Rosa Rugosa leaves have all turned brown
I've got two Rosa Rugosas that were planted almost 10 years ago. They've really been thriving until this summer. Now, almost all the leaves on one of them have turned brown and recently the other one is starting to do the same thing. The two plants are about 10' apart. Nothing has changed in terms of how much water they get. I've noticed some webs on some of the dry, brown leaves, but I think those appeared after the leaves had already died. Everything else around them is doing fine. What could it be?
Nevada County California
This may be a spider mite infestation. You can find more information here: http://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html. You might also look carefully at the crown and main stems of the plant (watch those thorns!) for any cankers or signs of damage. Prune out all the dying and dead branches and dispose of the plant material away from the plant, then feed and water appropriately to encourage new healthy growth.