Perennials that enjoy hot and humid coastal summers!

Published 4:32 pm Monday, May 30, 2022

By Patricia Drackett

Director of the Crosby Arboretum and

assistant extension professor of landscape architecture with the Mississippi State University Extension Service

Sign up for our daily email newsletter

Get the latest news sent to your inbox

In celebration of the upcoming Crosby Arboretum Pollinator Plant Flash Sale to take place on Saturday, June 4 from 10:00 a.m. to noon, this column will cover some of the top-performing perennials not only easy to care for but also attractive to pollinators. Installing plants that are useful to birds and pollinators will also increase the visual interest of your garden, causing it to come alive with movement for you and your visitors.

Today at the Arboretum, we saw several species of butterflies in the pollinator garden and greenhouse. Green Team volunteer and Pearl River County Master Gardener Teresa Covington skillfully snapped a photo of one of these winged jewels as it paused in the greenhouse, and team member/PRC Master Gardener Patti Murphy showed us a recent photo she’d captured of a viceroy butterfly. Viceroys look very similar to monarch butterflies, and sometimes it can be difficult to get them to sit still long enough to tell the difference!

A good many of the perennials you’ll see in our sale will prosper in summer’s heat and humidity. You’ll also find flowering shrubs, including several species of ave  azaleas. If your yard has areas that stay continually wet, you’ll be glad to know we’ll be carrying many species that will thrive in moist sites, such as southern blue flag iris, Texas star hibiscus, coastal Coreopsis, mountain mint, cardinal flower, and Stokes aster.

The Green Team has propagated a table full of Texas star hibiscus (Hibiscus coccineus), and we’ll both the red and white form (‘Alba’) at the sale. Although this plant will usually die to the ground each year, it quickly sprouts back in spring. Locate this plant in the rear of your bed, where it will be a stunning specimen and so you will not notice when it dies back. Another stunning and top-performing native perennial that enjoys wet conditions is the American crinum lily.  This plant will go in and out of bloom from mid-spring to late fall

Southern blue flag Iris is a signature plant at the Arboretum, and a low-care garden favorite common to the rich, moist soils in coastal wetlands, and where water stands year-round. The purple or blue flowers come in various hues. The plant typically grows two to three feet in height, although it can reach four feet or more. Southern blue flag blooms most abundantly in full sun in wet locations and in shifting shade. It is very easy to propagate by division or seed.

Native Iris offer a tapestry of shades of purple blooms in the spring. This perennial is abundant among the herbaceous plants fringing the Piney Woods Pond and Slough Exhibit. Both American crinum and the native Iris are perennials that will also perform well in a regular garden soil, if attention is given to providing supplement water in dry periods, and both will propagate easily from seed that follows.

One trick to keeping your property looking robust in the summer is to include moisture-loving species in these moist areas, as they will have water available to resist potential periods of drought. Many plants that grow in wet soils will also be just fine in regular garden soil.  Just remember to keep your eye on your new acquisitions during their first year, however.  Provide supplemental water when needed so that they will become established.  Once they have developed a good root system, they can then start living up to their reputation of being “drought tolerant”.

Our goal at the Arboretum is to carry tough, reliable, low-care plants for gardeners at our sales, the ones that are well-suited to beginning gardeners, are easy to propagate, and continue to increase in your garden.  While some of the more striking native species such as oakleaf hydrangea, bigleaf magnolia, native “honeysuckle” azaleas, and mountain laurel can be finicky, they will reward you with being glorious in the garden.  The key to the success with any plant is to provide it with the environmental conditions they prefer.  Next time you are at the Arboretum, pick up one of our resource handouts at the front information kiosk listing numerous websites to help you identify and learn more about plant species that will thrive in our coastal environment.

We are working on our summer program calendar, which will be released soon. In June, we are planning an Introduction to Beekeeping program on Friday, June 17 from 10:00 to 11:00 a.m. and an Introduction to Birding class on Saturday, June 18.  For more information, see our calendar at or the Arboretum Facebook page. In addition, you may sign up for our email list to receive notices of upcoming events.  Crosby Arboretum is located at 370 Ridge Road in Picayune, at I-59 Exit 4, and is open 9 AM to 4:30 PM Wednesday through Sunday.