Rent Shop Volunteer Join

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

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Sunday - August 01, 2010

From: Las Vegas, NV
Region: Rocky Mountain
Topic: Diseases and Disorders, Watering
Title: Arizona ash tree with brown leaf tips in Las Vegas NV
Answered by: Barbara Medford

QUESTION:

We've had an Arizona Ash Tree in our yard for over 7 years it was doing fine until last summer, the tree seems to be struggling with the heat, its leaves look like they are burning up and turning brown at the very top, is there anything we can do to help it?

ANSWER:

According to this USDA Plant Profile Map, Fraxinus velutina (velvet ash) grows natively in your area of Clark County, USDA Plant Hardiness Zones 8b to 9b, so your problem should not be with soil or climate. Unless you are having a most unusually hot summer, hotter than last year, you need to ask yourself what in the environment has changed to cause that tree to have leaf tips browning?

We will do a little research into the Arizona Ash and see if we can find what might be causing a symptom you have not seen before. None of the sites we looked at mentioned any disease that caused that sort of leaf browning, but there were several mentions that this tree depended on an underground water source or was "riparian" meaning it likes river bottoms or other locales where there is a constant supply of water for its roots. We are wondering if perhaps you are having an unusually dry year in Nevada and that underground water has diminished. One source recommended deep irrigations of the tree two or three times a month during extremely dry spells. This would mean getting a hose down in the dirt around the roots, turning it on to a slow dribble and letting it run until water appears on the soil surface. The leaves browning at the top of the tree would seem to be indicative of this, as all the moisture and nutrition for the tree comes up from the roots. The leaves at the very top, the end of the line, as it were, would be most susceptible to moisture deprivation. 

Another possibility, although more remote, is that of ash borers. See this article from Colorado State University Extension on Ash Borers.  This article points out that borers are more apt to attack trees weakened from drought or other reasons. However, first see if there are any signs of the beetles before you try pesticide. For more information on the possibility of ash borers in your vicinity, contact the University of Nevada Cooperative Extension Office for Clark County. 

 

More Watering Questions

Plants for oak shade from Whitney TX
December 24, 2012 - I live in Whitney, Texas and have a number of beautiful Live Oak trees in a portion of my yard providing deep shade. Asian Jasmine grows in about 5 ft circle around them and then nothing! I have walk ...
view the full question and answer

Problems with Texas Mountain Laurel in Dallas
May 04, 2010 - I have a Texas Mountain Laurel that is about 3 years old. When I bought it 2 summers ago, it was about a foot high. Now it is over 6 feet. It seems to have grown so fast that the branches can't ke...
view the full question and answer

Texas Pistachio trees dropping leaves in Austin
June 09, 2010 - I have several Texas Pistachio that are about 13 years old. Despite good rainfall in Travis county this year, they seem to be losing most of their new leaf growth now in early June. Leaves are simpl...
view the full question and answer

Why are the leaves of my century plants yellowing?
June 22, 2009 - I am taking care of the Agaves (century plants) for my condo community here in Austin. They are planted in 18" or 20" pots. A couple of the plants have leaves that are yellowing around the bottom....
view the full question and answer

Limp leaves on Texas purple sage in Magnolia TX
July 22, 2010 - Recently planted Texas purple sage, some of it looks healthy and has new blooms, but a few of the plants have limp leaves and are thin at the bottom. I read the article on cotton root rot, but am not ...
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.