How to Grow Wonderberries UK

Regional Planting Calendar

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.

Quick Facts

Factor	Value
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

Soil & Growing Conditions

Water: Prefers moist soil (PFAF)

Growth Stages

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

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

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…

Wonderberry Photo Gallery

Wonderberry plant in flower

A wonderberry plant with a white flower and hairy leaves.

Flower detail

Close-up of a white wonderberry flower with a yellow center and green fruit forming beside it.

Ripe berries

A bowl of ripe, dark purple wonderberries.

Unripe fruit cluster

A cluster of unripe green wonderberries on the plant -- these are poisonous and should not be eaten.

Leaf detail

Wonderberry leaves on a stem.

Plant in the wild

A wonderberry plant growing in the wild.

Ripe fruit on the plant

Ripe, dark wonderberries hanging on the plant.

Potted plant

A potted wonderberry plant with flowers and buds.

Flower with young fruit

A wonderberry flower with small fruit forming.

What the research guides add

An Illinois Extension educator grew wonderberries and wrote up what happened, which is rare for this crop.

• Wonderberry (also called sunberry) was created by the plant breeder Luther Burbank in the early 1900s and belongs to the nightshade family (Solanaceae). (Illinois Extension)
• The seeds were started in a small greenhouse until the threat of frost passed; the article says wonderberries are annual in growing zone 6 and will not tolerate a frost event. (Illinois Extension)
• In the high tunnel the stems were shredded by tomato hornworms, and the advice was to give plenty of water and increase pest monitoring. The plants then branched out with several hundred white flowers and clusters of berries. (Illinois Extension)

Sources for this section

• University of Illinois Extension: The quest of growing wonderberries

Section researched and checked on 25 October 2026 by the SoilCommander Editorial Team. How we check facts: editorial policy.

References

1. Plants For A Future (PFAF) - Solanum retroflexum (sunberry)

   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. University of Illinois Extension - The quest of growing wonderberries

   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.