Home gardeners, plant enthusiasts, and seasoned botanists can all agree that hibiscus plants bring warmth, dimension, colors, and tropical flair to a garden. Few plants are as majestic as a hibiscus in bloom. There are over 300 species of hibiscus in the world. Hibiscus plants can be categorized in two ways; tropical varieties (e.g. Hibiscus rosa-sinensis), and hardy varieties (e.g. Hibiscus moschuetos). Whether outside in the ground or potted indoors, aphids and other pests will find a way to take residency on these plants. One must be vigilant with care to monitor insect activity, identify threats and enemies, treat aphid infestations, and keep pest numbers under control.
Aphids are a well known and destructive pest in the garden. Notorious for being vectors for plant viruses, aphids spread disease by way of piercing into plants with their needle-like mouths to suck the sap from within. The more aphids on the hibiscus plant, the quicker the pathogens get to spread, and the chances of saving the plants begin to dwindle. Common viruses, spread by aphids, that affect hibiscus are mosaic virus and chlorotic ringspot. Aphids secrete a sticky, sap-like substance from their bodies called “honeydew”. This secretion coats whole areas on the hibiscus plant and is the perfect host for sooty mold. While sooty mold is a fairly benign symptom of infestation, it can prevent sunlight from getting through to infected leaves, and is a tell-tale sign that the aphids are winning.
Honeydew is a favored food for many numbers of ant species. Ants will actually farm aphids, herding them like cattle, protecting the aphids from danger to keep their all-you-can-eat honeydew buffet in business. Growing a population of aphids aside, ants will bring further damage to a hibiscus plant, as they can colonize close to their food source, disturbing and weakening the plant’s roots in the soil. Once the root system of the hibiscus has been compromised, the plant will wither and die due to a lack of water.
Aphids multiply quickly. Eggs laid in the fall are able to overwinter and the aphid will hatch in the spring when the temperature rises. The entirety of the overwintered eggs are female aphids. It only takes a few days to reach maturity, at which point those aphids will deliver female genetic copies through live birth. The process of birthing aphid clones continues, with up to forty generations having been produced by summer. When the temperatures begin to drop, winged male aphids are born. After mating, and the aphids lay their eggs, this process continues.
Examine each plant in your home or garden thoroughly. Check the stems, flowers, leaves, and undersides for insects. Aphids often hide underneath the leaves, but they also can’t resist flower buds and blooms, so one must use great care and be methodical in their horticultural examination. Check for egg clusters as well as diseased parts of the hibiscus branches.
After finding eggs, mature pests, or disease, it’s important to do a little research to be sure of what insects you’re dealing with. Knowing the difference between aphid, whitefly, and thrip damage, for example, can be quite helpful. This guide by the University of Minnesota Extension should help you with quick and accurate identification.
There are loads of different products to use to control aphids on hibiscus. From pre-mixed solutions, to DIY mixtures, even biological control methods that kill aphids. It’s important when mixing your own solution to take notes of dilutions used, so it can be tailored to your specific needs.
Finding the right pesticide product for pest management can get overwhelming. Below is a short list of options for dealing with aphid problems on hibiscus plants, their pros and cons, and tips for application.
Poisonous insecticides should be a last resort. Use them when you’re at the end of the list of natural ways to kill or control the growth of these insects. Though these products are easily found in your local big box gardening centers every season, they are generally incredibly hazardous to the surrounding area, including pets and children.
These pesticides come pre-mixed or more often as concentrates. When dealing with concentrates, care should be taken during dilution. There are products available on the market that attach to a regular garden hose, and mix with the water on demand to avoid tricky measurements. This allows you to use as much or as little pesticide spray as you need while the concentrated product retains its shelf life. Always read the store labels twice and use applicable safety measures to avoid contact. Spray the aphid infested plant, make sure all areas of the plant; stems, and foliage, have been hit.
Neem oil is a more tried and true, all natural way to rid hibiscus plants of aphids, and all other soft bodied, leaf suckers. Most pre-mixed pest control products labeled for organic gardening use neem oil as their active ingredient. The oil will coat the aphids, absorb into their bodies, and they die. The pungent neem oil odor will work to detract other pests from the plant as well.
Neem oil has some wiggle room when it comes to dilution, but not too much, follow the directions on the bottle, and adjust the measurements slightly if need be. You can mix up as little as a gallon for use in a small backyard environment. In order to dilute the oil in water, a small amount of dish soap is often added for emulsion. A couple drops of rosemary oil per gallon can be added to the mixture also, as rosemary has been proven to be a powerful additive as a natural insect deterrent. Shake the spray bottle until the oil and soap has blended. Spray every surface of the plant. Use care and a focused stream while you spray, as missing more than a few aphids or their eggs will result in another infestation. Feel free to blast them with water first, just take care not to harm the leaves of your hibiscus in the process. Neem must be reapplied if rain water showers the plants, otherwise the solution will last on the plant leaf for approximately a week.
For more long-term and sustainable methods to control clusters of aphids, ladybugs can be bought and dispersed throughout garden beds and pots.
Pest Control: One of the methods for dealing with infestations is to use lady beetles.
Aphids are their main food source, and establishing a healthy population of these predatory insects will keep aphids from taking over again. Certain predatory wasps will also kill aphids, so remember that not all the wasps and flying insects you get in your yard are enemies! When you’re working on your lawn or gardening, be on the lookout for small clusters of these pests on leaves, branches, buds and flowers.
Hopefully you got a lot out of this article and you’re better equipped to quickly deal with the harm these infestations can cause. More information on general care can be found at this article by Fertilizer for Less. Once you get the aphid populations under control, they are fairly easy to care for and produce Beautiful Flowers!