Spiraea

Spiraea: how do you recognise it?

Habit

Shrub of 0.5–2 m: bridal wreath with arching, overhanging branches, Japanese spiraea compact and rounded.

Leaf

Alternate, small (2–8 cm), lance-shaped and toothed.

Bark

Thin brown twigs.

Flower

Little white posies along the branches in April–May (bridal wreath) or flat pink heads in summer (Japanese spiraea).

Fruit

Small follicles.

Difference from cotoneaster

Cotoneaster has untoothed leaves and red berries.

Flowering: May–July · Pruning: March and May–June

Looks like it, but isn’t

• Cotoneaster Cotoneaster: untoothed leaves and red berries. Difference from cotoneaster

Why grow it?

• Masses of flowers, in spring or summer depending on the kind.
• Flowers for bees and hoverflies.
• Easy: grows in almost any soil, in sun or partial shade.
• Suitable for borders, low hedges and small gardens.

Spiraea: where does it grow best?

• Sun to partial shade; it flowers most freely in sun.
• Almost any good garden soil, neither too dry nor too wet.
• Allow 1–1.5 m in width for a bridal wreath; Japanese spiraeas often stay smaller.
• Lovely in a mixed border, as a low hedge or at the front of a shrub border.

Light

Sun or partial shade

Legal basis

Any garden soil

Moisture

Normal

Size

2 m tall, 1.5 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Forsythia: Yellow beside the white of bridal wreath in spring.
• Weigela: Flowers in May–June and takes over from bridal wreath in the shrub border.
• English lavender: A sunny, low border with Japanese spiraea, full of bees in summer.

Good and bad companions

Goes well with

• Suits the woodland edge or the light shade of: ginkgo, box elder, ash, honey locust, field maple, silver maple

Spiraea: when and how to plant it?

1. Plant from November to March; container plants all year, except in frost or drought.
2. For a low hedge: 2–3 plants per metre.
3. Mix some compost into the soil and plant at the same depth as before.
4. Water well after planting and in dry spells during the first year.

Care

Watering

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

Feeding

Some compost in spring is enough.

Deadheading

On Japanese spiraea, cut off the faded flower heads: it often flowers a second time.

Rejuvenating

Cut an old, bare shrub back hard: a summer-flowering one in March, a bridal wreath after flowering. It will shoot again.

Tip: Not sure which spiraea you have? Look at when it flowers: white posies along the branches in spring means pruning after flowering; pink heads at the tips in summer means pruning in March.

Spiraea: when to prune it?

Pruning months: March and May–June.

When: Spring-flowering types (bridal wreath) after flowering; summer-flowering types (Japanese spiraea) in March.

How:

• Summer-flowering types flower on new wood: cut them back to 20–30 cm above the ground in March.
• Spring-flowering types flower on last year’s wood: after flowering, just thin out the oldest branches at the base and cut faded shoots back to a young shoot.
• A low hedge of Japanese spiraea can be trimmed with shears in March.

Caution: Don’t cut back a bridal wreath in winter or early spring: you would remove all the flower buds.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Summer cuttings

In June–July, take semi-ripe cuttings of 10–15 cm and root them in a pot of cutting compost under plastic.

Hardwood cuttings

In winter, push 20 cm lengths of young shoots into the ground; they usually root by summer.

Spiraea: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• In winter, bridal wreath stands with bare, arching branches; the flower buds are already there.

Diseases and pests

• Aphids: Aphids on the young shoot tips in spring. Ladybirds and hoverfly larvae usually clear them up.
• Bare, woody shrub: Few leaves and flowers low down. Thin out some old branches every year, or rejuvenate the shrub in one go.
• No flowers: Usually pruned at the wrong time, or too much shade. Only prune spring-flowering types after flowering.

Through the year

• March: Cut back summer-flowering types (Japanese spiraea); planting.
• April: Bridal wreath starts to flower.
• May: After flowering: prune bridal wreath.
• June: Last pruning of spring-flowering types; Japanese spiraea starts to flower.
• July: Japanese spiraea in flower; remove faded heads.
• August: Summer flowers; water in dry spells.
• November: Planting.

What can you use it for?

Garden and landscape

Easy flowering shrub for borders and low hedges.

For wildlife

Flowers for bees and hoverflies.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Hoverflies

Open flowers for hoverflies; many of their larvae eat aphids.

Butterflies

Nectar for butterflies.

Did you know?

• The spring-flowering kinds are called ‘bridal wreath’, after their white veil of flowers.
• Aspirin owes its name to Spiraea: salicylic acid was once obtained from meadowsweet, which then still belonged to this genus.
• There are dozens of species and varieties, from half-metre ground cover to 2 m shrubs.
• Spiraea comes from the Greek speira, ‘wreath’ or ‘coil’: the flowering shoots were used to make garlands.
• The name aspirin refers to Spiraea ulmaria, the old name of meadowsweet, from which salicylic acid was once obtained.