Common rue

Common rue: how do you recognise it?

Habit

Compact, bushy sub-shrub 50–60 cm tall and 50 cm wide, with a woody base and irregular stems.

Leaves

Two to three times pinnate, fleshy and blue-green; the small leaflets have rounded tips and oil glands.

Flower

Small yellow-green flowers with four fringed petals, in loose clusters from June to August.

Scent

Strong, sharp and bitter. Not everyone finds the smell pleasant.

Fruit

Brown, lobed seed capsules in late summer and autumn.

Flowering: June–August · Plants: April–May and September · Pruning: April and August

Why grow it?

• Elegant blue-green foliage that looks good all year: an ideal contrast in a herb or perennial border.
• Drought tolerant and undemanding: suits a warm, dry spot where little else grows.
• The small yellow flowers attract bees and other insects.
• Evergreen and low-growing, good as a low edging or in a rock garden.
• The seed capsules and foliage can be used in dried arrangements (wearing gloves).

Common rue: where does it grow best?

• Full sun in a warm, sheltered spot; in shade the plant turns loose and green.
• Dry, free-draining soil: sand or loam, neutral to chalky. Wet clay causes root rot.
• Dry to normal: the plant tolerates drought and needs no extra water once established.
• Do not plant it beside a path or play area, so that children and pets do not brush against it.
• Allow 50 cm between plants.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Neutral or chalky

Moisture

Dry

Size

0.6 m tall, 0.5 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Lavender: The same warm, dry spot; the blue-green foliage contrasts with the purple flowers.
• Sage: Grey-green leaves and the same soil and sun requirements.
• Thyme: A low plant at the foot, also drought tolerant.
• Sea holly: A silvery-grey, drought-tolerant plant with striking foliage.

Common rue: when and how to plant it?

Plant in April–May and September.

1. Wear gloves and long sleeves when planting, as the sap can cause marks and blisters on the skin.
2. Plant in April–May or in September, when the soil is neither too wet nor too cold.
3. Dig a hole twice as wide as the root ball; in heavy soil, mix in sand or grit.
4. Set the plant at the same depth as in its pot, 50 cm from the next, and firm the soil.
5. Water when planting and mulch with grit or sand rather than compost.

Care

Water

In the first year, water in long dry spells. After that it is very drought tolerant.

Feeding

Usually not needed. Rich soil makes the plant loose and less aromatic.

Gloves

Always wear gloves and long sleeves when touching or pruning the plant, and avoid sun on the skin afterwards.

Deadheading

Cut off faded flower clusters to limit self-seeding, or leave a few as dried flowers.

Replacing

After 5–6 years the plant becomes bare and woody; replace it with a young plant grown from cuttings.

Tip: Pretty blue-green, strongly scented foliage. Wear gloves: the sap causes burns on the skin in sunlight, and the plant is poisonous if eaten.

Common rue: when to prune it?

Pruning months: April and August.

When: In April, as the new shoots start to grow, and lightly in August after flowering.

How:

• In April, cut back by a third to a half, just above young green shoots.
• Never cut into bare, old wood: the plant seldom regrows from it.
• After flowering, cut off the faded flower clusters.
• Wear gloves and long sleeves, and prune preferably on an overcast day or in the evening.

Caution: In combination with sunlight the sap can cause blisters and pigment marks on the skin. Always wear gloves and long sleeves.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In July–August: cuttings of 8–10 cm from semi-ripe shoots in sandy compost. They root in a few weeks; overwinter them indoors or in a cold frame.

Sowing

In spring in a seed tray, barely covered. Germinates slowly. Prick out and move outside after the Ice Saints.

Common rue: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C; the leaves stay on the plant all year, although they can turn brown in a cold winter.
• Wet feet are more dangerous than cold: provide free-draining soil or a pot with drainage holes.
• Cut out frost damage only in April, when you can see where the plant is growing again.

Diseases and pests

• Root rot: The plant yellows and dies on wet, heavy soil. Plant in free-draining soil or in a pot with drainage holes.
• Bare and woody: Without pruning the base becomes bare. Prune every year in April and replace the plant after 5–6 years.
• Frost damage: Brown leaves after a hard winter. Cut out in April; the plant usually regrows.
• Skin irritation: The sap can damage the skin in sunlight. Wear gloves and rinse the skin immediately with water.

Through the year

• March: Prepare the site. Check for dead wood.
• April: Plant. Cut back by a third to a half.
• May: Plant.
• June: Flowering starts.
• July: Flowering. Bees visit.
• August: Flowering. Cut off faded flower clusters. Take cuttings.
• September: Plant. Look after the cuttings.
• November: Rest. Check that the soil does not stay too wet.

Edible and useful

Not edible. Rue sap makes the skin hypersensitive to sunlight: after touching it on a sunny day, painful blisters and brown marks appear that last for months. Wear gloves and long sleeves when pruning. Taken internally, rue is poisonous and can cause miscarriage: do not use it as a herb or tea. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Did you know?

• Rue belongs to the rue family (Rutaceae), the family of the citrus fruits.
• It was already growing in medieval herb and monastery gardens.
• The variety ‘Jackman’s Blue’ is known for its especially blue foliage colour.