Snapdragons are hardy annuals that thrive in cool weather, and bloom not only in the spring and early summer but again in fall, providing welcome color and fragrance as summer blooms fade. With their long flower spikes, unusually-shaped blooms and graceful stems, snapdragons impart a feeling of old-fashioned romance and charm to any garden. It is easy to see why they were once believed to restore youthfulness to women. Snapdragons, or "snaps," as gardeners affectionately call them, are capable of blooming lavishly; with the proper care and feeding, you can ensure that they do.
Because of their four different-sized cultivars, snapdragons are versatile performers. The tall size, which can reach 3 feet tall, can be used as background flowers in a garden and look particularly attractive against a picket fence. The intermediate size, which top out at 2 feet, are well-suited for both gardens and cut bouquets. Short snapdragons, which won't grow more than 1 foot high, are good in flower beds and in containers as terrace decorations. At 4 to 9 inches high, dwarf varieties are ideal for edging or mixed containers. There are also trailing varieties, such as Chandelier and Luminaire cultivars, that are ideal for hanging baskets and container gardening. There are hundreds of snapdragon cultivars, and their blooms come in a veritable rainbow of colors, from pastel pinks to crimsons to canary yellows. The only color bloom that cannot be found in snapdragons is a true blue.
Fertilization for Maximum Blooming
A single snapdragon may produce seven or eight blossom spikes over the course of a summer. In order to accomplish this, the plants need full sun for at least five hours a day, about 1 inch of water a week, and good drainage. Before you plant snapdragons, mix an all-purpose 10-10-10 nitrogen-phosphorus-potassium (NPK) fertilizer into the soil. A good rule of thumb for snapdragons is to use 2 pounds of fertilizer per 100-square-foot area. Fertilize your snapdragons every two weeks from May to the end of July, then once a month till mid-September. You can supplement the 10-10-10 with a 20-20-20 NPK if desired, but avoid ammonium-based fertilizers, and beware of over-fertilizing. When your snapdragons stop blooming in summer--a normal occurrence--wait until they begin to look unsightly, then cut them back drastically by one to two-thirds. You'll then be rewarded by a second show of blooms in the fall. After cutting back, feed with 10-10-10 and water liberally to encourage growth. If well-watered and properly mulched, snapdragons can survive well past summer, even tolerating sub-freezing temperatures. They do stop blooming after the first frost, however, so enjoy them while they last.
Tips and Precautions
To avoid fungal disease, don't space your snapdragons too close together. They should be placed at least 1 foot apart, and large varieties should have 2 feet of room in which to spread out. To prevent rust disease, avoid overhead watering, and try to avoid wetting leaves.