Hibiscus trionum (Flower-of-an-hour)

Botanical name

Hibiscus trionum

Other names

Flower-of-an-hour, Bladder hibiscus, Bladder weed, Bladder ketmia, Venice mallow, Trailing hollyhock, Venus's mallow, Modesty, Goodnight at noon, Flower-of-the-hour, Devil's head in a bush, Black-eyed susan

Genus

Hibiscus Hibiscus

Species

H. trionum - H. trionum is a vigorous, tender, erect to spreading, hairy annual or short-lived perennial with ovate, palmately-lobed, toothed, dark green leaves and, from summer into autumn, trumpet-shaped, pale yellow flowers with dark brown centres and purple stamens. Flowers are followed by bladder-like seed capsules.

Foliage

Deciduous

Habit

Upright, Spreading

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Colour

Flower

Pale-yellow in Summer; Pale-yellow in Autumn

Foliage

Dark-green in Spring; Dark-green in Autumn

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How to care

Watch out for

Specific pests

Aphids , Mealybugs , Thrips

Specific diseases

Powdery mildew

General care

Pruning

Pruning group 9. Typically requires little or no pruning.

Propagation

Sow seed at 13-18C in spring.

Propagation methods

Semi-ripe cuttings, Seed

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Monthly care advice

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Where to grow

Hibiscus trionum (Flower-of-an-hour) will reach a height of 0.75m and a spread of 0.6m after 2-5 years.

Suggested uses

Sub-Tropical, Greenhouse, Containers, Conservatory

Cultivation

Under glass, grow in loam-based compost in bright, filtered light, ventilation & moderate humidity. Water freely & feed monthly in growth; sparingly in winter. Outdoors if frost-free, grow in moist, well-drained, neutral to alkaline soil in sun

Soil type

Loamy

Soil drainage

Well-drained

Soil pH

Alkaline, Neutral

Light

Full Sun

Aspect

South, West

Exposure

Sheltered

UK hardiness Note: We are working to update our ratings. Thanks for your patience.

Indoor heated (H1), Tender in frost (H3)

USDA zones

Zone 10, Zone 9

Defra's Risk register #1

Plant name

Hibiscus trionum (Flower-of-an-hour)

Common pest name

Cassava whitefly; Cotton whitefly; Sweet potato whitefly; Tobacco whitefly

Scientific pest name

Bemisia tabaci non-European populations

Type

Insect

Current status in UK

Absent

Likelihood to spread to UK (1 is very low - 5 is very high)

2

Impact (1 is very low - 5 is very high)

5

General biosecurity comments

Non-European populations of Bemisia tabaci pose an additional risk to European populations due to the potential for introducing non-European viruses.

Defra's Risk register #2

Plant name

Hibiscus trionum (Flower-of-an-hour)

Common pest name

Lance nematode; Nematode; Lance

Scientific pest name

Hoplolaimus spp.

Type

Nematode

Current status in UK

Absent

Likelihood to spread to UK (1 is very low - 5 is very high)

2

Impact (1 is very low - 5 is very high)

4

General biosecurity comments

Nematode species potentially affecting a wide variety of crops; prohibition of soil likely to mitigate risk substantially; keep under review in light of interceptions or findings should they occur in the EU.

Defra's Risk register #3

Plant name

Hibiscus trionum (Flower-of-an-hour)

Common pest name

Cassava whitefly; Cotton whitefly; Sweet potato whitefly; Tobacco whitefly

Scientific pest name

Bemisia tabaci European populations

Type

Insect

Current status in UK

Absent

Likelihood to spread to UK (1 is very low - 5 is very high)

2

Impact (1 is very low - 5 is very high)

4

General biosecurity comments

The UK has a protected zone in place for this pest which helps to mitigate the risk of entry and establishment. An EFSA opinion is currently being discussed at the EU Annexes Working Group which recommends further strengthening of the regulation.

About this section

Our plants are under greater threat than ever before. There is increasing movement of plants and other material traded from an increasing variety of sources. This increases the chances of exotic pests arriving with imported goods and travellers, as well as by natural means. Shoot is working with Defra to help members to do their part in preventing the introduction and spread of invasive risks.

Traveling or importing plants? Please read "Don't risk it" advice here

Suspected outbreak? Click here for contact details to report to the relevant authority.

Date updated: 7^th March 2019 For more information visit: https://planthealthportal.defra.gov.uk/