If ever there was a plant with 30% extra, plus added value, not to mention an attached free gift, it would be a salvia. I adore them. Salvias come in a rainbow of colours, bloom when they're teenagers, stay in flower for months, often produce their most spectacular display in autumn and are remarkably easy to grow.

Let's begin with what, in my opinion, is the best all round garden plant, South American Salvia guaranitica. This has been flourishing, without ever being divided, fed, staked, sprayed or fussed over for the last twenty years in the same position here. It enjoys, as many salvias do, cans of water during dry periods. Up to 1.5 metres tall, fresh green leaves contrast with royal blue flowers. It disappears completely below ground in winter but unfailingly emerges quite late the following spring, so you can interplant it with early bulbs. I did try its pale blue cultivar 'Argentine Skies' but decided it was a pleasant but unessential plant.

Last year I promised myself I'd never go through another summer without at least a dozen plants of Salvia uliginosa. (The second part of the name uliginosa means "of the marshes", but it seems to flourish in most soils in sun.) The flowers, the purest blue of a Madonna's cloak, like you see in Renaissance pictures, is very refreshing in autumn when the flowers are at their best. This is a tall plant (up to 2 metres) but is so airy I plant it in front of the border where it will form a veil of blue to hide the gradual collapse of plants behind. I seem to lose some plants every winter but it's easily propagated by cuttings or division.

I've barely begun to describe the great range of salvias available but I cannot say enough good things about this great family of plants. Give them a try