Rhus trilobata (three-leafed sumac) is a native shrub that is one of the more commonly planted natives in Albuquerque. This is easy to understand, because it is a compact shrub, grows quickly, and uses very little water. The three-lobed leaves are attractive and medium green to olive green. These reportedly turn color in the fall to red, orange and yellow. In late summer through winter, three-leafed sumac may have red berries at the tips of its branches, and although attractive, these aren’t usually produced in enough numbers to be impressive from a distance. Rhus trilobata’s growth can be accelerated by irrigating, and can thus grow more than 24 inches a year, although with greater growth, the plant can become lanky and weak, needing pruning. As the plant reaches the desired size, the water can be decreased to maintain plant size. Continued irrigation will produce a shrub that can reach 6-10 (or more) feet tall. Without irrigation, Rhus trilobata generally remains half that size. According to David Cristiani, the natural range of Rhus trilobata extends from the Colorado plateau south to Roswell.
There are several problems with this plant as it is used in Albuquerque today. The plants sold are generally not what you see growing in our foothills. Instead, what is sold is a broad leafed form, the color ranging from medium green to grass green. Some plants have broad cupped leaves. In contrast, the plants native to the Albuquerque foothills tend to have small leaves, with widely spaced leaflets, which are dark olive green. Although the broad-leafed plant is attractive in its own right, I suspect that these plants originated from plants of the higher rainfall areas. This may account for the significant differences between the wild form, and the form that is generally sold. Although the nursery plants tolerate drought fairly well (you may see them defoliate in the midsummer along Tramway), I have always been disappointed in the fall color of the sold plants. Although they are promoted as being colorful, I haven’t seen any in Albuquerque with the flaming colors that are seen in books. This may be because the climate isn’t right for these plants to develop color, and they just turn brown and fall off instead. The native plants in the foothills do turn color in the fall, but are more commonly an equally attractive plum purple rather than red-oranges.
Rhus trilobata is generally propagated from seed. Although this is beneficial for maintaining genetic diversity, the seedlings will be variable in quality. Judith Phillips warns that cuttings are tricky however, and timing is essential. This year, I attempted to root cuttings of a vigorous, small leafed plant with purple fall color and fall leaves that lasted into December. I took four-inch tip cuttings in mid-June. The spring growth was complete and the stems had firmed but were not woody. Two half-inch strips of bark were peeled from the lower ends of the cuttings. They were then dipped in a 10:1 dilution of Dip ‘N Grow brand rooting solution, and inserted into a mixture of small perlite and seed starting mix. The pot was placed in a plastic bag, and I left on vacation. 3 weeks later, I noticed growth on the cuttings, with roots showing though the drainage holes. Plants were then potted separately. If you have plants of Rhus trilobata that have especially good form and good consistent fall color, you might try taking cuttings. Or let me know, I would love to have a few!
