Southern sugar maple offers great fall color in Louisiana. (Photo by Allen Owings)

A flower bud opens on a sweetbay magnolia. (Photo by Allen Owings)

News Release Distributed 10/04/13

By Allen Owings
LSU AgCenter horticulturist

HAMMOND, La. – Fall is the best time of the year to garden in Louisiana, and it’s a great time to consider trees. Landscapes typically have trees as one of the dominant features.

Louisiana has an abundance of great native and exotic trees to select from for our home landscapes. You may want to consider one or two of these.

Very few landscapes in Louisiana could be complete without a Southern live oak, Southern magnolia or bald cypress.

The Southern live oak, while sometimes too large and spreading for a small home landscape, is one of the most popular and majestic and historical trees. Their broad reaching canopies and evergreen foliage offer great appeal.

Of course, our state tree and our state flower are the bald cypress and Southern magnolia.

Bald cypress provides exquisite fall foliage color. Bald cypress can be planted either in water or in drier spots in the landscape. It is one of our fastest-growing and best-adapted landscape trees.

For Southern magnolias, try the Little Gem variety. This dwarf selection still will mature at 30 to 35 feet tall. Southern magnolias do best in well-drained soil and can be grown in sun or in an understory environment. June is the peak bloom month. Southern magnolias are evergreen and slow-to-moderate growers. You can also select larger-growing varieties such as Bracken’s Brown Beauty.

For summer flowers, the tree most Louisianians instantly think of is the crape myrtle. Select crape myrtles based on mature size. They will bloom for 90 to 100 days beginning in May and continuing into early fall. You can find tall, intermediate, semi-dwarf, dwarf and miniature varieties. Be sure to check on the mature height of your selection before you make a purchase. LSU AgCenter-recommended varieties include Natchez, Sioux, Acoma, Muskogee, Tonto and Tuscarora.

Crape myrtles must have full sun (eight hours daily) in order to grow and flower their best. They also need well-drained soil.

Another summer bloomer is Shoal Creek vitex, a past Louisiana Super Plant selection. Its 12-inch, fragrant, deep lavender flower spikes appear in May and June and can continue through summer. This versatile plant blooms best in full sun and can be trained as a large shrub or small multi-trunked tree about 10 to 15 feet tall and wide.

Shoal Creek vitex is more vigorous and produces larger flowers and deeper color than common vitexes. Once established, it is very drought tolerant and fits well with a lower-maintenance landscape. The flowers also are attractive to butterflies and hummingbirds.

Nuttall, willow, Southern red, cherrybark and shumard are examples of deciduous oaks trees for Louisiana. Nuttall oak has superior fall foliage color. Nuttall oaks also grow over wider ranges of soil types. Willow oaks are a personal favorite. They have the finest-textured foliage of the common oak trees we grow.

The Southern sugar maple is a great deciduous tree for fall foliage color in Louisiana. This shade tree goes by the scientific name of Acer barbatum or Acer saccharum spp. floridanum. Sometimes you will see it commonly called Florida sugar maple or Florida maple – but we are not in Florida. This tree was selected as a Louisiana Super Plant last fall.

Normally found in bottomland forests, the Southern sugar maple has a moderate growth rate and moderate life span. Plants reach a height of 30 to 40 feet after 20 years.

Tree-like hollies to consider include the Savannah holly and American holly.

Savannah holly makes a beautifully shaped tree. Its form is open and narrow with a pyramidal shape. Individual trees can be 30 to 35 feet tall and 8 to 10 feet wide. Savannah hollies are known for their heavy clusters of red berries.

The American holly (Ilex opaca) continues to be a favorite, but it is more difficult to find at garden centers. This holly is native to the vast majority of the United States and has served a variety of uses throughout its history. This broadleaf evergreen reaches heights of 35 to 50 feet with a spread of 15 to 25 feet. American hollies grow more slowly than the other tree-form hollies.

You can also try the evergreen sweet bay magnolia. This is another Louisiana Super Plant. Sweetbay magnolias are native to a large portion of the eastern and southeastern United States. These magnolias perform well under a wide range of soil and planting conditions – their native habitat is swamp, bog, pond or sandy stream areas. But they grow best in fertile, moist, well-drained, silty loam soil. A slightly acid soil is preferred.

Mature trees will average about 30 feet tall with a spread of 20 feet, but larger sizes are common. Most of the time, these trees have a tendency to be semi-evergreen. The further south they are planted, the more likely foliage retention will extend into winter. Some improved selections of sweetbay magnolia are close to being evergreen.

A nice feature of the sweetbay magnolia is the silvery gray color on the underside of leaves. Flowers are creamy white and about 2 to 3 inches in diameter. Flowers are present in April and May and have a lemony fragrance.

All of these trees are great for landscape consideration. Now through February is a great time to add new shade and flowering trees to your landscape. Louisiana garden centers carry good inventories of trees during fall and winter.

You can see more about work being done in landscape horticulture by visiting the LSU AgCenter Hammond Research Station website. Also, like us on Facebook. You can find an abundance of landscape information for both home gardeners and industry professionals at both sites.

Rick Bogren