How to Grow Bearded Irises
Planting Time and Soil Conditions for Bearded Irises
Bearded Iris grow from rhizomes and best times to plant are July through September in USDA zones 3 through 9. You can purchase the rhizomes from a garden center or any big box retailer in late spring. They require 6 to 8 hours of direct sunlight. If you live in an area that has very hot summers, plant in an area that receives morning sun and afternoon shade. Irises are not very fussy about the type of soil only that it needs to drain well. I have mine growing in clay, but as long as they are not sitting in standing water, they will do fine.
Spacing and Planting Depth
Plant rhizomes very shallowly with the roots fanned out facing downward, just below the soil surface. Planting them too deep will affect how they grow and reduce flowering. Space your rhizomes 24 inches apart or you can go as little as 12 inches apart if you are trying to quickly fill in a planting area.
How much do you already know about Irises?
When to Divide Bearded Irises
Bearded Iris need to be divided every 3 to 5 years. A good indication is when you notice that your irises are no longer blooming or they have less blooms than the previous season.
Dividing them is easy:
- In late Summer or Early Fall, dig the entire clump with a shovel or garden fork.
- Separate out the rhizomes. It is very easy to tell where each rhizome can be separated from the others. Break apart or use a knife to separate.
- Trim the leaves/stalks of the plant to about 6 inches in height. This will force the plant to concentrate on putting out more roots instead of leaves in preparation for the winter.
- Replant each rhizome 12 inches to 24 inches apart, very shallowly.
- Water in well.
Bearded Iris Types and Classifications
There are several types of bearded irises. They are classified in a few different categories which are comprised of height and bloom times.
- Miniature Dwarf Bearded-Earliest bloom time of all bearded irises and maxes out at about 8 inches high. Good for the front of the border and planting en masse.
- Standard Dwarf-Another early variety but blooms slightly later than the miniature. The height on these max out around 16 inches.
- Intermediate Bearded- blooms later than the two above, but overlaps its bloom time with the two above. These range in size from 16 inches to 27 inches high.
- Border Bearded & Tall Bearded-these bloom late summer and with larger flower heads than the varieties above. The height on these are anything 27 inches or taller. These produce many flowers that can be ruffled or lacing types.
There are literally over 300 different types of Irises and they come in a rainbow of colors.
- Rhizomes are dried and used in some perfumes and medicine (known as Orris root).
- Some gin makers (i.e. Bombay Sapphire Gin) use the root and flowers for flavoring and coloring in their product.
- Irises have been the subject matter of many artists including the most famous painting by Vincent Van Gogh from 1889 entitled "Irises".
- The Fleur De Lis design adopted by France in the 12th Century is that of an Iris.
Iris Care Throughout the Growing Season
In Spring: remove all the old foliage and any dried leaves or mulch from around the plant. This will help with air circulation and any pests that might have made their home overwintering in the dead leaves.
Late Spring/Early Summer: Remove all spent flowers by deadheading. Irises do drop seeds, but the seeds are normally not true to the original plant.
Late Summer/Early Fall: Divide irises if needed.
Good Iris Companions
When creating a planting bed, these perennials make good companions:
Experiment in the garden and choose which plants are right for you!
For more information on Irises, visit the American Iris Society
© 2014 Lisa Roppolo