The Dry Garden: Dividing 1 plant into 2 (or even 3)
Pulling up a plant and ripping it in half at the roots is a violent way of showing affection, but for a school of groundcovers, including many grasses, bulbs and woodsy flowers, doing just that amounts to true love. So, if you have established giant rye, coral bells, irises or hummingbird sage, and you want more of the same, now is the moment to divide and separate the plants.
Short days and early showers are abetting this endeavor. If you can’t jump when the meteorologists say “rain,” do it when you have time, then give the transplants a steady, gentle watering.
How roughly or tenderly you handle division should depend on the plant. At the most painstaking end of the scale is native iris. Its relatively delicate, grass-like leaves and tuberous roots can trouble even experts such as Bob Sussman of Matilija Nursery in Moorpark.
“Non-natives you can divide at any time,” said Sussman, an iris specialist. Now, however, is the window to dig up native Pacificas. Plants moved too early -- say, in October heat -- can have a mortality rate as high as 50%. “It’s earliness that proves the killer.”
The telltale sign that the plant can be moved is new roots along the slender tuber. They are so important that the Society for Pacific Coast Native Iris advises on its website: “Consider taking only half the clump for division, leaving the other half in case the divisions do not survive.” The primer goes on to instruct: “After lifting and dividing, it is vital to keep the roots moist until they are back in the ground. Once replanted, they should be watered immediately and kept moist until they are well established.”
But when it comes to what technically falls under the unromantic heading of “asexual vegetative propagation,” suggestions go well beyond iris.
Say “divide” and Pete Veilleux of the East Bay Wilds garden design firm in Oakland will respond “ferns,” which take it with equanimity.
The first things that spring to the mind of author Barbara Eisenstein are grass and grass-like plants, including juncuses and sedges. A nice, round clump of deer grass will need time to regain its form, she warned. But it will.
The same applies to the beautiful alternative to New Zealand flax, the giant rye Canyon Prince, a California native that Eisenstein praises for its high survival rate.
Almost everyone canvassed for suggestions of good native plants to divide and multiply mentioned the exquisite spring flower coral bells, or more properly called heuchera. These not only divide with ease, but also start flowering in early winter. They keep tossing out spires worthy of a woodsy fairy tale through early summer.
Another dreamy flowering plant that can become divided is hummingbird sage. As the Theodore Payne Foundation’s Lili Singer pointed out, this plant isn’t divided at the root. It can multiply from cuttings or stems that have flopped close enough to the ground that they send down roots for a wee sip.
This plant likes to creep in semi-shaded, moist but not dank areas. After putting out a lot of large leaves in winter, an explosion of even larger magenta flowers will follow in spring. Then, in the heat of summer, the flowers will dry and leaves will shrivel up until the arrival of rain -- or the spade of a smart gardener who splits and spreads the plant’s roots and hydrates the winter soil.
-- Emily Green
Green's column on low-water landscaping appears here on Fridays.
Photo, top: Sisyrinchium bellum, a type of iris often called blue-eyed grass. Credit: Francine Orr / Los Angeles Times
Photo, middle: Huechera. Credit: Ricardo DeAratanha / Los Angeles Times
Photo, bottom: Francine Orr / Los Angeles Times