Wood sage

Wood sage: how do you recognise it?

Habit

Loose, upright clump 30–40 cm tall and about as wide, slightly woody at the base, spreading by short rhizomes.

Leaves

Oval to heart-shaped, 3–7 cm, wrinkled and softly hairy with a scalloped edge, in opposite pairs. They smell slightly aromatic when rubbed.

Flower

Small greenish-yellow flowers in pairs, in slender one-sided spikes, from July to September. They have only a lower lip; the stamens stick out above the flower.

Fruit

Four small nutlets in the persistent calyx.

Roots

Finely branched, with short rhizomes; it copes well with drought.

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

Why grow it?

• One of the few flowering perennials that thrive on dry, acid, poor sandy soil.
• Flowers from July to September, when many spring flowers in the heather garden have finished.
• A good bee plant: bumblebees and other bees visit the flowers throughout late summer.
• Native and drought-tolerant: after the first year you hardly ever need to water.
• The soft, wrinkled leaves stay fresh and decorative, especially on the crinkled form ‘Crispum’.

Wood sage: where does it grow best?

• Sun to partial shade; in sun it stays more compact and flowers more freely.
• Sandy or loamy soil, acid to neutral and preferably poor. It grows less well on chalky soil.
• Dry, free-draining soil. It dislikes heavy, wet clay in winter.
• Plant 30–40 cm apart, in groups among heathers or on a dry woodland edge.

Light

Sun and partial shade

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Dry

Size

0.4 m tall, 0.4 m wide

Hardiness

Hardy (to -25 °C)

Goes well with

• Heather: Purple flowers in the same late summer, on the same acid, dry, sandy soil.
• Harebell: Pale blue bells among the greenish-yellow spikes.
• Sheep’s-bit: Blue pompons, another bee plant of poor sandy soil.
• Wavy hair-grass: A fine, swaying grass as a loose background.
• Foxglove: Tall pink spikes on the woodland edge, earlier in summer.

Wood sage: when and how to plant it?

Plant in March–May and September–October.

1. Plant from March to May or in September–October.
2. Loosen the soil and, on heavy ground, mix in coarse sand for good drainage. Do not add fertiliser or potting compost.
3. Dig a hole slightly larger than the pot and set the plant at the same depth as in the pot.
4. Leave 30–40 cm between plants.
5. Firm in and water well. In the first year water weekly in dry spells, after that hardly at all.

Care

Water

Only in the first year during dry spells. After that it looks after itself, even in dry summers.

Feeding

Not needed. On rich soil it becomes floppy and falls open.

Mulching

Avoid a thick layer of compost; a little sand or fine gravel around the base keeps the stem bases dry.

Spent flowers

Leave them over winter for structure and for insects that overwinter in the stems.

Rejuvenating

Divide every three to four years when the centre of the clump becomes bare.

Tip: Plant it on dry, sandy, slightly acid soil and do not feed: the poorer the soil, the sturdier it stays. The variety ‘Crispum’ has crinkled leaves and looks good outside the flowering season too.

Wood sage: when to prune it?

Pruning months: March.

When: From late February to late March, before the new growth gets going.

How:

• Cut the old flower stems and the winter foliage back to a few centimetres above the ground or to just above the new shoots at the base.
• If you want fewer seedlings, cut off the spent spikes as early as September.
• Do not cut back in autumn: the old stems protect the base in winter.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April: lift the clump, cut it into pieces that each have roots and shoots, and replant at once.

Cuttings

In May–June: take 5–8 cm cuttings from non-flowering shoots and insert them in a sandy cutting mix. This keeps ‘Crispum’ true to type.

Seed

The species self-seeds on open sandy soil. Move seedlings in spring.

Wood sage: how does it get through the winter?

Hardy to −25 °C.

• Hardy to about −25 °C: in Belgium protection is usually not needed.
• Wet feet are a greater danger than frost. Make sure the soil drains freely.
• Leave the old stems until March: they protect the base and give insects shelter.

Diseases and pests

• Wet feet: On wet, heavy soil the roots rot in winter. Plant on sand or raise the spot with sand and gravel.
• Floppy growth: On rich soil or in too much shade the stems grow long and fall over. Do not feed, and choose a sunnier spot.
• Spreading too much: On loose sandy soil it spreads by rhizomes and seed. Cut off runners and pull out seedlings.
• Bare centre: After a few years the middle opens up. Dividing in spring rejuvenates the plant.

Through the year

• March: Cut back old stems. Plant or divide.
• April: Plant. New shoots appear.
• May: Take cuttings from non-flowering shoots.
• July: Flowering starts. Bumblebees on the spikes.
• August: Full flower. No watering needed.
• September: Last flowers. Cut off spent spikes if you like.
• October: Plant. Leave the stems standing for winter.
• December: Rest. The old spikes give structure in the heather garden.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• Despite its name it is not a true sage: it belongs to the germanders, the genus Teucrium, within the same mint family.
• The flowers have no upper lip, only a large lower lip, so the stamens stick out freely above the flower.
• In the past the leaves were used in some places, such as Jersey, instead of hops to brew beer.