Tree germander

Tree germander: how do you recognise it?

Habit

Loose, wide shrub about 1 m high and 1.5 m across, with slender, arching branches.

Leaves

Oval, grey-green above and white felted beneath; evergreen.

Stems

Young stems are white felted and stand out against the dark wood of older stems.

Flowers

Pale blue lipped flowers at the tips of the shoots, from May to September.

Roots

Deep and branching; it roots well in free-draining soil but does not tolerate wet feet.

Flowering: May–September · Plants: April–May · Pruning: April

Why grow it?

• The silvery grey, evergreen leaves give colour and calm to the border all year.
• Pale blue flowers from May to September, a long season for a shrub.
• Attracts bees and brings life to a dry garden in summer.
• Drought tolerant and happy on poor, chalky soil; also by the sea, where salty wind bothers it little.
• Clips well as a low, informal hedge or as a dome.

Tree germander: where does it grow best?

• Full sun and warmth: a spot by a south-facing wall or in a sheltered corner is ideal.
• Dry, free-draining soil: sand, loam or light clay, neutral to chalky.
• Wet soil in winter is fatal: make sure drainage is good.
• Sheltered from cold easterly winds and hard frost; salty coastal wind is fine.
• Allow 1–1.5 m per plant; as a low hedge, 60–80 cm.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry

Size

1 m tall, 1.5 m wide

Hardiness

Half hardy (to -10 °C): protect it in harsh winters

Goes well with

• Lavender: Same sunny, dry spot; purple flowers next to pale blue.
• Rosemary: Mediterranean shrub with blue flowers that likes the same soil.
• Rock rose: A larger shrub with big flowers in the same dry spot.
• Sheep’s fescue: Fine blue-grey grass between the silvery shrubs.
• Sage: Grey-green leaves and blue-purple flowers, also a bee plant.

Tree germander: when and how to plant it?

Plant in April–May.

1. Plant in April–May, when the worst frosts are over, so the plant can root well before winter.
2. Dig a hole twice as wide as the root ball; on heavy soil mix in sand or fine grit.
3. Set the plant at the same depth as in its pot and firm the soil well.
4. Plant a hedge 60–80 cm apart, a single shrub 1–1.5 m apart.
5. Water in thoroughly and keep the soil slightly moist in the first year during dry spells.
6. Lay gravel or chippings around the base instead of compost; avoid overwatering in autumn.

Care

Water

In the first year during dry weather, afterwards hardly ever. Better to water rarely and deeply than often and little.

Feeding

Hardly needed. On poor soil a handful of organic fertiliser in April is enough.

Mulching

Gravel or chippings keep the crown dry; avoid compost or leaves that hold moisture.

Frost protection

In autumn pile leaves or straw around the base and, in hard frost, wrap the branches in horticultural fleece.

Spent flowers

No need to remove them; just trim away anything untidy when clipping.

Tip: Plant it by a sheltered south wall or near the coast, on free-draining soil. Inland, a layer of leaves around the base in October and fleece in hard frost are a good insurance.

Tree germander: when to prune it?

Pruning months: April.

When: In April, when the risk of frost is over and new shoots start to grow.

How:

• Trim the plant or hedge lightly, about a third of the young shoots.
• Cut dead and frost-damaged branches back to healthy wood, which is often only clearly visible in May.
• Keep the base slightly wider than the top so light reaches the bottom.
• An old, bare plant can be renewed by cutting a little harder for a few years in a row.

Caution: Do not prune in autumn: it encourages soft shoots that are killed by the first frost. Do not cut deep into old, bare wood either.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Semi-ripe cuttings

In July–August take cuttings of 8–10 cm in sandy compost, under plastic or in a propagator. Overwinter them frost-free.

Seed

In spring in sandy seed compost, indoors or in a cold frame; seedlings are not always identical to the parent.

Tree germander: how does it get through the winter?

Hardy to −10 °C: protect in harsh winters.

• Moderately hardy, to about −10 °C: often fine on the coast and by a sheltered south wall, but inland you risk damage in hard winters.
• Protect the base with a layer of leaves or straw and wrap young plants in fleece during hard frost.
• In a pot: move it in winter to a bright, frost-free, dry place and water hardly at all.

Diseases and pests

• Frost damage: Leaves turn brown and branches die after a hard winter. Wait until May, then cut back to healthy wood; the plant often regrows from the base.
• Root rot: The plant fades after a wet spell. Improve drainage, water sparingly and plant on a raised spot.
• Floppy, bare growth: Too much shade or too much feed. Give more sun, less feed and trim lightly every year.
• Aphids: Sometimes on young shoots. A jet of water or ladybirds usually take care of them.

Through the year

• April: Planting. Light trimming. Leave frost-damaged branches until healthy wood shows.
• May: Planting. Flowering begins. Cut out frost damage.
• June: Flowering. Water young plants in dry weather.
• July: Flowering, plenty of bees. Take semi-ripe cuttings.
• August: Flowering. Take cuttings.
• September: Last flowers.
• October: Protect the base with leaves or straw.
• November: Move pots to a frost-free place.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The species name fruticans means ‘shrubby’ in Latin, to tell it apart from the low wall germander.
• White felted stems and leaf undersides are typical of many Mediterranean plants: the fine hairs limit evaporation.
• The cultivar ‘Azureum’ is known for its deeper blue flowers.