Hairy greenweed

Hairy greenweed: how do you recognise it?

Habit

Low, creeping to spreading shrub about 30 cm tall and 1 m wide, with thin green stems.

Leaves

Small, 1–2 cm long, obovate to lance-shaped, green above and silvery-hairy beneath; deciduous in winter.

Flower

Small yellow pea-like flowers, finely hairy on the outside, in May and June.

Fruit

Small hairy pods containing the seeds; self-seeding often happens by itself under good conditions.

Roots

Deep root system with nodules that fix nitrogen from the air; resents being moved.

Flowering: May–June · Plants: March–April and September–October · Pruning: June

Why grow it?

• A blanket of yellow flowers in May and June that almost completely covers the plant.
• Creeps over low walls, banks and stones, covering bare or dry spots.
• Native and suited to a natural garden; the flowers are visited by bees.
• Very drought tolerant and feeds the soil with nitrogen itself, so it never needs fertiliser.
• Goes well with heather and other plants that like acid, poor soil.

Hairy greenweed: where does it grow best?

• Full sun in a warm, open spot; in shade it hardly flowers and becomes open.
• Poor, sandy, well-drained soil, acid to neutral. Not suited to chalky soil.
• Dry: once established it needs no water; wet, heavy soil is fatal.
• Ideal for a heather or rock garden, dry bank, low wall or gravel garden.
• Allow 80–100 cm per plant; it spreads slowly.

Light

Sun

Soil type

Sand

Acidity

Acid or neutral

Moisture

Dry

Size

0.3 m tall, 1 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Heather: The same acid, poor sandy soil; pink and purple beneath the yellow.
• Bell heather: A small heath shrub that shares the same position.
• Sheep’s fescue: Fine blue-green grass that frames the creeping mat lightly.
• Thyme: Stays low and flowers, with the same need for sun and dry soil.
• Stonecrop: Low, fleshy foliage that fills out the carpet in a dry rock garden.

Hairy greenweed: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or in September–October, when the soil is neither frozen nor too wet.
2. Choose small, young plants in pots: they settle better than older specimens, because broom resents being moved.
3. Dig a hole as deep as the pot and twice as wide; open up heavy soil with sand.
4. Set the plant at the same depth as in its pot, with the stem base at soil level, and space 80–100 cm apart.
5. Water well after planting, then only during long dry spells in the first year.
6. Leave the soil bare or spread a thin layer of grit; no compost or fertiliser.

Care

Watering

Only in the first year during long dry spells; after that not needed.

Feeding

Do not. As a legume it makes its own nitrogen, and rich soil gives floppy growth and fewer flowers.

Mulching

No compost or bark. A thin layer of grit or sand is enough.

Weeding

Keep young plants free of weeds until the mat has closed.

Moving

Avoid it: the roots resent disturbance. Choose the right spot from the start.

Tip: A creeping broom of the heath, lovely over a low wall or between heathers. It likes poor, acid, sandy soil in full sun. Do not move it and never feed it.

Hairy greenweed: when to prune it?

Pruning months: June.

When: Straight after flowering, in June, if needed. It rarely needs pruning.

How:

• Lightly shorten the flowering shoots, by about a third, to keep the plant compact and dense.
• Remove dead or damaged stems back to just above a healthy shoot.
• Never cut into old, bare wood: broom and its relatives rarely shoot again from it.

Caution: Do not cut into bare wood: it rarely shoots again from it.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Semi-ripe cuttings

In July–August: take 5–8 cm cuttings with a small heel of the parent plant, insert in sandy compost under plastic in a bright spot. Rooting takes a few weeks to several months.

Seed

The seed has a hard coat: soak it overnight in warm water or nick it lightly, then sow in autumn or spring in a tray of sandy compost. Grow the seedlings on in pots before planting them out.

Layering

In spring, bend a low stem down, bury a section and pin it in place. Detach it a year later when rooted.

Hairy greenweed: how does it get through the winter?

Hardy to −25 °C.

• Very hardy, down to about −25 °C: no protection is needed in Belgian winters.
• It loses its leaves, but the green stems remain; do not cut anything back in winter.
• In a pot: choose a wide, free-draining pot, put it in a sheltered spot and make sure water drains away.

Diseases and pests

• Root rot: The plant turns yellow and limp in wet, heavy or rich soil. Move it to dry sandy soil or improve drainage.
• No regrowth after pruning: Branches cut back into old wood often do not shoot again. Prune only lightly and only green shoots.
• Aphids: Sometimes on young shoots in spring. A jet of water is usually enough.
• Poor flowering: Usually too much shade or too much feed. Give sun and no fertiliser.

Through the year

• March: Plant in sandy soil. Do not feed.
• April: Plant. Remove weeds.
• May: Flowering begins.
• June: Full flower. Trim lightly after flowering.
• July: Take semi-ripe cuttings.
• August: Take semi-ripe cuttings. Let the pods ripen for seed.
• September: Plant. Sow if you have seed.
• October: Plant. Sow.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Genista pilosa takes its name from the Latin pilosus, ‘hairy’: the undersides of the leaves and the flowers are finely hairy.
• As a legume it lives with bacteria in root nodules that fix nitrogen from the air; this is why it grows on very poor soil.
• According to tradition, the name of the English royal house of Plantagenet comes from the Latin planta genista, the broom plant.