Ready for cooler temperatures? You can start planning your fall garden now

By Heather Kirk-Ballard

LSU AgCenter Horticulturist

We’ve had a brutally hot summer here in Louisiana this year. It’s enough to make me daydream about fall — crisp temperatures, colorful leaves and the many plant possibilities the season brings in the garden.

While we still have a few more weeks of our blazing summer to get through, don’t despair. Autumn isn’t actually that far away, officially beginning with the fall equinox in late September, which is less than two months from now. It’s a good idea — and a great mental escape from the summer heat — to go ahead and start making plans for your fall garden.

Some of your summer-blooming plants will carry over into the fall in Louisiana, including butterfly bush, firebush, Turk’s cap, cassia plant, angel’s trumpet, salvias and sedums. You can also continue to plant marigolds and zinnias for great fall-flowering bedding plants.

Warm-season bedding plants such as periwinkle, blue daze, purslane, scaevola, impatiens and begonias are often relatively long lived in Louisiana. Don’t rip these plants out at the first sign of cooling temperatures. Instead, leave these beds alone for as long as you can enjoy the display. You can convert to cool-season plants a little later into the fall.

There are many great fall-blooming perennials out there. Maybe you already have some of these plants in containers. Consider transplanting them into your landscape for a different look.

One of my favorites is firebush (Hamelia sp.). Lime Sizzler firebush (Hamelia patens Grelmsiz) is a Louisiana Super Plant selection that can be found in most local nurseries. Hummingbirds love this plant, which has gorgeous orange and red flowers against yellow-green variegated foliage. This shrub will bloom best in full sun to partial shade.

Turk’s cap (Malvaviscus drummondii) is another great bloomer for the fall. A native plant of North America, it is a root-hardy perennial but may grow year-round in protected areas. Otherwise, it will come back from its roots in the spring. It grows well in full sun to partial sun. This plant has striking red flowers that never truly unfurl and dark green foliage. It’s a favorite of bees, butterflies and hummingbirds.

Cassias always come to mind when I think of fall bloomers. The gorgeous yellow flower clusters typically bloom between September to November in Louisiana, having a two-to-three-week bloom time.

There are a few different cassias commonly grown here. Cassia splendida is commonly known as the candlestick plant or tree. Other types include Cassia corymbosa and Cassia alata. You may also see popcorn cassia (Cassia didymobotrya) being sold and grown in Louisiana. All of the cassias tend to be medium to large herbaceous and sometimes woody shrubs. They are easy-care plants with few pest and disease problems. They grow best in full to partial sun and are another favorite of pollinators.

Salvias are another great choice for fall-flowering plants. Salvia guaranitica varieties Black and Blue and Argentine Skies start flowering in summer and save their best bloom for the fall. Some fall-blooming salvias are rosebud sage (Salvia involucrata) and forsythia sage (S. madrensis). Rosebud sage plants tend to be very large, growing 5 to 7 feet tall. They should be planted behind smaller plants in the landscape. Forsythia sage is much smaller. These plants grow well in both full sun and partial shade. And — you guessed it — salvias are another great flower for pollinator attraction.

Angel’s trumpet is a fantastic fall-flowering plant. It is a tropical plant that will freeze in the wintertime when temperatures drop low enough but will come back from the roots each spring and have showy, bugle-shaped flowers in later summer through the fall. A truly gorgeous addition to the landscape, it comes in all shades of colors — yellow, pink, white, purple and orange, just to name a few. The hummingbirds love this plant, too.

There are some sedums that bloom in the fall. One example is Autumn Joy, or Hylotelephium Herbstsfreude. It has succulent leaves and stems with showy clusters of rosy or copper to brown flowers that are gorgeous for the fall. They typically bloom in early summer and again in the fall. They perform best in full sun and can tolerate some drought and heat once established.

Marigolds and zinnias are another great blooming bedding plant for the fall. You can plant both now and enjoy until freezing temperatures hit.

Marigolds come in a wide range of varieties. The African marigolds are taller, larger and can be used as a cut flower. They are perfect for adding the fall primary colors of orange, gold and yellow to your landscape. The French marigolds are the shorter variety, with smaller flowers and more color variations.

Many zinnia species are available. Traditional, older zinnia varieties are the Zinnia elegans. Some of these varieties are good for cut flowers, like the Benary Giant series. Other varieties are better as short bedding plants, such as the Dreamland series. A wide range of flower colors are available in zinnias.

Both zinnias and marigolds are easy-care, profuse bloomers that love full sun to partial shade. The pollinators love these flowers just as much as we do. Remove faded flowers to encourage new blooms.

Last but certainly not least are chrysanthemums. They have become synonymous with fall, sporting all the gorgeous fall colors. These will be available a bit later in the season and can be used for fall decorating. They grow well in containers but can also be grown in the landscape in areas that get full to partial sun.

Fall is truly an exciting time of year for so many reasons. We have so much to look forward to once we get past this hot, dry summer.

Plant with yellow-green leaves and red flowers.

Lime Sizzler firebush has orange-red flower clusters perfect for adding fall color to the landscape. Photo by Jeb Fields/LSU AgCenter

Yellow flowers.

Chrysanthemum means “gold blossom” in Greek. These flowers are a symbol of fall. Photo by Anna Ribbeck/LSU AgCenter

Plant with green leaves and yellow blooms.

Candlestick trees are a great fall-blooming option for Louisiana landscapes. LSU AgCenter file photo

7/27/2023 1:07:44 PM
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