Q What causes the leaves of camellias to turn brown and fall off?
A Camellias show stress in various ways including shedding leaves. This can be caused by lack of water and, in hot conditions, camellias appreciate shade as well as water. In winter, leaf loss can be caused by frozen compost or soil. If frozen, the soil cannot supply the leaves with water, so they turn brown and leaf loss is likely. To avoid this, mulch plants growing in the ground, and move pots to sheltered spots, and insulate them with bubble-wrap.
Frosting of leaves, flowers and shoots also causes them to turn brown. This is especially likely if early-morning sunlight falls on frozen foliage. Provide early morning shade, or move containers to shady spots.
Overfeeding can also lead to leaf loss; don’t add more than the recommended levels of feed. Container-grown plants are especially vulnerable. It is best to feed camellias little and often during the growing season.