Boulder Creek, CA (Zone 8B)
|My madrone tree's leaves get these black spots on them and then slowly turn black all over. New leaves come out in spring, and then spot and then black by late summer. This is every leaf on the tree. I have noticed that the spot thing is spreading to other small madrones around me. I live in the Santa Cruz mountains and have noticed that most other madrones are not losing thier leaves in the same way. Will spraying the young madrone leaves for black spot (as for roses) and keeping the fallen ones removed, help this situation?
|Answer from NGA
May 27, 2006
|Foliage diseases of Madrone come in many forms and species. The fungi that cause leaf spots are not a serious threat to the tree unless repeated defoliation occurs. Madrone leaves are primary targets due to their high concentration of sugars. Most of our foliar fungi are more successful at attacking old leaves rather than new ones. The new foliage on the Madrone is rarely infected until fall. These fungal diseases intensify during periods of warm, wet weather. In some years, most of the foliage can be lost due to heavy fungal infections, but usually new leaves will replace this lost foliage in the summer. The good news is that foliar disease of the Madrone is not considered to be a major factor in their decline. There are no chemical sprays that are completely effective, so your best course of action is to rake the fallen leaves and remove them from the garden.
« Return to the Garden Knowledgebase Homepage