Bird's-foot trefoil

Bird's-foot trefoil: how do you recognise it?

Habit

Low, sprawling to ascending stems of 10–30 cm from a deep taproot; forms a mat about 40 cm across.

Leaves

Five small, oval leaflets: three at the tip and two at the base that look like stipules; hairless and slightly blue-green.

Flower

Bright yellow pea flowers 1–1.5 cm long in rings of two to eight, often orange or red in bud. Flowers from May to September.

Fruit

Straight, narrow pods 2–3 cm long that spread out like the toes of a bird’s foot.

Roots

Deep taproot with root nodules in which bacteria fix nitrogen.

Flowering: May–September · Sowing: March–May and September · Plants: March–May and September–October · Pruning: March

Why grow it?

• One of the best native bee plants: bumblebees and many kinds of solitary bee collect nectar and pollen.
• Food plant of the common blue and the six-spot burnet: their caterpillars eat the leaves.
• Long flowering from May to September.
• As a legume it fixes nitrogen from the air and does well on poor, dry soil.
• Low and creeping: ideal in a flowering lawn, on a dry bank or in a rock garden.

Bird's-foot trefoil: where does it grow best?

• Full sun; in shade it flowers poorly.
• Poor, free-draining sandy, loamy or clay soil, acid to chalky.
• Dry to moderately moist; thanks to its deep roots it copes well with drought.
• In a flowering lawn it thrives if you do not mow too often or too short.
• Plant 30–40 cm apart, or sow it in a wildflower mix.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.2 m tall, 0.4 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Self-heal: Purple flower spikes that also tolerate a closely mown flowering lawn.
• Brown knapweed: Purple-pink flower heads above the low trefoil, in the same poor soil.
• Wild thyme: Scented pink cushions for bees in the same dry, sunny spot.
• Oxeye daisy: White flowers in May–June, together with the first yellow trefoil.

Bird's-foot trefoil: when and how to plant it?

Plant in March–May and September–October.

1. Sow in March–May or in September; plant from March to May or in September–October.
2. Sow thinly on weed-free, loosened soil and rake in lightly; in a lawn, sow into bare patches or after scarifying.
3. If you like, soak the hard seed overnight or rub it lightly: it then germinates faster.
4. Set pot-grown plants at the same depth as in the pot, 30–40 cm apart. The taproot resents being moved, so plant them young.
5. Water in and keep the soil moist until the seedlings or plants have established.

Care

Water

Only at first; after that it copes even in dry summers.

Feeding

Never: it makes its own nitrogen, and fertiliser favours the grass.

Mowing

Mow a flowering lawn at most every four to six weeks and no shorter than 5–8 cm, so it can flower.

Deadheading

Not needed: the pods burst open and it self-seeds.

Tidying

In March, rake away last year’s dead stems.

Tip: Sow it in a flowering lawn or a poor verge and do not mow too often: at most every four to six weeks and no shorter than 5–8 cm. That way it can flower for the bees.

Bird's-foot trefoil: when to prune it?

Pruning months: March.

When: It hardly needs pruning. In March, cut or rake away the old, dead stems.

How:

• In March, rake or cut away last year’s withered stems before the new shoots appear.
• In a lawn, mowing is enough: not too often and not too short.
• On a bank or in a meadow, leave a section uncut until the following spring: caterpillars of blues and cocoons of the six-spot burnet sit among the stems.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow where it is to grow in March–May or in September. The hard seed germinates better after soaking overnight or a light rub with sandpaper.

Cuttings

In May–June, insert 5–8 cm cuttings of young, non-flowering shoots in moist, gritty cutting compost, in good light but out of full sun.

Bird's-foot trefoil: how does it get through the winter?

Hardy to −30 °C.

• Very hardy, to about −30 °C: no protection needed.
• The stems largely die back; the taproot overwinters and regrows in spring.
• On a bank or in a meadow, leave the stems in place: common blue caterpillars overwinter low down near the ground.

Diseases and pests

• Crowded out by grass: In rich grass or with too frequent mowing it disappears. Remove clippings, do not feed and mow less often.
• Few flowers: Too much shade or too many nutrients. Choose a sunny, poor spot.
• Aphids: Small black aphids on the shoot tips in summer. Ladybirds usually deal with them; otherwise hose them off.
• Seedlings: It self-seeds into bare ground. In a border, simply weed out the seedlings or move them while small.

Through the year

• March: Rake away dead stems. Sow or plant.
• April: Sow or plant. Keep seedlings moist.
• May: First yellow flowers. Still time to sow.
• June: Full flower. Bumblebees and blues on the flowers.
• July: Flowering. Do not mow the lawn too short.
• August: Flowering. The ripe pods burst open.
• September: Last flowers. Sow or plant.
• October: Plant. Leave part of the bank uncut.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The flower works like a little pump: when a bee lands on the lower petals, the pollen is pushed out of the tip of the flower against its belly.
• An old English folk name is eggs and bacon, after the yellow flowers with their orange-red buds.
• Like other legumes, it lives together with bacteria in nodules on its roots, which fix nitrogen from the air.