Siskiyou lewisia

Siskiyou lewisia: how do you recognise it?

Habit

Compact, evergreen rosette 10–15 cm wide, with flower stems up to 25 cm tall.

Leaves

Fleshy, spoon-shaped, 5–10 cm long, glossy dark green, sometimes with a wavy or toothed edge; evergreen.

Flower

Star-shaped flowers 2–3 cm across in loose clusters on reddish stems, from April to June.

Colour

Pink with darker stripes in the wild; cultivated forms in orange, yellow, apricot, magenta and white.

Roots

A thick, fleshy taproot that grows down into rock crevices: it dislikes being moved.

Flowering: April–June · Plants: March–May · Pruning: June

Why grow it?

• Gorgeous striped flowers in pink, orange, yellow or white, from April to June.
• Thick, glossy, evergreen leaves: an ornament even outside the flowering season.
• Compact and ideal for wall crevices, rock gardens, troughs and pots.
• Drought tolerant once established and very little work if the drainage is good.
• A true collector’s plant, but surprisingly easy to keep in the right spot.

Siskiyou lewisia: where does it grow best?

• Sun to partial shade; in full midday sun a little shade is welcome, especially in a pot.
• Very well-drained, poor, sandy soil with plenty of grit; lime-free, acid to neutral.
• Dry; it tolerates neither water in the rosette nor wet feet, especially in winter.
• Plant at an angle in a wall crevice or between stones so the water runs off the rosette. Allow 25–30 cm per plant.

Light

Sun and partial shade

Soil type

Sand

Acidity

Acid or neutral

Moisture

Dry

Size

0.25 m tall, 0.3 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Houseleek: The same thrifty, fleshy rosettes in the rock garden.
• Stonecrop: Drought tolerant and low, it suits the same spot.
• Saxifrage: Low rosettes with small flowers in rock crevices.
• Alpine pink: Low, flowering mats in pink and white.
• Ornamental grasses: Fine grass between the stones adds movement beside the rosettes.

Siskiyou lewisia: when and how to plant it?

Plant in March–May.

1. Plant between March and May, when the soil is neither frozen nor waterlogged.
2. Make a planting hole or crevice and fill it with a mixture of sand, grit and a little compost.
3. Set the plant at an angle of 45° so the rosette sheds water, and plant at the same depth as in the pot.
4. Leave 25–30 cm between plants.
5. Water a little after planting, then let the soil dry out.
6. Spread a layer of grit around the neck of the plant: it keeps the rosette dry.

Care

Water

Moderate during growth and flowering, on the soil and never in the rosette. Hardly any water after flowering and in winter.

Feeding

Little. A light dose of organic feed or a dilute feed once in spring is enough.

Mulching

Use grit or pebbles around the neck, not compost or bark.

Repotting

In a pot use a mix of half grit and half potting compost in a clay pot with a hole, every two years in spring.

Spent flowers

Cut spent stems back to the rosette; this keeps the plant tidy and encourages more flowers.

Tip: Plant at an angle in a wall crevice or between stones so that no water stays in the rosette. Use lime-free, gritty soil.

Siskiyou lewisia: when to prune it?

Pruning months: June.

When: Straight after flowering, in June.

How:

• Cut spent flower stems back to the rosette.
• Gently remove dead or brown lower leaves by hand.
• Remove rotten or soft parts back to healthy tissue.
• Use clean, sharp scissors to prevent infection.

Caution: While tidying, keep the rosette dry and pull leaves away carefully so as not to damage the neck.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Offsets

In June–July, after flowering: take a side rosette with a bit of root from the parent plant and plant it in gritty soil. Keep it lightly moist until it roots.

Seed

In autumn or spring on sandy seed compost, uncovered or very lightly covered; leave the tray outside. Seedlings flower after two to three years; cultivars do not always come true.

Siskiyou lewisia: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C, but wet winters are its biggest enemy: it is not the frost, but the wetness.
• In the ground: plant at an angle in a wall crevice and, if you like, place a pane of glass or a small roof over the rosette in winter.
• In a pot: stand it under an overhang or in a cold frame and give hardly any water from October to March.

Diseases and pests

• Rotting rosette: The leaves turn soft and brown in the heart. It comes from water in the rosette or soil that is too wet. Plant at an angle, use plenty of grit and water less.
• Slugs: The fleshy leaves and flowers get nibbled. Collect slugs in the evening or set a trap.
• Vine weevil: Rounded notches in the leaf edges are the adult beetles; the white grubs gnaw the roots in winter. Pick off the beetles in the evening by torchlight or use biological nematodes.
• Aphids: On young flower stems in spring. Rinse them off with water or wipe them away.

Through the year

• March: Plant. Spread grit around the neck.
• April: Flowering begins. Plant.
• May: Full flower. Water sparingly.
• June: Cut off spent stems. Take offsets.
• July: Take offsets. Water little.
• August: Rest, do not water unless it is very dry.
• October: Shelter from rain. No water in the rosette.
• December: Keep dry. Possibly a pane of glass above the plant.

Did you know?

• The genus Lewisia is named after Meriwether Lewis, who collected plants in western North America during the Lewis and Clark expedition (1804–1806).
• In the wild it grows in vertical rock crevices where rainwater runs off at once; that is why it hates water in its rosette.
• It is the best-known species of the genus and the basis of many cultivars in different colours.