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

Thursday - July 03, 2008

From: Tacoma, WA
Region: Northwest
Topic: Non-Natives
Title: Yellowing leaves in non-native Arbutus unedo in Washington
Answered by: Barbara Medford

QUESTION:

I live in the Pacific Northwest and have planted 2 dwarf strawberry trees. I have been giving them lots of water. Their leaves are turning yellow. Am I watering them too much? Not enough?

ANSWER:

What's going on in Pierce County, Washington? This is the second question today from people who planted non-native trees there and now have yellowing leaves on them. So, let's address the problem with your Arbutus unedo, dwarf strawberry trees.

Because your trees are native to Ireland, southern Europe and the western Meditteranean, we have no information on it in our Native Plant Database. Instead, we went to this USDA Forest Service Arbutus unedo; these USDA sites are usually pretty impartial about discussions of plants and the locales where they can do well. The map of distribution of this plant showed a small area around Puget Sound where the strawberry tree can be found. Since that's where Tacoma is, we're assuming you're in the right place.

Yellowing leaves on a tree usually indicates chlorosis, or the loss of chlorophyll in the leaves, which makes them green. This happens most often when an acid soil-preferring tree is planted in an alkaline soil. The plant needs the trace element iron from the soil, and in alkaline soils the iron may be inaccessible to the plant roots.

In the West, many plants don't get enough iron because their roots are unable to obtain it from the soil. Roots may be damaged by a lack of oxygen in overwatered or poorly drained soils--typical after a rainy spring--or by extreme soil temperatures. High concentrations of limestone (calcium carbonate) make the soil more alkaline, which makes the iron less soluble. The information we found on Arbutus unedo indicates that it "tolerates" alkaline soil and clay, but "prefers" sandy, slightly acid soil. And, too much water around around the roots in a clay, poorly-draining soil may also harm the tree's capacity to utilize iron from the soil.

So, you asked if you were watering too much? Probably so. To help amend the soil to a more acidic nature and better draining texture, first, add some iron tablets to the soil. Then, trying not to damage the roots, get some organic material, cottonseed meal, etc., in the soil around the roots. Mulch heavily with an organic mulch like shredded hardwood. This mulch will hold in the moisture, help keep the roots cool, and decompose slowly, adding to the organic material in the soil, again helping to neutralize the effect of the clay soil. If, when you water, the water pools on the surface and remains for 30 minutes or so, you are definitely dealing with poorly draining clay soil. Taper off on the watering, and try to create a better-draining environment for the roots.

 

More Non-Natives Questions

Identification of plant with orange sap that glows at night
June 06, 2012 - I was just pulling up a plant and noticed that its sap was a kind of orange then I noticed it glowing orange at night. What kind of plant is this and is it dangerous?
view the full question and answer

Failure to bloom of non-native viburnum in Dayton, Ohio
April 30, 2009 - I have a 3 year old Marie's Doublefire Viburnum that has healthy, abundant foliage but never blooms. I do not prune it. What am I doing wrong? Thanks
view the full question and answer

Why won't my Jacaranda flower in Oviedo, FL?
October 06, 2010 - I have a Jacaranda tree that is 12 years old and and nearly 30 feet tall. It is a beautiful healthy tree that has never produced flowers. How can I get my tree to bloom? Thank you
view the full question and answer

Moving potted plants from California to Georgetown TX
February 10, 2012 - Hi, I am moving from Gilroy CA to Georgetown TX, I have many potted plants I would love to take with me but I am not sure what would survive in my new location. These plants have been cared for so ma...
view the full question and answer

Use of non-native pothos for outside wall from Las Vegas NV
January 05, 2014 - I am in Las Vegas, NV. I live in a cottage-style apartment so I have a north facing porch with no one on the west so I get some there (and have an inherited cactus probably a yard all round) I would ...
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