Low Temperature and Hardy Hibiscus

Hardy hibiscus plants have tropical-looking blooms but they withstand frost and low temperatures. They grow well to USDA hardiness zone 4, making them a suitable choice for both cold and mild climates. The hibiscus plant goes dormant after frost exposure, but the roots remain alive. Although the roots usually survive without any frost protection, providing some protection in the coldest climates can prevent frost heave. Heave occurs when the soil pushes up during winter freeze and thaw cycles, which can cause broken roots.

Things You'll Need

Pruning shears

Mulch

Instructions

- 1
  Cut back the stems to within four inches of the soil after low temperatures in fall cause the plants to die back. Use pruning shears to make clean cuts through the dead stems.
- 2
  Apply a two-inch layer of mulch over the soil, covering the root zone of the hibiscus. Mulching provides insulation against low temperatures and prevents damage from temperature fluctuations.
- 3
  Move the mulch away from the crown of the plant in mid-spring, once most danger of a hard freeze has passed. Moist spring conditions can cause the crown to rot if wet mulch is covering it.
- 4
  Resume weekly irrigation in late spring after the temperatures warm and when new growth emerges from the base of the hibiscus. Hibiscus plants don't resume growth until May or June, after all danger of low temperatures passes.

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