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Golden Thryallis thrives and flowers in full sun
A plant I first saw early this year that has continued to amaze me through summer and fall is Galphimia glauca, commonly known as Golden Thryallis. It started flowering early in the summer, and the stand-out yellow flowers caught my full attention.
The flowers are a bright and cheery yellow and occur in clusters that are up to 6 inches long. Flowering begins in early June and continues through the fall. If warm temperatures linger, the flowering period will extend to the fall.
Even the branches of Golden Thryallis are attractive. Young branches are a rusty reddish brown that provides a nice background for the flowers. The slender branches form a dense interior network while the outer branches appear loose and open, displaying the flowers.
The plant’s light green leaves are oblong and about 1 to 2 inches long. The plant is evergreen, but during cooler temperatures, the foliage can take on a bronzy tint.
Plant Golden Thryallis in full sun for best flowering performance and to help keep the overall structure and appearance. It tolerates partial shade, but the plant will become a bit stretched and scraggly. Golden Thryallis tolerates pruning, so don’t be afraid to shape and maintain the size of the plant. You can even maintain Golden Thryallis as a hedge.
Golden Thryallis is a tropical plant that is native to Mexico and Central America. It is evergreen in U.S. hardiness zones 9B to 11, but this plant may surprise you with its 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, prune the plant to the ground after the first frost and mulch heavily with pine straw. You could even place a whole bale on top for winter protection.
The overall size of Golden Thryallis depends on where it is growing. In its native habitat, this plant can reach up to 10 feet tall. In our Mississippi landscapes, where the plant is exposed to regular cold temperatures in the winter, we can expect to enjoy a plant that is 3 to 4 feet tall and 2 feet wide.
Golden Thryallis doesn’t require much care or preparation. Plant in well-drained soil amended with quality compost. Feed with one-fourth cup of slow release fertilize per plant in the spring.
Golden Thryallis is a great choice for low-water use gardens, as it tolerates dry spells quite well. But even drought-tolerant plants need a bit of supplemental water during those dog days of summer, and Golden Thryallis is no exception.
This is a great addition to a flowering perennial border, where it will act as a background for other plants. It would look outstanding massed and used as a substitute for junipers or hollies in a large-scale ground cover.
You can also plant Golden Thryallis in containers and bring the plants inside to sunny windows when cold temperatures are forecast. Golden Thryallis will continue to bloom inside with its cheery yellow blooms.
As you plan your garden and landscape for next year, consider Golden Thryallis. I’ll bet you will wonder why you haven’t planted it before.