Hardy, low-maintenance irises do best with a light touch. The plants survive drought, heat and cold and reliably send up tall stalks featuring large, open flowers in late spring and early summer. A moderate amount of annual maintenance after the flowers fade keeps the plants healthy and flowering at their peak each year. There's no need to fuss over the plants; just clean them up a little so they can improve the appearance of your garden regardless of the season.
Pinch off the spent blooms along the flower stalk after the petals begin to fall off. Cut back the entire stalk to its base after all the buds have flowered, using clean pruning shears.
Sprinkle 1/4 cup of 5-10-5 blend fertilizer per three iris plants after they finish blooming. Turn the fertilizer into the top 2 inches of soil around the outside of the plant base, taking care not to damage the roots near the surface. Irises only require after-bloom fertilization if the foliage isn't a deep green healthy color.
Water irises sparingly after bloom. Allow the soil to dry completely between each watering, then provide just enough water to barely moisten the soil. Irises grow best in dry soil and overly wet conditions can cause root disease issues.
Cut back the foliage to within 8 inches of the ground in early fall. Use clean shears to make a straight cut at a slight angle.
Divide the iris roots in summer immediately after blooming or in the fall after trimming. Irises require dividing approximately every four years or if the plants seem crowded. Dig up the roots and cut them into 4- to 6-inch lengths, with each length containing a fan of leaves and healthy roots. Replant the divisions so the top of the root is 1 to 2 inches below the soil surface and space the roots about 18 inches apart.
Things You Will Need
- 5-10-5 fertilizer
- You can apply a light mulch on top the soil around the irises, but don't cover the roots. Wet winter weather, especially in mild coastal regions, can cause rot issues if the iris roots are buried under mulch.
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