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
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

What will grow under a California Pepper tree?
April 03, 2009 - What will grow under a California Pepper tree with a shady area oak tree nearby in a coastal community?
view the full question and answer

Plants for northern exposure in Wichita, KS
March 17, 2009 - What are good plants for the north side of the house with acidic soil in Zone 6, Wichita, KS?
view the full question and answer

Native ornamental grass for part shade in Austin
December 22, 2010 - Hi. I am looking for a fast-growing hardy ornamental grass that will grow in partial shade in south Austin that is not considered invasive. Unfortunately I purchased a few of the Pennisetum setaceum r...
view the full question and answer

Native vine for shade on west side in Texas
July 21, 2008 - I have just put in a trellis to cover the west side of my house for shade. What would be the best native vine to put their for quick growth. I plan on putting a rose (Fortunia) but can't do that till...
view the full question and answer

Want salt, shade, drought tolerant plant for Rochester, New York
September 21, 2010 - I am looking for a ground cover plant for western NY to grow on a strip alongside a road that gets very little sun in summer (lots of tree branches shading it). It gets a lot of road salt in winter a...
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