Brassica oleracea (Acephala Group) 'Purple Tree'

RHS Plant Profile

tree kale 'Purple Tree'

Annual Biennial

An annual, hardy kale up to 2m in height, with a long stem and bushy head of green to dark purple leaves, turning more purple as temperatures drop. May need to be staked in exposed conditions. Easily propagated, long-lived (possibly up to 20 years and beyond) and good resistance to cabbage white caterpillars and whitefly. Harvest from September through until late February. Makes a striking architectural vegetable for any garden

Position

Full sun

Soil Types

Loam, Sand

Size

Time to Maturity: 1 year

Growing Conditions

Loam Sand

Moisture: Moist but well–drained or Well–drained
pH: Alkaline or Neutral

Position

Full sun

Aspect: South–facing or West–facing
Exposure: Exposed or Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H4

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Brassicaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Bushy, Clump forming
Genus: Brassicas can be annual, biennial or perennial plants, most are upright with alternate, often glaucous leaves, long taproots and clusters of cross-shaped, yellow or white flowers. The genus includes a number of species bred to produce food crops, such as cabbages, turnips, mustards and oilseed rape, as well as others grown for their ornamental value
Name Status: Unresolved

How to Grow

Cultivation

Prefers well drained, loamy, alkaline soil. Water regularly in dry periods and add plenty of organic matter before planting. Harvest once they reach the size you want and formed a firm head. See kale cultivation for further advice

Propagation

Propagate by seed. See sowing vegetable seeds

Suggested planting locations and garden types

Architectural
City and courtyard gardens
Cottage and informal garden
Flower borders and beds
Wall side borders

Pruning

No pruning required

Pests

May be susceptible to cabbage caterpillars, cabbage whitefly, aphids, flea beetles and slugs and snails

Diseases

May be susceptible to black rot, downy mildew, foot and root rot, grey mould, leaf spot and white blister