How To Rejuvenate Rubber Tree

Q: I have a great big, old rubber plant in my living room that has gotten so tall its top is growing horizontally along the ceiling. It has no leaves or branches along the stem and it looks pretty ridiculous. Someone told me it would sprout if I cut it off near the bottom. Will it?

A: The rubber plant, Ficus elastica, is actually a tree, which in frost-free climates grows very large, 60 or more feet high. Because it is genetically programmed to grow with one stem. Like most tree species, and because indoor light levels normally are not high enough, rubber trees become very lanky and tall. Before any rubber tree ever gets so tall, it might be worthwhile to pinch out the growing tip of a newly acquired single-stem plant to try to induce it to branch. This may provide for a more busy plant especially if the tips are pinched consistently as the tree grows.

Any rubber tree or other tall, old woody houseplant can be cut off six or so inches above the soil line. After a bit the stump should sprout, and, if you're lucky, you may get more than one new shoot.

However, before cutting the thing off why not try air layering the leafy top to make a new plant out of it. Get up near the ceiling and cut about half-way through the stem. Force a bit of root-promoting hormone into the cut, and a toothpick or wooden match too, in order to prevent the stem from grafting back together. Place a large handful of moist, squeezed out sphagnum moss around the cut stem and tie a piece of clear plastic around it. Make it tight above and below the moss.

After a time a mass of roots will grow from the cut into the moss. When it appears filled with them, cut the top of the rubber tree off just below the plastic, and pot it up. You should then have a new, smaller rubber plant, which you can begin the pinching process on.

Because of genes, rubber plants and other tree species may never produce more than one new shoot after a pinch is done to the growing tip. In other words it is just about impossible to get them to grow in a more bushy manner. If you'd like more information on air layering and ground layering too, send a long, self-addressed, stamped envelope with a quarter to WSU Extension, 612 Smith Tower, Seattle, WA 98104. Ask for PNW 165, Layering to Multiply Plants.

Gardening runs Friday in the Scene section and Sunday in Home/Real Estate of The Seattle Times. It is prepared by George Pinyuh and Holly Kennell, Washington State University/King County Cooperative Extension agents, Mary Robson, Master Gardener program assistant, and volunteer Master Gardeners. Send questions to: Gardening, The Seattle Times, PO Box 70, Seattle, WA 98111. Questions of general interest will be answered as space allows.