Host an Event Volunteer Join Tickets

Suppport the plant database you love!

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.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

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

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Thursday - April 09, 2009

From: Medina, OH
Region: Mid-Atlantic
Topic: Trees
Title: Browning of Red Western cedars in Medina, OH
Answered by: Barbara Medford

QUESTION:

I have a row of Red Western Cedars bordering my yard. One week after my lawn people but down spring fertilizer and grub control, they began turning brown. Is there any correlation? If not, what causes Red Westerns to have their branches turn brown? Thank you.

ANSWER:

Well, it would certainly arouse suspicions because of the time frame involved, wouldn't it? From our Native Plant Database, we learned that Thuja plicata (western red cedar), while native to North America (or it wouldn't be in our database) it is not native to Ohio. If you have had them for a while and they have been okay, the fact they are not native to your area is probably not the reason for the browning. 

So, we'll begin with the possibilities of the fertilizer and grub control. If the fertilizer was of the "weed and feed" type, and was sprayed around, that could very well be the source of the problem. "Weed and feed" fertilizer is specifically a lawn fertilizer. Grasses are monocots, and the weed killer in the fertilizer is aimed at dicots, or broad-leaved plants. So, what benefitted the grasses by killing off their competitors, the broad-leaved weeds in the lawn, could very well have done a lot of damage to the cedar. As for the grub control, we could find nothing about whether the ingredients in grub control were specifically a threat to plants, but, again, they contain certain toxic substances in order to kill the grubs, and if applied to tree foliage could likely cause trouble.

Other reasons for this browning? We learned that the western red cedar needs a moist, slightly acidic soil, but can adapt to a little more alkaline soil. It is susceptible to bagworm damage and heart rot, but neither are considered serious threats.

Conclusion? We don't have one. Again, the timing leads us to believe the spraying may be the cause. Whether or not the tree can recover, we don't know that, either. This is a valuable tree, and grows to be very large, but slowly. Give it some care, maybe some extra water, but not fertilizer, and hope that time will help the tree heal itself. Next time, either get a different landscaper or watch them closely. Untrained personnel often don't understand the consequences of what they are spraying around indiscriminately. 

Pictures of  Thuja plicata (western red cedar)

 

More Trees Questions

Potential allelopathy of cultivar of Artemisia ludoviciana
March 09, 2009 - I recently submitted a question regarding allelopathic potential of artemisia ludoviciana on rusty blackhaw viburnum, not specifying that I meant Vibernum rufidulum. Mr. SP interpreted my viburnum as...
view the full question and answer

Deadheading seedless desert willows for continued bloom in Phoenix AZ
May 31, 2010 - We planted two seedless desert willow trees this spring. Both have bloomed nicely but we now have many stems with the spent flowers still on the tree. Your database for this plant says to "Remove spe...
view the full question and answer

Tan, rough, fan-shaped growth on mountain laurels
July 01, 2014 - A tan rough fan-shaped "something" is growing at the end of the mountain laurel branch where the flowers would be .. what is it and can it harm the plant?
view the full question and answer

Low Water Use Plants for a Pond Island
November 06, 2014 - We have a medium sized pond/tank with a small island covered in black willows. The pond loses a lot of water and we were told it was partially due to the willows. We want to remove them and replace ...
view the full question and answer

Viability of Desert Willow and Hong Kong Orchid Tree in Spring Branch, TX
December 26, 2006 - We live in Spring Branch, Rt 281 north of San Antonio. We want to plant a Regal Desert Willow tree and a Hong Kong Orchid tree. Will the cold / freeze be a problem? Where locally can we purchase th...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.