12 Toxic Flowers to Avoid in Your Garden

Foxglove poisonous plants lining cobblestone pathway with light purple bell-shaped flowers on tall thin stems

The Spruce / Evgeniya Vlasova

Attractive or fragrant flowers often make us forget that the plants growing in our backyard or on the patio might be toxic for humans or pets.

Whether you are planning to add new plants to your flowerbeds, or you move into a new home and want to check whether the existing landscaping is safe for your children and four-legged best friends, here is a list of common nursery plants that have toxic properties, and suggestions for alternatives. This list is not all-inclusive.

  • 01 of 12

    Lily of the Valley (Convallaria majalis)

    Lily of the Valley

     Julien Prieto / EyeEm / Getty Images

    In May, this shade-loving perennial ground cover develops stems with tiny, nodding, bell-shaped white flowers on one side of the stem. Your nose will also help you identify it: Lily of the valley has a characteristic sweet scent.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs, and cats
    • Non-Toxic Alternative: Virginia spiderwort (Tradescantia virginiana)
  • 02 of 12

    Wisteria (Wisteria spp.)

    Wisteria

    Natalia Ganelin / Getty Images

    This vigorously climbing perennial vine has large showy clusters of fragrant blue or purple flowers in the spring. After blooming, wisteria produces large seedpods with a velvety capsule. After drying, they pop with a startling loud noise.

  • 03 of 12

    Lily (Lilium spp.)

    Daylily

    KenWiedemann / Getty Images

    Many lilies are highly toxic for cats. These include the Easter lily with white fragrant trumpet-shaped flowers, the deep-orange tiger lily with its typical brown spots, Asiatic and Japanese lilies, lily hybrids, and daylillies such as the popular Stella de Oro Daylily.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Cats
    • Non-Toxic Alternative: Canna lilies and other lilies that are not members of the Lillium or Hemerocallis genus and therefore are not true lilies
  • 04 of 12

    Lantana (Lantana camara)

    Lantana

    dieter1freier1 / Getty Images

    As a frost-tender evergreen shrub, lantana is often grown as a trailing plant and as an annual in colder climates. It has small dense flower clusters in white, yellow, orange, red and purple. Sometimes different colors are mixed in the same cluster. The leaves give off a citrus fragrance aromatic when crushed.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs, cats. and livestock
    • Non-Toxic Alternative: Verbena
    Continue to 5 of 12 below.
  • 05 of 12

    Hydrangea (Hydrangea spp.)

    Hydrangea

    masahiro Makino / Getty Images

    There are countless varieties of hydrangea species and cultivars and they all stand out in the landscape by their large flowerheads that are shaped like large round mopheads, lacecaps, or long panicles.

    • Toxic Parts: Leaves, flowers, and bark if ingested
    • Toxic To: Humans, dogs, and cats
    • Non-Toxic Alternative: Spirea
  • 06 of 12

    Foxglove (Digitalis purpurea)

    Foxglove poisonous plant with flower stalks and light purple bell-shaped flowers hanging

    The Spruce / Evgeniya Vlasova

    A close look at a flowering foxglove reveals its most prominent characteristic: The inside of the bell-shaped flowers has many purple to maroon spots with a white ring. The flowers are mostly bright purple, but there are also white, cream-colored yellow, pink, or rose cultivars.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs and cats
    • Non-Toxic Alternative: Hollyhock
  • 07 of 12

    Oleander (Nerium oleander)

    Oleander

    Blanchi Costela / Getty Images

    You can identify an oleander shrub first and foremost by the fragrance of its white, purple, or pink flowers. When not in bloom, take a look at the leaves which are narrow and glossy with a distinctive midrib.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs, cats, and livestock

    Warning

    Due to its high toxicity, Oleander is not recommended for households with small children or pets.

  • 08 of 12

    Rhododendron and Azalea (Rhododendron spp.)

    Rhododendron poisonous plant with ruffled pink flowers clustered together closeup

    The Spruce / Evgeniya Vlasova

    During their bloom in April, all rhododendron and azaleas stand out by their abundance of lavender, rose, or pink flower clusters. The leaves are dark green, hairless, and leathery and turn purplish in the winter.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs, and cats
    • Non-Toxic Alternative: Lilac
    Continue to 9 of 12 below.
  • 09 of 12

    Mountain Laurel (Kalmia latifolia)

    Mountain Laurel

    seven75 / Getty Images

    The flower clusters of this broadleaf evergreen shrub are sometimes compared to tiny bowls or bells. The inside of each flower has symmetrical with dark rose- or maroon-colored dots and streaks. 

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs, and cats
    • Non-Toxic Alternative: Dogwood
  • 10 of 12

    Monkshood (Aconitum)

    Monkshood

    Josie Elias / Getty Images

    Monkshood flowers have two distinct characteristics – their striking deep purplish-blue to violet color, and an upper sepal in the shape of a hood like the one worn by medieval monks, which gave the plant its common name.

    • Toxic Parts: All parts of the plant if ingested
    • Toxic To: Humans, dogs, cats, and livestock

    Because of its high toxicity of monkshood, it is not a recommended choice unless gardening with proper protective gear.

  • 11 of 12

    Angel’s Trumpet (Brugmansia)

    Angel's Trumpet

    Rainer Lesniewski / Getty Images

    As a tropical small tree or shrub, angel’s trumpet is grown in containers in colder climates. The large, drooping flowers come in white, peach, pink, orange or yellow and can grow up to 20 inches long.

    • Toxic Parts: All parts of the plant
    • Toxic To: Humans, dogs, cats, and livestock

    Because of the high toxicity of this plant even when handling it, angel’s trumpet is not recommended in households with kids or pets.

  • 12 of 12

    Fall Crocus (Colchium autumnale)

    Fall Crocus

    bellanatella / Getty Images

    The fall crocus or autumn crocus, which blooms in early fall, has no foliage, unlike the spring crocus. The flower color ranges from lavender to lilac purple.

    Toxic Parts: All parts of the plant if ingested

    Toxic To: Humans, dogs, cats, and livestock

    In households with children or pets, planting crocuses, both summer and fall crocuses, in your yard is not recommended.

Article Sources
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  1. Guide to Poisonous Plants – College of Veterinary Medicine, Colorado State University

  2. Virginia Creeper & Wisteria Toxicity - Poison Control, Poison.org

  3. Guide to Poisonous Plants – College of Veterinary Medicine, Colorado State University

  4. Daylily 'Stella d'Oro', Denton County Master Gardener Association

  5. Guide to Poisonous Plants, Colorado State University

  6. Hydrangea (Hydrangea macrophylla), Children’s Health Queensland Hospital and Health Service

  7. Foxglove Toxic to the Heart, National Capital Poison Center
  8. Guide to Poisonous Plants, Colorado State University

  9. Azaleas and Rhododendrons, National Capital Poison Control Center

  10. Guide to Poisonous Plants, Colorado State University

  11. Guide to Poisonous Plants, Colorado State University

  12. Guide to Poisonous Plants, Colorado State University

  13. Guide to Poisonous Plants, Colorado State University