· John Heider's Answer
· Hi Diana-Like Brooks said, a picture would hopefully be helpful in determining what might be going on with your petunia flowers.
I have read that Petunia flower petals can curl up at times if watered from above. It is noted that petunias should be watered at soil level only. Never spray the blossoms. Soaker hoses or bubblers on an irrigation system works well for petunias. These flowers will close up for days after being rained uponwhether the water on the petals comes from the sky or your sprinkler. Most of my petunia are watered early morning with sprinklers and I have seen some closing of the flower now that I am looking. This small amount of closing looks as such only because they are limp from being wet. By mid day they are fine again.
I'm thinking that possibly what would make the petunia leave curl may also cause the blooms to curl and an alteration of the flowers form.
I noted below a few things that can be checked in order to help determine why leaves are curling, becoming deformed and dropping off. Possibly if any of these problems exist they might be contributing to the problem with the blooms.
Check closely for any spotting or deposits of any kind on the leaves. check for any clear, white or black sticky looking substances which may indicate aphids, mildew, or mold.
Check closely for insects such as aphids, green, brown, or black tiny insects that suck the sap from leaves and stems.
If there is no signs of insects it is very possible that the plants are getting too much water. This can be an easy mistake as we tend to water more often as the weather gets warmer. Petunias do well in moist soil, but too much water will curl leaves, brown leaf tips, and kill the plant is left to site in saturated soil long enought. Ding down a couple of inches and make sure the soil feels cool and moist not wet. If wet hold up on watering until the soil drys somewhat.
If the outside of the leaves are turning yellow along with the curling, Fertilize with a water soluble fertilizer to liquid feed every two to three weeks during their growing season. Always follow instructions on product label for application.
Let me know what you find.