Experts tackle readers’ garden questions.
Q: I have a red hibiscus that is 5 years old. It is planted in a large clay planter. I know they don’t like too much water, but in the summer if I don’t water it every other day, it wilts badly. Once I water, it snaps back in a few hours. Can I put this in the ground and just hope it does not perish in the winter? I usually put the planter against my brick fireplace and cover with burlap. Or should I remove from planter and trim the roots and replant in the same planter?
Master gardener Rachel Tooker: Hibiscus plants, in the family Malvaceae, produce big brilliant flowers in landscapes, containers, hanging baskets and raised beds. Depending on the zone in which they are growing, hibiscus can be annuals, perennials and even shrubs. They generally have funnel-shaped blossoms that bloom in a variety of colors, including white, yellow, red and pink. Many species bloom year round.
In the Sacramento region’s hot summers, hibiscus fare better with a little afternoon shade to protect them from wilting. They also require excellent drainage.
Watering should be adjusted by the season. In the hot summer months, watering daily may be necessary, but should be reduced in the cooler spring and later fall months. Restrict watering in winter only to times when the soil is dry to the touch.
Because hibiscus must be protected from frost (below 32 degrees), it is best to keep them in a container so they can be moved to shelter or even indoors during cold spells. Hibiscus can be planted in the ground if it is in a sheltered area that will provide protection during a frost.
However, remember that excellent drainage is critical. Organic amendments can be added to heavy clay soils before planting or the hibiscus can be planted in a raised bed.
To keep older plants growing vigorously, prune out about a third of old wood in early spring. Tip pinching in spring and summer increases flower production. Unless the plant is showing stress from extensive root compaction or the pot is so small that it cannot provide sufficient protection to the roots in hot summer months, repotting or root trimming is probably not necessary.
Rachel Tooker is a UC Cooperative Extension master gardener for Sacramento County.
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