Year-round care and troubleshooting

The salvia year begins in March when hardy types push new growth and overwintered pots wake up. Water sparingly at first — soggy compost rots crowns — but increase as growth accelerates. Feed fortnightly with half-strength tomato food from April onwards to build flowering strength. Harden off overwintered plants in a cold frame or against a wall for a week in late April, then plant out after the last frost (usually mid-May in the Midlands, early May in the south, late May in the north).

Through summer, the main task is deadheading. For hardy perennials like nemorosa, shearing back by half after the first flush in late June triggers a second wave in August. For tender and borderline types, pinch off spent flower spikes weekly — this keeps them producing new buds until October rather than setting seed and stopping. Water deeply once a week in dry spells rather than little-and-often; salvias have long roots and prefer a thorough soak. Avoid overhead watering if you can — wet foliage invites powdery mildew, especially on microphylla types in humid summers.

The two real enemies are waterlogged soil in winter and red spider mite on indoor overwintered plants. Winter wet kills more borderline salvias than cold does. If your soil is heavy clay, grow salvias in raised beds or large pots with loam-based compost and extra grit. Red spider mite thrives in warm, dry indoor air — you will see fine webbing and pale stippled leaves. Mist plants daily through winter or stand pots on trays of wet gravel to raise humidity. If infestation is severe, wash leaves with soapy water or use a biological control predator mite. Once spring arrives and plants go outside, the problem vanishes.