot could be damaging |
