North East Ohio Iris Society

Iris Care

Do my Iris need watering?

Iris initially need water after they have been planted and throughout the first growing season to help their root systems become established. Established Iris will benefit from watering in the spring, but need no other watering in most climates. Infrequent deep watering is much better than frequent shallow watering. It is always better to under water than over water.

What kind of fertilizer should I use?

One month before bloom season, while the tulips are blooming, apply a low-nitrogen, well-balanced fertilizer, such as 5-10-10 or 6-10-10. Keep the fertilizer several inches away from the rhizomes. In late September, fertilize again with bone meal.

What should I do when my Iris become crowded?

To ensure a good bloom, iris clumps should be thinned out every three or four years. In the late summer, dig up the clump, separate the new rhizomes, and replant.

What care do my Iris need once they are established?

Always keep your Iris beds clean and free of weeds. After they bloom, cut off bloom stems close to the ground. Watch for diseased or dying leaves, and remove them immediately. In the late fall or early winter, cut healthy leaves back to about six inches.

Do my Iris need winter protection?

It is a good idea to cover newly planted Iris, especially in areas with cold winters. Soil, straw, pine needles, and leaves are all effective covers. Remove the cover as early as possible in the spring. Early planting will also help your Iris become established before the first winter.

Are there any weed-killers compatible with Iris?

Unfortunately, there is no one chemical that will kill all weeds and not also harm your Iris. There are herbicides that will kill grasses while not harming the Iris. There are also pre-emergent herbicides that will keep weed seeds from germinating while not harming the Iris. Avoid using mulches, ground covers, or man-made weed barriers to control weeds around your Iris. If you cover your Iris with any of these, the Iris may quickly rot. There is really no substitute for hand weeding!