Blue Hill salvia

Sun

Full sun; tolerates light shade, but flowers less freely and may lean.

Water

Water regularly during establishment. Once rooted, water during prolonged dry spells; avoid persistently wet soil, especially in winter.

Soil

Well-drained soil, from sandy to loamy or gritty clay, with modest fertility. Tolerates a range of soil pH.

Height

1.5-2 ft (0.45-0.6 m)

Spread

1-1.5 ft (0.3-0.45 m)

Flowers

Violet-blue flower spikes in late spring and early summer, with a smaller repeat flush later in summer if cut back.

Foliage

Aromatic, mid-green leaves with a wrinkled surface and toothed edges, forming a low basal clump beneath the flower stems.

Growth

Moderate; usually forms a substantial flowering clump within two growing seasons.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Cold hardy
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.2 ft (0.37 m)

3. After 2 years

   1.5 ft (0.45 m)

4. After 3 years

   1.7 ft (0.53 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Water deeply when newly planted, letting the soil surface dry between waterings.
• Avoid heavy feeding; rich soil encourages soft stems that can flop.
• Keep mulch clear of the crown, particularly where winters are wet.
• Divide crowded or thinning clumps in spring, usually every three to four years.
• Staking is rarely needed in full sun and lean soil.

Pruning. After the main flower spikes fade, cut the flowering stems back to healthy basal foliage to encourage another flush. Remove dead stems in late winter or early spring before new growth develops.

Late winter

Remove last year's dead stems if they were left standing, avoiding new basal shoots.

Spring

Plant or divide clumps in well-drained soil and water thoroughly.

Late spring

Check young growth for slugs and snails, especially during damp weather.

Early summer

Enjoy the main flowering period; water newly planted clumps during dry spells.

Midsummer

Cut spent flower stems back to the basal leaves and water if the soil is dry.

Autumn

Clear fallen debris from the crown and check that water drains away freely.

• Repeat small groups along the front of a sunny border for a rhythm of blue flower spikes.
• Plant beside roses to contrast upright blue flowers with rounded rose blooms.
• Combine with yarrow and ornamental grasses in a free-draining perennial planting.
• Edge a gravel path, where its compact foliage keeps the planting low and its flowers attract bees.

Garden styles it suits: Cottage garden, English country, New perennial (prairie), Pollinator garden, Dry gravel garden and Low-maintenance.

Plant it with: Roses, Yarrow, Catmint, Lady's mantle, Hardy geraniums and Feather reed grass.

Wildlife: Flowers provide nectar and pollen for bees and attract butterflies. Deer and rabbits often leave the aromatic foliage alone, though browsing is still possible.

• Crown or root rot in wet soil: improve drainage, keep mulch away from the crown and avoid waterlogged planting sites.
• Flopping stems in shade or rich soil: move to full sun, stop high-nitrogen feeding and cut back after flowering.
• Slugs and snails eating spring shoots: inspect during damp evenings, remove pests and use wildlife-conscious controls if needed.
• Powdery mildew during dry, crowded conditions: improve airflow, water the soil rather than the leaves and remove badly affected foliage.

Not known to be toxic to people, cats, dogs or horses. No particular part is recognized as poisonous, but this ornamental salvia is not a culinary sage and should not be used as a food plant.

• May Night salvia (Salvia × sylvestris 'Mainacht')

  Has much deeper violet-purple flowers; Blue Hill has a lighter, bluer appearance.

• East Friesland salvia (Salvia nemorosa 'Ostfriesland')

  Usually has darker purple flowers and more conspicuous dark flower bracts than Blue Hill.

• Catmint (Nepeta × faassenii)

  Has greyer foliage, looser flower clusters and a spreading, billowy habit rather than Blue Hill's distinct upright spikes.

Salvia comes from the Latin salvere, meaning to be well, sylvestris means of woods, and the German cultivar name Blauhügel means blue hill.

Propagation. Divide established clumps in spring or take basal cuttings from fresh spring shoots. Seedlings may differ from the parent; division and cuttings preserve the named cultivar.

Accepted botanical name

Salvia sylvestris

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.