Aristea capitata

RHS Plant Profile

great blue flower-rod

Synonyms

Aristea major
Aristea thyrsiflora

Herbaceous Perennial

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A clump-forming rhizomatous perennial with erect, sword shaped evergreen leaves and dense spikes of purple-blue saucer-shaped flowers in summer.

Position

Full sun

Soil Types

Loam

Max Height

1-1.5 metres

Max Spread

0.5-1 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.5-1 metres
Max Height: 1-1.5 metres

Growing Conditions

Loam

Moisture: Well–drained
pH: Neutral or Acid

Position

Full sun

Aspect: South–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): H3

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Iridaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Clump forming
Genus: Aristea are compact, mostly evergreen perennials with linear leaves and short-lived, saucer-shaped flowers in spring and summer
Name Status: Correct

How to Grow

Cultivation

Grow in a well-drained, loamy soil in full sun. Will need winter protection in all but the most sheltered gardens.

Propagation

Propagate by seed (indoors) at 15-20°C in spring or autumn

Suggested planting locations and garden types

City and courtyard gardens
Gravel garden
Patio and container plants
Mediterranean climate plants
Flower borders and beds

Pruning

Cut faded flower spikes to the base. Remove older, untidy leaves.

Pests

Generally pest-free

Diseases

Generally disease-free