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

Container plants for cool weather in Cypress TX
October 02, 2011 - I am a novice gardener and I am looking for some ideas on potted plants for the fall/winter. They would be covered by a roof, but still susceptible to the elements. What can be planted now that will...
view the full question and answer

Ornamental grasses under desert willows from Dallas, TX
September 06, 2013 - I am planning on planting 3 desert willows in full sun, below the power lines at the back of my back yard in the White Rock Lake area of Dallas. I would like to plant some ornamental grasses in the be...
view the full question and answer

Privacy shrub in part shade to shade in Austin
April 29, 2010 - Barbara Medford's July 1, 2008 reply regarding Little Emperor Japanese Blueberry Tree is exactly my experience with cherry laurel in partial sun/shaded area in Austin, Texas. For 6 - 8' height si...
view the full question and answer

Need a shade tree in a limited space in Louisville, GA
October 29, 2009 - Mr. Smarty Pants, Hello! What kind of tree would be good to shade, in a limited space, and having a taproot? This is in middle Ga. One side of yard has main water pipe coming in off the road and ...
view the full question and answer

Plants for a shady garden in Wisconsin
June 22, 2009 - I have a shady garden in southeastern Wisconsin (Milwaukee) and am interested in introducing more native plants of all sizes and heights, hopefully with lovely flowers. I would love to know what you ...
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 | STAFF
© 2015 Lady Bird Johnson Wildflower Center