Here are averages that might help you know how often you should change the air filter at home: Vacation home or single occupant and no pets or allergies: every 6-12 months Average suburban home without pets: every 90 days
Rating Newest Oldest. Best Answer: Cut off dead blossoms and dead bloom stalks when the iris has stopped blossoming, but don't cut back the leaves until they begin to turn brown in the fall. The leaves are needed to produce next year's blooms. When you do cut, leave a fan shape about six inches long. Feed your irises a teaspoon of bone meal every fall and when you replant. You can feed again a month before they usually bloom if you like, but they are quite tolerant of just one feeding..
You will want to dig and divide them every 3-4 years to remove the old rhizomes in the center of the clump that won't bloom again. This is usually done in August or September . Siberian iris can be fertilized in early Spring and after bloom with regular fertilizer (like 10-10-10). They like even moisture through the growing season. You don't have to remove the bloom stalks if you don't want to, or if you want them to reseed. After the leaves die back, cut them off a few inches above the ground. * Apply a thin layer of compost around the base of plants each spring, leaving the rhizome exposed.