Winterizing Tropical Hibiscus

Winterizing hibiscus plants always produces many questions that vary greatly from one region to another.  We are located in the heart of Texas where year around average temperatures range from 32F (0c) to 98F (36.6c).  Most Regions will require bringing potted tropical plants indoors because anything below 40F (4.5c) can cause severe damage and possible death. The exception to the rule would be the perennial Hardy hibiscus (hibiscus moscheutos). These plants are able to withstand the cold winters even when planted in ground and are simply cut back to the base of the plant to allow new growth to return in the spring. Hardy hibiscus should be pruned to the base of the plant with a generous application of mulch for insulation and moisture retention.

 
A heated greenhouse would obviously be the best place to keep your potted plants in winter but not everyone is afforded the space or budget for one.  Inside your house is good, and provided there is enough room and plenty of sun, your hibiscus will bloom all winter.  Most people end up dragging those heavy pots in and out of their garage or basement until spring even though it is not necessary to do so with the right amount of light and humidity.  A fully insulated garage door can help keep the garage much warmer
during the winter months.  Tropical hibiscus can grow as tall as 5 to 6 ft. and take up a huge amount of space, so plan ahead before growing more than you have room for during the winter months.

 
Pruning should be done in early spring in order to provide plenty of blooms during the growing season; however our larger well established trees have been pruned extensively in July prior to the winterization process and had great success in the spring.  Your plants need very little water in the winter.  We recommend about a third of the amount they have been getting during summer.  Do not allow the plants to sit in water, it will cause the roots to become damaged or mold.  Continue fertilizing utilizing a fertilizer with low to 0 nitrogen content, no more than 5% every 15 days. Tropical hibiscus become dormant during this time and nitrogen promotes branch development. Start giving the hibiscus plants nitrogen as spring is stating to warm the potting soil. Do not get upset when the leaves turn yellow and drop as this is a natural occurrence of dormancy.  Yellow leaves that drop from your plant are mostly caused from shock due to a sudden lack of humidity and bright light.  It is recommended that your hibiscus receive at least 4 to 6 hours of light per day. Garage type florescent fixtures on a timer from Home Depot are perfect for providing adequate lighting when winterizing hibiscus.