Siam tulip

Siam tulip: how do you recognise it?

Habit

Clump 50 cm tall and 30 cm wide, from a rhizome with a bundle of fleshy tuberous roots.

Leaves

Lance-shaped, fresh green, 30–40 cm long, with a clear midrib; dies back in autumn.

Flower

Upright flower stalks with a cone of pink to magenta bracts with a green base; the true flowers are small, June to September.

Roots

A rhizome with a bundle of fleshy tuberous roots in which food is stored.

Rest

In autumn the leaves die and the rhizome rests dry until March.

Flowering: June–September · Plants: March–April

Why grow it?

• Striking pink flower cones from June to September, in summer when many houseplants flower little.
• A distinctive, tropical look with fresh green foliage.
• Lasts well in a vase: also suitable as a cut flower.
• Stays compact: 50 cm tall and 30 cm wide, also suitable for a small pot.
• The rhizome overwinters dry and grows again the following spring.

Siam tulip: where does it grow best?

• Bright partial shade: plenty of light but no fierce midday sun; an east or west window or a sheltered spot outdoors.
• Light, humus-rich and free-draining compost; acid to neutral.
• Evenly, lightly moist during growth, never wet.
• Warm: 20–30 °C in the growing season, never below 15 °C.
• Outdoors only from June, when nights stay warm (at least 15 °C), in a sheltered, warm spot.

Light

Bright, out of direct sun

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

0.5 m tall, 0.3 m wide

Temperature

Minimum 15 °C

Goes well with

• Caladium: Same warmth and winter rest, with colourful foliage.
• Begonia: A tuberous begonia flowers in the same summer pot.
• Canna: A larger tropical plant for a warm patio group.
• Ferns: A fresh, green filler between the flowers.

Siam tulip: when and how to plant it?

Plant in March–April.

1. Pot the rhizomes in March–April, as soon as it is warm enough (at least 18–20 °C).
2. Choose a 20–25 cm pot with drainage holes and fill it with light, airy compost with perlite.
3. Lay the rhizome horizontally or with the tuberous roots pointing down and cover it with about 5 cm of compost.
4. Put about 2–3 rhizomes in such a pot, 8–10 cm apart.
5. Water a little; not too much at first, until the first shoots appear (after 3–6 weeks).
6. Put the pot somewhere warm and bright; bottom heat speeds up sprouting.

Care

Water

After sprouting keep the compost evenly moist; do not let it dry out and avoid wet feet. When the leaves turn yellow in autumn, gradually cut back.

Feeding

From sprouting until flowering give half-strength flowering plant food every 2 weeks. Stop when the leaves turn yellow.

Humidity

Keep the air fairly humid and mist the leaves now and then.

Faded flowers

Cut a faded flower stalk off at the base; new ones often follow.

Position

Turn the pot now and then so that the flowers stay nicely upright.

Tip: The leaves die back after flowering: let the rhizome overwinter dry at 15–20 °C and repot it in fresh compost in March.

Siam tulip: when to prune it?

When: It is not pruned. Cut off faded stalks and, in autumn, the dead foliage.

How:

• Cut a faded flower stalk off just above the compost.
• In autumn, when the leaves have turned yellow, cut all the leaves off just above the compost.
• Use clean scissors to prevent infection.

Caution: Only cut the foliage off once it is completely dried: until then it feeds the rhizome.

Pruning calendar and basic rules

Propagation

Division

In March–April, when replanting: divide the bundle into pieces, each with at least one eye and two or three tuberous roots. Let the cuts dry for a day and plant them separately.

Siam tulip: how does it get through the winter?

• Not hardy: the rhizome needs at least 15 °C and must never get frost or cold.
• When the leaves die in autumn, stop watering. Let the rhizome overwinter dry in its pot at 15–20 °C.
• Repot it in March in fresh compost, keep it warm and only water when the first shoots appear.

Diseases and pests

• Rotting rhizome: From cold, wet compost or water in winter. Keep the rhizome dry and warm during its rest; throw away soft or slimy rhizomes.
• No shoots: Too cold or too wet. Put the pot somewhere warm (20 °C or more) and water very little until shoots appear.
• Few or no flowers: Too little light or feeding, or a start that is too late or too cold. Give more light, feed regularly and start on time.
• Spider mite and thrips: Fine webbing or silvery flecks on the leaves, especially in dry air. Rinse the leaves, raise the humidity and repeat weekly.

Through the year

• January: Rest: leave the pot dry and warm (15–20 °C).
• February: Rest: keep dry and warm.
• March: Replant the rhizomes in fresh compost. Put somewhere warm.
• April: Plant the rhizomes. Little water until shoots appear.
• May: Shoots grow. Keep evenly moist, start feeding.
• June: First flowers. Put outdoors when nights stay warm.
• July: Full flower. Water and feed. Cut flowers for the vase.
• August: In flower. Water and feed. Shade from fierce sun.
• September: Last flowers. Stop feeding. Bring indoors before it turns cold.
• October: Leaves dry out: gradually water less.
• November: Rest: stop watering, cut off the leaves.
• December: Rest: keep dry and warm (15–20 °C).

Did you know?

• The pink ‘petals’ are actually bracts; the true flowers are small and hidden between the lower bracts.
• It is related to turmeric (Curcuma longa) and ginger, and belongs to the ginger family.
• In Europe the rhizomes are sold in spring as ‘bulbs’; you pot them up to flower in summer.