Propagation and succession

Salvias root from cuttings with ridiculous ease. In late August or early September, take 8–10 cm lengths of non-flowering side shoots from the current season's growth. Strip the lower leaves, dip the cut end in hormone rooting powder if you have it (you barely need it), and insert four cuttings around the edge of a 10 cm pot filled with 50:50 multipurpose compost and sharp sand or perlite. Water once, cover loosely with a clear plastic bag, and place on a shaded windowsill. Roots appear in 10–14 days. By mid-October you have small plants that will sit happily on a windowsill all winter and grow into flowering-size specimens by June.

This technique works for almost every salvia — tender, borderline and hardy alike. It is how you insure your collection, how you make gifts, how you turn one expensive Salvia 'Amistad' into eight. For tender types like patens and guaranitica, cuttings are often more reliable than lifting the parent plant. For borderline types like microphylla, cuttings give you a backup if the mother plant dies over winter. For hardy types, cuttings let you expand a drift without buying more plants.

Seed propagation is less predictable because many garden salvias are hybrids that will not come true. But species salvias — patens, sclarea, viridis, horminum — are easy from seed sown in March at 18–20°C. Germination takes 10–18 days. Prick out seedlings when they have two true leaves; pot on into 9 cm pots; grow on in good light; harden off in May; plant out after the last frost. From a March sowing, you will have flowering plants by late July.