Scientific: Leucophyllum frutescens
Common: Texas ranger or Texas sage, Texas barometer bush, cenicilla, palo cenizo
Family: Scrophulariaceae
Origin: Northern Chihuahuan Desert of Texas, Rio Grande plains, southern Trans-Pecos and sparingly in the Edwards plateau south into
Coahuila, Nuevo Leon, and Tamaulipas, Mexico.
Pronounciation: Lou-co-FIL-lum fru-TES-cens
Hardiness zones:
Sunset 7-24
USDA 8-11 (arid and semi arid regions are best)
Landscape Use: Accent, informal hedge, background, screen, xeric and oasis design theme.
Form & Character: Globular and rounded to irregular, nearly deciduous in winter, xeric and dry looking, informal (even though in Phoenix this is the 'hort clod's 'shrub of choice' to butcher into common, obscure and/or commically creative geometric shapes).
Growth Habit: Evergreen to semi-deciduous, woody, broadleaf perennial shrub, moderately upright and spreading to 6- to 12-feet tall with near equal spread.
Foliage/Texture: Small to 1-inch long, elliptic to obovate gray (sometimes greenish) sessile leaves, densely tomentose; medium fine texture.
Flowers & Fruits: Many axillary magenta to lavender flowers bloom on new wood, flowers attract bees; fruits are inconspicuous. Texas ranger will on rare occasion reseed in and around irrigated Phoenix landscapes.
Seasonal Color: Texas ranger flowers episodically in intense bursts of color every 4 to 6 weeks during warm season usually starting in late March until November.
Temperature: Tolerant of both desert heat and cold. However, some Texas ranger shrubs (especially the var. green cloud) will go partially deciduous during the winter months.
Light: Full sun
Soil: Prefers alkaline soil
Watering: Apply no supplemental water during winter. Irrigate as necessary during summer, particularly during those summers when monsoon rains are sparse (such as the dry summer of 2020).
Special watering note: All in Phoenix must realize that the number one affector of plant productivity (stimulator of landscape plant growth) is the volumes of irrigation water applied to landscapes (which is upwards of 70% of all potable water use in Phoenix!). Therefore, use water wisely in your landscape! Texas ranger is an iconic plant to practice this concept. Water Texas ranger shrubs less and they will respond with slower growth thus needing less pruning to keep their size in check.
Pruning: One can remove any amount of vegetation from Texas ranger shrubs and they will respond with vigorous regrowth throughout the growing season. They are that resilient! My recommendation is to extensively rejuvenate Texas ranger shrubs during late February to early March and then leave them alone for the remainder of the year.
The result will be beautiful shrubs that have an appropriate size, a natural form, and flower profusely. When I prune Texas ranger shrubs this way I use hand pruners and/or loppers to remove stems at various lengths using heading and thinning cuts. When I'm finished pruning any Texas ranger shrub, I've removed about 2/3rds or more of its overall standing biovolume. I'm content then to not
prune them the rest of the year. I also water conservatively to promote a slow growth rate.
Toxic landscape abuse: Sadly though, Texas ranger shrubs in Phoenix ARE the 'Rubic's cube', 'organic ballons', 'outdoor beer pub table', 'loaf of bread', 'living totem pole', 'biologic traffic cone', 'dwarf Star Wars Imperial walker' or 'landscape blocks' shrub of choice for the ignoramus 'Horticultural clods of Phoenix' (aka 'Hort clods) to shear! Check it out and
see 'em do it! 'Hort clods' (as they are appropriately nicknamed) will frequently shear Texas ranger shrubs all year around, even when flowering. Why? My best guess is that it's to apparently show that they are indeed doing something called 'landscape maintenance' in order to justify receiving payment for their monthly billing statements. Please avoid this bogus practice and be a real horticulturist! Prune Texas ranger only once per year in late February to early March.
The ONLY exceptions to my professional pruning recommendation are when one is trying to create a migratory 'igloo for iguanas' in their front yard or when motivated by images from the Webb space telescope to simulate a cosmic planetary collision.
Propagation: Seed and cutting (softwood or semi-hardwood). Texas ranger shrubs will occasionally reseed in urban landscapes.
Disease and Pests: In the Phoenix area, Texas root rot can kill Texas ranger shrubs in late August (soil temperatures must be above 80oF) if soils are poorly drained and the shrubs are growing on former agricultural soils.
Additional comments: Texas ranger is a highly serviceable, water-conserving, accent shrub that is sadly chronically mis-used and mis-managed in Phoenix.
There are several varietal selections of Texas ranger that have different foliage and flower colors including:
Noteworthy allelopathic properties: Recent research has shown that leaf extracts of Leucophyllum have strong phytotoxic, antimitotic activity (diayangambin, epiyangambin, diaesartemin, and epiashantin) which can inhibit grass seed germination and seedling development of lettuce and onion.
A special advisory note: Because of their dense leaf pubscence, Texas ranger shrubs are dust magnets! Several people I know (including yours truly) have developed rather significant allergic reactions to the dusty foliage of this otherwise magnificent shrub. So when working with Texas ranger, it's not unusual to haved allergic reactions ranging from coughing, congestion, sneezing, itching, watery eyes to outright wheezing. So what's my advice? If you're working with this plant, then make sure to always wear a dust mask!!! Yeah, some will think you either have Covid or you're one of those fear-filled mask wearers, but in this case it's highly necessary.
Taxonomic tidbit: The genus Leucophyllum is latin for 'white leaves' and refers to the dense tomentose arrangement of short, white trichomes on the leaf surfaces.
