Siberian catmint

Siberian catmint: how do you recognise it?

Habit

Upright clump 70–80 cm tall and 50 cm wide, with square stems and underground runners.

Foliage

Lance-shaped, 5–10 cm, toothed edge; grey-green and aromatic.

Flower

Large lipped flowers in whorls along long, loose spikes, from June to August.

Colour

Lavender-blue to bluish purple.

Roots

Creeping rhizomes and runners by which the plant slowly spreads.

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

Why grow it?

• Long, loose spikes of lavender-blue flowers from June to August.
• A great favourite with bees, bumblebees and butterflies.
• Aromatic grey-green foliage with a fresh scent.
• Tough and drought-tolerant in sunny, well-drained soil.
• A second flowering often follows cutting back; handsome all season.

Siberian catmint: where does it grow best?

• Full sun; in partial shade it grows taller and flops open more easily.
• Poor to average, well-drained soil: sand, loam or clay, also chalky.
• Tolerates drought well; wet feet in winter do it a lot of harm.
• Plant 50 cm apart and expect it to spread by runners.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.8 m tall, 0.5 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Rose: Blue whorls dress the often bare base of roses.
• Coneflower: Pink flowers with an orange centre, the same sun and dryness.
• Yarrow: Flat heads next to the blue whorls; both like dry soil.
• Ornamental grasses: Airy plumes make a soft backdrop for the blue flowers.

Siberian catmint: when and how to plant it?

Plant in March–May and September–October.

1. Plant in March–May or in September–October, when the soil is not frozen or too wet.
2. Dig a hole twice as wide as the root ball and loosen the bottom; on heavy soil coarse sand helps.
3. Set the plant at the same depth as in its pot and firm the soil.
4. Allow 50 cm between plants and remember it spreads over the years.
5. Water in generously at once; do not mulch with compost, but gravel is fine.

Care

Water

In the first year, water weekly in dry weather; after that only in long dry spells.

Feeding

Usually not needed: soil that is too rich gives long, floppy stems.

Cutting back

After the first flush, in July, cut the flower stems back: this gives a second flowering.

Support

In rich soil or partial shade, push in a few twigs to keep the stems upright.

Runners

Dig up unwanted runners in spring and replant them elsewhere or discard them.

Tip: Cut it back after flowering for a second flush and dig out every spring the runners that spread too far. On poor soil it stays compact.

Siberian catmint: when to prune it?

Pruning months: March and July.

When: Twice a year: in July after the first flush and in March, before the new shoots appear.

How:

• In July, cut the spent flower stems back by half; it soon shoots again and flowers again.
• Leave the stems standing in winter as shelter for insects and protection for the crown.
• In March, cut all old stems to 5–10 cm above the ground.
• Remove dead or damaged parts.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September: lift the clump, divide it into pieces with roots and replant at once. Every three to four years is fine.

Lifting runners

In spring, cut rooted runners away with a spade and plant them elsewhere.

Cuttings

In April–May: take 8–10 cm cuttings from young shoots, remove the lower leaves and insert in sandy compost.

Siberian catmint: how does it get through the winter?

Hardy to −30 °C.

• Very hardy, down to about −30 °C: no protection is needed in Belgian winters.
• Leave the stems until March; they protect the crown and shelter insects.
• In a pot: choose a large pot with good drainage and do not leave it standing in water.

Diseases and pests

• Spreading: It makes runners and can crowd out its neighbours. Dig them out every year, or plant it in a wide border with room.
• Flopping open: The clump opens up in rich soil or shade. Plant in poor soil in sun, or give twigs as support.
• Powdery mildew: White powder on the leaves in dry weather or dense planting. Cutting back and giving more space helps.
• Root rot: Yellow leaves and a limp clump after a wet winter. Improve drainage with coarse sand or plant higher.

Through the year

• March: Cut back old stems. Plant, divide or lift runners.
• April: Plant or divide. Take cuttings.
• May: Plant. Put in supports.
• June: First flowers. Watch the bees.
• July: After the first flush, cut back for a second flowering.
• August: Second flowering. Water in dry weather.
• September: Plant or divide. Leave the seed heads.
• October: Plant. Leave the stems as winter protection.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The species name sibirica means ‘from Siberia’: in the wild it grows in Siberia, Mongolia and northern China.
• It belongs to the mint family with its square stems, like mint and sage.