sea kale

Photo: Siim at et.wikipedia — CC BY-SA 2.5 · source

Survives zone 4 through 8

Harvest calendar

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

Sea kale — blanched shoots, mild and nutty.

Hardiness

Zone 4–8

Habit

Herb

Edible part

Shoot, Seed

Ripens

Spring (blanched shoots)

Mature size

Herbaceous perennial ~60 cm

Light

Full sun

Soil pH

6.5–7.5

Environment

Coastal

Native range

The coasts of the Baltic, the North Sea, the Atlantic and the Black Sea — a true shingle-beach plant, growing above the strand line in bare pebbles with salt spray and no fresh water to speak of.

Status

Both wild and cultivated

Years to fruit

2–3 yrs

Growth speed

Slow to establish — three years to a first proper cut

Spacing

60 cm (24 in) apart — about 2.8 per m² (2.6 per 10 sq ft)

Leaf shape

Large, thick, wavy-edged and glaucous blue-grey with a waxy bloom, 20–35 cm, cabbage-like in texture — the wax is the plant's defence against salt spray, and it is handsome enough that sea kale is grown as an ornamental on its own account.

Root system

A deep, thick, brittle taproot with fleshy laterals reaching well down into shingle for fresh water. Broken pieces regrow readily — the basis of propagation by thongs — and mature plants transplant badly.

Fruit description

Not a food crop: the flowers give round, corky, one-seeded pods about 1 cm that float, which is how the plant colonises new beaches. The seed inside is edible but not eaten in practice.

Propagation

Root cuttings — 'thongs', pencil-thick pieces of lateral root cut flat at the top and slanted at the bottom, taken in autumn and planted the following spring. Seed works but the corky pod must be removed or it will not germinate.

Pollination

Self-fertile

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.