Q.I Have A Hibiscus Syriacus “Helene” . Several Buds Fall Off And The Blossoms Last Only A Day Or So.
I live in Colorado along the Front Range where we have intense sun and winds. Newly planted. Gets pretty sun pretty much full time. Generally hand water daily but today got sprinkler system extended to include this flower bed. Don’t have prior experience with this bush.
A newly planted hibiscus will be sensitive to its environment not being perfect so give it a break until it becomes established in the garden. Once established with a much larger root system, it should perform better. Here in Texas, they are very drought tolerant through out normally very hot summers from May through September. They can be found planted in the medians of many streets.
Too much or too little water. Wwhen recently planted, maintain the soil as evenly moist as you can during the growing season.
Too much fertilizer.
Check for thrips (very small, slender dark insects). If you find any, spray with either a water (1 gallon) + soap (1%) solution to suffocate them or you can use spray neem oil.
Check for gall midge and its eggs/larvae in the flower buds. The buds can fall off when the gall midge fly lays its eggs in the buds. The larvae is white. If you find larvae or eggs collect all fallen buds in a plastic bag and dispose of the bag in the trash. You can also try applying insecticides with the active ingredient imidacloprid but the spray may not reach eggs/larvae in unopened flower buds.