Giant salvia

Shrub · Tender perennial

Brillantaisia subulugurica

Giant salvia

Also known as: Brillantasia subulugurica (misspelling), Brillantaisia cicatricosa

A fast-growing tropical African shrub with big glossy leaves and tall spikes of large, violet, sage-like flowers.

  • Full sun, Partial shade
  • 1–2 m (3–7 ft)
  • 0.6–1.2 m (2–4 ft)
  • H2 · Zone 10
  • August–November
  • Evergreen

Overview

Often called giant salvia, this vigorous member of the acanthus family is not a true salvia but comes from the forests of eastern and south-eastern Africa. It grows quickly into a bushy, soft-wooded shrub with large, glossy, dark green leaves on square stems, and from late summer into autumn produces tall, branching spikes of big, hooded, violet to purple flowers that bees love. It is frost tender: light frost kills the top growth, though roots may survive just below freezing under a mulch. In climates with frosty winters, grow it as a summer feature in a large pot or border and keep cuttings or the whole plant frost-free over winter. In frost-free climates it can flower almost all year. Some botanists treat it as a form of Brillantaisia cicatricosa.

At a Glance

Sun Full sun, Partial shade
Height 1–2 m (3–7 ft)
Spread 0.6–1.2 m (2–4 ft)
Hardiness H2 · Zone 10
Flowers August–November
Soil Loam, Sand
Moisture Moist well drained
Habit Bushy, Upright
Water High
Maintenance Moderate
Brillantaisia subulugurica (Giant salvia)
Brillantaisia subulugurica (Giant salvia)

Growing Conditions

Min. Temperature 1°C (34°F)
pH Range 6–7.5
Fertility Fertile
Drainage Free Draining

Aspect Suitability

  • East-facing
  • South-facing
  • West-facing

Soil Tolerance

  • Sandy
  • Loam
  • Acid
  • Neutral pH
  • Alkaline

Foliage

Brillantaisia subulugurica (Giant salvia)
Brillantaisia subulugurica (Giant salvia)
Brillantaisia subulugurica (Giant salvia)
Persistence Evergreen
Colour Dark green
Leaf shape / texture ovate_large
  • Architectural foliage

Foliage interest: 12 months of the year

Seasonal Timeline

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flowering
Foliage
Propagate
  • Flowering Aug Sep Oct Nov
  • Foliage 12 months of the year
  • Propagate Apr May Jun Jul Aug

How to propagate

Ways to grow more Giant salvia: the usual steps for each method.

Softwood cuttings Apr–Jun Takes a little care

You'll need: Clean, sharp secateurs or a knife, small pots, gritty compost (half compost, half grit or perlite), a plastic bag, and rooting powder if you have it.

  1. Early in the morning, cut soft, non-flowering shoot tips about 5 to 10 cm long, and keep them in a plastic bag so they don't wilt.
  2. Trim each one just below a leaf joint and take off the lower leaves, leaving two or three at the top.
  3. Dip the cut end in rooting powder if you have some.
  4. Push them into the edge of a pot of gritty compost so their leaves don't touch, and water them in.
  5. Cover with a clear bag or put them in a propagator, somewhere bright but out of direct sun.
How long
Roots in about 3 to 6 weeks.
It's worked when
New growth at the tips, and roots showing through the pot's holes.
Then
Pot each one up on its own and grow it on. Keep young plants frost-free through their first winter.
From seed Apr–May Easy

You'll need: Seed compost, a seed tray or small pots, labels, and a clear lid or plastic bag.

  1. Fill a tray or pots with seed compost, level it and firm it gently.
  2. Water the compost and let it drain.
  3. Sow the seeds thinly on top. Cover them with a fine layer of compost or vermiculite about as deep as the seed is big; leave tiny seeds uncovered.
  4. Label them, cover with a clear lid or bag, and keep them somewhere bright but out of hot sun.
  5. Keep the compost just moist, and take the cover off once seedlings appear.
How long
Usually comes up in 1 to 3 weeks.
It's worked when
Seedlings with their first pair of leaves.
Then
When each has its first true leaves, prick them out into their own small pots, holding them by a leaf, never the stem. Harden them off for a week or two before planting out.

Soft stem cuttings root very easily in warmth from spring to late summer; take a few in late summer to overwinter indoors.

Maintenance Calendar

  • Mar Cut overwintered plants back hard in early spring to keep them compact and bushy
  • May Plant out or move pots outside once nights stay above about 10°C (50°F)
  • Jul Water and feed generously, as it needs plenty of moisture to flower well
  • Oct Take cuttings or bring the plant under frost-free cover before the first frost

Garden Design

Works well in: Modern / Contemporary, Tropical / Exotic

Plant it in a sheltered, partly shaded exotic border or a big pot, where the late violet spikes extend the season; regular water keeps it flowering.

Companion planting: Cannas, Salvias, Dahlias, Bananas

Wildlife Value

  • Bees
  • Other pollinators

Safety

Not known to be toxic to people or pets.