Crimson clover

Crimson clover: how do you recognise it?

Habit

Upright annual clover 30–50 cm tall and 20 cm wide, with hairy stems.

Leaves

Trifoliate, with broad, round to inversely oval, softly hairy leaflets.

Flower

Elongated, cone-shaped spikes a few centimetres long, crimson, from May to July.

Roots

Taproot with nodules in which bacteria fix nitrogen from the air.

Seed

Small; it forms in the calyx of the finished spike and self-sows easily.

Flowering: May–July · Sowing: March–April and August–September

Why grow it?

• Excellent green manure: the roots fix nitrogen and open up the soil structure.
• The crimson flower spikes feed bumblebees and bees from May to July.
• Covers the soil over winter, protecting it from leaching and weeds.
• Pretty in a wildflower meadow or on a temporary vacant patch.
• Cheap and easy to sow, even on light, freshly dug ground.

Crimson clover: where does it grow best?

• Full sun; in partial shade it flowers less well, so an open, sunny spot is ideal.
• Well-drained sandy or loamy soil, acid to neutral (about pH 5.5–7).
• Heavy, wet clay is less suitable: the plants rot easily there in wet winters.
• As a green manure, sow broadcast; in a wildflower meadow, sow it happily in a seed mix.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Acid or neutral

Moisture

Normal

Size

0.4 m tall, 0.2 m wide

Hardiness

Tolerates light frost (to -10 °C)

Goes well with

• Phacelia: A good partner as green manure and a big bee magnet.
• Winter rye: In a mix, rye holds the soil and the clover supplies nitrogen.
• Cornflower: Blue flowers contrast beautifully with the crimson of the clover in a wildflower meadow.
• Poppy: Red poppies and crimson clover give a warm, meadow-like picture.
• White mustard: A fast green manure that covers the soil early in a mix.

Crimson clover: when and how to plant it?

1. Sow in March–April for flowers from June, or in August–September for winter cover.
2. Clear the soil of weeds and rake it fine and level; clover seed germinates best in a fine, firm seedbed.
3. Sow broadcast, about 3–4 g per m², spread evenly.
4. Rake the seed in shallowly (1 cm at most) and firm the soil with the back of the rake or a roller.
5. Water if it does not rain for a few days; the seed germinates within 1–2 weeks.
6. Netting or a scarecrow protects the seed and young plants from pigeons.

Care

Water

Only in long dry spells until the plants are established; after that it manages by itself.

Feeding

Not needed: it fixes its own nitrogen. Too much nitrogen makes the root nodules less active.

Mowing

Mow or cut the plants in full flower, before the seed ripens. Leave the cuttings as mulch or dig them in shallowly.

Following crop

Wait 2–4 weeks after mowing before sowing or planting: the green material must break down first.

Weeds

In spring, pull or hoe weeds until the clover covers the ground.

Tip: Sow in August–September after harvest: it covers the soil over winter and flowers in May. Mow in full flower, before the seed ripens, and leave the cuttings as mulch.

Crimson clover: when to prune it?

When: It is not pruned, but as a green manure you mow it in full flower, in June–July.

How:

• Mow or cut the plants just above the ground as soon as the first spikes are open.
• Leave the cuttings as mulch, or dig them in shallowly.
• Leave the roots in the ground: they break down and improve the soil structure.
• If you want seed for next year, mow only once the spikes are brown.

Pruning calendar and basic rules

Propagation

Seed

In March–April or August–September, sown straight where it is to grow. Rake the seed in shallowly and firm; it germinates in 1–2 weeks.

Own seed

Let a few plants flower until the spikes turn brown. Cut them, dry them and rub out the seed; store it dry until the next sowing time.

Crimson clover: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Moderately hardy, to about −10 °C: in hard winters, autumn-sown plants may be killed by frost.
• Sow in August–September so that the seedlings are well developed before winter, but not too large.
• Frost damage? Simply sow again in March–April.

Diseases and pests

• Slugs: Young seedlings are eaten quickly, especially in damp autumns. Use iron phosphate pellets or sow a little thicker.
• Clover rot: White mould (Sclerotinia) on plants that rot away after a mild, wet winter. Do not sow clover too often in the same place and rotate with other crops.
• Birds: Pigeons and sparrows peck seed and seedlings. Cover the seedbed with netting or flags.
• Poor germination: The seed is too deep or in dry, cloddy soil. Rake fine, sow shallowly and firm.
• Weeds: Keep the young bed weed-free at first; later the clover suppresses them itself.

Through the year

• March: Sow as soon as the soil can be worked.
• April: Finish sowing. Water in dry weather.
• May: Flowering begins, bees arrive. Keep an eye on the bed.
• June: Full flower. Mow as green manure if wanted.
• July: Last flowers. Mow before seeding and leave as mulch.
• August: Sow again on cleared beds for winter cover.
• September: Last sowing time. Protect seed and seedlings from birds.
• October: Plants keep growing; nothing to do.
• November: It keeps the soil covered over winter.
• December: Rest; in hard frost the soil stays covered.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The species name incarnatum is Latin for ‘flesh-coloured’, although the flowers are crimson.
• Clovers live with bacteria in nodules on their roots that turn nitrogen from the air into a form plants can use.
• It is also known as Italian clover or French clover.