Why is My Hibiscus Dropping Flowers?

Hibiscus plants boast some of the largest and most colorful blooms among their perennial peers. The ultimate goal is flowers when you grow and care for one of these shrubs. We want as many as possible, for as long as possible. So when they fall off sooner than we expected, the disappointment is real. 

These shrubs aren’t exceptionally high-maintenance, but they aren’t low-maintenance either. Optimizing the blooming season requires a certain amount of finesse. Any gardener can do it; it just takes a little know-how and the right environment. 

Seeing your plant drop those beautiful flowers sooner than expected can be disappointing. Let’s do some troubleshooting and see if we can figure out what is going wrong. Then, hopefully, we can correct it and hold onto those amazing blossoms a little longer.

The Short Answer

Most hibiscus flowers only open for a day, and they are self-cleaning, so they deadhead themselves. With this in mind, there are ways to increase the length of the blooming season, and the number of blooms overall. 

However, if your hibiscus is dropping flowers before they have a chance to open, there’s another factor at play. Most commonly, pest infestations or issues with watering or fertilizing are the cause of dropping buds. 

The Long Answer

With all of their qualities, hibiscus shrubs can be finicky when it comes to their environmental needs, and may drop flowers in response to stress. If you want to see this plant do its best blooming, it’s important to familiarize yourself with its best care practices. There could be an easily solvable reason your shrub isn’t looking its best.  

Natural Causes

I would love to tell you otherwise, but when it comes to plants that retain open blooms, these shrubs are not at the top of the list. If your flowers are opening, chances are they are living their best, albeit brief, life. While some hybrid varieties have flowers that last up to three days each, this is unusual. Most only last for one day. 

As for why your hibiscus is dropping those flowers, the answer is simple. Hibiscuses are self-cleaning. This means that they drop their spent blooms without interventions, such as deadheading. It’s best to allow your plant to do this very thing. Otherwise, you run the risk of damaging emerging buds and reducing the overall bloom time. If you’re going to deadhead, use a sharp pair of hand shears and be aware of developing buds.

We will talk about some things that you can do to maximize the number of buds in a minute. This plant can bloom consistently for several months. Just don’t get attached to individual flowers. Let’s cover potential reasons why those flowers could be falling before they open. 

Watering Woes

These perennial shrubs have significant moisture needs. If they don’t get the water they need, all parts of the plant will droop and wilt. This includes buds, which are likely to drop if they don’t have enough resources to complete their purpose. If your leaves are looking dry, crunchy, and turning brown, your shrub is thirsty. 

On the contrary, if the leaves are turning a bright shade of yellow, the issue could be overwatering. Over time, an overwatered plant can develop root rot. This inhibits the intake of important nutrients it needs for blooming. Your buds may begin to develop but wither and drop before they open. 

Your shrub will be happiest with moist but not soggy soil. A newly planted hibiscus needs supplemental water in its first season, especially in summer. After that, it shouldn’t need you to water it except in times of drought. Hit that sweet spot by letting only the top inch of soil dry between waterings. 

Pest Problems

Hibiscus flowers are edible, and most creatures find them rather tasty. They are about as non-deer resistant as a plant can be. This means that they also tend to have issues with insects. A heavy enough infestation of any pest can deplete the shrub of nutrients. The buds are the end of the food chain in terms of the transportation of nutrients, so they will be the first to suffer. 

The hibiscus gall midge is a major culprit of bud drop. These insects are similar to thrips. They lay their eggs in developing buds, and when they hatch, that’s what they feed on. They destroy the bud and fall to the ground along with it. Gall midges typically attack the youngest buds. If you see larger ones dropping, thrips could be the issue. 

You can effectively manage thrips and many other pests with neem oil and other environmental controls. Midges, on the other hand, may require harsher treatment in conjunction with effective cultural management. Systemic pesticides are usually necessary to eradicate this infestation, but they are not readily available to home gardeners. Good sanitation is the best way to prevent pests on your hibiscus. 

Fertilizer Faux Pas

Over-fertilization is another reason that hibiscus plants drop flowers. Specifically, these plants don’t like high levels of phosphorus, so keep that in mind when selecting your fertilizer. A formula of 20-10-20 or 2-1-2 is ideal. 

The timing of your application is important, as well. When you first plant, work some compost into the soil to give your shrub a head start and help it establish roots. Once established, fertilize your hibiscus every two weeks, only during the growing season. Hold back during the winter when it won’t need additional nutrients as growth slows and the hibiscus is dormant. 

The exception to this is with tropical varieties or H. rosa-sinensis. These only grow outdoors in zones 10-12 and are very difficult to grow indoors because of their high exposure needs. If you’re growing a tropical variety in a tropical climate, it can bloom year-round, so you can fertilize year-round. Remember to reduce fertilizer during its slight dormancy in fall and winter.

How to Increase Overall Blooming

There are a few things you can do to maximize the blooming potential of your plant. Caring for these shrubs isn’t difficult. You just have to keep in mind that they require a moderate amount of care. Once established, they may require less, depending on your climate. 

In general, they need moist soil but good drainage. Make sure you give your plant a location with proper drainage. If your soil is sandy or otherwise poor, amend it with plenty of nutrient-rich organic material. This will help the soil to hold moisture. Then, water newly planted shrubs every two days for the first three weeks. After three weeks, reduce to twice weekly for the remainder of the first growing season. 

Established plants may not need additional watering, but if a week passes with no rain, definitely water your plant deeply. If you get regular rainfall, you won’t need to supplement a mature shrub. 

Fertilize your hibiscus every two weeks with a low phosphorus, high potassium formula throughout the growing season. They also need a considerable amount of sunlight. If there’s not enough light, flower production will be poor. Keep this in mind when choosing a location. 

Pinching your stems early in the season will encourage branching, which means more blooms. Just make sure you stop early enough in the season that your plant has time to set buds. Pinching too late can result in late, or a drastic reduction in blooms.