Birchleaf spiraea

Birchleaf spiraea: how do you recognise it?

Habit

Compact, rounded shrub about 0.8 m tall and 1 m wide, with fine, upright stems.

Leaves

Oval, 3–5 cm, with a toothed edge; fresh green in summer, yellow to orange-red in autumn.

Flowers

Flat heads of small white flowers, from June to July.

Autumn colour

Yellow, orange and red, especially in the cultivar ‘Tor’.

Roots

Fibrous and fairly shallow; it moves easily.

Flowering: June–July · Plants: March–April and October–November · Pruning: March and July

Why grow it?

• White flower heads in June and July, when many spring shrubs have finished.
• Bees and butterflies find nectar and pollen on it.
• Lovely autumn colour in yellow, orange and red.
• Compact and easy: it stays low and needs little maintenance.
• Works in a border, in a group or as a low hedge.

Birchleaf spiraea: where does it grow best?

• Sun to partial shade; in sun it flowers best and gives its finest autumn colour.
• Ordinary garden soil: sand, loam or clay, acid to chalky.
• Normally moist soil; it tolerates a short dry spell but not prolonged waterlogging.
• Not fussy about wind, even in an open spot in the garden.
• Allow 80–100 cm per plant; 50–60 cm for a low hedge.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

0.8 m tall, 1 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Cranesbill (hardy geranium): Blue or purple flowers fill the space under the shrub and bloom at the same time.
• Sage (Salvia nemorosa): Purple flower spikes look lovely with the white flower heads.
• Heuchera: Coloured foliage at the base sets off the orange autumn tints.
• Ornamental grasses: Fine stems and plumes add movement to the border.
• Hydrangea: Flowers in the same period and likes the same partial shade.

Birchleaf spiraea: when and how to plant it?

Plant in March–April and October–November.

1. Plant in March–April or in October–November, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and mix in a little compost.
3. Set the shrub at the same depth as it stood in its pot and firm the soil lightly.
4. Keep 80–100 cm between plants, or 50–60 cm for a low hedge.
5. Water in well straight away, even if it is raining.
6. Spread a layer of compost or fine wood chips around the base.

Care

Water

Weekly in dry spells in the first year. After that rain is enough, except in long dry summers.

Feeding

In March, a handful of organic fertiliser or a spadeful of compost around the shrub.

Mulching

A layer of compost or bark in spring keeps the soil moist and suppresses weeds.

Spent flowers

Cut off the faded flower heads in July to keep the shrub tidy and compact.

Upkeep

Remove dead or damaged stems as soon as you see them, ideally in spring.

Tip: Give it a spot in full sun for the best autumn colour, and cut off the faded flower heads in July to keep it compact.

Birchleaf spiraea: when to prune it?

Pruning months: March and July.

When: Late February to March for shaping, and lightly after flowering in July.

How:

• In March, shorten all the stems by a third to a half, just above a bud.
• Remove dead, weak and crossing stems right at the base.
• Every few years, cut a few of the oldest stems to the ground to keep the shrub young.
• In July, cut off the faded flower heads with a short piece of shoot.

Caution: It flowers on new wood: prune in late winter or after flowering, never in May–June, or you will cut off the flower buds.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Softwood cuttings

In June–July: 8–10 cm cuttings from non-flowering shoots, lower leaves removed, in moist cutting compost under plastic. Roots form after 4–6 weeks.

Hardwood cuttings

In October–November: 20 cm lengths of firm, ripe wood pushed into open ground; they root during the following year.

Division

In spring or autumn, lift a rooted piece from the edge of the clump and replant it elsewhere.

Birchleaf spiraea: how does it get through the winter?

Hardy to −35 °C.

• Fully hardy, down to about −35 °C: in Belgium it never needs protection.
• Leave the bare stems until the March pruning; they give shelter to small insects.
• In a pot: stand it against a wall and wrap the pot in hessian so the roots do not freeze.

Diseases and pests

• Aphids: On young shoots in May–June, sometimes with sticky honeydew. Ladybirds usually clear them; otherwise rinse off with a strong jet of water.
• Powdery mildew: White powder on the leaves in dry summers. Water at the base, leave space between plants and cut out affected shoots.
• Bare centre: Old shrubs get bare at the base and flower less. Renew them by cutting the oldest stems to the ground.
• Poor flowering: Usually too much shade or pruning too late. Move it to a sunnier spot and prune in late winter.

Through the year

• March: Prune: shorten all stems by a third to a half. Give compost.
• April: Plant or transplant. Apply mulch.
• May: Watch for aphids. Water in prolonged drought.
• June: Flowering begins. Take softwood cuttings.
• July: Flowering. Cut off faded flower heads. Water in dry weather.
• August: Water in prolonged drought.
• October: Plant. Autumn colour begins.
• November: Plant. Take hardwood cuttings. Autumn colour and leaf fall.
• December: Dormant. Leave the bare stems.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The species name betulifolia means ‘with birch leaves’: the foliage really does resemble that of a birch.
• Spiraeas belong to the rose family, like apple, strawberry and rose.
• The name Spiraea comes from the Greek speira, ‘coil’ or ‘wreath’, probably referring to the pliable stems.