Blanchard Southern Magnolia Tree Care

Lemony scented, flowers of the Blanchard magnolia occur from spring to summer.

Large white flowers in late spring and summer surrounded by large glossy dark green leaves with rusty fuzz on their undersides makes the southern magnolia one of the most prized trees for USDA Hardiness Zones 7 through 10. The Blanchard variety (usually listed as 'D.D. Blanchard') becomes 50 feet tall and 30 feet wide in an attractive pyramid shape. It's a nice shade tree or screen for hot-climate regions that occasionally have droughts.

Soil pH

The key to good health with any magnolia is maintaining an acidic soil pH. While tolerant of neutral soils, the results from soil test kit should reveal a pH in the range of 5.0 to 6.5, otherwise soil amendments or acid-producing organic mulches need to be used. Pine bark, pine straw, oak leaf mold and coffee grounds spread over the Blanchard southern magnolia's root zone will aid in the gradual lowering of the soil pH with little effort. Use of acid-forming mulches over sandy soils is a sound decision since both moisture and nutrients leach out quickly.

Watering

Southern magnolias demonstrate remarkable drought tolerance once established in the landscape, approximately three to five years after first planted. While a consistently moist but well-drained soil is ideal, figure the tree should receive one inch of rainfall or irrigation water weekly during the growing season. Consider watering the Blanchard variety every two to three weeks deeply during prolonged droughts to prevent abortion of leaves, flowers or new stem elongation. Again, use of a mulch cools the soil, retain moisture and prevents weeds from robbing the soil surface of moisture intended for the magnolia's roots.

Fertilizing

Fertilizer application tot he Blanchard magnolia is not warranted if it is already growing in an acidic, humus-rich soil that is covered in a three to four-inch layer of organic mulch. However, using a well-balanced, slow release granular fertilizer in spring and summer provides micro-nutrients that can assist in healthy growth. Avoid using liquid fertilizers as natural rainfall or irrigation washes it away quickly and the waxy foliage of southern magnolias shun foliage feeding.

Pruning

In general, little to no pruning maintenance is anticipated on the Blanchard magnolia. Dead or diseased branches or leaves need removal as soon as encountered. An errant branch or cracked/damaged branch after an ice or windstorm event may be cut back to 1/2-inch above a lower live branch or dormant bud. To diminish the sap bleeding from the magnolia, do not prune in spring if possible, wait until midsummer or the winter dormancy. Remember than pruning the tips of southern magnolia branches removes flower buds that will open next spring and summer.

Concerns

Southern magnolia trees that grow with good vigor and are not distressed from drought, injured trunks from colliding lawnmowers or weed-trimmers or compact soils do not typically suffer from plant diseases or pests. Too little sunlight can lead to aphids and sooty mold on shaded foliage and rabbits may browse upon bark. Overly wet soils lead to root rot or fungal infections, often entering in wounds on the trunk. Generally speaking, roots of magnolias remain near the surface, so avoid digging or compacting the soil within 10 feet of a Blanchard magnolia to keep its roots intact. Magnolias resent root disturbance and the southern magnolia should only be dug and replanted in the autumn if such a drastic task can't be avoided.

References

• Burncoose Nurseries: How to Care for Magnolias
• Learn2Grow: Magnolia grandiflora 'Blanchard'
• Oregon State University: Magnolia grandiflora