False spiraea

False spiraea: how do you recognise it?

Habit

Upright clump 50–80 cm tall depending on the variety, and about 50 cm wide.

Leaves

Finely cut and fern-like, glossy green; often reddish or bronze as they unfurl.

Flowers

Feathery plumes of hundreds of tiny flowers in white, pink, red or lilac; June to August.

Fruit

Dry, brown seed plumes that remain through winter.

Roots

A sturdy, woody rootstock with many fine roots just below the surface.

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

Why grow it?

• Colourful summer flowers in partial shade and shade, from June to August.
• The fern-like leaves look good from bud-burst to autumn, bronze in some varieties.
• A good cut flower; the plumes are lovely dried as well.
• The brown plumes stand through winter and look superb covered in frost.
• Very hardy and seldom troubled by disease, as long as the soil stays moist.

False spiraea: where does it grow best?

• Partial or light shade; full sun only if the soil always stays moist.
• Humus-rich loam, clay or peaty soil, acid to neutral; it is less happy on chalk.
• Soil that never dries out: moist to damp, even at the edge of a pond.
• Space 40–50 cm apart; it looks best in groups of three or more.

Light

Partial shade and shade

Soil type

Loam, clay or peat

Acidity

Acid or neutral

Moisture

Normal or wet

Size

0.8 m tall, 0.5 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Hosta: Big leaves as a calm backdrop for the airy plumes.
• Ferns: Fine green in the same moist shade.
• Siberian iris: Narrow, upright leaves and blue flowers in May–June, before the astilbe flowers.
• Lady’s mantle: A soft, lime-green edging at the front of the border.
• Smooth hydrangea: White flower heads above the pink and red plumes.

False spiraea: when and how to plant it?

Plant in March–April and September–October.

1. Plant in March–April or September–October.
2. Dig a generous hole and mix in plenty of compost or leaf mould.
3. Set the plant with its buds 2–3 cm below the soil surface.
4. Space plants 40–50 cm apart.
5. Water well straight away and keep the soil moist for the first few months.
6. Spread a layer of leaf mould or wood chips around the plants to stop them drying out.

Care

Watering

Regularly, especially in dry summers: drying out is the biggest danger. Water generously, preferably in the morning.

Feeding

In March–April, compost or an organic fertiliser; it is quite a hungry plant.

Mulching

A layer of compost or leaf mould every spring holds moisture and feeds the plant.

Cutting

Cut plumes for the vase when they are half open; for drying, when they are fully open.

Dividing

Every three to four years, when it flowers less in the centre (see propagation).

Tip: Make sure the soil never dries out: a thick mulch of leaf mould in spring works wonders. Leave the brown plumes in winter and only cut them off in March.

False spiraea: when to prune it?

Pruning months: March.

When: In March, before the new shoots appear. Leave the plumes standing over winter.

How:

• Leave the brown plumes and old leaves all winter: they look good and protect the buds.
• In March, cut all the old stems and leaves off just above the ground.
• Cut carefully around the red buds already visible at the base.
• After flowering there is nothing to do; cutting back does not give a second flush.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September–October, every three to four years. Cut the clump with a spade or knife into pieces, each with a few buds and roots, and replant them straight away.

Seed

Hardly worthwhile: these are hybrids and seedlings do not resemble the parent.

False spiraea: how does it get through the winter?

Hardy to −35 °C.

• Very hardy, to about −35 °C: no protection is needed in Belgium.
• It dies back; the dry plumes stay as winter decoration.
• In a pot: stand the pot in a sheltered place and do not let it dry out completely in winter.

Diseases and pests

• Drought: Brown, shrivelled leaf edges and dried-up plumes. Water generously, mulch and if necessary move it to a shadier, moister spot.
• Slugs: They eat the young shoots in spring. Pick them off in the evening.
• Vine weevil: The grubs eat the roots; the plant wilts and comes loose. Apply nematodes in spring or late summer.
• Fewer flowers: An old clump flowers less, especially in the middle. Divide it and give compost.

Through the year

• March: Cut off old stems and plumes. Give compost or fertiliser.
• April: Plant or divide. Apply mulch.
• May: The leaves unfurl. Water in dry spells.
• June: Flowering begins. Keep the soil moist.
• July: Full bloom. Cut plumes for the vase or for drying.
• August: Last flowers. Water in dry spells.
• September: Plant or divide.
• October: Plant. Leave the plumes standing.
• December: The brown plumes decorate the winter garden.

Did you know?

• The name arendsii honours the German nurseryman Georg Arends, who raised many of these hybrids at Ronsdorf near Wuppertal.
• Despite the name false spiraea, it is not related to spiraea: spiraea belongs to the rose family, astilbe to the saxifrage family.
• Dried plumes keep their shape and much of their colour in a dried arrangement for a long time.