dahlia 'Penhill Watermelon'

Grow in fertile, humus-rich, well-drained soil, enriched with organic matter and general purpose fertiliser, in full sun. Pinch out growing tips to encourage bushy plants and stake. Water freely in dry periods. Lift and store tubers in autumn to replant or use as a source of cuttings in spring. See dahlia cultivation for further advice

Deadhead to prolong flowering. Cut back to near ground level in the autumn, before lifting and storing for the winter

Propagate by softwood cuttings taken in spring from shoots from stored tubers, or divide the tubers ensuring each division has a viable bud

May be susceptible to aphids, leaf miners, glasshouse red spider mite and slugs. Earwigs sometimes damage blooms. Capsid bug and caterpillars are occasional pests

May be susceptible to powdery mildews in dry conditions. In wet weather grey moulds and other fungal rots can be a problem. Fungal rots can also damage stored tubers. A virus may cause stunting, leaf markings and distortion