These are Rhus lancea (African Sumac) trees. Pic #1 shows a healthy tree on the east side of the back yard 7-22-09. The pic in the middle shows the sick tree one year ago, 7-28-08 on the west side of the back yard. The last picture shows the tree today 7-22-09. The few leaves that are left are still shiny and look healthy but they keep getting fewer and fewer. I water these trees once a week with a soaker hose for 4 hours at a time. I have not pruned the trees on the west side of the yard to maintain a small privacy wall. Out of 12 trees this one looks the worst. Could anyone tell me why one tree would get sick while the others thrive? Thank you for any suggestions you may have.
Rhus lancea is listed as an invasive weed in Arizona* - maybe the local authorities have found some disease or other to assist in getting rid of it? * http://www.saguaro-juniper.com/i_and_i/invasive_spp/invasive_plants.html
I've been here 24 years and have never heard of that. But I'd much rather have these great shade trees than a bunch of Buffelgrass (Pennisetum ciliare).
There could be something unseen underground as simple as a wrapping root. So the answer may be hidden.
Given that they are of African origin could it be getting too much water. I know many of our natives get upset when they get over watered. Liz
Thank you for your responses. I don't think it's over watering because the other trees on the west side of the backyard seem to be alright and all the trees on the east side of the yard are in good condition. I water them all the same, 4 hours a week at night with long soaker hoses. I have no way of knowing if there is something wrong underground but yesterday I cleared all the ground underneath as far out as the drip line, fertilized with Vigoro evergreen food, soaked that in then topped off with Kellogg Growmulch, soaked that in and now I'll have to look for any rejuvenation signs. The temperature here has been between 105 and 112 degrees Fahrenheit, but these trees have been through this type of heat before and given their origin that doesn't worry me.
