The Stages of a Snapdragon

Perennial Versus Annual

• Snapdragons are perennials in their native Mediterranean homes. The Missouri Botanical Garden says they are also perennials in U.S. Department of Agriculture (USDA) Plant Hardiness zones 7 to 10, where they can survive, and in some cases blossom, through the winter. In the South, they are semi-dormant during summer heat and stop blooming until autumn. Sometimes they don't survive without some shade. In regions with freezing winters, snapdragons may survive if planted near a sunny wall and mulched. More often, northern snapdragons die by winter, although their prolific self-seeding creates new plants the next season. This annual-versus-perennial identity crisis results in snapdragons being classified as tender perennials or cool-season annuals.

Germination

• Snapdragons need exposure to light to germinate, so they must be sown on the surface of indoor growing media, such as peat pellets plumped up with water, or on outdoor soil. The date when this process begins depends on the season when the sets should be blooming outdoors.

  Although they grow well in cooler temperatures, snapdragons germinate best at 65 to 75 degrees F. Growing them indoors speeds up blossoming, because they can be transplanted outdoors when the nighttime soil temperature is somewhere from 45 to 65 degrees F. Whether planted indoors or outdoors, the seed takes seven to 12 days to crack open and push up its first set of leaves, called the radicle.

Reaching Maturity

• Suggestions vary from 45 to 72 degrees F for the best temperatures for growing snapdragons indoors after germination, with nighttime temperatures being the lowest. About 10 weeks after planting the seed, the snapdragon sets are sturdy enough to adjust to outdoor life. This involves gradually decreasing moisture and increasing sunlight exposure, as the sets are placed outdoors daily for about two weeks. The snapdragons will blossom about 16 weeks after planting.

Blossoming and Reseeding

• In the South, late-spring and early-summer blossoming is prolonged by planting snapdragons where they will receive some shade. In the North, spring blossoming is sped up by planting along warm, sunny walls. Pruning a few inches off the plants after they've finished blossoming helps them bloom again or get through a hot spell. If their spent blossoms are not removed, snapdragons reseed easily and are ready for a new round of life the following growing season. However, they are hybrids -- and subsequent plants will not be exactly like the originals.