Cleavers

How to recognise it

Habit

Annual sprawling or climbing plant with weak stems 30–150 cm long, which leans on hedges and other plants for support.

Leaf

Narrow and lance-shaped, 1–5 cm, with a bristly tip, in whorls of 6–8 around the stem. The edges and midrib carry backward-pointing hooks.

Flower

Tiny white flowers about 2 mm across with four lobes, in small clusters on stalks from the leaf whorls, from May to September.

Fruit/Seed

Two little balls 3–5 mm across side by side, covered in hooked bristles, which cling to fur, clothes and socks.

Stem

Square, with stiff hooks on the ridges: it feels rough and sticky.

Look-alikes

Hedge bedstraw has smooth, non-sticky stems and large, loose sprays of small white flowers. Woodruff grows in woods, has broader leaves in whorls, doesn’t stick and smells of hay when dried.

Flowering: May–September · Pruning: May–June

Why grow it?

• Food plant for the caterpillars of several moths, including the elephant hawk-moth and the hummingbird hawk-moth.
• Together with nettles it forms a dense tangle where insects, spiders and small birds shelter and look for food.
• The tiny white flowers are visited by small flies and other small insects.
• Fun for children: it sticks to everything, and the fruits cling to socks and fur.
• Its other English name, goosegrass, comes from the fact that geese and chickens love to eat it.

Cleavers: where does it grow best?

• In the wild: woodland edges, hedgerows, nettle patches, field margins, riverbanks and coastal dunes.
• Sun to half shade.
• Moist, fertile soil, especially where there is plenty of nitrogen, such as next to a compost heap.
• In the garden: under a hedge, in a wild corner or in a mixed native hedge, where it can climb without smothering other plants.

Goes well with

• Common nettle: Together a rich tangle full of caterpillars and insects, in a wild corner.
• Garlic mustard: Food plant of the orange-tip, in the same hedge bottom.
• Cow parsley: White umbels in May along the same hedge.
• Ground-ivy: A low, blue groundcover in the half shade under the hedge.
• Hawthorn: A native hedge to climb through.

Cleavers: when and how to plant it?

1. Planting is usually unnecessary: cleavers turns up by itself in almost every garden, via birds, animals and clothing.
2. If you do want it in a wild corner, buy seed from a native plant nursery or ask for ripe fruits from a plant in a nearby garden. Never dig plants up from the wild.
3. Sow in September–October where it is to grow and lightly rake the seed in; it germinates in autumn and early spring.
4. Choose a spot at the foot of a hedge or among nettles, where it finds support without smothering small plants.
5. No watering needed.

Care

Water

Not needed.

Feeding

Never: it already grows rampantly on fertile soil.

Spreading

Can smother and drag down young plants and low shrubs. Pull it out in May–June, before the fruits ripen: the roots are shallow and come away easily.

Self-seeding

In a wild corner the seed may fall; in the border and vegetable garden, pull it out before the fruits turn brown.

Composting

Plants pulled up without ripe fruits can go on the compost heap. With ripe fruits, use the green waste bin instead, as the seed survives in a cool compost heap.

Tip: Pull out cleavers before the end of June: the plant still comes away easily and there are no ripe fruits yet to end up in your clothes and your compost heap.

Pruning and mowing

Pruning months: May–June.

When: In May–June, before the fruits ripen, if you want to limit its spread.

How:

• Carefully untangle the stems from the hedge or border and pull the plant up, roots and all.
• In a wild corner, leave some for caterpillars and other insects.
• Dead plants disappear by themselves in late summer; no need to tidy up.

Caution: Wear gloves and long sleeves: in sensitive people the hooks can cause itching or small red marks on the skin.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

The only way: it seeds itself, and animals and people carry the sticky fruits around. It germinates in autumn and early spring.

Cleavers: how does it get through the winter?

Hardy to −20 °C.

• Autumn-germinated seedlings overwinter as small green plants with little whorls of leaves; you can see them among the dead leaves as early as January.
• The seed survives winter in the soil and germinates in spring.
• The old plants die in summer, after setting seed.

Diseases and pests

• Smothering: Forms a dense, heavy net over young plants, roses and low shrubs. Pull it out in good time, in April–June, before it climbs high.
• Sticky fruits: Cling to the fur of dogs and cats. Brush your pet after a walk and keep the plant away from paths your dog uses.
• Seedlings in the vegetable garden: Germinates in huge numbers on bare, fertile soil. Mulching and early weeding keep it under control.
• Itchy skin: In sensitive people the hooks can cause itching. Wear gloves.

Through the year

• January: Young autumn-germinated plants, in little whorls among the leaves.
• March: Fast growth. Weed out seedlings in the vegetable garden.
• April: Climbs into hedges. Weed where it smothers young plants.
• May: Flowering begins. Pull out before the fruits ripen.
• June: Flowers and first fruits. Last chance to pull it out before the seed drops.
• July: The fruits ripen and stick to everything.
• August: The first plants die back; late plants are still flowering.
• September: Sow in a wild corner. Last flowers.
• October: Autumn seedlings appear under hedges.

Did you know?

• Cleavers belongs to the same family as the coffee plant. Its roasted fruits were sometimes used in the past as a coffee substitute.
• The hooks on the stems and leaves all point backwards: that way the plant can climb up without sliding back down.
• The fruits travel in the fur of animals: that is how the plant gets spread over long distances.