Petty whin

How to recognise it

Habit

Low, prostrate to ascending dwarf shrub 10–50 cm tall, with thin, woody twigs.

Stem

Older twigs with sharp, straight spines 1–2 cm long; the young flowering shoots have no spines.

Leaf

Small (2–8 mm), oval to lance-shaped, hairless and bluish green; deciduous.

Flower

Yellow pea flower about 8 mm long, in short, leafy clusters at the shoot tips, from April to June.

Fruit

Hairless, slightly inflated pod 1.5–2 cm long, blackish brown when ripe; it bursts open and flings out the seeds.

Roots

Deep taproot with nodules in which bacteria fix nitrogen from the air.

Confusion with

Hairy greenweed and dyer’s greenweed have no spines. Gorse is much larger and has green spines on all its shoots.

Flowering: April–June · Pruning: July

Why grow it?

• A characteristic plant of heathland, a landscape in steep decline that you can help preserve a little in a heather garden.
• The flowers provide pollen for bumblebees and wild bees, which push the pea flower open.
• Like all members of the pea family, it fixes nitrogen from the air with the bacteria in its root nodules.
• Small and spiny: among the heather it gives shelter to insects and spiders.
• A splash of yellow in spring, long before the heather turns purple.

Petty whin: where does it grow best?

• In the wild on dry and wet heath, in acid grassland and along heathland paths.
• Full sun: in the shade of trees it disappears.
• Poor, acid, lime-free soil: sand or peaty sand. It cannot stand fertilised or limy soil.
• In the garden: only in a heather garden or a poor, sandy spot, together with heather and cross-leaved heath.

Goes well with

• Heather: The same poor, acid soil; flowers later in summer.
• Cross-leaved heath: For the damp part of a heather garden.
• Heath-grass: A low, native heathland grass that will not smother it.
• Heath bedstraw: Tiny white flowers on the same acid sand.
• Harebell: Blue bells in summer on poor soil.

Petty whin: when and how to plant it?

1. Buy plants or seed from a nursery specialising in native plants, preferably of regional origin.
2. Sowing: roughen the hard seed coat a little with sandpaper or soak the seeds overnight in lukewarm water, then sow in March–April or in autumn in a pot of sand.
3. Plant in October–November or in March–April. Because of its taproot it transplants badly: plant it young and with its root ball.
4. Space plants 30–40 cm apart, in poor sandy soil without compost or fertiliser.
5. Water in dry spells in the first year; after that, no more.
6. Never dig up plants on the heath: petty whin is rare and its sites are mostly in nature reserves.

Care

Watering

Not needed after the first year: it copes well with drought.

Feeding

Never: nutrients let grasses and brambles win. Poor soil keeps it strong.

Weeding

Remove grasses, brambles and seedling birch or pine, so it gets enough light.

Renewal

Old plants become bare and die; sow or plant new ones in good time.

Fallen leaves

Rake away leaves from trees: a layer of leaves enriches the soil.

Tip: Never give it compost or fertiliser and keep the spot open and sunny: the poorer the soil, the better it does.

Pruning and mowing

Pruning months: July.

When: After flowering, late June to July.

How:

• Trim lightly after flowering to keep the plant compact, but never into the old, bare wood.
• Remove dead twigs.
• On the heath, sheep grazing and small-scale turf stripping create open patches where young plants can germinate.

Caution: Wear sturdy gloves: the spines are sharp.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Roughen or soak the seeds and sow in March–April or in autumn. Move seedlings young into deep pots because of the taproot.

Cuttings

Semi-ripe cuttings in July–August in sandy cutting compost; they do not always succeed.

Petty whin: how does it get through the winter?

Hardy to −25 °C.

• In winter it is mostly bare; the greenish-brown, spiny twigs remain.
• Fully hardy.
• Its hard seeds stay viable in the soil for a long time and often germinate after turf stripping or other disturbance.

Diseases and pests

• Disappearing: On rich soil and in shade it soon disappears. Keep the soil poor and the spot open.
• Grass taking over: Purple moor-grass and wavy hair-grass smother it. Weed or mow around it.
• Old, bare plant: After a few years it becomes woody and bare. Sow new plants to replace it.
• Root rot: On heavy, wet clay the roots rot. Choose a free-draining sandy soil.

Through the year

• March: Plant or sow.
• April: First flowers.
• May: Full flower: bumblebees and wild bees.
• June: End of flowering. Pods form.
• July: Trim lightly. Pods burst open on warm days.
• August: Collect seed from ripe black pods. Take cuttings.
• October: Plant. Rake away fallen leaves.
• November: Plant. Keep raking away leaves.

Did you know?

• Anglica means ‘English’, but the species grows along the whole Atlantic side of Europe, from Portugal to southern Scandinavia.
• The English royal house of Plantagenet owes its name to planta genista, the Latin name for a sprig of broom.
• On hot summer days the ripe pods suddenly twist open and fling out the seeds with an audible little crack.