Hemerocallis 'Cool Jazz'

RHS Plant Profile

daylily 'Cool Jazz'

Herbaceous Perennial

An evergreen herbaceous perennial that reaches approximately 71cm in height when in flower. It forms a clump of arching, strap-like, green leaves and shell-pink flowers with a green throat to 14cm across in summer. The flowers remain open for more than 16 hours a day

Position

Full sun, Partial shade

Soil Types

Chalk, Clay, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.5-1 metres

Growing Conditions

Chalk Clay Loam Sand

Moisture: Moist but well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

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: Asphodelaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Clump forming
Potentially harmful: TOXIC to pets (cats) - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus: Hemerocallis may be evergreen or herbaceous perennials, with narrow, strap-shaped leaves and funnel-shaped flowers on erect stems in late spring or early summer
Name Status: Accepted

How to Grow

Cultivation

Grow in fertile, moist but well-drained soil preferably in full sun. Flowering is likely to be poor in shadier situations. Tolerant of heavy clay and poorer soils. May need watering in spring to early summer in dry conditions to ensure flowering. See hemerocallis cultivation or daylily cultivation.

Propagation

Propagate by division in early spring or early autumn

Suggested planting locations and garden types

Cottage and informal garden
Coastal
Flower borders and beds

Pruning

Cut back flower stems after flowering has finished. Remove dead foliage as required

Pests

May be susceptible to aphids, slugs, snails, hemerocallis gall midge, glasshouse red spider mite and Thrips

Diseases

May be susceptible to fungal leaf spot and rust diseases or bacterial leaf and stem rot