How to Grow Antirrhinum majus

Choose a spot in full sun with rich, fertile, well-draining soil. Depending on the variety you choose, make room for them in either the front, middle, or back of the flower border. If your soil is heavy clay, lighten its texture by adding peat moss and/or compost to the garden bed before you plant, and incorporate the amendments into the soil by digging them in with a shovel.

Plant snapdragons in early to mid spring for late spring and early summer flowers. Plant in late summer to early autumn for blooms throughout autumn and into early winter in mild areas. Space small varieties about 6 inches apart, medium varieties 8 inches apart, and large varieties 12 inches apart.

Water the plants individually with a watering can as you plant them. Thereafter, water with a soaker hose placed on the surface of the soil alongside the plants. Wetting the foliage can encourage development of a rust disease to which snapdragons are susceptible.

Mulch the flower bed with an organic mulch in a 3-inch layer. Use straw, hay, shredded wood bark or buckwheat hulls. Mulch will keep the soil evenly moist and discourage weeds from growing.

Remove faded individual flowers promptly, to keep the plants blooming for a longer period. Snapdragons bloom from the bottom up, so the stalks will last quite a while before all the blossoms are spent.

Fertilize with a granulated 10-10-10 fertilizer by side-dressing plants about four weeks after you plant them. Apply 1/2 cup of fertilizer for each 10 feet of row alongside the plants. Scratch the fertilizer into the soil with a garden claw.

Cut the plants back by about half their height when they stop blooming in the heat of summer. Keep them well watered during the hottest part of the year, and they very likely may begin blooming again when cool fall weather arrives.