Dropwort

Dropwort: how do you recognise it?

Habit

Low leaf rosette 15–20 cm high with upright flower stems to 60 cm; about 45 cm across.

Leaves

Finely divided, with many small, deeply cut leaflets; dark green and glossy, fern-like.

Flower

Loose, branched sprays of small creamy white flowers, usually with six petals; the buds are often pink. Flowers in June and July.

Scent

Light and sweet, especially on warm days.

Roots

Thin roots carrying small, elongated tubers, which give it its Dutch name, knolspirea.

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

Why grow it?

• Fern-like leaf rosettes that stay elegant from spring to autumn, even when it is not in flower.
• Creamy white, lightly scented sprays in June and July, with pink buds.
• Bees, hoverflies and beetles come for the pollen.
• Drought tolerant: unlike most Filipendula species, it does well in dry, chalky soil.
• Suits a wildflower meadow, a rock garden, a gravel garden or the front of a sunny border.
• Native and very hardy.

Dropwort: where does it grow best?

• Full sun; in shade it flowers poorly.
• Free-draining sandy or loamy soil, neutral to chalky. On acid sand you can mix in some lime or limestone grit.
• Dry to moderately moist; it dislikes wet soil in winter.
• Plant 30–40 cm apart, or in groups of three to five in a meadow.

Light

Sun

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry or normal

Size

0.6 m tall, 0.45 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Knapweed: Purple-pink flower heads in the same poor, sunny soil, a favourite of butterflies.
• Wild marjoram: Scented leaves and pink flowers for bees and butterflies, also on dry, chalky soil.
• Lady’s bedstraw: Small yellow, honey-scented sprays that contrast nicely with the cream.
• Salad burnet: More finely divided leaves and small reddish flower heads, ideal in a dry meadow.
• Harebell: Delicate blue bells in the same poor, sunny soil.

Dropwort: 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, on heavy ground, mix in coarse sand or gravel so water drains away well.
3. Dig a hole a little larger than the pot and plant at the same depth, with the heart of the rosette at soil level.
4. Leave 30–40 cm between plants.
5. Water in and water during dry spells for the first few weeks; after that it is rarely needed.
6. Mulch with gravel or grit rather than compost: it keeps the base dry.

Care

Water

Only in the first year during long dry spells; after that it looks after itself.

Feeding

Not needed: in poor soil it stays compact and flowers better.

Deadheading

Cut off the flower stems in August if you do not want seedlings, or leave a few for seed.

Support

Not needed in poor soil; on rich ground the flower stems may flop.

Dividing

Every 4–5 years, when the centre of the clump becomes bare.

Tip: Give it a lean, free-draining spot and do not feed: it then stays compact and flowers best. Wet soil in winter is its worst enemy.

Dropwort: when to prune it?

Pruning months: March and August.

When: Cut off the faded flower stems in August and clear the old, withered leaves in March.

How:

• After flowering, cut the flower stems just above the leaf rosette.
• If you want it to self-seed, leave a few sprays until the seed has turned brown.
• In March, gently pull dead leaves out of the rosette before the new leaves appear.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or in September, lift the clump and split it into pieces, each with a few tubers and a bud. Replant straight away and water in.

Seed

Sow fresh seed in autumn in a pot of gritty seed compost and leave it outside over winter: the cold helps germination. Prick out the seedlings in spring.

Dropwort: how does it get through the winter?

Hardy to −35 °C.

• Very hardy, to about −35 °C: no protection needed.
• Wet feet in winter are more dangerous than frost: make sure the soil drains well.
• Simply leave the leaf rosettes in autumn: they protect the heart of the plant.
• In a pot: use one with a good drainage hole and stand it against a wall in winter, out of the rain.

Diseases and pests

• Root rot: The plant dwindles and rots in heavy, wet soil, especially in winter. Move it to a drier spot or mix gravel into the soil.
• Powdery mildew: White powder on the leaves in dry summers. Usually harmless; cut off affected leaves and give plants space.
• Flopping stems: On soil that is too rich, the stems become weak. Do not feed and choose a leaner spot.
• Slugs: Young rosettes are eaten in spring. Pick them off in the evening or lay a rough layer of gravel around the plant.
• Few flowers: Too much shade. Move it to a sunny spot.

Through the year

• March: Pull old leaves out of the rosette. Plant or divide.
• April: Plant. New leaves appear.
• May: Flower stems appear. Watch out for slugs.
• June: Creamy white sprays in flower.
• July: Flowering. Bees and hoverflies on the flowers.
• August: Cut off faded stems, or leave a few for seed.
• September: Plant or divide. Collect seed.
• October: Plant. Sow fresh seed in a pot and stand it outside.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The Dutch name knolspirea, tuber spiraea, refers to the small tubers on its roots.
• The genus name Filipendula comes from the Latin filum, thread, and pendulus, hanging: the tubers hang from the roots as if on threads.
• You can tell dropwort by its flowers, which usually have six petals; meadowsweet has five.