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..
Irises usually don't change color. You may have had a yellow iris tuber among the blue irises and this year the yellow iris was a more vigorous grower and choked out the blue irises. Or the seeds from your irises may have ripened, dropped, and germinated. Iris seed does not grow true to the parent plant.