Summer-Flowering Perennials for Southern Louisiana

(News article for July 24, 2021; edited)

One of the perks of having an office on the grounds of the Hammond Research Station is the opportunity to observe and photograph a variety of ornamental plants.

I’m especially interested in herbaceous (non-woody) plants that are reliably perennial in our climate. Cold hardiness is one factor that determines what survives from year to year, but our hot summers and high rainfall conditions also impose limitations. There are plants, like peony and English lavender, that survive well in cooler or drier areas but would not be expected to tolerate our climate in the long-term.

Few things bring cheer to a landscape like the closely related blackeyed Susan and orange coneflower. A large patch of Early Bird Gold orange coneflower (Rudbeckia fulgida ‘Early Bird Gold’) caught my eye back in early June, when it was already in full bloom, and it was still visible from across the garden in mid-July. Early Bird Gold begins blooming earlier in the year than its parent variety, 'Goldsturm'. This particular planting has been in place for twelve years.

Flower stalks of Early Bird Gold reach about two feet tall. Orange coneflower should be planted in a well-drained bed in full to partial sun.

Another plant that has demonstrated longevity is Big Momma Turk’s cap (Malvaviscus x ‘Big Momma’). This plant is in the mallow family (Malvaceae), along with the various hibiscus species, flowering maple (abutilon), cotton, okra, and the cacao tree. Big Momma reaches approximately four to six feet tall and produces red flowers in summer and fall. A Big Momma planting next to one of our gravel parking lots was installed in 2014 and is still going strong.

Texas star hibiscus or scarlet rose-mallow (Hibiscus coccineus) is also in the mallow family. It can reach 10 feet tall and wide and produces striking five-petaled red flowers in summer and fall. While we need to take care to provide good drainage for many of our perennials, Texas star hibiscus is well-suited to wet areas.

The abovementioned plants support pollinators as well as providing color in the garden.

These are just a few of the perennial flowering plants on the grounds of the Hammond Research Station. If you’re interested in seeing more photos from the Station, I’d suggest follow the Hammond Research Station on Facebook, where my colleagues often post photos from the gardens, and visiting The Trials at Hammond website, through which you can find results of plant trials, videos from the gardens, and more. Videos made for the Summer 2021 Horticulture Field Day are now available.

Let me know if you have questions.

Contact Mary Helen Ferguson.

20210604_104016-croppedjpg 'Early Bird Gold' orange coneflower on June 4, 2021 (Photo by M.H. Ferguson)