Native Plants
![](../_images/smarty_plants.gif)
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.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
![](../_images/mr_smarty_plants_logo_web_200w.jpg)
rate this answer
![](../_images/star_00.gif)
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)
More Shade Tolerant Questions
Variety of native tall plants for a screen in shady area near Ft. Worth
June 12, 2007 - Hello, we live west of Ft Worth. We are looking for tall plants to form a visual screen along a chain link fence we share with a neighbor. We have post oaks there and it is very shady and the ground ...
view the full question and answer
Grass or ground cover for sun/part shade in Austin
December 30, 2007 - I live in Southwest Austin (a couple of miles from the Wildflower Center) and I would like to plant some grass in my backyard. I have a small yard with several oak trees and they have been cut back to...
view the full question and answer
Native turkscap failing to thrive in Shiro TX
March 19, 2013 - Dear Mr. Smarty Plants,
Two years ago I transplanted several native (not cultivars) Drummond's turkscaps in the proximity of water oaks in the front yard. All get shade and some sun. They seemed to ...
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
Vines for Shade in Upstate New York
April 23, 2013 - Hello! I am looking for a non-invasive vine that will grow in heavy shade near my house in upstate New York.
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |