Flower-of-an-hour is a low, hairy whose pale yellow flowers with a dark purple eye open in the morning and fade within a few hours, just as the name says. Native to the Old World, it arrived in the United States as a garden flower and now grows as a weed of crop fields, roadsides, and vacant lots. It's also called Venice mallow or bladder hibiscus.
Appearance
- Appearance
- Usually 4–24 in (10–60 cm) tall, sometimes more. Stems branch from the base, are sparsely hairy, and stand upright or sprawl.
- Leaves
- Leaves alternate and are usually split into three parts with rounded lobes, the middle one largest. They reach about 3 in (8 cm) long.
- Flowers
- Flowers are 2–2½ in (5–6 cm) across, with five overlapping pale yellow petals that turn deep purple at the base. The center holds many orange-tipped stamens and a fuzzy, dark red stigma with five branches. Fine ridges on the purple patch scatter light into a faint bluish shimmer that helped bumblebees forage in lab tests, though its effect in the wild is unknown.
- Flowering time
- Blooms July through September in Minnesota. Each flower stays open only part of a single day.
- Fruit
- The papery, veined swell around the fruit like a little pale green lantern with purple highlights. Inside is a five-part capsule of brownish-black, kidney-shaped seeds.
Where it lives
- Typical habitats
- Crop fields
- Roadsides
- Vacant lots
- Range
- Native to southeastern Europe, the Mediterranean, and western Asia. In the United States it is introduced and has naturalized across most of the country, mainly on disturbed ground.
- Preferred conditions
- Full sun on disturbed ground, such as cultivated fields, roadsides, and waste areas.
- Flowering
Flowers Jul–Sep
Flowers Jul–Sep
Life cycle
- Reproduction
- Flowers can be pollinated by insects or by themselves. If no pollen arrives in the first few hours, the bends so the stigma touches the flower's own anthers.
Growing it
- Propagation
- In a Colorado study, single plants grown without competition averaged about 3,100 seeds. Fresh seeds are mostly dormant, probably because of a hard, waterproof coat, and roughly a third or more of buried seeds stayed dormant in the soil for nearly two years.
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