Tree Collard (Brassica oleracea var. acephala)
1 sources cited · Verified
The short answer
- Plant
- Early March to late May
- Site
- 6+ hours of sun, soil pH 5.5–7
- Biggest risk
- Club root
In the UK, tree collards go in the ground early March to late May.
Tree collards (Brassica oleracea var. acephala) — perennial or partial perennial, living several years.
Timing is the decision that matters most in the UK: there are 4 separate regional sowing windows, ranging from early March in Southern England to early March in Scotland.
Core growing advice on this page is checked against named horticultural and university-extension sources — see References.
Regional Planting Calendar
| Region | Sow |
|---|---|
| Southern England | early March to late May |
| Midlands | early March to late May |
| Northern England | early March to late May |
| Scotland | early March to late May |
Southern England - detail & sources
Gardening Know How gives spring as the propagation window (stem cuttings, not seed) with no UK-specific dates, so a spring window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Midlands - detail & sources
Gardening Know How gives spring as the propagation window (stem cuttings, not seed) with no UK-specific dates, so a spring window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Northern England - detail & sources
Gardening Know How gives spring as the propagation window (stem cuttings, not seed) with no UK-specific dates, so a spring window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Scotland - detail & sources
Gardening Know How gives spring as the propagation window (stem cuttings, not seed) with no UK-specific dates, so a spring window is applied across all four sub-regions rather than inventing a north/south gradient the source does not support.
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 5.5 - 7 |
| Sunlight | 6-6 hours direct sun |
| Soil texture | well-draining, nutrient-rich; tolerates heavy clay (Gardening Know How) |
| Drainage | well-drained |
| Lifecycle | perennial or partial perennial, living several years |
| Edible parts | leaves |
At a Glance
Soil & Growing Conditions
Water: moderate, in rich fertile soil (Gardening Know How)
Soil pH range
Span reflects genuine variation between the cited authorities, not a single agreed figure.
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Propagation | 0 | Take 12-inch stem cuttings in spring, plant vertically with a third above the soil; rooting takes about six weeks (Gardening Know How). |
| Establishment | 3 | Full sun preferred, though partial shade produces more tender leaves; well-draining, nutrient-rich soil, moderate water (Gardening Know How). |
| Perennial growth | 3 | Develops a tall, woody stem up to 12ft over multiple years; prune every few months to the first leaf axil to prevent it becoming tall, spindly and leggy (Gardening Know How). |
| Leaf harvest | 8 | Harvest young leaves for sweetness year-round in mild climates, never taking more than a third of the foliage at once (Gardening Know How). |
Harvest & Storage
When to pick: Harvest young leaves for their sweetness -- all foliage is edible, but older leaves need cooking. Never take more than a third of a plant's foliage at once. Leaves keep several days refrigerated (Gardening Know How).
Diseases
Pests
Tree Collard, Cutting to Woody Perennial
References
-
Hardiness USDA zones 5-11 (varies by variety); most varieties tolerate down to 30F (-1C), some down to 14F (-10C), some withstand triple-digit summer heat; thrives in high humidity but adapts to arid zones. Full sun preferred, but moderately shaded areas produce more tender, flavourful leaves. Soil: well-draining, nutrient-rich; tolerates heavy clay and acidic soils; lime application improves leaf taste. Height up to 12ft (3.66m), spread up to 5ft (1.5m) depending on variety. Planted in spring; propagated from stem cuttings, NOT seed -- 12-inch cuttings planted vertically with one third above soil, rooting in about six weeks. Perennial or partial perennial, living several years; up to 20 years in mild climates, several years with protection in colder regions. Moderate water needs in rich soil; little supplemental feeding needed in fertile soil, manure side-dressing for poor soils, annual calcium supplement (oyster or eggshell powder) recommended. Harvest young leaves for sweetness (all foliage edible), never taking more than a third of the foliage at once; young leaves eaten raw, older leaves cooked; keeps several days refrigerated. PESTS: cabbage looper larvae (hand-remove or apply Bacillus thuringiensis), mice and rabbits feeding on lower leaves. DISEASES: root rot possible in heavy soils with poor drainage. Left unpruned, becomes tall, spindly and leggy with few leaves -- prune every few months to the first leaf axil for bushier growth. Container-grown plants should be repotted yearly or biennially and staked.
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.
Frequently Asked Questions
When should I sow tree collards in the UK?
In Southern England, from early March. In Scotland, wait until early March. Treat these as a guide rather than a fixed date — the governing rule is to sow only once frost risk has passed and temperatures are reliably warm enough.
When do I sow tree collards?
Sow early March to late May.
What soil pH do tree collards need?
A pH of about 5.5–7. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect tree collards?
Our data links 1 disease and 1 pest to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
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Last verified 2026-08-29
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.