En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Shade tree for Portland, OR

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
Not Yet Rated

Wednesday - March 18, 2009

From: Portland, OR
Region: Northwest
Topic: Shade Tolerant
Title: Shade tree for Portland, OR
Answered by: Barbara Medford

QUESTION:

Looking for shade tree for Portland, Oregon, with non-invasive root system. House will be 20 ft away, with basement.

ANSWER:

We wish we knew how to explain to a tree that it should not invade foundations, buckle sidewalks or pop roots up in the garden, but that's just the way trees are. Most of their roots are within 6 to 12 inches from the soil surface, and they are relentless in their search for water, oxygen and nutrients. The following is an extract from a previous Mr. Smarty Plants question:

"As to the exact distance either should be planted from foundations or sidewalks, that becomes a matter of personal judgment. Soil subsidence around foundations is more often the result of the soil becoming too dry. It is true that tree roots will range out from their trunk as much as twice the diameter of the tree crown in search of moisture but this is usually not a prime factor in foundation damage. 

In general terms regarding the planting of trees near structures, the ground area at the outside edge of the canopy, referred to as the dripline, is especially important. The tree obtains most of its surface water here, and conducts an important exchange of air and other gases. The most critical area lies within 6 to 10 feet of the trunk. Paving should be kept out of the dripline and no closer than 15 feet from the tree trunk."

With that in mind, we are going to look at Recommended Species in our Native Plant Database, and find smaller trees that will result in less extensive roots but still give some nice shade to the area. Also be aware, as noted above, of the damage roots can do to sidewalks and drives in their area. These trees will all be native not only to North America but to Oregon. Native plants grown in their natural habitat will require less water, food and maintenance.

TREES FOR OREGON

Juniperus scopulorum (Rocky Mountain juniper)

Pinus contorta (lodgepole pine)

Prunus virginiana (chokecherry)

Umbellularia californica (California laurel)


Juniperus scopulorum

Pinus contorta

Prunus virginiana

Umbellularia californica

 

 

 

 

 

 

More Shade Tolerant Questions

Hedge for a shady spot
November 12, 2010 - In the Statesman you recently provided good suggestions about a privacy screen. I need a hedge that will grow under a huge old oak tree. Will wax myrtle or red cedar work for us? I have yaupon and m...
view the full question and answer

Colorful native plants for oak tree shade in Houston
August 26, 2009 - I live in Houston Tx - our subdivision entrance has many oak trees. We cannot find anything that will "stay alive" around these trees. It is mostly shady, but gets a slight bit of sunlight. we wo...
view the full question and answer

Non-Poisonous, Shade Tolerant Vine for Austin
February 01, 2011 - Hello, I live in northwest Austin and have a very shady wood fence I would like to cover and was thinking about a vine. I have a toddler and a dog so anything poisonous is out of the question. I woul...
view the full question and answer

Groundcover for sun/part shade in Austin
May 07, 2008 - I live in Southwest Austin and I have a small backyard that has part sun/part shade. I have no grass in the backyard and my soil is not the healthiest, so I would like to plant some groundcover versus...
view the full question and answer

Evergreen Privacy Screen for Maryland
November 19, 2012 - I am looking for an evergreen that will suffice to be planted as a privacy screen between my property and my neighbors. Looking to plant a row at the property line. The lot is shaded most of the d...
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