Fall planting brings the best season lasting colors
The first of September marks some of the most important gardening of the year. This is the time to plant irises and mums for colors that impact the garden now through next summer. The latest varieties of iris arrive at garden centers now, several weeks before all other fall bulbs. The best crops of mums arrive now throughout the fall, and this year's crop is spectacular. Let's share the gardening practices that produce the healthiest plants and best bloom colors of these two garden workhorses.
Irises will be available for the next few weeks only and need to go into the ground now. Choosing the best rhizome, or root, is easy because rhizomes, like bulbs, corms and tubers are simply storage places for food. The more food stored in the roots, the bigger the bloom next spring. Because food is the key to stunning blooms, bigger is better with any iris root. From the many boxes of the latest varieties and colors on display, the largest roots are the ones you want. Squeeze gently to make sure the roots are firm, not squishy and rotted.
Root hairs protruding from the main root body should be trimmed off and discarded. The leaves are usually trimmed back to about 6 inches from the main root. If they have not been trimmed, this is the time to use scissors and cut back the leaves. Now they are ready to plant.
Other than the rhizomes there are three components needed for perfect flowers: mulch, gypsum and Gardener's Special. Prepare the bed by spreading a 2-3 inch layer of mulch over the planting bed. I don't recommend horse manure or the roots will rot during the winter. For better drainage and deeper root formation, I recommend a layer of gypsum over the flower bed.
Remember, plant foods that are high in phosphorus promote stronger, healthier flowers; and Gardener's Special, 11-15-11, is the best bulb and flower food I've found over the years. Sprinkle the recommended rate over the entire bed and turn in this three-component mixture at one spade's depth. Now you're ready to tuck in those nice, big rhizomes. After planting, water in well using Fertilome "Root Stimulator" every two weeks through Thanksgiving. The rooting hormones in this solution will stimulate formation of new root hairs that will thrive in the rich soil you just created.
Irises can have difficulties with our clay soils if they are planted too deeply. If in doubt, leave the entire leaf and tip of the rhizome above the soil level. They naturally "run" across the ground, picking up food and water as they go. Expect leaf growth starting in February and flowers around the first of May.
Re-blooming irises have been touted as the best bulbs. My own experience says maybe not. It's true that the re-blooming bulbs will produce another show of flowers, but I find that the single-blooming bulbs have the more impressive flowers with better colors and much larger blooms. They truly are more beautiful. For best results from these two varieties, my advice is to plant those spectacular single-bloomers in your favorite colors with a few re-bloomers blended into the bed.
A side note that may be of interest: If you were to slice open an iris rhizome, you would see a tiny pale flower stalk folded accordion-style waiting for spring.
Mums require the same soil preparation and can be planted in the same flowerbed with irises. Over the years I've planted dozens of mums using this planting technique. At this altitude mums are perennials, meaning that every year they come back bigger than the year before. Because mums bloom every fall, they are invaluable components of any garden. Right now these large 2-foot x 2-foot plants are covered with hundreds of flower buds that will open in September and bloom past Halloween. The best crops of the year are waiting for you right now at your garden center.
For season-long color, the dynamic duo of the garden is a combination of irises and mums. Both are perennial bloomers with larger than usual flowers, and they are naturals for the tri-cities. They are two of those unique plants that can be planted in large beds by themselves, in combination with each other, or mixed in with other perennial and shrub plantings. The plants are so hardy they require little care other than occasional watering and a few strategic feedings for guaranteed flowers.
If you live in an area fraught with animals, irises and mums are must-haves for you. I know them to be resistant to javalina, deer, elk, squirrels, and rabbits.
For more details on planting irises correctly at this altitude, make sure to visit my web site at wattersonline.com. Look for the 'Garden Talk Topics' link and visit the garden talk topic on 'How to Plant Better Iris.' Of course, you can visit me here at Watters Garden Center as well.
Until next week, I'll see you in the garden center.