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Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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Monday - May 11, 2009

From: Canton, MI
Region: Midwest
Topic: Diseases and Disorders
Title: Problems with Thuga occidentalis in Canton MI
Answered by: Barbara Medford

QUESTION:

I have emerald arborvitae that have become very "shaggy" and somewhat orange at the base of some leaves, while my neighbors look compact and dark green. What am I doing wrong?

ANSWER:

Thuja occidentalis (arborvitae) or white cedar is a widely-used evergreen hedge plant. We found out that the 'Emerald' cultivar is also referred to as 'Smaragd' and is considered a smaller version of the traditional plant. About the only clue we found is that after an especially cold winter, the foliage will turn yellow-brown. That's not orange, and if your neighbors are not having the same problem, then we can only think that there must be some kind of stress on your trees that the others are not experiencing. Have your plants been watered sufficiently? Are they in the neighborhood of a large tree that might have roots interfering with your arborvitae? Have you examined the tree for bagworms? Here is an article from Ohio State University on arborvitae that includes some of the things that can cause problems with the tree and that mentions the 'Emerald' cultivar.
 

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