|Poplar or cottonwood growing in desert |
landscape. It is difficult to water these
types of trees in our climate due to their high
water demand and our irrigation systems not
intended for very large, high water-demand trees.
I really appreciate your help. It would be a shame to lose these beautiful trees.Jim
Cottonwood trees require lots and lots of water. I hope these are not growing in a rock or desert landscape or you will have problems. If you will be successful they should be growing in a large turfgrass area with you supplying supplemental water to them deeply twice a month. This means not only are they receiving water from the lawn, but you would be watering them with extra water down to a depth of 18 to 24 inches twice a month during the growing season. The area that you are watering under the tree should be approximately the same area that is under the canopy or spread of the tree.
It is hard to judge but my guess would be that you are getting branch dieback from a lack of total water applied to the tree. These trees will not survive for any length of time if they are in drip irrigation. I would highly recommend that these trees be watered with a bubbler that releases large amounts of water quickly into a basin beneath the tree. This basin should be the size I mentioned above.
I don't believe that there is anything wrong with this tree that lots of water applied under the canopy would not cure. Watering schedule during the summer months would be every 2 to 3 days. The frequency of applied water decreases in the cooler months but the volume of water applied remains the same... that water needs to travel in the soil to a depth of 18 to 24 inches beneath the tree.