Solanum rantonnetii

A cheerful, fast-growing shrub covered in vivid purple-blue flowers with golden centres throughout a long blooming season. Prune it regularly to maintain shape and encourage repeat flowering.

Solanum rantonnetii produces clusters of small violet-blue trumpet flowers with golden centres almost continuously from spring through autumn in the Mediterranean — typically April through November, with peaks in May–June and September. The dark green evergreen leaves remain attractive year-round in mild winters. Hardy to -3°C with the plant regrowing from the base after frost, drought-tolerant once established, the shrub tolerates poor soils, alkaline conditions, salt spray and reflected heat from walls. Like all Solanum species, the small fruits are toxic if eaten.

Blue potato bush grows quickly to 1.5–3 m tall and as wide as a free-standing shrub, or can be trained against walls and over pergolas to 3–4 m. Use as a continuous-flowering blue accent in mixed Mediterranean borders, as a small informal hedge along sunny paths and pool decks, against warm walls where the violet-blue flowers stand out against pale plaster, and in large terracotta pots on terraces. The cool blue palette combines particularly beautifully with the yellow of Bulbine frutescens and Euryops pectinatus, the orange of Bulbine and Lantana, the silver of Stachys byzantina and Convolvulus cneorum, and the warm gold of stone walls. Cut back hard in late winter to maintain a compact shape.