Quick Questions
Which salvias are fully hardy? Lindsey Noad, by email
It’s often hard to assess how hardy salvias are without reference to the plant label because many are quite complicated hybrids. Reliably hardy ones include Salvia
nemorosa selections, such as ‘Caradonna’, and hybrids of S.
sylvestris, such as ‘Blauhügel’ and S. jamensis, such as ‘Peter Vidgeon’. Delay pruning of all salvias grown outdoors until spring when new buds can be seen on lower stems.
How do I get my poinse ia to colour up again? Mandeep Kamara, by email
Poinse ias are grown for their brightly coloured bracts. To get them to colour up again you need to prune hard back in April to about 10cm (4in). Pot up in early May and place in good light for the summer. Bract colouring is initiated by short winter day-length in December and January.
To speed this up, give plants an uninterrupted period of total darkness of 14 hours every day from November. Keep them at 18C (64F). Commercially grown poinse ias are treated with dwarfing chemicals to keep them compact, but plants grown on for a second year at home will revert to their naturally taller habit.