Hydrangea

Hydrangea L.

Family: Hydrangeaceae

Whole-Genus Guide
Identify To Species When Possible

Pet & Human Safety

People: Not researchedPets: Toxic to pets

People: not researched yet.

Toxic to pets

Every hydrangea species in PlotAndPetal has an independently confirmed toxic verdict (cyanogenic glycosides; vomiting, depression, diarrhea in dogs, cats and horses per ASPCA). Since species can be hard for a non-expert to tell apart at a glance, this general entry treats any hydrangea as toxic by default rather than waiting on identification: the safe assumption given 100% of PlotAndPetal's identified hydrangea species share the verdict.

PlotAndPetal cannot tell you whether a plant you found can be eaten. Only someone who can see the plant can identify it.

Poison control

If someone has collapsed, cannot be woken, is having a seizure or has trouble breathing, call 911 now. For any other possible poisoning, call Poison Help: 1-800-222-1222.

Emergency number source: U.S. federal law (47 U.S.C. § 251(e)(3)), read 2026-10-07.

Naturalist Lore

Historical Background & Breeding Lore

The history of this plant and its name, and how it was bred, where we have them.

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Care

Hardiness zones: Varies by species, roughly USDA 3-9 across the genus as commonly grown; check a species-specific guide once identified.
Mature size: Varies by species: see species-specific guides once identified.
Where it comes from: Varies by species: see the species-specific guides in PlotAndPetal (bigleaf, panicle, oakleaf, and smooth hydrangea) for a plant identified to species.

Soil & Drainage

Pruning & Flush Rhythm

Feeding Schedule

How to prepare the soil, when and what to feed, and how and when to prune where that applies.

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