Half 20 year old Emerald Cedar browning


We have an row of 6 Pyramidal Emerald Cedars, about 10 feet high. The one at the end has 2 stems, one is browning the other is green. Suggestions what I can do to bring the browning one back?


Thank-you for contacting Toronto Master Gardeners with your question about your browning Emerald Cedar (Thuga occidentalis ‘Smaragd’).

Emerald cedars are very popular for hedging, and this is no surprise since they are beautiful conifers when they are in good health. Unfortunately, these trees do suffer from a number of pests and diseases as well as being fairly particular about their growing conditions. The first step is to determine what has caused the browning. There are many potential causes. You haven’t mentioned whether you see any sign of insects on your tree. Certainly, an infestation can cause browning of the foliage. Too much, or too little, water can also cause browning on cedars. Emerald cedars are not particularly hardy and a harsh winter can also cause some die-back. Over use of fertilizers can be a problem, as can an elevated acidity level in the soil.

Both the cause and the extent of the browning will be key factors in whether the brown part of the tree can be brought back to good health. If you can correct the underlying cause of the problem, and there is still some healthy green growth on the stem, you may be able to save it. If the brown stem dies off, you have the advantage of the additional healthy leader. (As a general rule, a single leader is better than a double leader. A pyramidal shape is more easily achieved with a single leader and the structure of the tree is stronger.)

Answers to similar questions about Emerald cedar browning can be found on the Toronto Master Gardeners website using the search term “emerald”. One that deals with the issue in older trees (as opposed to newly planted ones) can be found HERE . The response contains useful links to other answers the TMG has given as well.

Good luck diagnosing and correcting your cedar problem!