Photo: Jamain, CC BY-SA 3.0 · source

Perennial · Commelinaceae

Spiderwort

Tradescantia × andersoniana

In other languages: Eendagsbloem (Nederlands) · Éphémère de Virginie (Français)

Spiderwort is a group of garden hybrids of North American species, mainly Tradescantia virginiana. It forms clumps of narrow, grass-like leaves, above which clusters of three-petalled flowers open from June to September, in blue, violet, purple, pink or white, with a fluffy centre of hairy stamens. Each flower opens in the morning and fades the same day, but new ones follow for weeks. Gardeners value it because it is easy, flowers for a long time and grows well even in moist, heavy soil. Well-known varieties include ‘Osprey’ (white with blue stamens), ‘Concord Grape’ (purple, with blue-grey leaves) and ‘Sweet Kate’ (golden-yellow leaves with violet-blue flowers).

Caution: Mildly toxic. The sap can irritate the skin of people and pets. Wear gloves when cutting back and dividing, and keep an eye on cats and dogs that chew plants.

Updated on 10 October 2026

Light
Sun or partial shade
preferably some sun
Moisture
Normal to wet
must not dry out
Legal basis
Loam, clay or peat
acid to neutral
Hardiness
Fully hardy
down to -30 °C
Size
0.5 m
tall, 0.5 m wide
Flowering
June–September

Key facts
Pruning months	March and July
Height	0.5 m
Native to Belgium	No, planted
Good for bees, butterflies and birds	Yes, for bees
Poisonous to people and pets	Yes, take care with children and pets
Flowering	June–September

Identify

Spiderwort: how do you recognise it?

Habit: Loose clump 40–60 cm tall and about 50 cm wide, with upright to arching stems.
Leaves: Long, narrow and grass-like, slightly fleshy and channelled; when broken they release a slimy sap.
Flower: Three broad petals in a triangle, 2–4 cm across, in clusters at the stem tips. From June to September.
Colour: Blue, violet, purple, pink or white, with yellow anthers on hairy, often blue stamens.
Roots: Fleshy roots in a compact clump that slowly widens.

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

In your garden

Why grow it?

Flowers from June to September, with a second flush if you cut it back after the first.
Grows well in moist and heavy soil, even at the edge of a pond.
Bees collect pollen from the flowers.
Unusual flowers: three broad petals in a triangle around a fluffy centre.
Little work: it is hardy and seldom troubled by disease.

Spiderwort: where does it grow best?

Sun or part shade. In full sun only if the soil stays moist; on sunny days the flowers then close by mid-afternoon.
Humus-rich, moisture-retentive soil: loam, clay or peaty soil, acid to neutral.
Moderately moist to wet: it tolerates wet soil and does well at a pond edge. On dry sand it struggles.
Plant 40–50 cm apart, in groups of three or more.

Light: Sun and partial shade
Soil type: Loam, clay or peat
Acidity: Acid or neutral
Moisture: Normal or wet
Size: 0.5 m tall, 0.5 m wide
Hardiness: Hardy (to -30 °C)

Goes well with

Daylily: Also has flowers that last one day, and also likes moist soil.
Siberian iris: Similar narrow leaves and blue flowers in June, in the same moist soil.
Lady’s mantle: A soft yellow edging at the front, lovely next to blue and purple.
Hosta: Large leaves as a calm counterpoint in part shade.

Maintenance

Spiderwort: when and how to plant it?

Plant in March–May and September–October.

Plant from March to May or in September–October.
Dig a hole twice as wide as the root ball and mix in compost or leaf mould.
Set the plant at the same depth as it was in its pot and firm the soil.
Leave 40–50 cm between plants.
Give a full can of water straight away and keep the soil moist for the first few weeks.
Spread a layer of leaf mould around the base to hold in moisture.

Care

Water: Keep the soil moist and water generously in dry spells. Drought causes brown leaf tips and fewer flowers.
Feeding: Compost in spring and again after cutting back in July. Too much fertiliser gives lots of floppy leaves and few flowers.
Mulching: A layer of leaf mould in spring keeps the soil cool and moist.
Support: The foliage flops open after rain or after the first flush. A low plant support put in place in May keeps the clump tidy.
Dividing: Every 3–4 years in spring, when the clump goes bare in the middle and flowers less.

Tip: After the first flowering, cut the plant right back to the ground and give water and compost: a few weeks later it looks fresh again and flowers once more.

Spiderwort: when to prune it?

Pruning months: March and July.

When: Cut the whole plant back to just above the ground after the first flush of flowers, usually in July. In March, clear away the old, dead leaves.

How:

Cut all stems and leaves back to 5–10 cm above the ground.
Then water and add a spadeful of compost: within a few weeks fresh leaves appear, followed by a second flowering.
In between, snip off faded clusters if you do not want seedlings.
In March, clear away last year’s dead foliage.

Caution: Wear gloves: the slimy sap can irritate the skin.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division: In March–April or September: lift the clump and split it into pieces, each with a few shoots and roots. Replant straight away and water.
Self-sown seedlings: It often self-seeds. Seedlings may differ in colour from the parent; move them to a good spot in spring.

Spiderwort: how does it get through the winter?

Hardy to −30 °C.

Fully hardy, to about −30 °C. The top growth dies back and the plant shoots again in spring.
No protection needed; a layer of leaf mould over the clump is enough.
In a pot: place it against a wall and make sure the pot does not freeze into a puddle.

Diseases and pests

Untidy, flopping foliage: After the first flowering or rain the clump falls open. Cut it back to the ground: it regrows fresh and compact.
Slugs: They eat young shoots in spring. Pick them off in the evening, especially in damp weather.
Few flowers: Too much shade, soil too dry or too much fertiliser. Water, feed less and divide old clumps.
Seedlings: Young plants in other colours appear among the parent. Snip off faded clusters or pull out the seedlings.

Through the year

March: Clear old leaves. Plant or divide.
April: Plant. Give compost and mulch.
May: Plant. Put in a low support. Watch for slugs.
June: Flowering starts. Water in dry spells.
July: After the first flush, cut back to the ground. Water and give compost.
August: Fresh leaves and new buds. Water in dry spells.
September: Second flowering. Plant or divide.
October: Plant. The foliage starts to die back.

Use

Edible and useful

Not edible. The sap in the leaves and stems of tradescantia can irritate the skin: in sensitive people it causes itching and redness, and dogs and cats that often brush through or against the plant or chew it sometimes get red, itchy skin, mostly on the belly, paws and muzzle, or an upset mouth and stomach. Hang or place it out of reach of pets, wear gloves when pruning, taking cuttings and repotting, and wash your hands afterwards. In the garden, do not let dogs lie in a bed of spiderwort. Put surplus stems of small-leaf spiderwort in the green-waste bin or on the compost, never in the wild. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees: Nectar and pollen for honeybees and wild bees.

You and this species

Did you know?

Each flower lives for only one day. The petals do not drop but shrivel into a kind of jelly.
The name honours John Tradescant and his son, 17th-century English gardeners and plant collectors. Tradescantia virginiana came from Virginia to England in their time.
The hairs on the stamens are made of chains of single cells. Under a microscope you can see the cytoplasm streaming inside them, and scientists use them to measure the effects of radiation.

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