Why are my hydrangeas not blooming? A Q&A with Trent Shreckhise
Like clockwork, I can guarantee out of 5 landscape design consultations with homeowners, I’ll get a question of “why isn’t my hydrangea blooming?”
There are a variety factors to the correct answer in each individual case, but the majority come down to one determination: does your Hydrangea bloom on old or new wood?
Knowing the genus and species is very important in how you maintain and treat your Hydrangea. For example, Hydrangea paniculata ‘Lime LIght’ blooms on new wood while Hydrangea macrophylla ‘Endless Summer’ blooms on old wood. Old wood term meaning blooms will appear this coming year on growth from previous years – blooms will not form on new growth. These are the two most popular Hydrangeas species (with many varieties available) found in the landscape over the past decade. With that in mind, I’ll focus the answers below between these two and Oakleaf Hydrangeas.
Old Wood vs New Wood
How should they be pruned differently?
- Bloom on old wood: Selectively cut 1/3 of stems (ideally tallest with balance in mind). Do not trim all stems in same pruning.
- Bloom on new wood: Hydrangeas blooming on new wood require much less precision as the entire canopy can get cut back to 1/3 of its growing season height and one bud beyond where it was pruned previously.
What species of Hydrangea bloom on old wood?
- Hydrangea macrophylla (Big Leaf Hydrangeas ‘Endless Summer’)
- Hydrangea quercifolia (Oakleaf Hydrangeas ‘Pee Wee’, ‘Munchkin’, ‘Sykes Dwarf’, ‘Snow Queen’)
- Hydrangea petiolaris (Climbing Hydrangea)
- Hydrangea serrata (Mountain Hydrangea)
What Hydrangeas bloom on new wood?
- Hydrangea paniculata (Panicle Hydrangeas ‘Limelight’, ‘Little Lime’, ‘Bobo’, ‘Pinky Winky’, ‘Fire Light’
- Hydrangea arborescens (Smooth Hydrangeas)
Okay, I’ve been pruning correctly (or not pruning at all), but still very few to no blooms?
Sun exposure/shade
- Panicle hydrangeas need full sun to mostly sun. Too much shade stunts or hinders completely the plant canopy and bloom performance.
- Big Leaf Hydrangeas and Oakleaf Hydrangea prefer mix of sun and shade and to be protected by severe weather elements (wind, extreme cold/hot location, persistently dry soil)
Frost/cold vulnerability:
- Big Leaf Hydrangeas are vulnerable to late frost (April, May) damage to their buds that can inhibit bloom production while Panicle Hydrangeas have no ill effects from frost or winter damage.
- Panicle Hydrangeas are exceptionally hardy even in harsher northern climates. Big Leaf Hydrangeas are hardy enough, but are closer to the fringe and could experience damage in extreme winters of western and northern VA areas.
Deer
- You may not seem them actively eating, but evidence of chewed leaves or stems is often left behind. If you have deer even seldomly in your garden, likelihood is high that you’ll see some bloom hinderance.
Why won’t my Hydrangea bloom blue in color like others I’ve seen?
Certain Big Leaf Hydrangeas (‘Endless Summer’) varieties can change bloom color based on the acidity of the soil, but the same dynamic is not the case for other Hydrangeas species. That being said, acidic soils encourage blue color while alkaline encourage pink with Big Leaf Hydrangeas.
What’s the best type of Hydrangea to use in my garden?
- Ultimately, there isn’t one particular best Hydrangea to use in your garden. There are various factors, but most importantly, is the amount of sunlight. What may be best on the south side of your house is often different from what you should use on the north side.
What we at Shreckhise Landscape & Design use the most: Panicle Hydrangeas
- Panicle Hydrangeas are the consistently the most prolific, dependable bloomer. They do require full to mostly sun locations. They are very easy and simple to maintain by blooming on new wood each year making them attractive to “low maintenance request”.
Article Written By: Trent Shreckhise, Owner/Designer
