Hibiscus is a large flowering shrub that blooms in the summer. Generally, they can be maintained in the 4’-6’ range. The flower colors range from white to lavender-pink to reddish purple. They prefer full son, grow well in most any soil (except extremely wet or dry), and transplant easily. Hibiscus should be pruned in early spring.
Hibiscuses are good performers, both in the garden and in bright areas inside the house. If they receive just a small amount of care they reward us with many magical blooms throughout the year. Here, in short, is what they need:
1. Most important, a WARM place where their tropical origins are respected. It is often said that hibiscus like much the same conditions as people and with temperature, that is pretty much true. For best results and lots of blooms, hibiscus should be located where the temperature remains between 60 and 90 degrees most of the time. Short periods of either hot or cold will not injure them though they may show their displeasure by shedding a few leaves or dropping some developing flower buds.
If temperatures routinely drop below 50 degrees, particularly at night, most growth and blooming will stop until it warms up again. Flower size will become much smaller and the occasional blooms may also be misshapen.
Temperatures below freezing will injure hibiscus. Factors such as how cold and for how long, the age of the plant, and whether it is dehydrated determine how extensive the damage. Less than 30 degrees for many hours will most likely kill the plant entirely. Such temperatures should be avoided.
Temperatures over 95 degrees will often cause most flower buds to drop off. Hibiscus can survive temperatures even as high as 115 degrees, provided they have adequate water. When the weather is hot, it is best to maintain a steady supply of water to the plant, rather than have it go through wet/dry cycles.
2. Watering is divided into two areas—cold weather watering and hot weather watering. In hot weather hibiscus will use lots of water and prefer a steady supply of it. Avoid flooding the roots or allowing the plant to stand in a saucer full of water for an extended time. Hibiscus will develop droopy leaves in hot weather if they do not have enough water. The cure is simple, provide some water and the leaves will regain their crispness. In cold weather there is a danger of fungus disease attacking the roots of the hibiscus. Cold and wet conditions are what encourage this. Avoid this problem in colder weather by watering only as much as the plant needs. It is better to let it get too dry than to over water it. This is one of the few things that will cause the early death of a hibiscus plant. If you can keep the roots warm you will have few problems with this.
3. In order to maintain a healthy hibiscus that blooms a lot, you must feed it. Purchase a good quality plant food and use it regularly according to directions on the container. Look at the label for what is often called “minors” such as iron, copper, manganese, and other minerals as these are also good for hibiscus. If you don’t like to fertilize, try using a time-release product like Osmocote that can last for months with just one application.
4. Defend your hibiscus against insects as necessary. Many insects can be driven away simply by spraying the plant with a water hose. There are other safe treatments our professionals can advise you about too.
5. Do not over pot or change the pot size more than 1 step at a time. In other words, if the plant is in a 2-gallon pot the next step up should be a 3-gallon. Equally important is good potting soil, with lots of drainage. If planting in the ground, be sure the hole and location are such that water will not build up around the roots of the plant.