Greater periwinkle

Greater periwinkle: how do you recognise it?

Habit

Trailing, 30–45 cm tall; long stems of over a metre that root at the tips.

Leaves

Oval to heart-shaped, 4–9 cm, glossy dark green, opposite, with fine hairs along the edge.

Flower

Five obliquely cut petals like a little propeller, 4–5 cm across, borne singly in the leaf axils.

Colour

Violet blue; rarely white.

Roots

The stems root wherever they touch the ground, which is how it spreads so quickly.

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

Why grow it?

• Evergreen: a dense, glossy carpet even in winter.
• Grows in shade and in dry soil under trees, where little else will.
• Holds slopes and banks together with its rooting stems.
• Large blue flowers in spring, early food for bees and bumblebees.
• Little work: cutting it back once a year is enough.

Greater periwinkle: where does it grow best?

• Partial to full shade, for example under trees or on the north side of a hedge.
• Almost any soil: sand, loam or clay, acid to chalky.
• Dry to moist; once established it tolerates drought under trees.
• Plant 40–50 cm apart; it soon knits together.
• Keep it away from small, delicate plants and from natural areas: it is a vigorous spreader.

Light

Partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.4 m tall, 1.5 m wide

Hardiness

Hardy (to -15 °C)

Goes well with

• Daffodils: They flower through the green carpet, which later hides their fading leaves.
• Ferns: A fresh, green partnership for deep shade.
• Lenten rose: Flowers in shade in early spring, in white, pink and purple.
• Holly: An evergreen shrub above the carpet, for a green winter corner.

Greater periwinkle: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or in September–October.
2. Loosen the soil and mix in some compost, especially under trees.
3. Set the plant at the same depth as it was in the pot; peg long stems down onto the soil.
4. Space plants 40–50 cm apart.
5. Water well and keep the soil moist during the first year.
6. Mulch with leaf mould or wood chips until the carpet has closed.

Care

Watering

In the first year during dry spells; after that only in long, dry summers.

Feeding

A thin layer of compost in spring is enough.

Keeping it in check

Cut or pull out runners that stray too far, especially near small plants and paths.

Cutting back

Cutting it short in March keeps the carpet dense and free-flowering.

Weeding

Weed carefully in the first year until the plants knit together.

Tip: Cut the carpet back every March with hedge shears or a mower on its highest setting: it stays dense and keeps weeds out.

Greater periwinkle: when to prune it?

Pruning months: March.

When: Cut it back hard in March, before new growth starts. For the rest of the year, only trim runners that stray too far.

How:

• In March, cut the whole carpet back to 10–15 cm with hedge shears or a mower on its highest setting; this keeps it dense and bushy.
• Remove old, bare or damaged stems.
• During the season, cut back long runners that grow over paths or other plants.

Caution: Put clippings on the compost heap and never dump them in the countryside: cut stems root easily.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Layering

The stems root by themselves. Cut off a rooted stem and plant it, ideally in March–April or September.

Division

In spring or autumn, lift clumps with roots and replant them elsewhere.

Cuttings

In summer, root 10 cm pieces of stem in moist cutting compost; they root quickly.

Greater periwinkle: how does it get through the winter?

Hardy to −15 °C: protect young plants.

• Hardy to about −15 °C: no problem in most Belgian winters.
• In a severe winter the leaves may brown or drop; the plant shoots again in spring.
• Evergreen: in a normal winter the carpet stays green and protects the soil.

Diseases and pests

• Spreading: It smothers its neighbours. Cut back the edges every year and do not plant it near natural areas.
• Rust: Pale, upright shoots with brown spores under the leaves. Cut out affected stems and dispose of them.
• Bare patches: Caused by deep shade or exhaustion. Cut back in March and add some compost.
• Leaf spot: Brown spots and dying stems in damp weather. Cut out affected parts and improve air flow.

Through the year

• March: Cut back to 10–15 cm. Plant. Flowering begins.
• April: Full flower. Plant. Add compost.
• May: In flower. Keep runners in check.
• June: Last flowers. Keep runners in check.
• July: Take cuttings. Water during long dry spells.
• September: Plant. Move rooted stems.
• October: Plant. Divide clumps.

Edible and useful

Not edible. All parts of greater periwinkle are poisonous: they contain alkaloids (such as vincamine) that cause vomiting, stomach ache and diarrhoea if eaten and, in larger amounts, can affect blood pressure and the heart. It is a relative of Madagascar periwinkle, but a different plant. Do not make teas or remedies from it. Do not let children eat the leaves or flowers, keep dogs, cats and grazing animals away, and do not throw trimmings into a field or pen, nor into the wild, as it spreads rampantly. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• You can recognise it by the fine hairs along the leaf edge; lesser periwinkle has smooth leaf edges.
• It belongs to the same family as oleander.
• In English and French, periwinkle or pervenche is also the name of a pale lavender-blue colour, named after the flower.