How To Grow Perennial Salvias
Pair with David Austen shrub roses for a stunning display
Salvia 'Mystic Spires Blue'
Perennial salvias are one of those plants that are absolutely invaluable in the herbaceous border, flowering from early summer until the first frosts. They belong to the mint family and are the largest genus with almost 1,000 species, with many more hybrids. They are widely distributed throughout the Americas and Europe, with the most well known being Salvia officinalis, or Common Sage, that we use in cooking. They consist of perennials, annuals and shrubs, ranging in hardiness from fully hardy to tender. The tender species are S. confertiflora, S. fulgens, and S. leucanthe, these will need to be lifted at the end of October and brought into a frost-free environement over winter. The half-hardy S. greggii varieties can be left outside over winter if planted in a frost-free, sheltered, well-drained position, otherwise these will have to be lifted too. The hardy varieties which are much less problematic are S. microphylla x jamensis, S. involucrate and S. patens.
They are great for attracting bees, butterflies and other pollinators to your garden. They can range in height from 45cm – 1.5m (18” – 5’) and come in a huge variety of colours including amazing intense blues and scarlets. Yellow and white forms can be a little hard to find so you may have to seek out a specialist nursery.
Sunny and really well-drained. At the base of a south facing house wall would be ideal. The soil doesn’t want to be too rich.
Plant in late spring to early summer after any threat of late frosts has passed. Sprinkle a little general purpose fertiliser into the planting hole, not too much as they tend to put on a lot of soft, sappy growth, which can get caught by the frost if they are grown in too rich soil. If planting a tall variety in a windy spot they will have to be supported otherwise the more brittle types will snap; just use some short twiggy peas sticks or circular supports which encircle the whole plant. They look fantastic planted along with David Austin shrub roses and hardy geraniums.
In the first year after planting make sure they don’t dry out too much, in a prolonged hot spell give them a little water. Don’t cut back until spring when the new shoots have appeared then cut back all the old growth. Keep deadheading to promote the growth of new flowers. If it has mainly flowered by mid-summer cut back by about a third to encourage new shoots which should flower well into autumn.
Pull off side shoots in summer but don’t trim them, leave on the heel. Place 3 – 5 around the edge of a 10cm (4”) pot filled with a 50/50 mixture of John Innes Potting Compost and horticultural grit. Keep them over winter in a frost-free greenhouse or cold frame. Plant up into individual pots in spring and when they have put on growth plant them into their flowering position. Take cuttings from the half hardy and tender perennials just in case the parent plants don’t survive the winter.
- Creme Caramel - creamy white; half hardy
- Hot Lips & Pink Lips - red/white, pink/white; Hot Lips has blackcurrant scent; may not be hardy in northern UK
- Love and Wishes - dark, rich purple pink; tender
- Mystic Spires Blue - good bright blue; may not be hardy in hard winter
- Royal bumble - bright scarlet