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

Can trimmings from non-native globe willows be planted from Broken Arrow OK?
June 13, 2010 - We have 2 globe willow trees in our back yard. We trim low hanging branches. Can we take these cut branches, -plant them and have it grow into a new globe willow tree?
view the full question and answer

Alternative for Pittosporum limelight
March 22, 2012 - Is it ok to plant a Pittosporum limelight by pool? Don't want bees! Needs to be 6 feet. Thanks.
view the full question and answer

Care for non-native plumeria in Inverness FL
October 05, 2009 - I have several plumeria plants that I planted in the ground this spring. I will soon need to dig them up and store them in the garage for the winter, as I left some last year that died with the frost...
view the full question and answer

Getting rid of giant ragweed in Austin
October 25, 2008 - How can I get rid of a large field of giant ragweed? Part of the site is a steep slope, which is difficult to mow. I want to encourage native grasses but they are crowded out by the ragweed.
view the full question and answer

Transplant shock for non-native Plumbago auriculata
May 19, 2008 - I planted some full plumbago plants that were in containers, in a partially shaded area, they had beautiful flowers when I purchased them, but have since lost them all and the plant is looking very wi...
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