The snapdragon is one of the most beautiful plants for fall color, and it thrives right through winter until late spring heat arrives. Snapdragons love those times when night temperatures are in the low 40s and day temperatures reach the low 70s - which makes them ideally situated for fall in the South.
The ideal time for planting is when temperatures are 60 to 75 degrees during the day and 50 to 55 degrees at night. Many gardeners don't realize snapdragons are very cold hardy. Once established in the bed and hardened off, they can take sub-freezing temperatures. Make sure they stay well watered during these cold spells. With a layer of pine straw during extra cold spells, they can last for quite some time.
Snapdragons prefer well-drained, organic-rich beds prepared much like what you do for pansies. Till 3 to 4 inches of organic matter to a depth of 8 to 10 inches. While tilling, work in two pounds of a slow release, 12-6-6 fertilizer per 100 square feet of bed space.
Colors include red, yellow, pink, burgundy, bronze, orange, white and multiple colors. For the most effective landscape display, I still believe massing the beds in single colors is the way to go.
Don't forget that as these fragrant spikes get larger, they are also good for cut flowers, particularly the old-fashioned Rockets. Sonnets and Liberty that get about 18 to 24 inches tall have been my favorites, but the Freesong and the Crown Series are gaining recognition.
The Terra Cotta mix in the Crown Series may be among the prettiest snapdragons I have ever seen. The colors are rust and orange with a little creamy yellow.
Trailing varieties have really caught on with gardeners for use in the landscape, baskets and mixed containers. The Chandelier and Lampion series have been the most popular, but the new Luminaire series under the BallFlora Plant label should satisfy a lot of gardeners. As is typical of the large varieties, the trailing types come in several colors.
Miniature varieties have always been popular, particularly the Tahiti, Bells and Floral Showers. These are great in the landscape but also super for growing in containers. There is a new group called Montego that will turn heads.
Snapdragons work well in combination with pansies, panolas, and ornamental kale or cabbage. Plant in bold drifts in front of evergreen shrubs to show off their color. Try planting them close to beds of spring-flowering daffodils.
Snapdragons are not that hard to grow. Deadhead to keep flowers producing, and keep water on all fall bedding plants to help them survive times of drought. If record cold should threaten, cover snapdragons with pine straw for a few days until the chill has passed. When temperatures warm back up in the spring and faster growth begins,give the bed a dilute application of water-soluble 20-20-20 fertilizer.