SUCCESSFUL IRIS GROWING
Iris Growing Guide
Why Irises?
Diverse: Bearded irises come in a variety of colours, from delicate soft tones to bold hues that command attention, allowing you to choose the colours that suite your taste and garden style.
Bold focal flower: Tall bearded irises are around 3 feet tall with large statuesque blooms. They are truly a majestic site in a spring garden when little else is blooming.
Hardy: Bearded irises are hardy to zone 3, resilient and require minimal care once established.
Low maintenance: Bearded irises do not require staking, or digging to store over winter, no fussy fertilizer or watering regimes, and they come back every year!
Enchanting Fragrance: Many bearded irises produce a light, alluring fragrance (check details on each variety.
Shop Irises
Growing Guide
Tall bearded irises are elegant focal flowers that add a touch of grandeur to the garden or bouquets with their long stems and large blooms. Beautiful & low maintenance!
Site Selection
Sunlight: Choose a sunny or part shade spot for irises. They require at least 6 hours of sun a day.
Soil: Choose a well draining area, you can add sand, pea gravel or organic materials if the area has too dense of soil, or plant them in raised beds. Ensure humus rich soil or amend the soil if it is packed clay. Irises are drought resistant when established, so don’t choose an overly wet site for them
Spacing: Choose an area where the rhizomes can spread. I like to leave around 2' between my iris plants. You can plant 2-3 of the same type closer together to create a bigger display. But they may need to be split sooner as irises spread relatively quickly.
Protection: Occasionally I will stake a tall bloom spike if I am worried a wind storm may knock it down before it blooms.
Planting Your Iris Rhizomes
- Plant your irises anytime after they are done flowering from midsummer to early autumn. We send out our iris rhizomes in early August/late July for immediate planting
- Loosen the soil in the area you are planting. Add compost (I like the Sea Soil brand at garden centers), worm castings, bone meal/blood meal if you are amending the soil. Take care not to add extra manure to the area as high nitrogen can lead to less blooms and more leaves as well as rot. Irises can handle a less nutrient dense soil compared to some flowers.
- Dig a shallow hole of 4”. Build a little mound in the center. Place the rhizome on top of the mound, allow the roots to spread down along the sides
- Gently back fill, while barely covering the top of the rhizome. Most iris growers leave the top of the iris rhizome fully exposed. The rhizomes like to 'bake' in the sun a little. When they are young though they are a little delicate so you may wish to slightly cover it while it is rooting.
- Press soil down in place and water in
Staking
Irises don't need staking. Occasionally though, I will add a stake to the tall flower spikes to prevent windstorm damage in spring when they are setting flowers.
Watering
Young Plants:
Water periodically (every 4-7 days depending on heat levels) while the iris is getting established. After your iris is established, they will not need as much watering, except in quite dry conditions. I usually water mine every week or two depending on the weather, though sometimes I go much longer as they can handle drying out a little.
Feeding
At Planting:
Mix compost (I like seas soil brand at garden centers), worm castings (full of healthy soil bacteria!) or a little bit of bone meal/blood meal into soil.
During Growing Season:
- I do not fertilize my irises, but will add a bit more compost to their soil every year or two.
- If you are using a fertilizer, use a low nitrogen one or balanced fertilizer (6-10-10 or 10-10-10) in early spring and once again after flowering. Apply only around the area, not on top of the rhizomes to prevent burning
Ongoing Care
First Winter Care: In general, don’t apply mulch on irises to ensure rhizomes stay dryer and prevent rot. However, for their first winter, I do recommend mulching iris plants as they are getting established. I mulch them as late as possible, just before winter for the first year. If you are in a climate with freeze and thaw cycles, these cycles can heave the new roots out of the ground. An airy product such as straw or evergreen boughs works well for this. I have skipped covering them for winter, but it does provide peace of mind in Alberta when we hit -40 and sometimes have very little snow coverage. Remove mulch immediately in the spring as this can encourage rot on the rhizomes if left in place.
Deadheading: Remove spent blooms to prevent the plant from spending energy developing seed pods.
Pest Management: Irises are relatively pest free in our growing area.
Disease Prevention: Ensure good air circulation and avoid watering right onto the rhizome. Rhizomes can rot if left covered with mulch. If you notice a squishy rotted part of your iris rhizome you can cut out the rot and then use diluted bleach (10 pts water:1 pt bleach) to kill off any rot/bacteria present on the rhizome. I have dug out irises/cut apart/removed rot//disinfected rhizomes and then replanted irises that had squishy rotted rhizome parts with much success.
After Blooming
It can be beneficial to mulch with straw before winter in areas with
low snow, or high freeze thaw cycles. Remove mulch in early spring once new growth appears.
Remove spent flowers so the plant does not use energy producing seed pods (unless that is what you would like)
Let leaves continue growing all summer, unless they are rotting or diseased, then remove.
In the fall, you can cut back leaves to 6-8” to tidy up beds if desired, but wait until after
winter when the rest of the leaves have died in order to fully clean up the
plant.
Clean up the plants in the spring, trimming away old leaves and ensuring that the top of the rhizome can be exposed to a bit of air in wet springs.
Irises can be lifted and divided every 3-5 years (in summer after blooming) to prevent over crowding which can sometimes cause less blooms
Irises are drought resistant once established so you don’t need to worry about watering them too much. Water once every week or two during dry spells and water while they are getting established.
Troubleshooting
No blooms?
May need more sun, less nitrogen fertilizer, or time to establish.
Spots on leaves?
Could indicate fungus. I remove any browning or spotted leaves to keep the iris patch clean and healthy. Leaves pull right off at the rhizome base.
Stunted growth?
Make sure your iris rhizome is not rotting. Cut away squishy rot and disinfect the rhizome to save it. Ensure adequate drainage.
Disease Prevention: Ensure good air circulation and avoid watering right onto the rhizome. Rhizomes can rot if left covered with mulch. If you notice a squishy rotted part of your iris rhizome you can cut out the rot and then use diluted bleach (10 pts water:1 pt bleach) to kill off any rot/bacteria present on the rhizome. I have dug out irises/cut apart/removed rot//disinfected rhizomes and then replanted irises that had squishy rotted rhizome parts with much success.
SUCCESSFUL IRIS GROWING
About Irises
Irises have two types of petals. The standards, which are the upright petals at the top of the flower. Then there is the fall, which refers to the three lower petals.
The beard is a fluffy bit between the standards and falls that looks like a fuzzy caterpillar. There is usually only one, but sometimes multiple beards or none,
depending on the iris variety.
Fans- the leaves create a fan like shape while growing
Rhizome- an underground stem that sends out shoots and roots (turmeric and ginger are also rhizome plants). In simplistic terms, the rhizome is a chunk of root that I dig up and mail to customers.
