Lesser meadow-rue

Lesser meadow-rue: how do you recognise it?

Habit

Airy, upright clump 40–80 cm tall and about 50 cm wide, with thin, branching stems.

Foliage

Fine, blue-green, two to three times pinnate with small round to lobed leaflets, like a maidenhair fern.

Flower

Small greenish-yellow flowers with dangling yellow stamens, in loose sprays from June to July; no petals.

Roots

Short, branching rootstock that slowly forms a clump; it dislikes being moved.

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

Why grow it?

• Fine, blue-green foliage that is attractive even without flowers and gives an airy texture.
• Tolerates drought and a sunny spot, where much fern-like foliage struggles.
• A good filler between flowering plants in a sunny border.
• A native species, lovely in a natural or wild garden.
• Low maintenance: one cut back a year is enough.

Lesser meadow-rue: where does it grow best?

• Sun to partial shade; in full sun it stays more compact.
• Well-drained soil: sand or loam, neutral to chalky.
• Dry to reasonably moist; once established it tolerates drought well.
• Allow about 40–50 cm between plants.

Light

Sun and partial shade

Soil type

Sand or loam

Acidity

Neutral or chalky

Moisture

Dry or normal

Size

0.6 m tall, 0.5 m wide

Hardiness

Hardy (to -30 °C)

Goes well with

• Woodland sage: Purple spikes above the fine blue-green foliage.
• Coneflower: Sturdy flowers contrast nicely with the fine foliage.
• Feather grass: Another airy grass in the same dry, sunny spot.
• Cranesbill: Flowers at the same time and fills the space between clumps.

Lesser meadow-rue: 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 neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and mix in a little 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 40–50 cm between plants.
5. Water thoroughly straight away and keep the soil lightly moist in the first season.
6. Spread a thin layer of compost around the plant, keeping the crown clear.

Care

Water

In the first year water weekly in dry weather. After that it tolerates drought well; water only in long dry spells.

Feeding

Usually not needed. Over-rich soil gives long, floppy stems.

Support

Usually not needed; in a windy spot or rich soil, twigs help.

Spent flowers

You can leave the sprays on or cut them off after flowering for fresh foliage.

Dividing

Rarely needed and only in spring: it dislikes disturbance.

Tip: Use it as a filler between flowering plants for an airy texture. Cut the stems back after flowering if the foliage dries out: fresh leaves follow. Wear gloves: the plant is poisonous.

Lesser meadow-rue: 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 5–10 cm above the ground.
• If you like, cut the flower stems off after flowering to encourage fresh foliage.
• 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

Seed

Sow fresh seed outdoors in autumn, or in the cool in spring; the seed germinates best after a cold spell. Seedlings may differ from the parent plant.

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.

Lesser meadow-rue: 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: use free-draining compost and wrap the pot in hessian in severe frost.

Diseases and pests

• Powdery mildew: White powder on the leaves, mostly in dry weather and when plants are too close together. Give space, water at the base and cut off affected leaves.
• Slugs: They eat young shoots in spring. Collect them in the evening and protect young plants.
• Rust: Orange to brown pustules under the leaves. Cut off affected leaves and put them in the household waste.
• Flopping stems: On over-rich soil or in wind. Feed less and support with twigs if needed.

Through the year

• March: Cut the old stems back to 5–10 cm. Plant. Add compost.
• April: Plant. Watch for slugs.
• May: Plant. Stems grow up.
• June: Flowering begins. In the first year, water in dry weather.
• July: Flowering. Optionally cut back after flowering for fresh foliage.
• August: Water in long dry spells.
• September: Plant. Watch for powdery mildew.
• October: Plant. Leave the stems.
• 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.

Did you know?

• The flowers have no petals: what you see are dangling yellow stamens.
• The cultivar ‘Adiantifolium’ is named after the maidenhair fern (Adiantum), which has similar foliage.
• Thalictrum minus is a variable species that grows wild on chalky grassland and in dunes.