Spending more time outdoors with pets means paying closer attention to the plants they encounter. Many popular landscaping plants can cause mild to severe poisoning in dogs and cats if chewed or ingested. With pet ownership at an all-time high and changing garden trends, now is the perfect time to revisit which plants may pose a risk.

This guide covers five common toxic outdoor plants, safer alternatives, and steps you can take to make your garden pet-friendly throughout the year.

5 toxic outdoor plants to keep away from pets

1. Azalea & rhododendron

Toxic component: Grayanotoxins
Risk level: High for both dogs and cats

Azaleas and rhododendrons are widely used for their vibrant, full blooms—yet even small amounts can trigger vomiting, diarrhea, drooling, weakness, abnormal heart rhythms, and, in severe cases, cardiovascular collapse.

What to do: If these shrubs are already in your yard, restrict access or replace them with pet-safe flowering shrubs. Always bag and dispose of pruned branches immediately.

2. Asparagus fern (asparagus densiflorus)

Toxic component: Sapogenins
Risk level: Moderate for dogs and cats

Often used as a decorative groundcover, asparagus fern can cause vomiting, diarrhea, and skin irritation when pets brush against or chew on it.

What to do: Avoid planting it in areas where pets roam, especially if you have young animals that like to dig. Consider pet-safe groundcover options instead.

3. True lilies (lilium species)

Toxic component: Unknown nephrotoxin
Risk level: Extremely high for cats

Lilies—including Easter lilies, tiger lilies, and daylilies—are particularly dangerous for cats. Ingesting even a tiny amount of pollen, petals, or water from a vase can cause rapid kidney failure. Dogs may get gastrointestinal upset, but cats face the greatest risk.

What to do: Avoid planting lilies in any outdoor area accessible to cats. If you cannot identify a lily type, default to caution and treat it as toxic.

4. Aloe vera (outdoor varieties)

Toxic component: Saponins and anthraquinones
Risk level: Mild to moderate for dogs and cats

While aloe is known for its human health uses, many aloe species can cause vomiting, diarrhea, and lethargy in pets if chewed.

What to do: Use elevated planters or choose a verified pet-safe succulent if you want a similar aesthetic without the toxicity risk.

5. Nightshade family (tomato plants and related species)

Toxic component: Solanine
Risk level: Mild to moderate, depending on the amount ingested

Tomato plants are garden staples, but the stems, leaves, and unripe green tomatoes contain solanine—a compound that can cause gastrointestinal distress and, in large amounts, neurological symptoms.

What to do: Fence off vegetable beds or use raised containers. Remove fallen unripe fruit promptly so curious pets cannot sample them.

Pet-safe alternatives for a beautiful yard

If you love gardening, the good news is that there are plenty of visually appealing, low-toxicity plants to choose from:

Marigolds (tagetes)
Snapdragons (antirrhinum)
Basil, sage, thyme, and other culinary herbs
Sunflowers (helianthus)
Camellia shrubs

Tip: Before buying a new plant, look up its species in ASPCA’s Toxic & Non-Toxic Plants database.

Checklist: how to create a pet-safe garden

Use this quick checklist during seasonal clean-ups or when replanting:

Review your yard for any of the high-risk plants listed above.
Restrict access or remove toxic species entirely.
Clean up dead leaves, flowers, and fruit promptly.
Plant pet-safe species where pets roam frequently.
Use raised beds, borders, or fencing for toxic or edible gardens.
Keep the ASPCA Poison Control number accessible (888-426-4435).

Future-proofing your outdoor space

Plant availability and landscaping trends evolve, and so does toxicity guidance. As you update your yard, be sure to:

Include plant safety in your selection criteria.
Use native plants when possible—they require fewer chemicals and tend to be hardier.
Mark areas containing specialty or exotic plants to help guests and pet-sitters stay aware.
Re-evaluate your garden yearly to adjust for new pets, new plants, or aging animals.

A safe outdoor environment doesn’t mean sacrificing a beautiful landscape. With the right plant choices and proactive maintenance, you can create a yard that’s healthy, enriching, and safe for both your pets and your family.