How far apart should I plant Woad?

About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–60 cm (12–24 in).

Does Woad need full sun?

Full sun: at least 6 hours of direct sun a day.

How much water does Woad need?

Low water. Drought tolerance is moderate and waterlogging tolerance none.

How cold-hardy is Woad?

It tolerates about -25 °C (-13 °F) once established, roughly USDA zone 5. As a biennial it is usually planted out after the last frost and flowers in its second year.

When does Woad flower?

About 43–57 weeks after planting, for 4–6 weeks.

Is Woad poisonous to cats and dogs?

For cats it is not well documented; for dogs not well documented; for people mildly toxic. Not used as food; mustard-family compounds may upset the stomach. No reliable pet data.

What grows well with Woad?

Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.

Woad Isatis tinctoria

Woad (Isatis tinctoria) is a biennial herb in the Brassicaceae family, native to Steppes of south-eastern Europe to central Asia. It grows 60 cm–1.2 m (24 in–3.9 ft) tall and 30–60 cm (12–24 in) wide, wants full sun and low water, and is hardy to about -25 °C (-13 °F). Space plants about 30 cm (12 in) apart.

Plan Woad in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.

Woad at a glance

Type	Biennial herb
Family	Brassicaceae
Mature height	60 cm–1.2 m (24 in–3.9 ft)
Mature spread	30–60 cm (12–24 in)
Spacing	30 cm (12 in) centre to centre
Sun	Full sun, at least 6 h of direct sun a day
Water	Low; drought tolerance moderate, waterlogging tolerance none
Soil pH	6–8
Cold hardiness	About -25 °C (-13 °F) once established (roughly USDA zone 5)
Heat stress	Likely above about 32 °C (90 °F)
Flowering	about 43–57 weeks after planting, for 4–6 weeks
Days to maturity	About 365 days from planting
Wind tolerance	Low
Pollinator value	Moderate
Edible	Not grown as food
Native to	Steppes of south-eastern Europe to central Asia
Common in gardens of	🇬🇧 United Kingdom, 🇩🇪 Germany, 🇫🇷 France, 🇮🇹 Italy, 🇨🇳 China, 🇺🇸 United States
Invasive in	western USA (Utah, Idaho, Oregon, California and other states): check local rules before planting

Is Woad toxic?

People: mildly toxic
Cats: not well documented
Dogs: not well documented
Parts: leaves, seeds

Not used as food; mustard-family compounds may upset the stomach. No reliable pet data.

If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.

Companion planting: what to grow with Woad

Good neighbours

good With Rhubarb: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Evidence D
good With Nasturtium: Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas. Evidence C

Questions about Woad

How far apart should I plant Woad?: About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–60 cm (12–24 in).
Does Woad need full sun?: Full sun: at least 6 hours of direct sun a day.
How much water does Woad need?: Low water. Drought tolerance is moderate and waterlogging tolerance none.
How cold-hardy is Woad?: It tolerates about -25 °C (-13 °F) once established, roughly USDA zone 5. As a biennial it is usually planted out after the last frost and flowers in its second year.
When does Woad flower?: About 43–57 weeks after planting, for 4–6 weeks.
Is Woad poisonous to cats and dogs?: For cats it is not well documented; for dogs not well documented; for people mildly toxic. Not used as food; mustard-family compounds may upset the stomach. No reliable pet data.
What grows well with Woad?: Traditional lore says rhubarb planted near brassicas helps against clubroot and pests; the evidence is weak and not confirmed by trials. Nasturtiums act as a trap crop for cabbage white butterflies and blackfly, drawing some pressure away from brassicas.

Sources and evidence

Evidence grade A (A: strong evidence).

Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
Natural Dyes: Sources, Tradition, Technology and Science (Cardon, 2007), Archetype Publications, London
CABI Invasive Species Compendium, CABI

Notes and assumptions

First-year leaves give the blue dye (indigotin) after fermenting; the second spring brings clouds of tiny yellow flowers and dangling black seed pods. Europe’s blue until Indian indigo replaced it in the 17th century; Toulouse grew rich on woad balls (cocagne). Remove seed heads to stop it spreading.

Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.

Related plants

Broccoli Brassica oleracea var. italica
Cauliflower Brassica oleracea var. botrytis
Cabbage Brassica oleracea var. capitata
Kale Brassica oleracea var. sabellica
Radish Raphanus sativus
Bok choy Brassica rapa subsp. chinensis
Brussels sprout Brassica oleracea var. gemmifera
Kohlrabi Brassica oleracea var. gongylodes