Irises are perennial flowering plants that are known for their sword-shaped foliage and showy blossoms that bloom in all colors of the rainbow, according to Clemson University Cooperative Extension. Available in both spring-blooming and reblooming varieties, irises make excellent garden specimens and elegant cut flowers. To get garden irises to bloom again after cutting or cut irises to bloom indoors, provide them with growing conditions that stimulate healthy growth and blossoming.
Spring-Blooming Vs. Reblooming Irises
While standard spring-blooming irises, such as "starlight waltz," "watercolor" and "piece of cake," bloom only once per year, reblooming iris varieties like "plum wine," "honey glazed," "ultra echo" and others may bloom up to three times in a single year. Pruning spring-blooming irises mid-season won't result in a second round of blooming, though cutting the plants down to the ground at the end of their growing season will result in revitalized growth the following spring. Reblooming irises can be cut back at the end of each blooming cycle to encourage a new flush of flowers.
Reblooming Iris Care
Reblooming iris varieties require a bit more effort for successful cultivation than their spring-blooming counterparts. To ensure that your reblooming irises will actually bloom again after being cut, make sure to irrigate and fertilize them regularly. Reblooming irises appreciate weekly irrigation during the spring and summer months; apply as much water as necessary to maintain lightly moistened soil. Fertilize reblooming irises with a 5-10-5 fertilizer in the early spring and after each blooming cycle to promote healthy root, foliage and flower development.
Despite the fact that they don't last very long, irises make beautiful cut flowers and are a great way to bring a little of your garden indoors. Cutting your irises before they have opened their blossoms is actually the best way to extend their vase life and make the most of your cut flowers. Wait to harvest the irises until they have formed closed blossoms that are just starting to color. Cut the flowers from the plant using sharpened and sterilized pruning shears. Plunge the cut ends of the stems into tepid water while your prepare the vase and floral preservative.
The use of a floral preservative is essential to getting your irises to bloom after they've been cut. Floral preservatives contain nutrients that your irises need to bloom and ingredients to inhibit the growth of microorganisms, which can cause the flowers to start decomposing more quickly. Commercial floral preservatives, also called flower food, can be obtained from your local garden center or nursery. If you'd rather use what you have on hand, a homemade floral preservative can be made by adding 12 oz. non-diet lemon-lime soda, 1 tbsp. sugar and 1 tsp. household bleach to 2 pints of spring or purified water.
Prepare Cut Irises
Lingering bacteria in glass or plastic vases can also cause cut irises to decompose more quickly and make it difficult for them to bloom. Thoroughly wash the vase in a solution of hot water and antibacterial dish soap before putting your flowers in it. Fill the vase halfway with the floral preservative. Prepare your cut irises by cutting off the bottom 1-inch of their stems while they're still plunged in tepid water; remove any leaves that fall below the vase's water line. Transfer the flowers to the prepared vase quickly to prevent air bubbles from entering their stems.
Encourage Cut Irises to Bloom
Provide cut irises with a suitable indoor climate to encourage vigorous blooming. Keep your cut flowers at least six feet away from air conditioners, heaters, drafts and ripening fruit, all of which speed up their decomposition. The best place for cut irises is in a cool room that receives filtered or indirect sunlight. If the flowers on your cut irises haven't bloomed after a couple of days indoors, remove the bracts around the outside of the blossom. Change the floral preservative every three days to prevent it from stagnating.