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Tuesday, September 3, 2013

Raywood Ash Showing Signs of Dying Back

They seemed to be fine after our week of 117F weather.
Q. Four years ago we planted two Raywood ash trees in our back yard. They have been very healthy and have grown wonderfully to over 25-30 feet. One is growing in the grass and the other in decorative rock. We usually water about 30 gallons every 2-1/2 week in the summer. Both trees are planted in a wide circular of dirt and mulch, about 25 feet apart. There are no other plants near these trees, so they are not susceptible to any weed killer or fertilizer that should not be used near the trees. They seemed to be fine after our week of 117F weather.

            Two weeks ago one began to lose leaves. Now the other one is doing the same thing. We gave them a little extra water because the leaves are beginning to dry and feel like crepe paper and turning yellowish. We checked the limbs and bark and there doesn’t seem to be any seepage, cuts or insect damage.

A. My first reaction is the trees are not getting enough water. When leaves begin to drop over the entire tree it usually points to a problem with the trunk or roots. Since water affects the entire tree, the amount of water applied is also looked at closely.

            Thirty gallons every 2 1/2 weeks is not enough for trees 25 to 30 feet tall. So they must be getting water from somewhere else besides your deep watering. It is good to water trees infrequently but every two weeks is quite extreme for trees that have no other source of water.

            I would normally give 30 gallons of water three times a week when temperatures are in the 110F range. Once the temperature drops back around 100F I would drop it to twice a week.

            As long as this amount of water is spread in a 3 to 4 foot diameter basin under the tree or distributed by multiple drip emitters under the canopy it should wet the soil deep enough, about two feet down.

            You might consider is that the extra water the trees were getting might have “dried up” for some reason. When this happens, the leaves on the tree would scorch, dry up, turn crispy, and drop. This leaves the roots to rely on other sources of water to support its size.

            When tree roots find water, their roots expand into a wet area. In areas where very little water is present, tree roots grow poorly. Tree roots can spread, if water is present, distances of two to three times their height. So your 25 foot Raywood ash could have roots as far as 75 feet from the trunk.

            Tree roots do not necessarily grow symmetrically around the trunk. The greatest abundance of roots is in wet areas of your landscape or your neighbors. Also, if your neighbor had a pretty wet landscape, the roots could be over there. If that is the case, how your neighbor waters, or doesn’t water, could affect your trees.

            I would construct a basin or depression under your trees about four to five feet in diameter and deep enough to hold about 30 to 40 gallons. I would fill this basin with water once a week for the next several weeks.

            Leaves that are crunchy will not grow back. They will dry and fall from the tree. You will have to wait for a new flush of leaves if water is the problem. This might take a couple of weeks.

            To supplement the tree you can plant under the canopy of the tree (not in the lawn) with other plants that require watering. This will help to supplement that trees water requirement.

            The tree in the lawn is puzzling. This would make you think there is another problem but if things happen to BOTH trees it usually points to a management problem; water, fertilizer, pesticides, etc.

            When one tree is affected it usually points to outside factors that are more hit and miss like diseases. However, ash is not affected by that many diseases and is a good tree for Las Vegas.


  1. We planted a Raywood Ash (5 gal.). Not having a problem and everything was looking good until today. I noticed that the top leaves are curling in a ball. We live in Laughlin, NV. HELP??

    1. It is very hot and dry in Laughlin a 5 gal size tree should be watered at least twice a week for the 1st couple years then deep water once a week. Trees need water during the dormant period as well that is when the root system is storing food for the big push in the spring.

  2. planted a 5 gallon Raywood Ash on 7/6/2017. We just noticed that the leaves are starting to curl up in a ball. We live in Laughlin, NV

  3. We just planted a five gallon tree three weeks ago at first we where watering our tree every day as the nursery directed then it was every other day but the leafs are all falling of today help I live in Victorville ca it's the high desert it's been hot in the day around 80 to 85 and it drop to 40 at night

    1. This falls under the general category of "transplant shock"...the plant was "traumatized" in human terms during the time it was at the nursery through the time it was planted. This "trauma" can be from how it was transported from the nursery and planted but it can also result from a change in conditions at the nursery to being plunged outside in the ground in full desert environment. Basically, the plant went through a radical change in its environment and dropped its leaves. It's not dead. It will now produce new leaves and begin readjusting to its new environment. Sometimes this kind of shock can be so minor we don't see it and other times it can be pretty extreme including some die back and even death. Your job right now is to not overwater it and drown the roots but give it enough water so it can spring back. The nursery was right to tell you to water it every day immediately after planting. Now you need to back off and water it only when it needs it. But give it at least one day between waterings when it receives nothing and let the water in the soil drain and let the roots breathe.