Autumn Color in the Desert

Autumn may just be my favorite season, if such a thing were possible. Unlike the frenetic activity of the spring, fall is a time to slow down, to take it easy. In the spring, I hardly have time to appreciate everything that is growing and changing, for I am so busy with garden chores. In the fall, when a chore is done it mostly remains that way. There is time to relax and enjoy the garden. It is a bittersweet enjoyment however, viewing the work of the growing season gone by, but also anticipating the long winter to come.

Fall color in the high desert is unlike that of the East coast. There, the background for fall color is the remaining green on the trees, the evergreens and the dark moist soil. This contrast makes the reds and yellows stand out. In the desert the background colors are frequently the browns of the grass gone dormant, the pale beige of dry sand and rock, the olive of pinon pines and mountain mahogany (whose fall seedheads catch light), or the grays of the native plants that remain leafed out until snow falls. Because of this, rich colors are made subtle. Reds can look brown and yellows can appear muddy. Dry weather doesn’t help, either, as plants need moisture to prevent premature leaf drop and to develop the fall colors. Like spring flowers, the fall leaves offer only a few weeks of intensity before dropping, like fireworks leaving a smoke trace before a long quiet night.

We know it is fall here, when the rabbitbrush (Chrysothamnus nauseosus) blooms, and earns its botanical name. The bright yellow flowers cover the grey bushes and although colorful, they are indeed overwhelmingly pungent, some liken it to cat urine, my neighbor calls it the sweaty-gym-sock plant. Scent notwithstanding, the yellow flowers form a striking contrast to the purple aster (Aster bigelovii and other species) that blooms at the same time. To my eye the mauve of the aster doesn’t quite hold up to the dark golden yellow of the rabbitbrush, unless the aster is a particularly dark version, or exists in large numbers, but it is a quintessential New Mexico scene. One of the most striking combinations I’ve seen is in my neighbor’s side yard, where the purple of the aster blooms against the fluffy white seed heads of a wild Asclepias (Asclepias macrotis).

Agastache cana’s flowers last well into the fall, and form a bright color contrast to the rabbitbrush as well. This Agastache takes very little water, but needs some moisture to bloom. Interestingly, the spikes will hold on the plant until there is moisture, then the spike erupts into color. With some fall rains or supplemental moisture, this plant glows with the Sandia color. An additional benefit is that Agastache cana has wonderfully, sweetly fragrant foliage. This scent is released with the lightest touch. To my nose, the other Agastache don’t have as sweet a fragrance, but they do offer a great variety of color and form. In a garden, Autumn sage (Salvia greggii) blooms all summer despite the name. Fall blooms can be particularly abundant. The dark red varieties forms a nice contrast to the many golden flowers of fall such as Threadleaf Groundsel (Senecio longilobus), which has silver leaves and abundant yellow daisies. Blue sage (Salvia azurea), which has been growing steadily all summer bursts into bloom in the fall with too-blue-to-be-real flowers, almost the same color as the New Mexico sky. Blooms fade in a day, but new flowers open each morning of its 3 week display. Be aware that the plant has a lanky, almost weedy form, but fantastic drought tolerance.

Lately I’ve been entranced by the autumn crocuses. Crocus speciosus produces luminous pale purple flowers that appear magically and suddenly from bare ground in early fall. Saffron Crocus blooms later with reddish purple flowers and bright orange stigmas.

The end of summer is marked by the blooming of the Bricklebush (Brickelia californica). Although the plant is rather shabby, and the flowers are nearly insignificant pale yellow brushes, once the sun sets the fragrance makes it all worthwhile. The sweetness of the blossoms at night lifts me up so that I feel like I’m walking a few feet off the ground. Some non-native shrubs for scented flowers include the Silverberry (Eleagnus pungens) with diminutive bells hidden among the leaves and unnoticed except for the lily-like fragrance. Fortunately the plant requires little water, but will grow long almost vine-like shoots. It is easily pruned but don’t make a gumdrop out of it. Osmanthus heterophyllus from southeast Asia has wonderfully fragrant flowers in late fall, just when the air develops a bite. The fragrance is worth venturing outdoors just to bury your nose in the exotic fragrance. This shrub is at its best with moist soil but can get by on less.
Maple is famous for its fall leaves and a native dry-land version of the sugar maple is the bigtooth maple (Acer grandidentatum). This maple has the expected colors of orange, red and yellow, in a small tree. With watering it will grow taller, but not likely to be as large as the East coast varieties. Box Elder (Acer negundo) is a native maple, that can develop a substantial trunk and size, but only plant it if you can tolerate its messy ways and the multitudes of box elder bugs that it may attract.

Sumacs are famous for their blazing fall color (even though not all do). The most popular are the three-leaf sumac (Rhus trilobata), staghorn sumac (Rhus typhina) and smooth sumac (Rhus glabra). R. typhina and R. glabra have some of the most brilliantly colored leaves of native plants. The large feathers turn brilliant orange red and last a good amount of time. The cultivar R. glabra ‘lacinata’ has serrated edges to the compound leaves. The effect is quite lacy despite leaves which grow to a foot or more in length. Be aware, however, of these sumac’s tendency to sucker. These suckers can pop up yards way, and digging them is a sure way to provoke the plant to produce more. Choose three-leaf sumac in the fall to be more certain of its ability to produce colorful fall leaves, but even so, color quality may vary slightly from year to year. It is generally more compact than the smooth sumac or staghorn sumac, but Agua Fria nursery has one in its driveway that is at least ten feet tall. Place three-leaf sumac where the sunlight shines through the leaves for best effect, as the color seems to be intrinsic to the leaf rather than on its surface. With southern sunlight the view from the south may be a dull purplish-red, but the view from the north will be glowing red. The Chinese Pistache has a deservedly growing popularity. A small tree, with a rounded form, the fall color can be blazing red. Plants seem to be either a red-purple variety or a yellow-orange variety so choose in the fall if you have a preference.

Other leaves include the grasses, my favorite of which is little bluestem (Andropogon scoparius). Although there are several cultivars, my favorite is the wild version, which has stiffly upright stems, red to russet fall color and seeds that catch the low fall light and sparkle like fairy magic. Plant a bunch and pick your favorite colors. You can also purchase a strain called ‘Blaze’ but I’ve found wild type plants with even brighter colors. There are other grasses which catch the eye in the fall. There is Silver Beardgrass (Andropogon saccharoides) with tufts of seed heads and Indian Rice grass with clouds of seeds that can almost look like a cloud of gnats. A high plains native, Big Bluestem (Andropogon gerardii) earns its name “turkeyfoot” in autumn with three-pronged seedheads and rusty red-orange fall color. I’ve been impressed with Deergrass (Muhlenbergia rigens) which forms an attractive fountain of foliage and produces a multitude of wands in late summer and fall, which catch light when backlit. Muhlenberia capillaries ‘Regal Mist’ is becoming quite common for its impressive cloud of autumn pink. This Texas native is not quite so attractive when out of bloom, with rather scraggly foliage.

Speaking of seedheads, an incredible autumn vision is the Mountain Mahogany (Cercocarpus brevifolius is our local species). In the fall, the plumes on the seeds extend to a few inches, like a feather in a cap. In the light of a rising or setting sun, they sparkle like dewdrops covering the sculptural shrubs. C. montanus is similar and more readily available, but deciduous instead of evergreen. C. ledifolius (Curl-leaf Mountain Mahogany) is evergreen, more dense, and tends to have a more upright structure.

Fall in Albuquerque may just be the best season. Not only are the temperatures moderate and enjoyable, but we have autumn experiences that are uniquely New Mexico. Not only are there the reds and yellows of leaves, but the yellow and purple native flowers, floral scents and sparkling seeds. Time for a cup of hot chocolate with cinnamon, and put off winter for one more day.