My petunias are growing brown buds that turn hard and crack open with many tiny black round things in them. Are these seeds from the petunia and if so can you save them and replant for future flowers, or is it a bug I'm harboring?
These are seeds in the pods. They can certainly be planted next year, but if the plant is a hybrid, there is no guarantee that the new plants will be identical to the parent plant.
To find out if the plant is a hybrid, contact the nursery where you purchased the plants, or look up the variety on the internet for more details.
Just as a FYI, only heirloom plants, otherwise referred to as open-pollinated varieties, can be replicated with seeds. Hybrid seeds, bred and propagated for disease resistance and unique growth habits, should always be purchased through reputable seed companies.
I hope this answered your question. Please write again if I can ever be of assistance.