Portulaca looks beautiful when the sun shines, but has a nasty habit of closing its blossoms in late afternoon, in very early morning or on cloudy days. Overhead watering causes also blossoms to close. /It's a/ good time to water in early morning, when blossoms are naturally closed.

Why do portulaca flowers close at night?

Scientists know the mechanism behind the phenomenon: In cool air and darkness, the bottom-most petals of certain flowers grow at a faster rate than the upper-most petals, forcing the flowers shut.

How do you keep Portulaca blooming?

You don't have to deadhead the flowers to keep portulaca blooming all season long, but you can pinch or cut the long stems to remove spent blossoms if you want to prevent self-seeding, shape your plants or keep them in bounds.