giant viper's bugloss

Under glass, grow in a loam-based potting compost (JI No3) in full light. Water freely when in growth, sparingly in winter. Outdoors, grow in moderately fertile, well-drained soil in full sun. Protect from winter frost in situ with horticultural fleece

No pruning required

Propagate by seed sown at 13-16°C in summer, overwintering seedlings at 5-7°C

Outdoors slugs may be a problem; indoors glasshouse whitefly and glasshouse red spider mite can be troublesome; vine weevils may also be found

Generally disease free