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..
Conflicting info on many sites. I think Schreiner says to cut the fans back. Others say not to. I definitely will cut off the brown or spotted foliage but I wait until after the first hard frost. I suppose it depends on where you live (zone) and how badly things like too much rain or snow you get affect your irises.