It doesn’t really make sense for plants with leaves to keep them after the first hard frost of the season. Who would want to spend the energy protecting your weak regenerating appendages from frostbite night after night rather than just going dormant and waiting for warmer times to regrow your beautiful hard-won foliage? The evergreens, that’s who.
Evergreen plants are a special group. They provide important habitat for overwintering plants, and although they might not flower during the winter months, they can provide a year-round screen for a yard, or some pretty greenery in an otherwise bleak, woody landscape.
It’s deceptively hard to be an evergreen plant in southern Arizona. The intense swings in temperatures are rarely felt as we cozy up indoors in the dead of night, but often the local valleys and cold air drainages coming off the peaks of the Santa Rita’s or Patagonia Mountains can make our nighttime lows dip into the teens and single digits. This is a tough shift for many plants, making the decision to go dormant a simple one for most perennial natives.
Our plant of month is the evergreen sumac, scientific name, rhus virens. It’s in the Anacardiaceae family, which interestingly makes it related to cashews and mangoes, as well as poison ivy and poison oak. Evergreen sumac is not poisonous, and some say its berries are quite tasty despite the hard seeds you should spit out. Here’s a description from the Borderlands Restoration Flora catalogue:
“Rhus virens or “evergreen sumac” is an evergreen native shrub found between 3500-6000 feet elevation in full sun in grassland and woodland habitats. It grows eight feet tall and wide and is true to its name as it does not drop its leaves in winter like other native sumacs. White flowers cover the plant from August-September, turning into berries that feed birds and other wildlife.”
The evergreen sumac is also fairly drought tolerant compared to nonnative evergreens that depend on strong winter rains. If you’re considering planting an evergreen perennial, it’s important to follow the watering rules. This means making sure your transplant gets plenty of water in the first year after planting. Just because a plant is native does not mean a container plant can make a transition into the ground without help. In the wild, plants have massive root systems that are intricately tied into the earth through moisture pockets and mycorrhizal webs. When irrigating perennials to get them established, opt for long irrigation times that are spaced out at a few times a month versus short watering times throughout the week. This will ensure that your perennials send their roots deep to find and keep moisture in the ground versus staying close to the surface of the soil where they can dry out quickly and suffer if they miss a watering or two.
Keep an eye out for this dark green beauty. You can find it along the highways, in woodland hills, and all the way to the top of Red Mountain in Patagonia. The evergreen sumac sticks out this time of year for being so leafy and lovely when everything else has taken a break.