PlantFiles: Golden Thryallis, Gold Shower, Shower of Gold, Rain of Gold
Galphimia glauca

This plant isn't nearly as delicate as others make it sound. It tolerates alkaline clay, freezing for days at a time and lows to at least 18f (-8c). Has no insect or disease problems, grows quickly but stays full in sun to half-day shade. It's only real fault is brittleness.

It should be mentioned that this is a very brittle plant. If planted alongside a walkway, it may be broken if bumped into. That doesn't change my positive opinion, because you just need to be aware of this when you place it in the landscape.

Very hardy plant. Highly resistant to heat and dry conditions.
Prefers neutral to alkaline soils with high drainage. Easy to care for, requires minimum pruning to maintain height and width.

San Antonio, TX
At garden centers, Thryallis glauca is sometimes labelled Yellow Plumbago (does not resemble a plumbago at all!) or Lluvia de Oro. This evergreen tropical shrub (native to the tropical regions pf Mexico to Guatemala) is a non-stop bloomer that provides bright splashes of color all through the year. A fast grower, it has bright green oblong leaves that are about 1to 2 inches long, They take on bronze tones during cooler periods. The beautiful bright yellow blossoms appear in late summer to fall. Some flowers can be expected at all times during warm temperatures. The almost glowing yellow flowers are about 3/4 inch in diameter and are held in clusters at the stem tips. Three part seed capsules emerge after the flowers fade.

It prefers full sun (becoming leggy in partial shade with the flowering being minimal), well drained soil and moderate water. Thryallis can take some frost and freezing, but may be killed to the ground by temperatures less than 30 F. It self-seeds (alot) and cuttings may be taken in the summer. A superior background plant for perennial beds, it is low-maintenance, easy to grow, drought resistant, is not attacked by insects (at least not in the last year) and blooms almost all year around. In addition, it provides cool weather interest when the foliage turns color. Its shape is easily controlled by pruning in the spring. One of the best purchases I have made in 30 years!

Note (1/17/07): Several large trunks broke after the plant was covered in ice after a sleet/freezing rain storm that lasted for quite some time and is very unusual for my geographic area.

Note: (12/2/08) This plant has withstood temperatures in the upper to middle 20s (not of long duration) with little or no freeze damage except for blooms.

A tropical plant that should be protected from freezing weather. Flowers appear on the new wood, so prune back in the early spring; enjoys a dose of fertilizer regularly. Flowers prolific yellow clusters on stalks - blooms all summer. Fast grower, and great summer flowerer.