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Conservatory Greenhouse

Costus pulverulentus

Rhizomatous, upright perennial about 2m tall, with large, dark green leaves, arranged in a spiral form, and tubular red to orange-red flowers with basal bracts, produced in dense terminal heads at any time of year

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Ultimate height

1.5–2.5 metres

Time to ultimate height

2–5 years

Ultimate spread

0.5–1 metres

Loam

Moisture

Moist but well–drained

pH

Acid

	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Full shade
Partial shade

Aspect

East–facing or North–facing

Exposure

Sheltered

Hardiness
Hardiness ratings
All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets
H1a: under glass all year (>15C)
H1b: can be grown outside in the summer (10 - 15)
H1c: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20)

H1A

Botanical details

Family: Costaceae
Native to GB / Ireland: No
Foliage: Evergreen
Habit: Clump forming
Genus: Costus are rhizomatous perennials with spirally arranged leaves and tubular, 3-petalled flowers usually in terminal clusters on leafy shoots and often with showy bracts
Name status: Correct
Plant range: Mexico

How to grow

Cultivation

Grow in a warm greenhouse or conservatory in a container or raised bed, using ericaceous potting compost, in bright indirect light, with high humidity. Water freely from spring to summer and use a general fertiliser monthly. Reduce watering in autumn and water sparingly in winter. Pot on or replant in spring. In humid tropical climates grow in a shady border

Propagation

Propagate by seed with heat, as soon as ripe, or by division in spring

Suggested planting locations and garden types

Sub-tropical
Conservatory and greenhouse

Pruning

No pruning required

Pests

May be susceptible to glasshouse red spider mite under glass

Diseases

Generally disease-free

Get involved

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