|I recently planted petunias in a hanging basket and some planters by my front door. A few of the petunias in one of the hanging baskets are developing
|Based on your description I think your plants may be suffering from budworms -- small worms or caterpillars that are the larvae of a moth. These are unfortunately difficult to treat because they are protected from sprays by being inside the bud. You might have some success by picking off buds with holes in them, scouting and picking off any caterpillars you see (dusk is a good time to look) and treating the plants with Bt (in products such as Dipel) to try to stop the caterpillars from feeding. Also, keep the plants away from lights at night to avoid attracting the adult moths. This pest overwinters in the soil, so either leave the pots outside for the winter where they will freeze solid or dispose of the potting soil in the trash at the end of the season. If you have geraniums or nicotiana, also check them for infestations.