ToxiPetsToxiPets
Plants & Flowers
Vet Reviewed

Is hydrangea macrophylla toxic to dogs?

Quick Answer

Yes, hydrangea macrophylla is toxic to dogs. If your dog has ingested hydrangea macrophylla, contact your veterinarian or pet poison control immediately.

For Dogs

TOXIC

For Cats

TOXIC
Hydrangea macrophylla

Your pet ate Hydrangea macrophylla?

Get a personalized risk assessment for Hydrangea macrophylla based on your pet's weight — free in the app.

About Hydrangea macrophylla

### Hydrangea macrophylla (Hydrangea) #### Safety Information for Pets - **Toxicity**: Hydrangea macrophylla is toxic to cats, dogs, and horses. - **Toxic Compounds**: The plant contains cyanogenic glycosides, which can release cyanide when metabolized. - **Symptoms of Poisoning**: If ingested, pets may exhibit symptoms such as vomiting, diarrhea, lethargy, depression, and in severe cases, respiratory distress and convulsions. Immediate veterinary attention is recommended if ingestion is suspected. #### General Description - **Common Names**: Hydrangea, ajisai, Hortensia, Hortensia à grosses feuilles, Hortensia, Hydrangelle hortensia, Hortensia, gaku-ajisai, hortensia à grandes feuilles, hortênsia, Chinese sweetleaf, Garten-Hortensie, French hydrangea, hortensias, hortensia. - **Family**: Hydrangeaceae - **Plant Type**: Shrub #### Morphological Characteristics - **Size**: Typically grows to about 3 to 6 feet in height and width, though some cultivars may grow larger. - **Leaves**: The leaves are large, opposite, and deciduous. They are generally oval to elliptical with serrated margins and a glossy green surface. - **Flowers**: Hydrangea macrophylla is renowned for its large, showy flower heads that can be mophead (rounded) or lacecap (flat with a center of fertile flowers surrounded by sterile flowers). The color of the flowers can vary depending on the soil pH: acidic soils (pH < 6) produce blue flowers, while alkaline soils (pH > 7) produce pink flowers. Neutral soils may result in purple or mixed colors. #### Growing Conditions - **Sunlight**: Prefers partial shade to full sun. However, in hotter climates, it benefits from afternoon shade to prevent leaf scorch. - **Soil**: Requires well-drained soil that is rich in organic matter. Soil pH can be adjusted to influence flower color. - **Watering**: Needs regular watering, especially in the first few years after planting and during dry periods. Ensure the soil remains moist but not waterlogged. - **Fertilization**: Benefits from balanced, slow-release fertilizers in the spring and early summer. Avoid high-nitrogen fertilizers, as they may promote leaf growth at the expense of blooms. #### Care and Maintenance - **Pruning**: Pruning should be done after the plant has finished blooming, typically in late summer. Remove dead or damaged wood and shape the plant as needed. For mophead types, avoid heavy pruning as flowers are produced on old wood. - **Pests and Diseases**: Generally resistant to pests and diseases, but can occasionally be affected by aphids, spider mites, and scale insects. Diseases include powdery mildew, leaf spot, and root rot in poorly drained soils. #### Landscaping Uses - **Aesthetic Appeal**: Hydrangea macrophylla is widely used for its ornamental value in gardens, borders, and as a focal point in landscape designs. Its vibrant and long-lasting blooms make it a favorite for cut flowers and floral arrangements. - **Companion Plants**: Pairs well with shade-tolerant perennials such as hostas, ferns, and astilbes. It also complements other flowering shrubs like azaleas and rhododendrons. By providing a combination of beauty and adaptability, Hydrangea macrophylla remains a popular choice for gardeners and landscapers. However, due to its toxicity to pets, it is important to consider planting it in areas that are less accessible to animals.

Be honest — you won't remember this article at 2am when your pet eats something.

Skip the Googling next time. Scan Hydrangea macrophylla (or anything else) in ToxiPets and get an instant answer personalized to your pet's weight and breed.

Emergency Pet Poison Hotlines

ASPCA Poison Control

(888) 426-4435

*Consultation fee may apply

Pet Poison Helpline

(855) 764-7661

*Consultation fee may apply

Related Information

Dr. Kamala Freeman

Dr. Kamala Freeman

DVMEmergency Veterinarian

Dr. Kamala Freeman is an emergency veterinarian with extensive experience in urgent pet care and toxicity cases. She works at an emergency veterinary hospital treating pets exposed to poisons, toxins, and other life-threatening emergencies.

Stop Googling. Start scanning.

Next time your pet gets into something, skip the articles. Open ToxiPets, scan it, and get a personalized answer in seconds — based on your pet's weight, breed, and health.

Free to download • Used by 50,000+ pet parents