Need advise on what to do with this year's petunia
I planted a stretch of petunia about 30' x 3' this spring. They colored by bed nicely and even now still have lots of blooms. Now that rainy season is starting and weather getting colder, what to do with them?
Should I leave them be, wait until they completely die down then amend and mulch the area for next year's planting? or just mulch on top of them now? They can't survive our winter, can they? Do they self seed or they are sterile due to hybridizing?
Thanks for helping.