Hydrangea
- Hardiness
- 3-9
- Mature size
- 3-8 ft by type
- Growth rate
- Moderate
- Pollination
- Lacecaps and paniculatas feed pollinators; sterile mopheads don't
- Bloom season
- June - September by type
- Harvest season
- Dry heads for everlasting arrangements
The illustrated growing guide
Hydrangea
Family Hydrangeaceae
Hydrangea here covers 3 types: Hydrangea, Climbing Hydrangea and Oakleaf Hydrangea. Hardiness alone runs USDA 3–9 across them, so which type you have decides where it survives. Mature size, growth rate and bloom season are given below across all 3 types rather than as one plant's figures. Pollination and harvest season have no single answer here — which of the 3 types you have decides it.
Attracts bees☤ Juglone-sensitiveHydrangea is sensitive to juglone — the toxin exuded by black walnut, butternut, and their relatives. Keep it 50+ ft from any walnut or hickory, or its leaves will yellow, wilt, and die back for no obvious reason.
I
Overview
Will hydrangea suit your garden, and what goes wrong.
Zone fit depends on which hydrangea you have
Hardiness varies across the types of this plant — check the care groups below and the cultivar catalogue to match one to your climate.
Hydrangea at a glance
HardinessUSDA 3–9 across typesEach type has its own narrower range — Hydrangea 3–9; Climbing Hydrangea 4–8; Oakleaf Hydrangea 5–9. Match the type to your zone before you buy.
Mature size3–50 ft across typesSpans the 3 types this guide covers — each type's own figure is narrower.
PollinationNo single pollination rule covers all 3 types — compare them below.
Bloom seasonMay–September across types
Harvest seasonNo single harvest window covers all 3 types — compare them below.
Growth rateSlow to moderate by type
Common hydrangea problems
No pest or disease records on file for hydrangea — which means the library has none, not that the plant has none.
Which one do you have?
The 3 types this guide covers
Where these differ, the key facts above give the span across all of them. Each type’s own figures, as the catalogue records them:
Climbing Hydrangea
- Hardiness
- 4-8
- Mature size
- 30-50 ft eventually; 5 years to start moving
- Growth rate
- SLOW start, then stately
- Pollination
- Lacecap plates feed bees
- Bloom season
- June - July (white lace against green)
Oakleaf Hydrangea
- Hardiness
- 5-9
- Mature size
- 6-8 ft
- Growth rate
- Moderate
- Pollination
- Cone panicles feed bees; a NATIVE hydrangea
- Bloom season
- May - July (white cones aging to pink-rose)
- Harvest season
- Dry the cones for arrangements
II
Growing
Light, water, soil, propagation and the season’s jobs.
How to grow hydrangea: light, water & soil
Hydrangea merges several types whose light, water and soil needs differ — the care groups and the growing playbook carry what applies to each.
III
The year
What hydrangea asks for, month by month.
The hydrangea year, month by month
No fixed season calendar for hydrangea — its care follows conditions, not the calendar.
IV
Ecology & uses
What it does for the garden, and what it is grown for.
Hydrangea in the garden system
AttractsBees
MoistureFacultative / average
DeerBrowsed — protect young plants
What hydrangea is grown for
! Some parts toxic — see notesToxic to dogs, cats and horses (ASPCA; cyanogenic glycoside) — usually vomiting, depression and diarrhoea rather than true cyanide poisoning, which is rare.
Edibility, identification, and traditional-use notes here are general reference — not medical or veterinary advice, and not a claim that any plant treats or prevents anything. Medicinal ratings record how strongly a plant features in herbal tradition, nothing more. Never eat or dose a plant you have not positively identified. More on how to use this library.
V
Cultivars
Named varieties of hydrangea, ruled as a catalogue.
Best hydrangea varieties & cultivars
No named cultivars on file for hydrangea yet — the species itself is what nurseries sell.
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Sources & plant ID
Where the care distinctions come from, and how the plant is filed.
Research basis
Sources behind this profile
No extension citations are attached to hydrangeayet. The care figures below come from the library's own catalogue rather than a traced primary source.
Plant ID
FamilyHydrangeaceae
Invasive riskLow
VII
Where to buy
Third-party nurseries — not Story Thyme Farms.
Third-party nurseries, not Story Thyme Farms. Prices are theirs.
Story Thyme Farms may earn a small commission from these links, at no cost to you — it never changes what we recommend.
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Questions
Hydrangea questions, answered straight.
Is hydrangea safe for kids and pets?
With care. Toxic to dogs, cats and horses (ASPCA; cyanogenic glycoside) — usually vomiting, depression and diarrhoea rather than true cyanide poisoning, which is rare. Site it accordingly if children or pets roam the garden. This is general reference, not medical or veterinary advice — call a vet or poison control if something has actually been eaten.
IX
Elsewhere
Where hydrangea sits in the library.
Sunflower
Zinnia
Peony
Daylily