Garden Detective

Garden Detective: Propagation of lilacs challenging

Starting a new lilac bush from a rooted cutting can be tricky.
Starting a new lilac bush from a rooted cutting can be tricky. Sacramento Bee file

Q: I have tried many times to transplant a portion of a lilac tree/bush that I have had in my yard for many years. I have attempted at least three or four times over the years to remove a small sprig and transplant it, but they never take.

Here is what I have attempted: In the spring, when it starts to show green leaves, I remove a small branch, wrap it in newspaper and soak in water for several days. I then plant it in Miracle-Gro soil, but to no avail, as they all end up not taking. What am I doing wrong?

Tony Tambini, South San Francisco

A: Growing lilacs is very difficult, according to UC master gardeners. Early spring softwood or semi-softwood cuttings within a narrow period in early spring shortly after growth commences are best. When shoots reach 4 to 6 inches, take your cuttings. Root the cuttings in a mixture of 25 percent peat moss and 75 percent sand. Keep it moist and give plenty of light.

Or try this method: In late spring, cut 6- to 8- inch-long sections from new shoots with two to three leaves or nodes (where the leaf attaches to the stem). Dip the bottom ends of cuttings in a rooting medium (available at nurseries) to aid in the rooting process. (The rooting medium contains hormones that stimulate new root growth.) Plant in the above peat-sand mixture. When new roots appear and soil temperature is at least 55 degrees, plant outdoors.

Another method of propagation that is useful for lilacs that are not grafted is to dig suckers from around the base of the plant and replant them. These suckers are sprouts that developed from the roots and have formed their own roots. This is perhaps the easiest way for most homeowners to propagate lilacs.

More on dogwood

Harry Andris, a retired farm adviser in Fresno County, noted that lack of iron isn’t the only mineral deficiency that can lead to yellowed leaves.

“I recently read your article, ‘Dogwood unhappy amid changes,’ in the Dec. 5, 2015, Sacramento Bee,” Andris wrote. “I would just like to point out to you that there are a number of things that can cause yellowing and inter-veinal chlorosis. Iron deficiency is certainly one of the deficiencies that causes inter-veinal chlorosis; however, manganese deficiency is also one element to consider.”

Judging by the photo, Andris suspects manganese deficiency. “Both can be caused by excess soil moisture but iron deficiency has a very fine network of green veins with areas of inter-veinal yellowing along the major and minor veins,” he said. “(In the photo), the major wide green veins are the symptoms of manganese and not iron deficiency.”

Garden questions?

Questions are answered by master gardeners at the UC Cooperative Extension services in Sacramento and Placer counties. Send questions to Garden Detective, P.O. Box 15779, Sacramento, CA 95852. Send email to h&g@sacbee.com. Please put “Garden Detective” in the subject field and include your postal address. To contact UC Extension directly, call:

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