Hibiscus is commonly known as tropical hibiscus and Chinese hibiscus. Their extremely large, gorgeous, colorful blossoms easily identify them. The hibiscus is a deciduous shrub or small tree. A mature hibiscus can reach a height of 15 feet. Blossoms are yellow, peach or red, and some blossoms can grow as large as 6 inches in diameter. These large and colorful flowers attract butterflies and hummingbirds. Aphids can be a problem for the hibiscus. A severe infestation of aphids can damage the plant and blossoms.
Care of Hibiscus
Hibiscus will do well in full sun and well-drained soil. Some gardeners prefer to grow them in containers. They require approximately 1 inch of rain or irrigation per week. During the growing season they will need to be fertilized two times a month. Pruning is minimal—prune to maintain shape and size within your garden or landscape. The hibiscus is extremely sensitive to cold weather and will need protection when temperatures drop to the 30-degree range.
Aphids are also known as plant lice. They are small insects that feed on plants. There are approximately 4,400 species of aphids. Aphids vary in color; they can be green, white, yellow, brown, red or black. It is quite common for aphids to attack the hibiscus plant. These small insects are normally found on the upper top of the stem of the hibiscus. You will see them around the flower buds. Besides feeding on the flowers and leaves, they secrete a fluid/waste material known as honeydew. Black sooty mold then grows on the honeydew.
Aphids increase in numbers quickly—that is why it is important to monitor the hibiscus regularly so you can avoid a severe infestation. Female aphids do not lay eggs; they give live birth to other female aphids. There can be as many as 40 generations of aphids in one summer season alone.
Ladybugs and lacewings are natural predators of aphids, and in some cases these insects are able to keep the aphid population in check. It is important to treat your hibiscus for aphids before they multiply. If the aphids are on a single branch or two you can prune the infected branch away. Be sure to destroy the infested plant material. When you have a severe infestation of aphids, the National Gardening Association recommends using a horticultural oil or insecticidal soap to control them. Insecticides should be sprayed directly on the aphids.
Imidacloprid is a chemical that is used as a soil treatment to destroy aphids. The chemical is absorbed into the plant, aphids ingest the chemical and they die. Imidacloprid is extremely toxic and could potentially contaminate the soil as well as surface water. Care should be taken when using this chemical. Horticultural oil or insecticidal soaps are a safer method of destroying aphids and should be tried first before resorting to imidacloprid.