Answer: Once the flowers fade, they should be trimmed off promptly to encourage reblooming. Sometimes by late summer the entire plant can be trimmed back to encourage regrowth and increased blooming again in the fall.
If the buds are browning without opening, it might be due to several different reasons including overly dry soil or possibly a fungal infection due to high humidity or wetting the flower buds when watering combined with poor air circulation. In general, you would trim off any damaged buds and adjust your watering if needed.
The soil should be kept evenly moist like a wrung out sponge, not sopping wet and not dried out. Using an organic mulch about three inches thick will help keep the soil moister between waterings. To know if you need to water, dig into the soil with your finger. If it is still damp, do not water yet. When you do water, apply it slowly at the soil surface (do not wet the foliage) and make sure it soaks down deep to the deeper roots. It is better to water deeply less often than to sprinkle lightly every day.
You may also want to check with your county extension for a more specific diagnosis of the problem, but I hope this helps you trouble shoot.
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