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Get It Growing for 11/22/24
Fall is an ideal time for planting flowering perennials. And we could write a long list of reasons why you should think about adding some to your garden.
First, perennials don’t have to be replaced each season like short-lived annual bedding plants. That means less work for you as the gardener! Perennials come back year after year, providing a beautiful display of blooms for several seasons.
Another great thing about perennials is that many of them are native to the United States. Native plants serve as critical sources of food and shelter for native wildlife and insect species. Because they are adapted to our climate, they also tend to be hardy and easy to grow.
One more reason to plant perennials is the wide range of available choices. You can find species that will thrive in wet or dry, sunny or shady locations. Some bloom in spring and summer while others save their flowers for early fall. You can plant cultivars that bloom at different times to ensure a steady supply of flowers in your garden.
So why plant perennials now? Perennials grow slowly and intently, and they can get their best work done during the cooler days of fall, which are far less stressful than the heat and high nighttime temperatures we experience in spring and summer.
Most perennials are considered herbaceous plants — they don’t form woody structures that get larger over time like a shrub. Instead, they focus much of their effort on root growth. These plants like to concentrate on establishing a strong root system before they are ready to put on a show in the landscape.
There’s an old garden saying about perennials: “The first year they sleep, the second year they creep and the third year they leap.”
You can plant perennial transplants purchased from a local garden center or, for some native perennial species, fall is the perfect time to try to sow seeds directly into the landscape.
Do your research before buying perennial plants. They’ll be part of your landscape for years to come, and you want to pick plants that will keep you happy for the long term.
Make sure your selections are true perennials from temperate climates and not another category of herbaceous plants we call root-hardy tropicals. An example of this group is ornamental bananas, and plants like these are best planted in spring during warm weather.
There are fewer perennials available for our hot Southern climate than for the northern United States, where these plants also tend to grow much larger and are more robust. Still, there are some outstanding options for Louisiana gardens. Below are a few of LSU AgCenter horticulturist Jason Stagg’s favorites.
This plant can tolerate wet sites in either sun or partial shade. In summer, you’ll be rewarded with tall, purple flower spikes that pollinators love. The flowers resemble snapdragons.
Obedient plant (Physostegeia virginiana) will slowly spread over the years to form a large clump. Besides purple, there are two other cultivars on the market: light pink and pure white.
Some of the most familiar perennials out there are species of the genus Rudbeckia, commonly called black-eyed Susans. Their cheery, bright yellow, daisy-like flowers are medium in size. These plants love the heat and have a long bloom season.
Stagg advises sticking to smooth-leaved species such as Rudbeckia fulgida and Rudbeckia hirta. Other species have rough or fuzzy leaves, and although they have gorgeous blooms, they generally prefer drier weather and better drainage.
Asters are making a splash in landscaping these days. They generally bloom in fall, bringing color to the landscape at a time when many of our warm-season bedding plants are fading.
You may have noticed tall native asters blooming along roadsides or fields starting in September. Garden asters are shorter, bushier and more compact than their native counterparts.
“I’ve noticed an increased interest from plant breeders to continue to improve these plants,” Stagg says. “They are completely covered with small, daisy-like flowers in colors ranging from white to yellow and from lavender to purple. One of the best cultivars I’ve found is called Raydon’s Favorite, and it will reach 2 feet tall and wide after a few years.”
Stagg suggests cardinal flower, which is native to Louisiana, for wet areas. Native echinacea, or purple coneflower, is a nice choice for well-drained soils.
LSU AgCenter horticulturist Jason Stagg talks about some of his favorite flowering perennials.
This is the time of year for planting flowering perennials such as obedient plant, at left, and black-eyed Susans, at right in background. Photo by Randy LaBauve/LSU AgCenter
An excellent flowering perennial for Louisiana landscapes is obedient plant, which you can find at local garden centers. Photo by Randy LaBauve/LSU AgCenter
Obedient plant has tall, purple flower spikes that pollinators love. Photo by Randy LaBauve/LSU AgCenter
Many gardeners are familiar with black-eyed Susans, a popular perennial. Photo by Randy LaBauve/LSU AgCenter
