En EspaŅol

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
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
1 rating

Friday - April 09, 2010

From: Bucks County, PA
Region: Mid-Atlantic
Topic: Shade Tolerant, Trees
Title: Arborvitae thinning in Bucks County, PA
Answered by: Barbara Medford

QUESTION:

My arborvitae trees are about 11 ft. tall. I had them put in about 3 years ago. They were 8 to 10 ft. when planted. After the first year, I have noticed they are thinning to the point where you can see right through them. What can I do to make them full like they once were, or are they dying? Any help would be much appreciated.

ANSWER:

Bucks County in the southwestern corner of Pennsylvania and USDA Hardiness Zone 6b would seem to be the appropriate place for  Thuja occidentalis (arborvitae) to grow.

However, we picked up some facts that may explain the thinning of your plants; the first was from our webpage on Thuja occidentalis (arborvitae).  That offered the information that in a crowded environment, this tree is slender and not well-branched. In the open, it improves in form and density. This Ohio State University site commented that it prefers a moist, well-drained, loamy soil in full sun, but tolerates soils that are poor, rocky, clay, compacted, dry, and of various pHs extremely well, and is very urban tolerant to heat, drought, humidity, and pollution; however, not tolerant of shady situation. From that same article, we also learned that old foliage from the self-shaded middle of the shrub abscises (sheds) noticeably in Autumn, and falls through the interior of the canopy directly to the ground below.

Our conclusion is that if your arborvitae are not in an open area, with plenty of sun, that is probably causing their decline. They are not likely to be dying, but are not going to prosper as much as you might wish. Some of the openness is no doubt the result of the shedding of the interior branches, caused by the plant's own shade, which you can hardly do anything about. 

Pictures of Thuja occidentalis (arborvitae) from Google

From our Native Plant Image Gallery:


Thuja occidentalis

 

 

 

More Trees Questions

Failure to bloom of one of two Texas persimmons from Wimberly TX
May 04, 2013 - Last year my son planted two texas persimmon trees. One is blooming ok this year and the other is not. It does not seem dead. What can I do or is is in fact dying?
view the full question and answer

Suffering Yaupon in Austin
July 14, 2012 - I am in the Austin area and I planted a Pride of Houston Yaupon in my back yard in March. It is in full sun. Lately the leaves have been turning pale green and now they fall off the tree upon touchi...
view the full question and answer

Control of borers attacking Prunus serotina
August 30, 2006 - Where can I find information to control borers that seem to attack only Prunus serotina v. exemia?
view the full question and answer

Oak roots damaged by ax from Austin
July 03, 2013 - Hello. I am attempting to create my own tiny copy of the Wildflower Center within my yard. I'm using all native, drought tolerant plants. My front yard is full of live oaks. I used a sod cutter la...
view the full question and answer

Desert Willow Roots from Lubbock, TX
September 18, 2014 - I have a very, very happy Desert Willow that has grown larger than we expected and is probably too close to the house. Do I need to worry about a cracked foundation or pipe problems? Thanks!
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center