Lavender mist

Lavender mist: how do you recognise it?

Habit

Tall, upright clump 1.5–2 m tall and about 60 cm wide, with slender purplish stems.

Foliage

Fine, blue-green, several times pinnate with small rounded leaflets, like columbine.

Flower

Large, airy sprays of small lavender flowers with pale yellow stamens, from July to September.

Colour

Lavender to lilac, with yellow; the colour comes from the sepals and stamens, because the flower has no petals.

Roots

Fibrous root system that slowly forms a clump; it dislikes being moved.

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

Why grow it?

• Flowers from July to September with an airy cloud of lavender flowers.
• Gives height up to 2 m without looking heavy: you can see through it.
• Sturdy stems that usually need no support.
• The fine, blue-green foliage is attractive all summer.
• Bees and bumblebees visit the flowers.

Lavender mist: where does it grow best?

• Partial shade is ideal; sun is fine if the soil stays moist.
• Humus-rich, moisture-retentive soil: loam or clay, acid to neutral.
• Moist to wet; in dry summers the leaves scorch and the flowers drop sooner.
• Sheltered from strong wind, because the tall stems can bend.
• Allow about 50–60 cm between plants.

Light

Sun and partial shade

Soil type

Loam or clay

Acidity

Acid or neutral

Moisture

Normal or wet

Size

2 m tall, 0.6 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Bugbane: Tall white flower candles in the same damp partial shade.
• Japanese anemone: Keeps flowering in September, when the meadow-rue finishes.
• Miscanthus: A tall ornamental grass that supports the airy sprays.
• Plantain lily: A leafy edge in front of the tall stems.

Lavender mist: when and how to plant it?

Plant in March–May and September.

1. Plant in March–May or in September, when the soil is not frozen.
2. Dig a hole twice as wide as the root ball and mix in plenty of compost.
3. Set the plant at the same depth as in its pot, with the top of the root ball level with the soil.
4. Leave 50–60 cm between plants.
5. Water thoroughly straight away and keep the soil moist in the first season.
6. Spread a layer of leaf mould or compost mulch around the plant.

Care

Water

Keep the soil moist at all times. In dry summers water generously at the base, otherwise the leaves scorch.

Feeding

A layer of compost or well-rotted manure in spring.

Mulching

A layer of leaf mould in spring keeps the soil cool and moist.

Support

Usually not needed; in a windy spot, supports or shelter help.

Spent flowers

Leave the sprays for the winter silhouette, or cut them off for a tidy border.

Tip: Put it at the back of a damp, sheltered border: the airy sprays rise above lower plants. Keep the soil moist; in dry summers the leaves scorch.

Lavender mist: when to prune it?

Pruning months: March.

When: In March, before the new shoots come through.

How:

• Cut all the old stems back to about 10 cm above the ground.
• Use sharp secateurs or shears and clear away the clippings.
• Now and then, remove dead or broken stems at the base.

Caution: Wear gloves: the plant is poisonous.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April: carefully detach a piece of the clump with roots and shoots and replant at once. It dislikes this, so do it only when necessary.

Seed

Sow fresh seed outdoors in autumn, or in spring in seed trays; the seed germinates best after a cold spell.

Lavender mist: how does it get through the winter?

Hardy to −30 °C.

• Fully hardy, down to about −30 °C: no protection is needed in Belgium.
• Leave the old stems standing until March: they protect the base from frost.
• In a pot: too tall and too big for most pots; plant it in the open ground.

Diseases and pests

• Slugs: They eat the young shoots in spring. Collect them in the evening and protect the new shoots.
• Scorched leaves: Brown edges in a spot that is too sunny or too dry. Water generously, mulch thickly and move it to partial shade.
• Powdery mildew: White powder on the leaves at the end of summer, especially in dry weather. Water at the base and cut off affected leaves.
• Bending stems: In strong wind. Put it in a sheltered spot or support the stems.

Through the year

• March: Cut the old stems back to 10 cm. Add compost. Plant.
• April: Plant. Apply a thick layer of mulch.
• May: Plant. Watch for slugs.
• June: Stems shoot up. Water in dry weather.
• July: Flowering begins. Water generously in dry weather.
• August: Full flower. Water in dry weather.
• September: Last flowers. Planting is still possible.
• October: Leave the sprays. Dormant.
• November: Dormant.

Edible and useful

Not edible. All parts of meadow rue (Thalictrum) are poisonous if swallowed: they contain alkaloids that cause vomiting, stomach ache and diarrhoea, as do many plants in the buttercup family. Despite the name it is not a kitchen herb and not common rue, and its fine leaves look like those of columbine or a fern: do not pick them for tea, salad or as a herb. Grazing animals such as horses, cows, sheep and goats are at risk if they eat it; common meadow rue grows wild in wet meadows. Do not plant meadow rue in or beside a field, and never throw trimmings into a field or pen. Keep young children, cats and dogs away, and wear gloves when cutting back if you have sensitive skin. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The lavender colour does not come from petals: the flower has none, and what you see are sepals and stamens.
• The species comes from the mountains of Japan.
• With its thin stems and fine flowers, it is a true see-through plant: you can still see the plants behind it.