The American Society of Prevention of Cruelty to Animals says colorful snapdragons (Antirrhinum majus) are nontoxic to dogs, cats and horses. Researchers at the University of California include snapdragons on their list of safe plants for adults and children.
The designation "safe" assumes that you're not making snapdragon tea or using any part of the plants as an herbal medicine. Individuals may have an allergic reaction to handling some plants that contain no known toxins.
Snapdragons are short-lived perennials typically grown as annuals in U.S. Department of Agriculture plant hardiness zones 4 through 11. In USDA zones 9 through 11, they can be planted in autumn for winter color. They like cool weather but don't do well in summer heat of these warm zones.
Cultivars of the 40 species of snapdragons are grouped as tall, from 2 to 3 feet tall; intermediate, 1 to 2 feet tall; short, 9 to 12 inches tall; dwarf, 4 to 9 inches tall; and trailing varieties. They're best planted from 10 to 14 inches apart in full sun, but they can tolerate some shade.
Basics of Care
Work 1 pound of slow-release 12-6-6 fertilizer into the top 6 inches of 50 square feet of space before you plant snapdragons. Apply 1 1/2 to 2 1/2 pounds of 10-10-10 water soluble fertilizer over the same area every three to four weeks as a side dressing.
To side dress, dig a shallow trench about 5 inches from the base of the snapdragons, sprinkle the fertilizer into the trench and cover with soil. Water well.
Snapdragons like moist soil. Water them when the top 1 inch of soil is dry to the touch.
Pinch the tips of 2-to-4-inch-tall snapdragons to grow more flowers. If you remove flowers as they mature, the plants will grow more flowers later in the season.
Insects and Diseases
Pesticides are seldom effective in treating the aphids that sometimes afflict snapdragons, causing their foliage to turn brown in hot weather. Fungal plant rust may cause yellowed leaves, small flowers and early death. Spacing plants properly to let air circulate helps avoid rust, and resistant varieties are available. Proper spacing also helps avoid the fungal disease anthracnose that discolors leaves and causes sunken spots on the stems. Destroy plants infected with anthracnose.
- American Society for the Prevention of Cruelty to Animals: Common Snapdragon
- Cornell University: Snapdragon
- Floridata: Antirrhinum majus
- University of Florida IFAS Extension: Antirrhinum Majus Snapdragon
- University of Nebraska Extension: An Easy-to-Grow Annual Flower
- Washington State University Extension: Snapdragon
- University of California: Safe Plants (by Common Name)
- Mississippi State University Extension:
- Florida State Horticultural Society: Snapdragon Culture in Florida
- Nutrients for Life: Side Dressing Fertilizer in the Home Garden
A one-time farm boy, Richard Hoyt, holder of a PhD in American studies, is a former newspaper reporter, magazine writer and college professor. While writing 27 novels of suspense, he has lived on sugar cane, pepper and papaya plantations and helped keep bees in Belize.