Beauty beholds the Bearded Iris

By Melanie Mathieson
Gardening Guru

Although there are many different species of irises, the bearded iris is one of the most popular perennial flower. Not only a popular garden plant, it is often seen in artwork including a famous Van Gogh or depictions from local artists. Quebec’s provincial flag sports the fleur-de-lis, a stylized version of the bearded iris. And those who have seen my garden soon realize that the bearded iris is my favourite flower.
There are hundreds of varieties of bearded irises available on the market today, including a range of sizes from tall to dwarf. A rainbow of colours and colour mixtures are available, with new varieties becoming available each year. The colours range from pure white to black with every popular flower colour and shades in between. My personal collection boasts over 40 varieties in varying sizes and colours, and each year I see a new “must have” for the garden.
Almost all of the varieties available are hardy to Zones 3 and 4, with a good percentage hardy down to Zone 2, so you should have no problems growing them in our district. Bearded irises are classified as rhizomes, which is a cylindrical shaped (bulb-like) underground stem that produces leaves on the topside and roots on the underside. The rhizome is where the food source and nutrients for the plant are developed and stored, but also provides the plant with stability in the ground. The rhizome is planted with roots facing down but sitting three-quarters on top of the soil. When planting I always dig a hole deep enough to accommodate the length of the roots. I suspend the rhizome over the hole, at the soil surface level, with one hand, letting the full length of the roots dangle into the hole. With other hand I add soil to the hole being careful not to compact the roots. Once the hole is full I firm up the rhizome by adding some soil around the edges of the rhizome and making sure to keep three quarters of the rhizome exposed on top of the soil. Once the roots are established the plant becomes very firm and stable in the ground. Planting Tip: For the best show of flowers plant the rhizome with flat side of the leaves facing the direction in which you will want to view the flowers.
Bearded irises are sun-loving perennials. Their rhizomes are also sun-loving, hence the reason for planting them so they are partially exposed on the soil. When planning for your bearded irises make sure that they are positioned in the garden to receive plenty of sun. Bearded irises can tolerate the intense sun of a southern exposure garden but will also thrive in an east- or west-facing garden as well. I do not recommend a north facing exposure though as the conditions are usually too moist and too low in light. When positioning the irises in the garden make sure surrounding plants or shrubs do not shade the irises. Also remember the rhizomes also love sun, so do not cover them with mulch or shade them with other low growing plants. The bearded iris cannot tolerate wet conditions very well. They will rot very quickly if planted in soil that holds the moisture. Make sure you plant them in healthy well-drained soil that will stay moist but not wet. Also make sure to plant them in the garden in areas where melting snow will not form puddles or extended wet areas. Because of their tolerance to heat and full sun, the bearded iris can also tolerate dryer and drought–like conditions much better than most other perennials.
Easy to grow and often maintenance free, the bearded iris will soon become your favourite too. They are some of the earliest flowering perennials with season starting in early to mid-May extending into late June depending on the variety that you choose. Usually the dwarf varieties bloom first, with the tall variety developing their flowers in the latter part of June. The flowering period for each variety usually lasts about a week. New hybrid varieties are available in which the plant will bloom in the spring and the fall in the same year. This is a real bonus for the iris lover and are available from are local nurseries so give them a try. The bearded iris is identified by its erect leaves that are flat and strap-like. For this reason this plant makes a great border plant, with dwarf varieties at the front of the garden and the larger varieties for the back. The leaves provide a fantastic backdrop for other perennials or annual flowers after the iris blooms have faded. A very showy flower with only six petals is the bearded irises claim to fame. Three of the large petals fall downwards on the flower and these petals are called ‘falls’ the other three erect petals are called ‘standards’. The centre of the ‘falls’ petals will have a fuzzy, yellow or white area identified as the ‘beard’. Some of the most popular varieties have ‘standards’ in one colour and ‘falls’ in either a contrasting colour or another colour shade from the ‘standards’. This is the main reason that so many varieties are available because the colour and shade combinations are endless. Ranging in height from a few inches to around one foot the dwarf varieties make a great plant for the front of the garden. Dwarf varieties produce showy flowers relative to their leaf size up to about four inches tall. Medium height varieties usually have a flower ranging from four to six inches tall and flower stalks are usually twelve to twenty-eight inches in height. In order to be classified a giant variety the flower stalk must be taller than twenty-eight inches and the flower does not disappoint, with sizes ranging from six inches to almost twelve inches in some varieties.

Considered a low maintenance perennial the care is fairly straightforward. I apply the appropriate fertilizer, spring, summer and fall to the bearded iris beds. Trim away leaves only after they have turned brown, especially before the snow flies. I also trim away spent flowers immediately to promote longer bloom times and to allow the rhizome to regenerate its food stores faster. Bearded irises need to be divided and separated about every 3-4 years but this can vary with the growing conditions and the size and vigour of the variety. It is always best to wait until they have finished blooming before dividing but after flowering they can be divided anytime during the growing season. To divide them successfully, dig up the clump and cut the healthy rhizomes away from the dead and woody looking centre. Keep only the rhizomes that are healthy and as I always say with all bulbs “look good enough to eat”. Compost any of the woody and shrivelled looking parts of the clump. Replant the healthy rhizomes following the guidelines stated above. Generally a bearded iris survives without many problems, but wet conditions can easily cause harm with two bacterial diseases known as rhizome rot and bacterial soft rot. Of course mouldy or diseased plants or rhizomes shouldn’t be added to your composter, so make sure you dispose of any thing like this promptly in the garbage before it has a chance to spread to other irises. Leaf spot can be another prevalent problem so prevent spread by cutting away affected leaves promptly. If you encounter damage from the iris borer remove the affected rhizome quickly and dispose of it to prevent further damage by these pests. Generally good housekeeping habits, the right soil, sun exposure and moisture conditions will keep your irises happy and disease free.
In many people’s opinion, the bearded iris’ only downfall is its short blooming season but this can be extended by planting a few varieties with staggered bloom times. Offering a spectacular show in the garden or as a fantastic cut flower with a strong scent, indoors, the bearded iris may become your favourite perennial too.