How to Grow Nine Star Perennial Broccolis USA | Planting & Establishment

Soil & Growing Conditions

Water: moist but well-drained (RHS)

Soil pH range

6.5 7.5

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

Stage	BBCH	Notes
Sowing/planting	0	Propagate by seed; plant 90cm apart given the eventual size of this large, long-lived perennial (RHS).
Establishment	3	Time to first maturity about 1 year; full sun, moist well-drained soil, sheltered position (RHS).
Perennial cropping	3	Once established, produces one large central head plus smaller spears each spring, continuing for three to four years before decline (RHS).
Harvest	8	Cut heads once well formed and tight, before flowers open; remove unused heads before seeding to keep future years productive (RHS).

Quick Facts

Factor	Value
Soil pH	6.5 - 7.5
Sunlight	6-6 hours direct sun
Soil texture	chalk, clay or loam (RHS)
Drainage	well-drained
Lifecycle	herbaceous perennial, cropping for 3-4 years before decline
Edible parts	flower heads

At a Glance

Harvest & Storage

When to pick: Harvest when heads are well formed and tight, before flowers begin to open. Remove any unused heads before they go to seed, to improve future cropping across the plant's 3-4 year lifespan (RHS).

Diseases

Club root

high_where_present

Plasmodiophora brassicae

RHS names this directly: "may develop ... club root (particularly in acidic soil)."

Blackleg

moderate

Pectobacterium atrosepticum

RHS names this directly: "may develop black leg."

Pests

Mealy cabbage aphid

moderate

Brevicoryne brassicae

RHS names this directly: "susceptible to ... mealy cabbage aphid."

Cabbage root fly (US: cabbage maggot)

moderate

Delia radicum

RHS names this directly: "susceptible to cabbage root fly."

Cabbage caterpillars

high

Pieris brassicae; Pieris rapae; Pieris napi; Mamestra brassicae; Plutella xylostella

RHS names this directly: "susceptible to ... cabbage caterpillars."

Nine Star Perennial Broccoli, a Genuine Multi-Year Cropper

A large, long-lived perennial

RHS: a short-lived herbaceous perennial that crops for three or four years, reaching 0.5-1m in height and spread -- genuinely needs generous 90cm spacing.

Broad, leafy foliage most of the year

Unlike annual broccoli, this plant spends most of the year as a leafy perennial, only producing its namesake heads each spring.

Genuinely frost-hardy

RHS rates it H4, hardy through most of the UK down to -10C.

A dense rosette of leaves

Grows best in full sun on moist but well-drained chalk, clay or loam soil, at a neutral or alkaline pH, in a sheltered spot.

Smaller spears alongside the main head

RHS: each spring produces one large, yellowish, cauliflower-like central head surrounded by several smaller broccoli-like spears.

References

1. Royal Horticultural Society - Brassica oleracea 'Nine Star Perennial'

   Herbaceous perennial producing crops for three or four years before plants begin to decline -- a heritage variety, distinct from annual broccoli and cauliflower. Hardiness H4 (hardy through most of the UK, -10 to -5C). Full sun; south or west-facing aspect; sheltered exposure. Soil: chalk, clay or loam; moist but well-drained; neutral or alkaline pH. Height and spread 0.5-1m; plant 90cm apart, large plants needing substantial space. Time to maturity 1 year (to first harvest; the plant itself then continues cropping for several years). Produces one large central head each year surrounded by several smaller heads. Harvest when heads are well formed and tight, before flowers begin to open; remove unused heads before they go to seed, to improve cropping. PESTS: susceptible to cabbage root fly, cabbage caterpillars, cabbage whitefly, mealy cabbage aphid. DISEASES: may develop black leg, downy mildews, powdery mildews, and club root (particularly in acidic soil) -- named directly for this variety, not inferred. Avoid growing brassicas in the same soil year after year to prevent soil-borne disease accumulation.

1 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.