July through August
12 to 18 in.
4 to 6 ft.
southern Utah, Colorado to Texas, northern Arizona
USDA zones 4-8
hardy to 8,000 ft.
Colorado four o'clock is a native perennial flower that is naturally found in dry, stony desert areas.
It produces a profusion of deep rose-pink trumpet-shaped flowers for several months, which are only open from dusk to dawn-- or on very cloudy days. This plant has an enormous taproot, which is allows it to grow in unwatered areas once it is established.
Colorado four o'clock grows as a mounded plant with fleshy leaves.The leaves emerge in spring with a purple color, then turn green once they fully expand.
Colorado four o'clock has grown with variable results at the Xeriscape Demonstration Garden. Some plants have grown very well, producing large mounds of leaves and lots of flowers. Other plants have suffered from insect damage. A piercing-sucking insects feeds on the leaves until they brown and shrivel. It is worth planting in a sunny, dry location. When not damaged by insects, it is a spectacular plant that supports native pollinators and hummingbirds.
This plant spreads 4 to 6 feet wide when mature, so plant it in a spot where its width won't be problematic.
The current year's growth is killed by the first frost. All the stems and leaves turn brown and should be removed.