About 10 years ago I planted some Siberian iris plants around a whiskey barrel fountain on the north side of my house. In addition to that if you heavy soil it is said to give the bulbs a break. They can even flower on and off throughout the year! I read that from time to time you need to dig them out and split the bulbs as they have created daughter bulbs and all the energy is going into them instead of the flowering. Irises need to be divided every three to four years. Bearded iris are propagated and planted as rhizomes.. Rhizomes are sideways-growing stems that shoot out laterally, just beneath the surface of the soil. Use a fertilizer with a … Pretty disappointing show in my garden this year. It is also important to note that leaf spot does not permanently affect the plant’s rhizome. Problem #1: Planting Your Bearded Iris Too Deep. In My … Ask the Expert: Why wont my Iris bloom? This is one of the most common reasons for How to Plant Bearded Iris not to grow in size or to produce the big, fabulous blooms they're known for. As the plants did well for a number of years, the first two items likely don’t apply – unless there are other plants nearby that have grown tall enough to hog the sunlight (irises need at least 6 hours of sunlight a day). Bacterial Soft Rot Here are a few simple reasons why your daylilies may not be showering you with their floral display: They may need to be in an area that has more sunlight. I did it it this year and tripled my irises like that. Too much nitrogen can also be a problem. Help answer a question about Why aren't my Japanese irises not blooming - Gardening Know How Questions & Answers. 4. It does generally offer a two-year cycle and will have an adverse effect on blooming the following year but the plant should be fine the year after. Since this is the 1st year I've had so few flowers I'm not sure where to begin, to improve blooming for next year. I know in most areas bearded Iris need the rhizome top exposed but have always planted mine with the top of the rhizome just under the surface because it gets so hot in summer. Always avoid transplanting irises in wet weather because you can spread the disease. Maybe your irises did not bloom because they got too little (or too much) water last year. The area got some nice afternoon sun and the iris seemed happy and bloomed for me every year until the past 3 years or so when they just stopped blooming.. Hot, humid weather seems to stress reblooming irises … and not in the right way. Also, help answer other questions about General Gardening and Japanese Iris Plants, and plants at GardeningKnowHow.com 2) They also won't bloom if they're planted too deep, or 3) they receive too much nitrogen from a fertilizer combination high in nitrogen. (Answer) The usual reasons that irises might not bloom are not enough sun, wrong planting depth or overcrowding. My Iris' get great green leaves but I fail to get a bud, which in turn I don't get a bloom? In California, on the other hand, where the climate is both mild and on the arid side, some reblooming irises will bloom a third or even fourth time!