How to Grow Wonderberries UK | Regional Planting Calendar

Wonderberry (Solanum retroflexum)

A wonderberry plant with a white flower and hairy leaves — “Solanum retroflexum 1DS-II 1-2313” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons

2 sources cited · Verified

The short answer

Plant
Early March to late March
Site
6+ hours of sun, soil pH 6–7.5

In the UK, wonderberries go in the ground early March to late March.

Wonderberries (Solanum retroflexum) — Grown as an annual outside the tropics.

Timing is the decision that matters most in the UK: sowing early March, and that same window applies across all 4 regions covered here.

Core growing advice on this page is checked against named horticultural sources — see References.

Regional Planting Calendar

Region Sow
Southern England derived early March to late March
Midlands derived early March to late March
Northern England derived early March to late March
Scotland derived early March to late March

Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.

Southern England - detail & sources

Neither source addresses UK growing directly (PFAF and University of Illinois Extension are both US-facing). Both agree it is frost-tender and grown like a tomato -- sown under cover in spring, planted out only after frost danger passes -- so this indoor-sowing window (March) is derived from that shared fact, applied as one UK-wide window across all four sub-regions, matching the tomato-like treatment pattern used for other frost-tender Solanum crops in this catalogue.

Midlands - detail & sources

Neither source addresses UK growing directly (PFAF and University of Illinois Extension are both US-facing). Both agree it is frost-tender and grown like a tomato -- sown under cover in spring, planted out only after frost danger passes -- so this indoor-sowing window (March) is derived from that shared fact, applied as one UK-wide window across all four sub-regions, matching the tomato-like treatment pattern used for other frost-tender Solanum crops in this catalogue.

Northern England - detail & sources

Neither source addresses UK growing directly (PFAF and University of Illinois Extension are both US-facing). Both agree it is frost-tender and grown like a tomato -- sown under cover in spring, planted out only after frost danger passes -- so this indoor-sowing window (March) is derived from that shared fact, applied as one UK-wide window across all four sub-regions, matching the tomato-like treatment pattern used for other frost-tender Solanum crops in this catalogue.

Scotland - detail & sources

Neither source addresses UK growing directly (PFAF and University of Illinois Extension are both US-facing). Both agree it is frost-tender and grown like a tomato -- sown under cover in spring, planted out only after frost danger passes -- so this indoor-sowing window (March) is derived from that shared fact, applied as one UK-wide window across all four sub-regions, matching the tomato-like treatment pattern used for other frost-tender Solanum crops in this catalogue.

Quick Facts

A wonderberry plant with a white flower and hairy leaves — “Solanum retroflexum 1DS-II 1-2313” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Solanum retroflexum 1DS-II 1-2313” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.
Factor Value
Soil pH 6 - 7.5
Sunlight 6-8 hours direct sun
Soil texture Light (sandy), medium (loamy) or heavy (clay) (PFAF)
Drainage Fertile, well-drained preferred (PFAF)
Lifecycle Grown as an annual outside the tropics; killed by frost (PFAF; University of Illinois Extension).
Edible parts fruit

At a Glance

Close-up of a white wonderberry flower with a yellow center and green fruit — “Solanum retroflexum 1DS-II 3-7161” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Solanum retroflexum 1DS-II 3-7161” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.
Solanum retroflexum Wonderberry Hornworms PESTS

Soil & Growing Conditions

A wonderberry plant growing in the wild — “Solanum retroflexum 50D 1964” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Solanum retroflexum 50D 1964” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.

Water: Prefers moist soil (PFAF)

Soil pH range

6 7.5

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

Growth Stages

A wonderberry flower with small fruit forming — “Solanum retroflexum 1DS-II 3-7160” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Solanum retroflexum 1DS-II 3-7160” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.
Stage BBCH Notes
Sowing and establishment 0 Sow seed under cover/indoors in spring; transplant out only once frost danger has fully passed -- treat much like a tomato (PFAF; University of Illinois Extension).
Vegetative growth 3 Bushy, upright-branching growth; needs full sun and a fertile, well-drained, consistently moist soil (PFAF). Watch closely for tomato hornworm -- a University of Illinois Extension trial found a severe infestation (55 caterpillars hand-collected) on this crop.
Flowering 6 Small white flowers, produced in quantity once established -- one University of Illinois Extension trial plant recovered from pest damage to produce "several hundred" flowers.
Fruiting and harvest 8 Small (about 1cm) dark blue-purple fruits form in clusters (PFAF). Only pick and eat fully ripe (dark) berries -- green, unripe fruit is poisonous (University of Illinois Extension; PFAF).

Harvest & Storage

Ripe dark wonderberries hanging on the plant — “Solanum retroflexum jule” by Max071086 is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Solanum retroflexum jule” by Max071086 is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.

When to pick: Pick only fully ripe, dark blue-purple berries -- green, unripe fruit is poisonous and reactions to it vary by individual (University of Illinois Extension). Ripe fruit is soft and juicy with a mild, bland, slightly sweet flavour; not very appetizing eaten raw, and best used cooked into jelly, jam or pie filling (PFAF; University of Illinois Extension).

Pests

Wonderberry leaves on a stem — “Solanum retroflexum 1DS-II 3-7146” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons
“Solanum retroflexum 1DS-II 3-7146” by SAplants is licensed under CC BY-SA 4.0. Source: Wikimedia Commons.
Hornworms
high

Manduca spp.

A University of Illinois Extension field trial recorded a severe infestation -- 55 hornworm caterpillars hand-collected from the planting, alongside five-spotted hawk moths (the adult form) -- before the crop recovered…

References

  1. Annual, spring-sown under glass, planted out after last frost. Soil: light/medium/heavy, mildly acid to mildly alkaline, prefers fertile well-drained. Full sun required, prefers moist soil. Fruit about 1cm diameter in small bunches. Edible: fruit only, raw or cooked (improved by cooking); many Solanum members have poisonous leaves and sometimes unripe fruit too. Native to Ethiopia, South Africa, Tanzania and other African countries.

  2. Solanum burbankii (synonym used in this source). Annual in zone 6, cannot tolerate frost; started indoors, transplanted after frost danger passed. Bushy, elevated growth habit, small white flowers. Trial in open garden and high-tunnel raised bed. Real trial finding: severe tomato hornworm infestation (55 hand-collected) plus five-spotted hawk moths present; recovered with more watering/monitoring to produce hundreds of flowers and berry clusters. Toxicity: green berries poisonous, do not pick green, ripe berries safe. Taste: soft, juicy, mild/bland, best as jelly/jam/pie filling. No final verdict reached on community-garden suitability.

2 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 wonderberries 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 wonderberries?

Sow early March to late March.

What soil pH do wonderberries need?

A pH of about 6–7.5. 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.

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.

Get the UK Garden Planner →

Instant PDF download · Written for UK growing conditions

SoilCommander Editorial Team

UK vegetable growing guides · Checked against RHS & Met Office guidance

Every SoilCommander guide is written and maintained by our editorial team for real UK growing conditions, and reviewed against Royal Horticultural Society growing advice and Met Office climate data before publication.

Vegetable Growing Guides UK

Last verified 2026-09-03