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Annual Biennial

Hibiscus trionum

black-eyed Susan

H. trionum is an upright annual, to 60cm tall, with oval, serrated leaves. The creamy-white or pale yellow flowers, with purplish-brown centres, are borne from late summer to early autumn and followed by bladder-like seed capsules

Other common names
bladder hibiscus
bladder ketmia
see moredevil's head in a bush
flower of an hour
flower of the hour
goodnight at noon
modesty
trailing hollyhock
Venice mallow
Venus's mallow
African ketmia
Synonyms
Hibiscus africanus

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Size
Ultimate height
0.5–1 metres
Time to ultimate height
1–2 years
Ultimate spread
0.1–0.5 metres
Growing conditions
Loam
Sand
Moisture
Well–drained
pH
Alkaline, Neutral
Colour & scent
StemFlowerFoliageFruit
Spring Green
Summer Brown Cream Purple Yellow White Green
Autumn Brown Cream Purple Yellow White Green
Winter
Position
  • Full sun
Aspect

South–facing or West–facing

Exposure
Sheltered
Hardiness
H2
Botanical details
Family
Malvaceae
Native to the UK
No
Foliage
Deciduous
Habit
Columnar upright
Genus

Hibiscus can be deciduous or evergreen shrubs, trees, annuals or perennials, with simple or palmately lobed leaves and large, funnel-shaped flowers over a long flowering season

Name status

Correct

Plant range
Africa, SW Asia

How to grow

Cultivation

Plant outside when threat of frosts has passed and grow in a well-drained soil in full sun

Propagation

Propagate by seed

Suggested planting locations and garden types
  • Cottage and informal garden
  • Sub-tropical
  • City and courtyard gardens
  • Patio and container plants
  • Flower borders and beds
Pruning

None required

Pests

May be affected by aphids and thrips

Diseases

Powdery mildews may be a problem

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