Woad
Isatis tinctoria
also called dyer’s woad
Undemanding in poor, dry ground, though it carries the brassica family's weakness for club root.
Spacing & sowing
- Plant spacing
- 11.8 in
- In-row spacing
- 11.8 in
- Between rows
- 15.7 in
- Square-foot density
- Not suited to SFG
Growing
- Type
- Flower · Perennial
- Botanical family
- Mixed / other
- Sunlight
- Full sun — shade is not worth attempting.
- Watering
- Once established it rides out dry weather unwatered.
- Feeding
- It asks for no feeding at all.
- Frost tolerant
- Yes
- Flowering
- April
Through the year
- Mar–Apr Spring Growth
- Apr–Jul Flowering
- Jul–Oct Growing
- Oct–Dec Leaf Fall
- Jan–Mar Leaf Fall
Companions
Weld, Madder, Cornflowers, Meadow grasses
Pests & problems
- Flea beetle Tiny jumping beetles that pepper seedling leaves with shot-holes, worst on brassicas and rocket in dry spells. Keep seedlings growing fast with steady water and cover with fine insect mesh.
- Slugs & snails Slugs while the plants are still small
- Clubroot Club root, so keep it off ground that has grown brassicas
Garden allies
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Beneficial nematodes Steinernema & Heterorhabditis spp.Hunts Slugs & snails
Microscopic worms watered onto damp soil that hunt down soil-dwelling grubs and release a bacterium that kills them within days. Timing is the whole thing: warm, damp soil and a small target grub, which means late summer for most of what they are used against.
- Big-eyed bug Geocoris spp.Hunts Flea beetle
A stubby 3 mm bug with enormous wrap-around eyes, working the soil surface and the low foliage for aphids, mites, thrips and insect eggs. It is the main natural check on chinch bugs in a lawn and it is killed outright by insecticide.
- Centipedes ChilopodaHunts Slugs & snails
Flat, fast, one pair of legs to a segment — and a predator, unlike the slow round millipede it is constantly confused with. It hunts slugs, cutworms, springtails and woodlice by night under mulch and stones. Learn the difference and leave this one alone.
- Damsel bug NabidaeHunts Flea beetle
A slender, mantis-armed bug that grabs aphids, small caterpillars, and thrips in low crops and meadowy edges. Leave a strip of unmown grasses and flowers for it to overwinter in.
- Frogs & toads AnuraHunts Slugs & snails
A resident toad works the beds every night for slugs, cutworms, and weevils. Recruit them with water — even a sunken basin pond — plus damp shade and an upturned-pot toad house; skip the slug pellets that poison their prey.
- Garden birds PasseriformesHunts Slugs & snails
Both things are true: birds strip your currants and a brood of blue tits takes several thousand caterpillars out of one fruit tree in a fortnight. Net what you must and welcome them everywhere else — a nest box near the apples is worth more than a spray.
- Ground beetle CarabidaeHunts Slugs & snails
Fast, glossy night hunters that patrol the soil surface for slugs, cutworms, and root-fly larvae. Give them daytime cover — thick perennial edges, stepping stones, a log — and skip the tillage that wrecks their burrows.
- Hedgehog Erinaceus europaeusHunts Slugs & snails
A European animal, and worth saying so plainly: there are no hedgehogs in North America, and the ally that does the same night shift here is the toad, the opossum or the ground beetle. Where they do occur, cut a gap in the fence and skip the pellets.
- Rove beetle StaphylinidaeHunts Slugs & snails
Slim, quick beetles with short wing cases that hunt in soil and litter, taking root-fly eggs and larvae, fungus-gnat larvae, and mites. Mulch and undisturbed ground keep them resident year-round.
- Salamanders & newts CaudataHunts Slugs & snails
Damp-loving hunters of slugs, worms, woodlice and beetle larvae that spend the day under a log or a stone and work the beds at night. Companions to the toads: they want the same damp shade, the same log pile, and the same absence of slug pellets.
- Snakes & lizards Colubridae & PhrynosomatidaeHunts Slugs & snails
A garter snake works the beds for slugs and voles and a fence lizard clears grasshoppers off a sunny wall. Almost every snake a gardener meets is harmless and useful; give them a log pile, a warm flat stone and a bit of cover and they stay.
- Spiders AraneaeHunts Flea beetle
Webs, ambushes, and night patrols make spiders the garden’s steadiest generalist predators, taking whatever flies or crawls past. Mulch, ground cover, and undisturbed corners keep the population dense.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com