Gooseneck loosestrife

Gooseneck loosestrife: how do you recognise it?

Habit

Upright, broad clump 80–90 cm tall and up to 90 cm wide, spreading by rhizomes.

Leaves

Lance-shaped and pointed, 7–15 cm long, scattered along the stem; often red to orange in autumn.

Flower

Dense spikes 10–20 cm long with dozens of small, star-shaped flowers; the tip curves gracefully.

Colour

Pure white, above fresh green foliage.

Roots

Fleshy rhizomes that spread quickly, especially in moist, loose soil.

Flowering: July–September · Plants: March–May and September–October · Pruning: March and November

Why grow it?

• Flowers late, from July to September, when many perennials have finished.
• The curved white spikes are distinctive and bring movement to the border.
• An excellent cut flower that lasts a long time in the vase.
• Bees and other insects visit the many small flowers.
• The foliage often turns red to orange in autumn before dying back.
• Thrives in moist soil and partial shade, where few late bloomers do well.

Gooseneck loosestrife: where does it grow best?

• Sun to partial shade. In full sun the soil must stay moist.
• Loam, clay or peaty soil, acid to neutral and preferably rich in humus.
• Normal to wet soil: it copes poorly with prolonged drought.
• Plant about 60 cm apart, three plants per m², and give it room or a root barrier.

Light

Sun and partial shade

Soil type

Loam, clay or peat

Acidity

Acid or neutral

Moisture

Normal or wet

Size

0.9 m tall, 0.9 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Japanese anemone: Flowers at the same time, in pink or white, and likes the same partial shade.
• Purple loosestrife: Purple spikes beside the white ones, in the same moist soil.
• Joe Pye weed: Tall pink flower heads behind the loosestrife, also popular with insects.
• Hosta: Large leaves at the front in partial shade.
• Miscanthus: Fine, airy grass leaves that contrast nicely with the dense spikes.

Gooseneck loosestrife: when and how to plant it?

Plant in March–May and September–October.

1. Plant from March to May or in September–October, when the soil is not frozen or waterlogged.
2. Dig a generous hole and mix in a few spadefuls of compost.
3. In moist soil it is best to set a root barrier about 30 cm deep around the hole straight away, or to plant it in a large tub.
4. Set the plant at the same depth as it was in the pot and firm the soil well.
5. Water in thoroughly and keep the soil moist for the first season.
6. Mulch with compost or leaf mould to hold in moisture.

Care

Water

Keep the soil moist. In dry summers water deeply every week, or the leaves curl and it flowers less.

Feeding

A little compost in April. Too much fertiliser gives floppy stems and even more runners.

Edging

Every spring, slice off the runners around the clump with a sharp spade.

Support

Usually stands firm. In shade or very rich soil a plant ring helps.

Cutting flowers

Cut the spikes when the lowest flowers are open: that is when they last longest in the vase.

Rejuvenating

Divide every three to four years, especially when the centre of the clump becomes bare.

Tip: Give it room or a root barrier and cut spikes regularly for the vase: the white goosenecks look wonderful in a bouquet.

Gooseneck loosestrife: when to prune it?

Pruning months: March and November.

When: Cut the stems down in November, after the autumn colour, or leave them until March.

How:

• Cut all stems back to just above the ground.
• If you wait until March, cut before the new shoots appear.
• Combine the March clear-up with edging the clump.

Caution: Pruning does not slow its spread: that happens underground. Edging with a spade or a root barrier does work.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September–October, lift a clump and split it with a spade into pieces with a few buds each. Replant straight away and water.

Rhizomes

Pieces of rhizome with a bud, found while edging, root easily in a pot of moist, compost-rich soil.

Gooseneck loosestrife: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, to about −30 °C: no protection is needed in Belgium.
• After the autumn colour it dies back above ground; in spring it regrows from the rhizomes.
• In a tub: stand it in a sheltered spot against a wall and do not let the compost dry out.

Diseases and pests

• Spreading: It takes over the border with runners. Edge it every spring or install a root barrier.
• Slugs: They eat the young shoots in April–May. Pick them off in the evening or put a ring of coarse sand around the clump.
• Brown leaf edges: A sign of drought, especially in full sun. Water thoroughly and mulch.
• Few flowers: Too much shade or too dry a spot. Move it to a lighter, moist position.
• Aphids: Sometimes on young shoots and flower spikes. Ladybirds usually deal with them; otherwise hose them off with water.

Through the year

• March: Cut down old stems. Edge the clump. Add compost.
• April: Plant or divide. Watch out for slugs.
• May: Plant. Water in dry spells.
• June: Buds are forming. Keep the soil moist.
• July: Flowering begins. Cut spikes for the vase.
• August: Full bloom. Water in dry spells.
• September: Last flowers. Plant or divide.
• October: Autumn colour. Plant.
• November: Cut down the stems. Rest.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The name clethroides means ‘resembling Clethra’: the white flower spikes recall those of sweet pepperbush, a North American shrub.
• The spikes all bend the same way, like a group of geese with outstretched necks, which explains the name gooseneck loosestrife.
• Loosestrifes belong to the primrose family, like primulas, although you would hardly guess it from the flowers.