Rudbeckia hirta 'Denver Daisy'

RHS Plant Profile

black-eyed Susan 'Denver Daisy'

Annual Biennial

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A compact, deciduous perennial often grown as an annual/biennial with green foliage and large, bright golden-yellow daisy-like flowers with a mahogany-brown central eyezone and a dark brown button-shaped centre, appearing from summer through until the first frosts

Position

Full sun, Partial shade

Soil Types

Clay, Loam

Max Height

0.5-1 metres

Max Spread

0.5-1 metres

Size

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

Growing Conditions

Clay Loam

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): H3

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Asteraceae
Native to GB/Ireland: No
Foliage: Deciduous
Habit: Columnar upright
Genus: Rudbeckia may be annuals, biennials or rhizomatous herbaceous perennials, with simple or pinnately divided leaves and large daisy-like flower-heads with yellow or orange rays surrounding a prominent conical disk
Name Status: Accepted

How to Grow

Cultivation

Best grown as a half-hardy annual. Grows well in moderately fertile, preferably heavy but well-drained soil in full sun or partial shade. See rudbeckia cultivation for further advice

Propagation

Propagate with seed sown by gentle heat in spring

Suggested planting locations and garden types

City and courtyard gardens
Cottage and informal garden
Patio and container plants
Wildlife gardens
Cut flowers
Flower borders and beds

Pruning

Deadhead spent flowers

Pests

Generally pest-free

Diseases

May be susceptible to grey moulds if air circulation is poor