White clover
Trifolium repens
Botanical family: Fabaceae
Trifolium repens, a small perennial of Europe's meadows, is recognisable by its trifoliate leaves marked with a pale crescent. Sown as green manure or integrated into the grassed paths of a permaculture garden, it enriches the soil with nitrogen while offering a nectar cover appreciated by bees.
Full sun
Any soil, tolerates moisture and trampling
Undemanding once settled in
Very hardy (perennial, withstands -20 °C)
Overwinters in your zone
Role in permaculture
Like most Fabaceae, white clover captures nitrogen from the air to make it available to the soil, a nitrogen input documented by classical agronomy (Bourguignon, Le Sol, la Terre et les Champs). A low, creeping perennial, it forms a dense ground cover that limits weeds and protects soil life, and is among the nectar plants most visited by bees.
Good companions
Attract pollinators and beneficial insects
Traditional companion planting (benefit not demonstrated)
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…”.
Its roots associate with this bacterium to fix atmospheric nitrogen in nodules, the symbiont specific to the clover genus, which nodulates no other legume. The mechanism is solid, but deliberately not quantified here: fixation values (kg of nitrogen per hectare) circulate without a single one having been verified at the source. Rather remember: fixation is not constant, cold (10–15 °C) markedly slows root infection and nodulation.
scientific study
- · Janczarek et al. (2024), Scientific Reports 14:6264, DOI 10.1038/s41598-024-56988-1
The clover shares part of the nitrogen it fixes with neighbouring grasses, but far less than believed. In isotopic tracing, barely 3% of the ryegrass's nitrogen came from the living clover; it's its decomposition, once cut and left on the soil, that transfers about three times more. Lawn clover therefore feeds mainly through its residues, not its living roots. Measured in a microcosm, not in an open-field meadow.
scientific study
- · Reay M.K., Pears K.A., Kuhl A. et al. (2022), Plant and Soil 480:369-389, DOI 10.1007/s11104-022-05585-0
Clover residues left on the soil mineralise in two stages: the tender parts (blades, flowers) release their nitrogen within a few weeks, the fibres follow more slowly. An essential nuance from the authors: in autumn, this nitrogen stays largely immobilised in the soil micro-organisms and only becomes available again in spring. And under bare soil, nitrogen capture falls to about half that obtained under a growing crop, mulching clover with nothing grown afterwards loses part of the benefit.
scientific study
- · Anderson et al. (2025), Frontiers in Agronomy, DOI 10.3389/fagro.2025.1708560
A mutual relationship, not a mere service rendered: white clover is largely self-sterile and depends on pollinators to set seed, while its massive flowering feeds them in return. Its nectar contains cyanogenic glycosides, but at the natural measured levels, the survival of bees fed on it stays comparable to controls, no detectable toxicity. An abundant but brief resource.
scientific study
- · Lecocq A. et al. (2018), Insects 9(1):31, DOI 10.3390/insects9010031
A white clover kept alive under a crop is not neutral: it takes its share of water and light. The reference review is candid, the effects range from positive to negative depending on climate, soil, and management, and the water data contradict one another. A documented case: wheat yield reduced at low sowing densities, the effect softened by sowing the crop more thickly. To be managed, not ignored.
scientific study
- · Dzvene A.R. et al. (2023), Air, Soil and Water Research 16, DOI 10.1177/11786221231180079
Seasons & availability
A perennial ground cover sown from March to June, or in autumn; it covers the soil from spring to autumn and flowers at length, from May to October, to the delight of bees.
Available: March, April, May, June, July, August, September, October, November.
Guidance for the oceanic / temperate climate; it may vary with your region, altitude, exposure and growing method.
Sources
- Plants For A Future, « Trifolium repens » (pfaf.org/user/Plant.aspx?LatinName=Trifolium+repens)
- Tela Botanica, « Trifolium repens L. » (tela-botanica.org/bdtfx-nn-69341-description)
- Jardiner Malin, « Le trèfle, un excellent engrais vert pour le potager » (jardiner-malin.fr/fiche/trefle-engrais-vert.html)
Nutritional & medicinal properties
For educational purposes. Not a substitute for medical advice. Effects depend on the form, the dose and personal context.
Precautions & contraindications
Edible in moderation: raw and in large quantities, it is reputed to be difficult to digest. Identify the plant carefully.
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.
Understanding families means learning one rule per family rather than every pairing one by one. Learn more →
Species & varieties
The best-known species and varieties in France.
Common varieties
Voices of peoples
Paraphrases attributed to their documented sources. Never an invented quote.
Irish shamrock tradition of St Patrick's Day, put into writing by the botanist Caleb Threlkeld · Ireland; custom attested from the late 17th century (1681), the Trinity legend put into writing in 1726
In Ireland, the shamrock, a small clover, is worn on St Patrick's Day. Wearing the plant on that date is attested as early as 1681 by the account of the traveller Thomas Dineley, with no mention of the Trinity. The legend according to which St Patrick used the three-leaflet leaf to teach the mystery of the Trinity appears in writing only in 1726, from the pen of the botanist Caleb Threlkeld, who himself gives it as an already-widespread tradition. Threlkeld identifies the shamrock with white clover, but the species remains debated: surveys point sometimes to the lesser yellow trefoil (Trifolium dubium), sometimes to white clover (T. repens).
Caleb Threlkeld, Synopsis Stirpium Hibernicarum (1726), pour la légende trinitaire donnée comme « tradition courante » ; port du shamrock attesté en 1681 par le récit de Thomas Dineley ; enquêtes botaniques de Nathaniel Colgan (1893) et de 1988 sur l'identité de l'espèce, rapportées par E. Charles Nelson, Shamrock: Botany and History of an Irish Myth (Boethius Press, 1991).
The custom, attested from 1681, is clearly distinct from the Trinity legend, put into writing only in 1726 and presented by Threlkeld as an already-common oral tradition (the same structure as the Welsh leek emblem). The botanical identity of the shamrock remains uncertain: the species is not settled here, white clover being only one candidate among others, the most frequently cited being the lesser yellow trefoil (T. dubium). No medicinal claim is at stake: it's a cultural emblem, not a therapeutic use.
Keep in mind
As a 'living mulch' under a crop (maize, cabbage, pepper, squash), white clover enriches the soil with nitrogen as its residues decompose and competes with weeds, but it also competes with the crop for water, light, and nitrogen: in a South Dakota State University trial, in the clover's establishment year, peppers yielded less than on bare soil, whatever the in-row management. Sources: Clark A. (ed.) (2007), Managing Cover Crops Profitably, 3rd ed., SARE; Lang K., Barnes A., Burrows R. (2023), “Clover Cover Crops as a Living Mulch for Pepper Production in Eastern South Dakota: 2022 Preliminary Results”, SDSU Extension.
A note on rigour: many companion pairings are gardening folklore; this note sums up what the sources say, where there are any.
Key takeaways
- • Prefers full sun exposure.
- • Ideal soil: any soil, tolerates moisture and trampling.
- • Classic companion: Squash.