This article appeared in the July/August 2001 issue of Horticulture Update, edited by Dr. Douglas F. Welsh, and produced by Extension Horticulture, Texas Agricultural Extension Service, The Texas A&M University System, College Station, Texas.
Photo by Cynthia W. Mueller
Southern Magnolia By Dr. William C. Welch,
Professor and Landscape Horticulturist
Texas A&M University, College Station
As suburban yards and landscapes become smaller, larger sizes of magnolias become difficult to fit into the available space. Smaller cultivars of M. grandiflora can be popular substitutes. ‘Little Gem’ is a particularly good choice for a smaller garden space. In 15 years it may reach 12 feet in height, and has the added bonus of flowering at a much younger age. The underside of the leaves of ‘Little Gem’ are covered with a soft, furry brown growth of hairs called indumentum. Growth is narrow and upright, and its leaves and blooms are correspondingly smaller than the standard varieties.
The Southern Magnolia will perform best in Texas on loose, acid soils and may appear stunted or be short-lived on heavy, poorly drained ground. Oftentimes in more alkaline areas magnolias will do well for a number of years until roots reach the compacted substrate soil, then decline. They do best in full sun. When situated in partial shade there will be fewer blooms. My experience is that magnolias should be planted only in areas that have deep soils that are acid and are, at least, neutral in pH. Numerous problems occur when attempts are made to grow them in other areas.
When planning to use a magnolia in the landscape, it is good to take into consideration the fact that grass will do poorly underneath, and that there will be considerable leaf litter during the spring when the majority of leaves are shed. Many homeowners become concerned at this time because the plant looks unthrifty, and leaves droop before finally being shed, but this is a normal process. Leaving lower branches in place will help to minimize the messiness of fallen leaves and cones. Magnolias are sometimes troubled by beetle attacks which damage or kill the ends of branches and cause unsightly dieback through the tree.
Seedlings will sometimes appear under trees, but most propagation is done through seed, cuttings taken in the summer, or from grafting. Most propagation is done through seed, cuttings taken in the summer, or from grafting. Cutting grown plants are vastly superior to most seedlings because they begin flowering the first year or two after propagation while seedlings may take 15 to 20 years to bloom. Rooting magnolias is not easily done. Even with intermittent mist systems and rooting hormones, he percentage of successfully rooted cuttings is often very low and best left to nurserymen and other professional horticulturists.
There are frequent requests to my office for instructions on growing magnolias from seed. The seeds should be collected as soon as possible after the fruit is mature which is usually mid-September or early October. The cone-like fruit should be spread out to dry for several days until they open. The seeds can then be shaken from the dried cone or fruit.
If the seed is to be kept for any length of time, the red pulp should be allowed to dry enough to lose its fleshy character, placed in sealed containers and stored at 32 to 41 degrees F. If stored over winter at room temperature seed will lose its viability. The seed should be cleaned before planting or stratifying. To remove the fleshy seed coat, soak the seed overnight in warm water. Remove the seed coat by rubbing against hardware cloth or window screening. After cleaning, the seeds should be sown immediately or stored for 3 to 6 months at about 40 degrees F and planted in the spring. An excellent way to stratify seeds is to use a polyethylene bag and place alternating layers of a moist medium such as a sand and peat mixture and seeds in the bag. Tie the top of the bag and place in a refrigerator at about 40 degrees. The medium should be just moist enough to stick together but not so wet that it will drip if squeezed by hand.
Whether sown in the fall or stratified in the refrigerator and sown in the spring, the seeds should be covered with about l/4" of soil and mulched to prevent drying. Seedbeds should be kept moist until germination is complete. Partial shade should be provided the first summer for seedlings.
The southern magnolia is a truly magnificent tree in areas where it thrives. Smaller growing cultivars and propagation by cuttings of outstanding types have made them useful even on smaller sites. They are an important part of our “sense of place” in East Texas and the South. Even though they are evergreen, magnolias drop litter most of the year and can be a burden when planted adjacent to pools or other areas where litter may create a problem.
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