If there is spotting on the leaves, and the leaves are falling, it could be entomosporium leaf spot, a fungus that pops up during warm, wet spring weather. Entomosporium is a fungal disease that spots the leaves of plants in the Pomoideae group of the rose family, including apple, flowering crab apple, evergreen pear, hawthorn, pear, photinia, pyracantha, quince, Rhaphiolepis (pictured), and toyon. If that is the case, remove infected leaves from the ground and the shrub. Also, avoid overhead watering. Making sure there is room between the plants for good air circulation can help. If that is impractical, try removing some of the lower branches.
And, in a rare instance where mulch can be counterproductive, the experts at UC say to remove any mulch beneath the plant, which may harbor the fungus.