By Dan Gill

LSU AgCenter Horticulturist

Many small flowering trees help brighten our landscapes from late winter through the spring season. One of the more beautiful of our early spring-flowering trees is the Japanese magnolia.

The Japanese magnolia, or saucer magnolia, opens its fat, furry flower buds in February or March before the foliage emerges. Unlike the native Southern magnolia Magnolia grandiflora, it is deciduous and drops its leaves in winter. The flowers blooming on leafless branches are particularly noticeable.

The flowers are large and showy and come in a variety of colors, such as white, lavender-pink, rose-purple, dark reddish purple and light yellow. The brightest color is on the outside of the petals, while the inner surface tends to be creamy white. The flowers range in size from about 4 to 6 inches across, sometimes larger. The Japanese magnolias generally grow to be about 15 to 25 feet tall with a spread of 10 to 15 feet.

When the flowers are young, the petals are held fairly upright, giving the flowers a distinctively tulip-like appearance. As the flowers age, the petals tend to open more and lay down, creating a more saucer-shaped flower. The flowers have a spicy to musky fragrance.

The Latin name for the Japanese magnolia is Magnolia x soulangiana. The “x” in the middle of the name indicates that this is a hybrid rather than a true species. The Japanese magnolias we grow in our landscapes are the result of a cross between two species, Magnolia liliiflora (lily magnolia) and Magnolia denudata (white saucer or Yulan magnolia).

Now is a great time to plant Japanese magnolias if you would like to add one to your landscape. The weather is still cool and the hot weather of summer is still months away. That means it is possible to select a blooming tree at the nursery. This is important because a number of varieties are available with different flower colors and shapes.

Selecting and planting

When you go to the nursery, you will likely see several varieties of Japanese magnolias available. One called Alexandria is popular and common. It produces the classic light purplish-pink flowers typically seen in these plants. You may also see Susan (deep purplish-red), Betty (rosy pink) or Jane (reddish-purple slightly twisted petals). These varieties tend to be shrubbier and bloom somewhat later, which minimizes the chance they will be damaged by a freeze. As far as I know, all of the varieties available at your local nursery should do well here. You can make your selection based on flower color and shape and growth habit of the tree.

When selecting Japanese magnolias, you will notice that the trees are generally grown with numerous trunks. It is common to grow these small trees with several trunks, but too many looks untidy. Generally, in the second and third years after planting, thin the number of trunks to about five for a more attractive tree.

Plant Japanese magnolias in a well-drained, sunny to partly sunny location. Make sure you do not plant it too close to the house – it will need room to spread about 10 or 15 feet. Dig a hole just as deep as the root ball and two or three times its width. Take the tree out of its container and set it in the hole. The top of the root ball must be level or slightly above the surrounding soil. Thoroughly pulverize the soil removed to make the hole and backfill in around the roots, firming gently as you go. (Nothing should be added to the backfill soil.) Finally, water the area thoroughly to finish settling the soil, add more soil if necessary and mulch the area 2 or 3 inches thick. If the tree is tall enough to be unstable, stake it to provide support for about a year.

Care after planting

Like all newly planted trees, your young tree should be watered regularly during hot, dry weather this summer. No fertilizer is required the first year, but you may begin fertilizing next spring.

As the years go by and the tree grows taller, gradually remove the lower branches to raise the canopy of the tree to the desired height, generally 8 to 10 feet from the ground.

Japanese magnolias, particularly the first several years after planting, frequently look terrible in late summer, from about July until they drop their leaves. This is mostly due to stress during the first few years when the trees are getting established. The foliage gets spots, scorched edges and may even drop early. This is exacerbated by dry weather, and proper irrigation will help.

Don’t expect these trees to grow quickly. Growth rate is moderate and improves over the years as trees get better established. If a tree grows very little and stays rather stunted after several years in the ground, the tree may not like the selected location. In that situation, moving it to a different location sometimes helps.

Other magnolias

Another species that blooms in spring is the star magnolia, Magnolia stellata. The tree is smaller, more like a large shrub, and the flowers are typically white, star-shaped and very fragrant. A variety called Dr. Merrill produces especially large, attractive flowers and is generally available at nurseries.

(03/04/16)