Crocus olivieri subsp. balansae 'Zwanenburg'

RHS Plant Profile

crocus 'Zwanenburg'

RHS

Synonyms

Crocus balansae 'Zwanenburg'

Bulbs

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A cormous perennial, to 7cm tall, with golden-yellow flowers almost completely suffused with dark reddish-brown on the outside

Position

Full sun

Soil Types

Chalk, Loam, Sand

Max Height

Up to 10 cm

Max Spread

0-0.1 metre

Size

Time to Maturity: 2–5 years
Max Spread: 0-0.1 metre
Max Height: Up to 10 cm

Growing Conditions

Chalk Loam Sand

Moisture: Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun

Aspect: South–facing or West–facing
Exposure: Exposed or 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): H6

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Iridaceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Tufted
Potentially harmful: Ornamental bulbs - not to be eaten. Wear gloves and other protective equipment when handling. Pets: Ornamental bulbs - not to be eaten - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus: Crocus are dwarf, deciduous perennials growing from a corm, with linear leaves usually with a silvery central stripe, and goblet-shaped, sometimes fragrant flowers in autumn or early spring
Name Status: Accepted

How to Grow

Cultivation

Grow in a gritty, poor to moderately fertile, well-drained soil in full sun. See crocus cultivation for more advice

Propagation

Propagate by removing cormlets when dormant

Suggested planting locations and garden types

Coastal
Gravel garden
City and courtyard gardens
Cottage and informal garden
Patio and container plants
Rock garden
Wildlife gardens
Banks and slopes
Flower borders and beds

Pruning

No pruning required

Pests

May be susceptible to rodents and birds

Diseases

Generally disease-free, corms may rot in storage