Richard Bogren | 10/14/2016 2:47:18 PM
By Dan Gill
LSU AgCenter Horticulturist
(10/14/16) Many plants seem to save up all summer for the spectacular display of flowers, fruit and foliage showing up in our gardens now. If you want to punch up the color level in your garden from late September through early December, here are some trees, shrubs and perennials you may consider including in your landscape.
Three species of cassia grow 8 to 10 feet tall and produce a brilliant display of golden yellow flowers from September to December.
The candelabra plant (Cassia alata) is a tall (up to 12 feet), lanky plant that produces bold, dramatic foliage and spikes of globular gold flowers. Flowering in this species starts in late summer and usually finishes some time in late October or early November.
Cassia corymbosa is shrubbier in appearance and generally grows 5 to 8 feet tall. Starting in September clusters of 2-inch yellow flowers are produced in great quantities followed by green bean-like seed pods.
The most spectacular of the three is the golden wonder tree (Cassia splendida), which blooms from October through the first hard freeze. The large, golden yellow flowers almost cover the foliage and are bound to attract attention in any landscape that includes it.
These three cassias (you may also see them listed under the genus Senna) are generally hardy in south Louisiana and will typically survive milder winters in north Louisiana.
Another plant that creates a similar look in the landscape and is known for its late summer and fall flowering is a plant called golden bells or esperanza (Tecoma stans). It produces large clusters of bell-shaped, golden yellow flowers over a long season.
Two shrubs that will produce outstanding flowers this month through early December are sasanquas (Camellia sasanqua) and various roses.
Sasanquas are among those indispensable shrubs for our area. Dwarf types stay around 3 feet tall while standard varieties will slowly grow to 10 to 12 feet tall and can be trained as a clipped hedge, large shrub or tree. The 2-to-3-inch, fragrant flowers are produced in abundance and come in shades of light red, rose, pink and white, depending on the cultivar you choose. Soon, camellias (Camellia japonica) will begin to bloom and continue through the winter.
Everblooming roses, such as hybrid teas, floribundas, Chinas, Bourbons, teas and landscape roses, will produce outstanding flowers from October until the first hard freeze – and longer if the winter is mild. Deadhead them frequently to keep them looking nice and to encourage blooms.
Although generally not known for fall blooming, azaleas that bloom during seasons other than spring are becoming more available and popular. Particularly notable are some of the Robin Hill azaleas such as Watchet, the popular Glen Dale cultivar Fashion and the Encore azaleas. Check out local nurseries now, and you can see them in bloom and pick out the color you like. These azaleas will continue to bloom until spring, but do not produce the shrub-covering display of flowers that the spring-flowering Indica azaleas, such as Formosa and George Tabor, do.
Although they bloom through summer, salvias always seem to look especially good in fall. Two species, Mexican bush sage (Salvia leucantha) and forsythia sage (Salvia madrensis), are outstanding this time of year. Mexican bush sage produces spikes of furry purple or white flowers on 3-to-5-foot-tall plants. Forsythia sage is an unusual yellow-blooming salvia that makes large spikes of mellow yellow on a 5-foot plant with dark green, quilted leaves.
Lots of herbaceous perennial wildflowers are in bloom along roadsides now, and two that make excellent additions to the garden are wild ageratum (Eupatorium coelestinum) and goldenrod (Solidago species). Wild ageratum produces powder puff clusters of lavender-blue flowers on plants about 24 inches tall.
Goldenrod is a well-known fall bloomer that often gets blamed for causing hay fever. It doesn’t, but it does produce spikes of intensely golden flowers that enliven the garden. The culprit is its cousin giant ragweed (Ambrosia trifida), but no one notices the thin green spikes of flowers it produces.
Now and through winter, trees provide color with fruit. Hollies are notable in this regard and are beginning to color their brilliant red berries now. Excellent choices for our area include the popular Savannah holly and Foster’s holly (Ilex x attenuata Savannah and Fosteri), both small trees. The Savannah holly grows to about 25 feet tall and the Foster’s to about 15 feet tall. A great thing about holly berries is that they are excellent food for birds.
Don’t forget citrus trees when searching for trees with attractive fall fruit. The kumquat and Calamondin orange are particularly effective. They will survive mild winters in the ground in north Louisiana or they can be grown in pots. In south Louisiana, all citruses add color to the landscape with fruits of orange and yellow.
Mexican bush sage produces spikes of furry purple or white flowers on 3-to-5-foot-tall plants. Photo by Allen Owings
The Savannah holly is an example of a variety that is a female clone that will produce berries. (Photo by Tom Pope)
The candelabra plant (Cassia alata) produces bold, dramatic foliage and spikes of globular gold flowers from late summer to late October or early November. Photo by Allen Owings