Salvia

Salvia: how do you recognise it?

Habit

Dense, upright clump 40–50 cm tall and about 45 cm wide, with square stems.

Leaves

Oblong, dull green and wrinkled, with a scalloped edge. They smell herby when you rub them.

Flower

Narrow, straight spikes of small lipped flowers, from May to September in two or more flushes.

Colour

Mostly violet-blue to purple, also pink and white. The coloured bracts keep the spike attractive for a long time.

Roots

A compact rootstock that does not spread. After a few years the centre of the clump sometimes goes bare.

Flowering: May–September · Plants: March–May and September · Pruning: March and July

Why grow it?

• Long flowering from May to September, especially if you cut it back after the first flush.
• One of the best plants for bees and butterflies in a sunny border.
• Drought tolerant: once established it rarely needs watering.
• The straight, vertical spikes add structure among round and flat flower shapes.
• Fully hardy and rarely troubled by disease; also lovely in a gravel garden or a large pot.

Salvia: where does it grow best?

• Full sun: in shade it flowers less and flops open.
• Well-drained soil: sand, loam or clay, acid to chalky. It does not mind poor soil.
• Dry to moist. It dislikes wet feet in winter.
• Plant 40–45 cm apart, 5–6 plants per m², best in groups of three or more.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.5 m tall, 0.45 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Roses: Blue spikes next to pink or white roses: a classic combination in the sun.
• Yarrow: Flat yellow or pink heads as a contrast to the straight spikes.
• Catmint: Just as drought tolerant and also loved by bees, in a softer blue.
• Purple coneflower: Large pink flowers that take over in late summer.
• Ornamental grasses: Swaying stems add lightness to the stiff spikes.

Salvia: when and how to plant it?

Plant in March–May and September.

1. Plant in March–May or in September, when the soil is not frozen or waterlogged.
2. Loosen the soil and mix heavy clay with some coarse sand or fine gravel for better drainage.
3. Dig a hole slightly wider than the pot and set the plant at the same depth as it was in the pot.
4. Firm the soil well and water in thoroughly straight away.
5. Water in dry spells during the first weeks. A thin layer of gravel around the base keeps weeds down and the crown dry.

Care

Water

Regularly in dry weather during the first season. After that only in long dry spells, and a bit more often in a pot.

Feeding

Little needed: a handful of compost in spring is enough. In rich soil it grows soft and flops.

Deadheading

After the first flush, cut the spikes back to just above the leaves: a second flowering follows in August–September.

Support

Rarely needed. If it does flop, cut it back a little harder after the first flowering.

Rejuvenating

Divide the clump every 3–4 years, when the centre goes bare or it flowers less.

Tip: After the first flowering, cut the flower stems back to just above the leaves: within a few weeks it flowers again. Give it one good soaking at the same time so it regrows faster.

Salvia: when to prune it?

Pruning months: March and July.

When: After the first flowering, usually in July, and in March to clear the old stems.

How:

• After the first flush, cut the faded spikes back to just above the leaves or above new side shoots.
• If the plant flops open, cut the whole clump back to 10–15 cm: it regrows compactly within a few weeks.
• Leave the last stems standing over winter; they protect the heart of the plant.
• In March, cut all old stems down to just above the new shoots at the base.

Caution: In March, spare the young shoots at the base: the new plant grows from them.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or in September: cut the clump into pieces with a spade, each with roots and a few buds, and replant straight away.

Cuttings

In April–May: 5–8 cm cuttings from young, non-flowering shoots at the base, in moist cutting compost under plastic. They root within a few weeks.

Seed

Possible, but named varieties do not come true from seed. Division and cuttings give plants identical to the parent.

Salvia: how does it get through the winter?

Hardy to −25 °C.

• Fully hardy, to about −25 °C: no protection is needed in Belgium.
• Wet soil in winter is more dangerous than frost: in heavy, wet clay the rootstock can rot.
• In a pot: make sure there is a drainage hole and raise the pot on feet so excess water can drain away.

Diseases and pests

• Slugs: They eat the young shoots in spring. Check in the evening, pick them off or spread a layer of gravel around the plant.
• Powdery mildew: White powder on the leaves in warm, dry summers. Remove affected leaves and give the plant enough space.
• Root rot: The plant wilts and the base turns soft, mostly in wet, heavy soil. Move it to a drier spot and improve drainage.
• Flopping: The stems fall apart in soil that is too rich or in too much shade. Feed less, give more sun and cut back after the first flowering.

Through the year

• March: Cut off old stems. Plant and divide.
• April: Plant. Watch for slugs on the young shoots.
• May: First flowers. Take cuttings from young shoots.
• June: In full flower. Bees and butterflies in the border.
• July: After the first flush, cut back to just above the leaves. Water well once.
• August: Second flowering. Water in long dry spells.
• September: Last flowers. Plant or divide.
• November: Leave the stems standing as winter protection.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• Salvias have a lever mechanism: when a bee pushes its head into the flower, the stamens swing down and dust pollen onto its back.
• One of its parents, meadow clary, also grows wild in Belgium, on sunny, chalky grassland. It has become rare there.
• Like mint and lavender, salvia has square stems and opposite leaves: typical of the mint family.