Hibiscus Flower Falling Off. They differ from thrips which cause large almost-ready-to-open buds to turn an off-color brownish and fall from the plants. After grasping the stem of the flower behind the swollen base pinch off the old bloom.
Environmental factors often play a role. The appearance of the plant is improved. One of the most common causes of hibiscus blossoms falling off plants is insect pests particularly thrips.
Scratch marks on flower petals in midsummer or fall.
Any stressful condition can prompt the plant to drop its buds. Theses tiny insects feed on hibiscus flower buds causing them to fall off prior to blooming. Called the hibiscus gall midge. One of the most common causes of hibiscus blossoms falling off plants is insect pests particularly thrips.