Laidback Gardener Tip of the Day

When A Conifer Loses Its Head

The leader of spruce has been killed. If allowed to grow on its own, it will produce multiple leaders and will lose its natural symmetry.

Many conifers have a naturally pyramidal shape. This is the case of, among others, firs (Abies), spruces (Picea), pines (Pinus) and larches (Larix). They’re called whorl-branched conifers, because a whorl of new branches appears near the stem tip each spring. They all have a main trunk topped off by a single terminal shoot called the leader. As long as the leader is healthy, symmetry is maintained. This is called apical dominance. But if the tree loses its leader, its future symmetry is threatened. Fortunately, that’s something you can fix. And there are two ways of going about it.

The first technique simply consists of allowing the tree to grow on its own. Since whorl-branched conifers only put on new growth in spring, you’ll have to wait until next spring to see what happens. Typically the conifer will then produce not only one terminal shoot near where the old one was lost, but two or more. Or sometimes side branches near the top start to grow vertically and thus start to become leaders. Typically, there are also usually two or more.

Since, for symmetry’s sake, you can’t allow your conifer to produce multiple leaders, you’ll have to make a choice. Pick whichever new leader appears the strongest and remove all the others. By doing so, you’ll restore apical dominance and the conifer will resume its expected symmetrical growth.

20150712BThe other method is to be proactive. As soon as you realize the leader is dead, broken or missing, choose a side branch and direct it upward. You can do this by fastening the branch to the stub (if there is one) with insulated wire or duct tape. If there is no stub, simply attach a stake to the trunk and fix the side branch to it so it remains upright. It will quickly come to dominate the other branches and react like a leader (terminal shoot).

When this new leader has lignified enough to hold its shape, usually 3-8 months later, just remove the ties and the stake. Apical dominance will have been restored and the tree will then resume its attractive pyramidal growth pattern.

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

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