Poison primrose

Poison primrose: how do you recognise it?

Growth habit

Compact, short-lived perennial forming a rosette of leaves, about 30 cm tall and wide.

Leaves

Round to heart-shaped, 5–10 cm, softly hairy, with a slightly wavy edge, on long stalks.

Flower

Clusters of flowers 2–4 cm across on stalks 20–30 cm tall: white, pink, salmon, red, lilac or blue-purple.

Flowering time

December to May: new flower stalks replace the faded ones.

Hairs

The glandular hairs on leaves and stalks contain primin and can cause a rash in sensitive people.

Flowering: December–May · Plants: May–June · Pruning: May–June

Why grow it?

• Flowers for a long time, from December to May, in the darkest months of the year.
• Plenty of colours: white, pink, salmon, red, lilac and blue-purple.
• Compact size (about 30 cm) for a cool, bright windowsill.
• Likes a cool room: a good choice if you do not heat much.
• Easy to grow from seed, as long as you avoid contact with the hairs.

Poison primrose: where does it grow best?

• Bright light without direct sun: near an east- or north-facing window. Strong sun makes leaves and flowers wilt.
• Loose, humus-rich potting compost with a fifth of perlite or sand, acid to neutral, in a pot with drainage holes.
• Cool: 10–16 °C. In a warm room (above about 20 °C) it flowers for less time and the flowers fade quickly. Never below 5 °C.
• Evenly, lightly moist compost and air that is not too dry; away from radiators and draughts.

Light

Bright, out of direct sun

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

0.3 m tall, 0.3 m wide

Temperature

Minimum 5 °C

Goes well with

• Cyclamen: The same family and the same cool, bright spot in winter.
• Indoor azalea: A second winter-flowering plant for a cool, bright room.
• Cineraria: Daisy-like flowers in vivid colours, also fond of coolness.
• Ferns: Green foliage as a calm backdrop for the colourful flowers.

Poison primrose: when and how to plant it?

Plant in May–June.

1. Repot in May–June, after flowering, in fresh potting compost. Wear gloves: the hairs can cause a rash.
2. Choose a pot with drainage holes that is only slightly larger than the rootball.
3. Use loose, humus-rich potting compost with a fifth of perlite or sand.
4. Set the plant at the same depth as before, with the rosette just above the compost: do not bury the heart. Fill in and firm gently.
5. Water and keep it cool and bright without sun in summer, or outdoors in shade.

Care

Water

Keep the compost lightly and evenly moist, never wet. Water at the edge or in the saucer (empty it after a quarter of an hour), not into the heart of the rosette. Too dry makes the flowers droop, too wet causes rot.

Feeding

During flowering every 1–2 weeks, half a dose of liquid houseplant feed. Little or none during the summer rest (June–August).

Faded flowers

Pinch off faded flowers and stalks at the base to keep it flowering. Wear gloves.

Humidity

Normal room air that is not too dry is enough; do not put it above a radiator.

Resting period

After flowering (June–August) keep it cool, bright and moderately moist in half shade; from September give more water and feed again.

Tip: It flowers for a long time in a cool, bright spot without sun. Keep the compost evenly, lightly moist and wear gloves: the hairs on leaves and stalks can cause a rash in sensitive people.

Poison primrose: when to prune it?

Pruning months: May–June.

When: Real pruning is not needed. Remove faded stalks and yellow leaves all year round; after flowering, in May–June, also clear away the old leaves.

How:

• Wear gloves because of the hairs.
• Pinch off faded flower clusters with their stalk at the base, without damaging the heart.
• Remove yellow or dead leaves with their stalk at the base.
• After flowering, take away the old leaves and repot the plant in fresh compost.

Caution: Wear gloves and do not touch your face: the hairs can cause a rash in sensitive people. Wash your hands after handling the plant.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

From March to June: sprinkle the very fine seed on moist seed compost, press it down but do not cover it (it germinates in light) and keep it at 15–20 °C. It germinates after 2–4 weeks; prick out when there are two true leaves. The young plants need a few months before they flower.

Division

In May–June, after flowering: on older plants with several rosettes, carefully divide the rootball into pieces with their own roots and pot them separately.

Poison primrose: how does it get through the winter?

• Not hardy: the minimum temperature is 5 °C. Indoors it flowers precisely in winter.
• Keep it bright (without sun) and cool, at 10–16 °C: it then flowers weeks longer than in a warm room.
• Keep it away from radiators and draughts: in a warm, dry room the flowers fade quickly.
• Water evenly: the compost must not dry out, but must not stay wet either.

Diseases and pests

• Fading flowers and drooping leaves: Too warm, too dry or too much sun. Move it somewhere cooler and shadier and water evenly.
• Yellow leaves: Too much water or hard water (iron shortage: yellow leaves with green veins). Let the top layer dry out and use rainwater or low-lime water.
• Grey mould (Botrytis): Grey, fluffy mould on dead flowers and leaves, especially in humid, still air. Remove affected parts straight away, keep the heart dry and ventilate.
• Aphids: On buds and young shoots. Rinse them off or dab them with soapy water and repeat weekly; wear gloves.

Through the year

• January: Flowering. Cool and bright, water evenly. Pinch off faded flowers (wearing gloves).
• February: Flowering. Feed every 1–2 weeks.
• March: Flowering. Remove faded stalks. Sowing is possible.
• April: Last flowers. Keep feeding and watering evenly.
• May: Flowering ends. Remove old leaves and repot. Reduce feeding.
• June: Summer rest: cool, half shade, water moderately. Repotting still possible; sowing.
• July: Rest in half shade. Watch for drying out.
• August: Rest. Check for aphids.
• September: Water more again. Start feeding. Bring indoors when it turns cold.
• October: Indoors, cool and bright, before nights fall below 5–10 °C.
• November: Buds appear. Keep cool (10–16 °C) and bright.
• December: Flowering begins. Keep away from radiators.

Edible and useful

Not edible. The glandular hairs on the leaves and stems of poison primrose contain primin, a compound that can cause a severe rash in sensitive people: redness, itching and small blisters, often only a day later, mostly on the hands, forearms and face, and wherever your hands have touched. Wear gloves when tending it, do not touch your face and wash your hands afterwards; if you have had such a rash before, choose a primin-free variety (often labelled as such). Eating it upsets the stomach and gut of children, cats and dogs: keep the pot out of their reach. Do not confuse it with the cowslip (Primula veris) in the garden, whose flowers you can use. If any is swallowed, call a poison centre (in Belgium 070 245 245) or your doctor at once.

Did you know?

• The name poison primrose refers to the skin irritation caused by the primin in the hairs.
• Primula and cyclamen belong to the same family (Primulaceae) and both like a cool, bright room.
• The seed is so fine that you sprinkle it on the surface: Primula obconica germinates in light.