How (& Why) You Might Want to Grow Irises
Why should you grow irises? For starters, they are an easy-to-grow flower that comes back every year. They will grow in almost any part of the US. The flowers are great for attracting hummingbirds and butterflies.
Irises also make beautiful cut flowers. You plant them once and each year they will give you gorgeous color in your flower garden. They come in a multitude of colors and are very hardy. They make a great plant for the back of a flowering border.
(Please note that some of the links in this article may be affiliate links and I may receive a small commission if you purchase something through a link. It will not change your cost. As an Amazon Associate I earn from qualifying purchases. For more information, check out my disclosures page.)
(This article was co-written with my sister, Robin Armstrong.)
How to Grow Irises
Irises aren’t difficult to grow. They grow well in zones 3-9. However, there are a few things to consider when planting your irises to ensure they bloom well for years to come.
- Irises grow best in full sun; they need at least 6 hours a day to bloom well.
- Well drained soil is essential. If irises sit in water, they will rot.
- With clay soil, adding compost, gypsum, or soil conditioner (such as fine pine bark) will help improve drainage. Iris can also be planted in raised beds.
- Irises are very drought tolerant, but grow and bloom best with a half inch or more of rainfall a week.
- With reblooming varieties, summer rainfall or supplemental watering will increase fall bloom.
- Fertilize twice each year-around March 1 and again around August 15.
- Use a fertilizer that is low in nitrogen, such as 5-20-20 or 5-20-10. Too much nitrogen will produce lots of leaves but little bloom and can lead to rot.
- Every two or three years, use a complete fertilizer that contains minor and micronutrients.
- The best time to plant bareroot plants is July through September.
- Prepare your soil by removing any grass or weeds and tilling or digging the soil to loosen.
- Dig a wide hole, with a small mound in the bottom. Place the rhizome (the swollen root) on the mound, and firmly pack the soil around the rhizome until only the top of the rhizome is visible.
- Water gently immediately after planting, then every week for the next month.
- When planting multiple irises set rhizomes 6-12 inches apart.
- After spring bloom, cut down the bloom stalks. If not, they can produce seed, which will not be the same as the parent plant.
- Remove any leaves that turn brown during the growing season and all brown leaves in the fall. This will keep insects from overwintering in the dead foliage.
- Every three or four years, it is best to dig and divide the plants in late summer. For more information on dividing irises, read this post.
- Some varieties have the ability to bloom again in the summer or fall.
- Rebloom is not guaranteed and it is often affected by weather conditions.
A Few Notes on Growing Irises
While it is best to plant irises July through September, they can be planted any time as long as you can dig a proper hole. (Don’t try planting them in frozen ground.)
Are you looking to purchase some Irises for your landscape? If so, check out Pecan Grove Farms on Etsy. (Full disclosure…this is my sister’s shop, however I am not receiving any compensation for this post.)
Do you grow flowers in your yard? Have you ever grown Irises before? If you’ve grown them before, what is your favorite variety?