Asiatic dayflower is an annual weed from East Asia, now common in gardens, roadsides, and crop fields across much of the eastern and central US. Each flower lasts just one day, which gives the plant its name. Look for two rounded blue petals above a tiny white one; "Mickey Mouse plant" is another name for it.
Appearance
- Growth form
- A sprawling or upright annual, 1–3 ft (30–90 cm) long, that often roots where stem joints touch the ground.
- Leaves
- Smooth, lance-shaped leaves up to 5 in (12 cm) long wrap the stem in a sheath instead of a leaf stalk.
- Flowers
- Flowers about ½–1 in (1.3–2.5 cm) across peek out from a folded, heart-shaped green . Two bright blue upper petals sit above a small white lower petal. Showy yellow attract insects, since the flowers make no nectar.
- Flowering time
- Summer through fall (July to October in Minnesota)
- Fruit
- A small capsule with two chambers, each holding two brown seeds.
Look-alikes
Where it lives
- Typical habitats
- Gardens
- Roadsides
- Crop fields
- Woodland edges
- Range
- Introduced across most eastern and central states, from Massachusetts and New York west to Minnesota, south through the Great Plains to Texas, and east to Florida. It also grows in Ontario and Quebec.
- Preferred conditions
- Moist soil in part shade or shade; waste ground and disturbed spots.
- Flowering
Flowers Jul–Oct
Flowers Jul–Oct
Growing it
- Propagation
- Spreads by seed and by rooting stems.
Conservation
- IUCN Red List
- NENot EvaluatedNot yet assessed
- Threats
- It became a bigger problem in crop fields after glyphosate-resistant soybeans arrived, because the plant tolerates glyphosate.
Culture and stories
- Culture and stories
- In Japan, a large-flowered form was grown to make a blue pigment used in 18th- and 19th-century woodblock prints.
- Its leaf skin peels off in a single thin layer, so scientists use it to study the tiny pores (stomata) that let leaves breathe.
More species to explore
Record what you meet and build your own collection
Your photos are kept with their date and place, and you can fill regional albums one species at a time.