I was recently reminded about the hardiness and natural beauty of Thryallis, a.k.a. Rain of Gold, so I decided to highlight it here in our plant profiles. 

Even though Thryallis (THRYE-al-iz) is not hard to pronounce, like some plants and their Latin-sounding and bizarre pseudonyms, I still don’t understand why Rain of Gold hasn’t taken on more popularity.  I mean we seldom call Angel’s Trumpet by its other technical name – Datura!  Or, while the Plumeria is a cool sounding name, technically it should be called Frangipani — see what I mean?

Anyhow, Thryallis is compact upright rounded, evergreen shrub and is covered during most of the year with small, very showy, yellow flowers; hence the nickname Rain of Gold!  I also love the loose, open natural growth habit, which I believe is ideal for informal plantings.  Whether you plant it informally or whether you like the idea of a hedge row of Thryallis, it will need some pruning to keep from being too leggy.  And, yes, some will be trimmed of at each pruning.   And if you ever feel like your pruning is leaving a thinned out look at the bottom of the plant, then change your pruning practices to keep the bottom of the plant slightly wider than the top to allow sunlight to reach to the lower foliage.

Full sun is normally required for best growing conditions, but Thryallis can tolerate some shade.  However, flowering may be sparser without a full day of sun.  They are not freeze tolerant, in as much as they will die back to the ground in most winters if temperatures dip below 25 degrees, but like another yellowing flower plant that loves sun – Esperanza – every Thryallis I’ve ever planted regrows quickly from the root system in the spring.  

Any of the slow or controlled-release blooming plant foods that we endorse, such as Nelson’s Color Star of Nitro Phos’s Color X-Press, will work fine at keeping the Thryallis blooming all summer and fall.  But much like plants such as oleanders that’ll seemingly feed on anything, you can use just about anything such as rose food or even hibiscus food to keep the Thryallis thriving.  

The actual scientific name for Thryallis is:  Galphimia glauca. Pronunciation: gal-FlM-ee-uh GLOCK-uh. Which I guess makes the name Thryallis a bit more inviting.   And while it’s not a “true” native plant, the two best attributes for planting here in Texas:  1. They are technically “Pest-Free” 2.  Deer will not eat them.   

For those who don’t live in southeast Texas and try to follow the advice in this and tip sheet, I should forewarn you that Thryallis is considered for zone 9-10-11.  That translates to me that if you have soils that can ‘freeze’, you likely may not get them to rebound every spring the way we can along the Texas Gulf Coast.