Crimson clover
Trifolium incarnatum
Botanical family: Fabaceae
Trifolium incarnatum owes its name to its bright red flowers, in conical spikes, that cover the cover-crop fields in spring. Sown at the end of summer, it protects the bare soil through winter and feeds the first bees before being incorporated into the soil in spring.
Full sun
Light, well-drained
Moderate, content with autumn and spring rains
Hardy, but annual or biennial (killed by hard frosts in a continental climate)
Overwinters in your zone
Role in permaculture
An annual clover with beautiful red flowering, sown as an autumn green manure: it captures nitrogen from the air and restores fertility to the soil before spring crops. Killed by frost or mown before it goes to seed, it leaves a rich mulch to break down.
Insects attracted or useful
Documented synergies
Relationships backed by a named source, with their real scope. A synergy without a named reference has no place here, no “it is said that…”.
Like its clover cousins, it fixes atmospheric nitrogen by nodulating with this bacterium; inoculation is advised in soil that has never carried clover. The mechanism is established, but the magnitude in the garden very variable: the ranges in cover-crop manuals (on the order of several tens of kg of nitrogen per hectare) are trial estimates, not measurements. Key point: the nitrogen mostly benefits the FOLLOWING crop, after the cover is destroyed and decomposed, far more than through transfer from a living clover.
institutional source
- · SARE, Managing Cover Crops Profitably, 3rd ed. (2007), Crimson Clover sheet (extension manual)
Its blood-red flower heads produce a nectar sought by bees, and pollination in return increases its seed production. The documented effect concerns the seed yield of the clover itself (seed gains with a few colonies per hectare), not a service rendered to neighbouring crops.
scientific study
- · Blake G.H. Jr. (1958), Journal of Economic Entomology 51(4):523-527
A winter green manure: once destroyed, it decomposes and releases nitrogen. The title and abstract of the cited study relate this release to the clover's growth stage when it is destroyed and to the composition of its tissues. No figure from it is repeated here, and the full content of the article was not read.
scientific study
- · Ranells N.N. & Wagger M.G. (1992), Agronomy Journal 84:424-430, DOI 10.2134/agronj1992.00021962008400030015x
The cover offers pollen and early-season shelter to this small bug that preys on thrips, aphids, and mites, which can then move to neighbouring crops. The habitat role is reported; the magnitude of the biological-control service in the garden is not quantified in a primary source.
institutional source
- · SARE, Managing Cover Crops Profitably, 3rd ed. (2007), Crimson Clover sheet (extension manual)
Seasons & availability
A green manure sown in spring, in March and April, or in late summer, in August and September: sown before winter, it covers the soil from autumn to spring, then is cut at its crimson, nectar-rich flowering, from May to July depending on the sowing date.
Available: January, February, March, April, May, June, July, September, October, November, December.
Guidance for the oceanic / temperate climate; it may vary with your region, altitude, exposure and growing method.
Sources
- La Ferme de Sainte Marthe, « Réussir la culture du trèfle incarnat : semis et culture » (fermedesaintemarthe.com/en/blogs/comment-reussir-la-culture-de/reussir-la-culture-du-trefle-incarnat)
- Tela Botanica, « Trifolium incarnatum L. » (tela-botanica.org/bdtfx-nn-69142-description)
Nutritional & medicinal properties
For educational purposes. Not a substitute for medical advice. Effects depend on the form, the dose and personal context.
Precautions & contraindications
Mainly agronomic and beekeeping use; human consumption anecdotal and in moderation.
Family behaviour: Legumes
In general, Legumes fix nitrogen from the air in most cases, thanks to the Rhizobium in their root nodules. They mainly enrich the soil for the following crops, as their residues decompose. Ideal in a rotation, before nitrogen-hungry plants such as nightshades.
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Species & varieties
The best-known species and varieties in France.
Common varieties
Key takeaways
- • Prefers full sun exposure.
- • Ideal soil: light, well-drained.