By Chris Freeburn, Master Gardener
June brings a great show of Bearded Iris into the garden. Iris germanica flower in spring and although the bloom time seems short, the big colourful blooms are breath taking. Iris come in different heights, have big showy flowers in lots of fabulous colours and their elongated fan-like leaves give a different shape in the mixed border. There are 3 parts of the flower – “standards” which are the 3 upright petals, “falls” which are the lower petals usually hanging down and the “beard” which is the fuzzy hairs and is often yellow in colour. There are many varieties available, with colours ranging from shades of blue, purple, pink, peach, orange and combinations of colours where standards are one colour and falls another. Stunning!
Iris want a sunny location facing south or west, in well drained soil. They do not want to sit in water and will rot if they are too wet. Iris have rhizomes which produce roots to hold the plant in place and draw up water and nutrients. Rhizomes want their tops to be near the surface of the soil or slightly exposed, especially in heavy soil. A heavily mulched bed will not work for iris unless you leave a large area bare. Fertilize in early spring.
Dead-head flowers by cutting spent blossom stems right down, which encourages more bloom on rebloomers. Leaf fans should be cut back to 3” to 6” in the fall with sharp scissors.
Plants need to be divided every 3 to 4 years to reduce crowding and encourage blooming. Dividing should be done when plants are dormant in August or September. When dividing, check rhizomes for signs of disease and cut out any soft, wrinkled or marred parts. Let rhizomes dry overnight before replanting to allow cut areas to seal over to protect
Watch for Iris borer which will eat through the rhizomes. If you do get borers, dig up and cut off the damaged rhizomes.
Iris are often sold bare root from seed companies and there are several online iris companies in southern Ontario. They tend to ship for fall planting when plants are dormant. You can purchase plants in containers in garden centres in spring or summer.
Royal Botanical Gardens in Burlington have a wonderful display garden if you are up for a trip. Check out their website https://www.rbg.ca/gardens
Iris siberica is another showy plant in the early summer garden. Siberian Iris grow 15” to 36” tall with lots of smaller flowers having standards and falls. Their leaves are narrower and almost grass-like. Siberian Iris can be planted into the soil rather than on top although they still have rhizomes. They can take full sun or part sun and do like a moist area. Dividing needs only to be done every 10 years or if the centre dies out.
One of the earliest iris is Iris reticulata which is actually a bulb that you would plant in the fall. They are short and usually purple.
In Ontario we have native iris that are classed as wildflowers and known as Flags. They include Iris versicolor which you will find in shades of blue and Iris lacustris which is a smaller wildflower and very rare. These are often used in pond settings as they prefer to be wet. Iris pseudacorus is the non native yellow flag iris which is listed on the Ontario Invasive list.
Iris are poisonous for cats, dogs and humans if eaten.
For more information check out these websites: