Southern gardening: Enjoy golden thryallis in summer and fall gardens

November 3, 2012 8:26:12 PM



A couple of years ago, I wrote about a new plant I found for the fall landscape called golden thryallis. We planted some in our landscape at Coastal Research and Extension Center in Biloxi, and I have it growing in a large container at my house. 


After making seasonal observations of golden thryallis, I have come to the conclusion that it's a must-have plant for our Mississippi landscapes. 


Flowering starts around the end of June or early July. Plants are in full flower from Aug. 1 until the frosts and freezes of early winter. Flowers are a very bright yellow that you simply can't miss. Their red stamens and pistils make them even more brilliant. The bases of the flower petals are also tinged with red. 


Golden thryallis is very tolerant of pruning, so don't be afraid to shape and maintain the size of the plant. Since flowers develop on new growth, pruning an untidy plant will not hurt flower production. 


The leaves are a bit oblong in shape and about 1 to 2 inches long. In the coastal counties, leaves take on a bronzy color with cooler temperatures. 


One thing I really like about golden thryallis is its growth habit and branching structure. It looks a little open, and it only takes a slight breeze to create motion in the branches. As the branches grow, they are initially a rusty brown, which complements the color of the flowers. 


In Mississippi landscapes, golden thryallis plants can grow to 3 to 4 feet tall and 2 feet wide. 


Golden thryallis came from Mexico and Central America and is evergreen in U.S. Department of Agriculture hardiness zones 9b to 11. Mississippi's coastal counties are in zone 9a, and golden thryallis has been deciduous there. 


If you live away from the coast, you may be surprised by this plant's cold hardiness. In coastal Mississippi, temperatures in the mid- to low 20s will most likely kill the plant back to the ground. In north Mississippi, treat it as you would a butterfly bush. Prune the plant to the ground after the first frost, and mulch heavily with pine straw. You can even place a whole bale on top for winter protection. 


Plant golden thryallis in full sun for best flowering performance. Full sun also helps the plant keep its best overall structure and appearance. Golden thryallis can tolerate partial shade, but the plant will become a bit stretched out and scraggly. 


Plant in well-drained soil amended with quality compost. Feed with one-fourth cup of slow-release fertilizer per plant in the spring. 


Golden thryallis is a great choice for low-water-use gardens as it tolerates drought conditions with the best of them. But even drought-tolerant plants like a bit of supplemental water during the dog days of summer. Golden thryallis is no exception.