when do hydrangeas bloom
Group 1: Plants that bloom on new growth (this yearâs stems) These hydrangeas, which form their buds in early summer on new growth, will flower reliability each year, requiring no special care. Panicle hydrangeas ( H. paniculata) are hardy to Zone 3 and boast fat, cone-shaped flower heads. They are a good choice for a beginner. The most common cultivar is âGrandifloraâ, or P.G. (PeeGee) after its initials, a big old-fashioned floppy shrub that is 10 to 15 feet tall.