Will a Star Magnolia Bush Come Back From Too Much Sun Exposure?

Lighting Needs

• Star magnolias grow and flower their best in full to partial sun exposures in the landscape. They naturally tolerate more than six hours of direct sun daily in all seasons. It's not likely that over-exposure to sunlight is the primary reason a star magnolia falters. However, reflected hot, strong summer sun rays can lead to leaf scald, such as if planted close to a light-colored patio pavement or the western facade of a white building. You can offset this by cool, moist soil conditions.

Other Environmental Factors

• The star magnolia grows best and handles substantial sunlight and heat when it's growing in good health. A full sun exposure does lead to warmer temperatures and potentially drier soil that would cause leaves to prematurely yellow, brown and drop. For the star magnolia to persist and "recover" from full sun exposures, the soil must be acidic, moist but well-drained, fertile and rich in organic matter. If the roots dry out, rot in soggy soil, or do not absorb ample nutrients, the plant weakens and can die.

Improving Magnolia Health and Vigor

• Rather than worrying about the sun exposure, focus energy on maintaining the best soil conditions. If the soil remains perfect, the star magnolia is more likely to bounce back from any number of temporary issues in its lifetime. Irrigate the root zone of the plant year round as long as the soil isn't frozen. The root zone extends from the trunk to 3 to 5 feet beyond the reach of the branches. Supplement rainfall to keep the top 12 inches of soil evenly moist. Placing a 3- to 4-inch layer of organic mulch over the root zone deters weeds, conserves moisture and moderates soil temperatures in full sun garden sites. Keep the soil pH between 5.5 and 6.5.

Recovery Time Frame

• Don't expect the star magnolia to show new growth and improved vigor until the next spring when the growing season begins. If the soil is fertile and moist leading into spring, the roots will already be providing necessary materials for healthy flower and new leaf growth. Over the course of the summer, the magnolia will maintain green leaves and look lush as long as the soil remains moist. Keep in mind that sandy soils or trees planted on hillsides endure faster soil drainage so irrigation is needed more frequently to maintain rejuvenated growth.