Is Hydrangea Toxic to Dogs and Cats? (2026)
Hydrangea arborescens
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Quick facts
| Toxic to dogs | Yes |
|---|---|
| Toxic to cats | Yes |
| Toxic to horses | Yes |
| Toxic component | Cyanogenic glycosides |
| Onset of symptoms | A few hours |
| Indoor / outdoor | outdoor |
If your pet ate this plant
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Symptoms in dogs
- Vomiting
- Diarrhea
- Lethargy
Symptoms in cats
- Vomiting
- Diarrhea
- Lethargy
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What to do
Large ingestions carry a theoretical cyanide risk but clinical cases are rare and typically mild GI upset; contact a vet if a large amount of flower buds/leaves was eaten.
Toxic component and mechanism
The toxic component in Hydrangea is cyanogenic glycosides.
What makes this plant different
Hydrangea's cyanogenic glycosides sound alarming, but clinical toxicology reports describe mostly mild GI upset in real cases — the flower buds carry a higher theoretical concentration than open blooms, but severe cyanide poisoning from ornamental hydrangea in pets is genuinely rare.
Plant identification
- Scientific name
- Hydrangea arborescens
- Family
- Hydrangeaceae
- Also known as
- Hydrangea, Hortensia, Hills of Snow, Seven Bark
- Typically found
- outdoor
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Last verified: July 2, 2026 · Cross-referenced with ASPCA Animal Poison Control