Cats
Potentially toxicConsulted references classify the plant as toxic or irritating for that pet type.
Verified against ASPCA/provenance audit 2026-05-06 on May 6, 2026.
cat safety reference
Is Smooth Hydrangea safe for cats?
Hydrangea arborescens
Hydrangea arborescens is a deciduous shrub known for its large, rounded clusters of white flowers. It contains cyanogenic glycosides which can cause gastrointestinal distress if ingested by pets.
Hills of SnowHydrangea arborescensSmooth HydrangeaWild Hydrangea
- Light
- Partial shade to full sun
- Habit
- Deciduous shrub
- Care
- Moderate
Safety status
What this means for your cat
Hydrangeas contain cyanogenic glycosides, which sounds frightening but in practice almost always cause stomach upset rather than cyanide poisoning. Cats are more sensitive than dogs because of their smaller body size, but full-blown cyanide signs are rare. Expect vomiting and a quiet, withdrawn cat in most cases.
What to watch for
Most common: vomiting, diarrhea, and depression — your cat retreats and won't engage. Possible: drooling, abdominal discomfort. Rare: signs of cyanide effect, such as bright red gums, panting, or weakness.
Time window
Pet Poison Helpline notes signs of cyanide effect can appear within 15–20 minutes of a large ingestion. The far more common GI upset is usually self-limiting once the plant has cleared the stomach.
When to call the vet
Call immediately if your cat shows weakness, panting, or bright red gums (possible cyanide effect). For mild GI signs, call if vomiting or diarrhea continues past a few hours, especially in kittens or seniors who can dehydrate quickly.
Sources: ASPCA, Pet Poison Helpline.
If a pet has chewed or swallowed plant material and is showing symptoms, contact a veterinarian or poison resource immediately. This product is for structured reference, not diagnosis.
Cats — concern notes
Common signs
Vomiting, diarrhea, lethargy, and potential abdominal pain.
Escalation note
Ingestion can lead to gastrointestinal upset. Please contact your veterinarian or a pet poison control center if you suspect your cat has consumed any part of this plant.
Safer alternatives
No hand-picked alternatives for this plant yet. You can still pick your own using the Compare button on any other plant.
Source evidence
Same cat verdict
Related plants for cats
Eastern Wahoo
Euonymus atropurpurea
Euonymus atropurpurea is a deciduous shrub known for its vibrant fall foliage and deep red berries. It contains cardiac glycosides which can be harmful if ingested by pets.
Potentially toxic for cats & dogs.
Maleberry
Lyonia sp.
Maleberry is a deciduous shrub in the heath family known for its clusters of small, bell-shaped flowers. It contains grayanotoxins, which can cause significant illness if ingested by pets.
Potentially toxic for cats & dogs.
Wahoo
Euonymus occidentalis
Euonymus occidentalis, commonly known as the Western burning bush or Wahoo, is a deciduous shrub containing cardiac glycosides that are harmful if ingested. It is best kept out of reach of all household pets.
Potentially toxic for cats & dogs.
Monstera
Monstera deliciosa
Monstera deliciosa is a popular tropical houseplant known for its large, fenestrated leaves and vining growth habit. It contains insoluble calcium oxalate crystals that can cause irritation if ingested by pets.
Potentially toxic for cats & dogs.