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Horticultural Math: Divide To Multiply
By Norman Winter
Central Mississippi Research & Extension Center
Propagating favorite plants is something every gardener wants to do at some time. This is a good time of the year to put the thought into practice.
Division equals multiplication when you talk about perennials. Dividing not only makes your perennial garden better, but gives you additional plants to create wonderful new gardens. The rule of thumb is to divide perennials in the season opposite their bloom.
Some perennials can be divided at just about any time, but there is always a recommended or ideal time. Two popular plants in Mississippi are irises and daylilies, and both are good candidates for fall division.
To begin a new planting of bearded iris, remove the rhizome from the parent clump. The entire clump can be removed with a spading fork and divided, or you can remove the individual rhizomes from the sides of the plant.
Remove old rhizomes that have bloomed and no longer serve any purpose except to hold the clump together. The new planting can consist of either twin rhizomes or a single rhizome. When transplanting, be sure to cut about half the foliage away from the fan.
The best time for transplanting daylilies is late summer and early fall. A plant moved in the late summer usually has a better bloom the following season than a plant moved in spring.
To divide the plants, loosen them with a spade fork or sharp shooter about 6 to 8 inches from the clump on all sides of the plant. Lift the plant. The clump will consist of several plants. Separate them from one another and plant. Remove half the foliage for fall and late spring transplanting.
Propagating plants by cuttings is a fun and rewarding horticultural practice.
I give a lot of talks on roses, and someone always wants to know how I root rose cuttings. Probably the best time to root roses is in late fall, even though I do it all season.
The easiest part of the rose to root is the tip of a stem that has recently bloomed. Ideally these tips have withered flowers or hips. It is not uncommon to see people take home roses that had been entered in rose competition and root them.
Remove the flower head or hips down to the first set of healthy leaves. Cuttings should be about 6 to 8 inches long and cut from the parent plant with a sharp pair of pruning shears.
Never let your cuttings dry out. I like to use a rooting hormone purchased from any garden center. Dip the stem in the hormone and place in the medium. My favorite is to use wet sand. Before sticking the cuttings, remove all foliage from their lower halves, but leave the upper half of leaves intact.
Use a pencil to poke a hole in the sand for each individual cutting. Stick the cuttings several inches deep or at least half the length of the cutting. Then place the pot of sand containing the cuttings in an area receiving only filtered light and keep moist. In just a few weeks you will have some rooted roses.
This method works great on buddleia, Mexican bush sage and many woody-type plants. Try taking tip cuttings from lantanas, verbenas and coleus.
Released: Sept. 6, 1999
Contact: Norman Winter, (601) 857-2284