Perennial Propagation

Wednesday, August 15, 2012
Propagate Flowering Perennials We dig up and divide perennial clumps to make new ones or rejuvenate a planting that has stopped blooming due to overcrowding. Gardeners seem to fall into two categories when it comes to this important garden routine. Some fear they’ll kill the main plant and let it go too long while others are overeager for new plants and take on plants that have no need of dividing. There’s a happy medium in there someplace, usually 3-4 years after planting. Even the best, most proper divisions are top heavy with leaves that can wilt and sap strength from the rooting process. Tops can be trimmed like I cut iris or daylily into a shorter fan to reduce transpiration and better balance the top and roots. But roots need stimulation to get well established in their new pot or bed and Hormex Liquid Concentrate can be your best friend to get this task done right. Even if, like me, you aren’t the perfect gardener. It is remarkable that perennial plants survive sometimes mangled attempts to propagate them. Common tools of torture include short shovels that chop off long roots, forks that can pierce bulbs and roots, and dull blades that tear instead of slice. Sharpen your tools and resist the urge to just lift plants from around the edge of a big clump. Most often that effort disturbs the crown and gets fewer roots than the preferred way. Dig up the entire clump and set it on the ground or bench and then get to work. To be called a division, there must be top growth, a crown, and at least some roots. It takes all three to make a new plant. Leaves and roots are obvious, but the crown may not be. It is the heart and soul of a perennial, the place between the shoots and roots that controls both. Now that I’ve scared you, it is important to note that this is not a difficult process and common perennials regrow easily. I despise spending valuable garden time in fruitless exercises and I’m sure you do, too. With the right tools, some practice, and Hormex Liquid Concentrate, we can successfully propagate more perennials than we need and have plenty to swap, too. That’s why I suggest potting up at least a couple of divisions while you are replanting – plan for success and envious friends. Traditionally, flowering perennials are divided in the season opposite when they bloom. But there are reasons why that cannot or does not happen. Summer can be hot and dry or rain soaked so spring bloomers are attended as soon as flowering stops. Late summer’s flowers can linger and so are divided before the first snow flies or on a mild winter day. Gardeners get busy or forget, too, and finally turn their attention to the perennial bed when it is convenient. My rule of thumb is to avoid dividing perennials when they are in bloom. That’s it. Pick a pleasant, cloudy day with little wind, or at least expose the plants late in the afternoon. Don’t dig if the soil is very wet and water the day before if it is very dry. Dig up entire perennial clumps whenever possible and divide cleanly into as many new starts as possible. I am not big on digging, so will cut around the clump with a sharpshooter (a shovel with a long, narrow blade), pry a little at each cut, and use the digging fork to lift the clump out. Dividing perennial clumps takes several paths. Ajuga and monkey grass, for example, usually fall right apart while iris and daylily seldom do. Sometimes a pair of knobby gloves is all it takes to get a perennial to come apart neatly. Occasionally a chain saw is helpful, as when I divide fountain grass. Where I live it gets to be 3 feet across in 3 2 years – I’ve given away a dozen just trying to keep it in bounds. Most often, I use a sharp kitchen knife long ago consigned to garden duty. Hand shears and serrated saws usually crush as much as they cut and can set back the plants’ recovery. Ideally, divisions are single plants, but leaving a group together can regenerate the clump faster in the landscape. Once you have the divisions made, it’s time to set up a dishpan with 1 gallon of water mixed with 2 tablespoons of Hormex Liquid Concentrate. Soak the roots and clump base in the solution for 15 minutes before replanting. Use HLC (1T/gal) at 2 week intervals until late October to water the new planting and stimulate plenty of roots. Treat the ones you pot up the same way and cut your losses during this annual chore.
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