Snapdragons (Antirrhinum spp.) are herbaceous perennials grown for their large quantities of colorful flowers and ease of care in the home garden. The plant's flowers snap closed after being manually opened, hence the name snapdragons. Perennial snapdragons bloom during late spring, summer and fall, producing numerous stalks that hold flowers in all colors except blue. Native to North America, snapdragons thrive in USDA hardiness zones 5 through 11. They perform as perennials with proper winter care and make a colorful addition to flower gardens and borders throughout most of the year.
Plant perennial snapdragons during spring in a location that receives full sunlight throughout the day and consists of light, well-drained soil. Spread a 1- to 2-inch layer of compost over the planting site and use a garden spade to work it into the soil to increase fertility to necessary levels. Space perennial snapdragons 12 to 18 inches apart.
Apply a 2- to 3-inch layer of organic mulch over the ground surrounding perennial snapdragons to deter competitive weeds, improve water retention and provide insulation. Start the mulch at least 3 inches from the base of the plants to minimize the risk of disease by allowing adequate air circulation.
Water perennial snapdragons once every five to seven days to prevent the soil from drying out completely. Do not water during winter, when the plants are not experiencing active growth. Apply water to the soil and avoid wetting the leaves, which increases vulnerability to fungal diseases. Provide at least 2 inches of water at each application.
Feed your snapdragons once every two to three months during spring, summer and fall to provide plenty of nutrients for root, flower and foliage formation. Apply following the manufacturer's instructions for proper dosage. Water lightly after feeding, soaking the soil to a depth of about 1 inch, to distribute the fertilizer and prevent root burn.
Pinch back snapdragon tips by about 1 inch when the plant is 2 to 4 inches in height to increase production of flower spikes when blooming begins. Remove dead flowers whenever possible, a process known as deadheading, to prolong the blooming season.
Spread a 4-inch layer of organic mulch over the soil surrounding perennial snapdragons during mid-fall to provide winter protection. Remove the mulch during late winter, just before new growth begins to allow the plants to resume their normal growth.