Everybody loves four o’clock flowers, right? In fact, we love them so much that we hate to see them fade and die at the end of the growing season. So, the question is, can you keep four o’clock plants over winter? The answer depends on your growing zone. If you live in USDA plant hardiness zones 7 through 11, these hardy plants survive the winter with minimal care. If you live in a cooler climate, the plants may need a little extra help.
Winterizing Four O’clock in Mild Climates
Four o’clocks grown in zones 7-11 need very little help to survive the winter because, although the plant dies down, the tubers remain snug and warm underground. However, if you live in zones 7-9, a layer of mulch or straw provides a little extra protection in case of an unexpected cold snap. The thicker the layer, the better the protection.
Overwintering Four O’Clocks in Cold Climates
Four o’clocks winter plant care is a little more involved if you live north of USDA zone 7, as the gnarled, carrot-shaped tubers are not likely to survive the winter. Dig the tubers after the plant dies down in autumn. Dig deep, as the tubers (especially older ones), can be very large. Brush excess soil off the tubers, but don’t wash them, as they must remain as dry as possible. Allow the tubers to dry in a warm place for about three weeks. Arrange the tubers in a single layer and turn them every couple of days so they dry evenly.
Cut a few holes in a cardboard box to provide air circulation, then cover the bottom of the box with a thick layer of newspapers or brown paper bags and store the tubers in the box. If you have several tubers, stack them up to three layers deep, with a thick layer of newspapers or brown paper bags between each layer. Try to arrange the tubers so they aren’t touching, as they need plenty of air circulation to prevent rotting.
Store the tubers in a dry, cool (non-freezing) location until planting time in spring.
Oops! If you didn’t getting around to take care of the preparation needed to save your four o’clocks flowers in winter, all is not lost. Four o’clocks self-seed readily, so a new crop of the lovely flowers will probably pop up in spring.