My first remembrances of gray in the garden was not the many chilly, overcast days gardeners in more northern latitudes experience (Wisconsin), but the gray leafed annual Senecio cineraria and the perennial, Artemisia stelleriana both commonly known as Dusty Miller, or one of its cousins, Silver Brocade or Silver Cascade. It would usually catch my attention late in the season, alone by itself in a pot after it's companions have given up from neglect. Spindly and ratty looking, it adversely colored my vision for gray and silver foliaged plants for many a year. You would think I should have celebrated its ability to survive. Such was my bias towards green.
Many associate gray foliage with both high and low desert ecosystems. While a good many plants with silver plated appearances are native to dry regions, flora with gray leaves are also native to windswept craggy mountaintops, steppes and salty coastlines around the world, most notably the Mediterranean region. For many gardeners whose first experience was garnered in locals outside the Southwest, gray foliage is more associated with the allure and romance of the Mediterranean coastal areas. It is only in the past decade or two that our native arid flora has made its way into the trade and available for gardeners worldwide.
Having hailed from a rich green-leaved country myself, an appreciation for the finer merits of green color-challenged plants developed after my appreciation for their drought tolerant qualities. Gray and silver foliage plants contain tiny hairs that reflect solar radiation, cooling the surface of the leaf by several degrees, offering protection from the wind, and slowing evaporation. Having adapted to extreme growing conditions, gray and silver leaved plants make excellent companions in gardens with our climate and soil conditions.
This fall, an excursion to Great Sand Dunes National Park, perfectly contrasted negative publicity associated with the harsh reality of growing conditions of gray matter with the stark natural beauty of their environment. In their own environment, such as it is, these plants don't just survive, they thrive. Subject to frequent winds, low moisture, sun seared days and chilly winters, gray and silver leaved plants are thrivers of some of the most challenging habitats. Perhaps the tiny hairs that cover many of the leaves of these tough and rugged specimens deflect wind and sand, lessening evaporation, reduce heat and solar radiation and maybe even help warm the surface of the leaves when temperatures plummet. Additionally, their hairy or waxy coatings deter consumption by herbivores.
A quick pop-in at our local conservatory even brought to fore a growing condition not normally associated with gray leaved plants. As I walked in at the bottom level, right in front of me lived a gray tillandsia, an epiphyte. Normally, epiphytes live their lives under canopies of trees, however, gray tillandsias can be found in tropical deserts, mountains or tropical arid regions. And like many gray foliaged plants, this tillandsia has tiny hairs covering the leaf surface, reflecting back a lightish color. In a conservatory greenhouse enveloped by green foliage, at least this tillandsia found a way to be noticed.
The color of the foliage, is in fact, most often due to the density, color and length of the hair on the leaf. Underneath the gray or silver appearance more often than not is a green leaf. The chlorophyll in the leaves give plants the green color. Gray and silver leaved plants do contain chlorophyll as do nearly all plants. In some cases, actual leaf color (hairs not withstanding) may vary as it does in the typical green world.
Gray Matter, An Intelligent Choice
After over a decade of growing gray and silver leaved plants, I have learned to love their light color, thin wispy appearance, rougher hairy (tomentose) or smooth glaucous (gray green) surface and their rugged individualism in their native setting while at the same time appreciating their versatility and compatibility with flowers of all other colors.
I think of the neutral gray color, as in real life, to include many shades of gray – dull gray to shiny silvery white, hues of blue-green and gray-green colored leaves. They come in all sizes from thin and tiny (Cerastium tomentosum, snow in summer), to large, flimsy (Salvia argentea, silver sage), tough and fleshy (Stachys byzantina, lambs ear) and thick succulent (Agave parryii, Parry's agave and Echinocereus reichenbachii albispinus, white spined lace cactus), both smooth and prickly. Regardless of the form and appearance, silver and gray leaved plants found in nature (as opposed to white, hybridized variations) can usually be relied upon to be more drought tolerant and sun adaptable than their green relations.
Gray, interspersed with green foliage plants, increases the interest of a bed or border, although all silver or gray gardens can be dull, gloomy and unappealing. Following nature's cue is often a safe bet. Even in desert communities the combinations of green with the gray is common. Only in the more extreme environments, mainly in highly salty or sodic soil communities, does gray appear to overwhelm, at least with our green-trained vision.
One of the most commonly seen color combinations is gray or silver with yellow flowers. Desert marigold, gray santolina, desert brittlebush, Algerita, paperflower are just a few to choose among. Blue flowers, white flowers, mauve and purplish flowers frequent gray matter. However paired, the gray leaves add a certain punch to the combination.
Plants with gray and silver foliage pair exceptionally well with pastel and bold colors alike from their green leaved relations. Monet, in his garden at Giverny, was fond of the color combination silver, red and green and silver, red, green and pink. In our climate these combinations can be achieved by using Salvia “Raspberry Delight' with gray creeping germander's mauve flowers matching the green foliage of the salvia with the gray-green of the germanders. Or planting Texas red yucca with Artemisia versicolor 'Sea Foam'; the dark green and long blooming red flowers of the red yucca matched with the artemisia's silver gray foliage and indistinct blooms.
One of my favorite color combinations, that I've termed Zen Gray, are the colors black, gray and yellow. Any combination of silver or gray mattered plants accompanied by plants with yellow flowers mulched with smooth and polished black river rocks presents a contemporary and Southwestern take on Eastern gardens.
Mediterranean gardens featuring lavender, germander, the gray or silver thymes, rosemary, curry plant (Helichrysum italicum), sage (Salvia officinalus), gray santolina, Greek and Serbian yarrow was my first introduction to the evocative appeal of gray foliage. Whether depicting far-away cultures or remote landscapes, coupled with the proper combination of design, plants and accents, gray foliage plants naturally add style to substance in any garden or any container.
Gray by Any Other Name
When reading through plant catalogs, sometimes the Botanic Latin name will give us a clue to the leaf color or hairy appearance (but sometimes the name refers to other plant parts). Here are a few prefixes and suffixes or genus/species names to watch for that signify gray, silver, white or hairy.
- alb, albi, albo – signifying white;
- albescens – whitish, becoming white
- albopilosus, albispinis – having white hairs; having white spines
- arachnoides, spider-like, covered with long and scraggly hairs, cobweb-like
- argent, argentus, argenteus, argenteoe – signifying silver
- argyro, argrophyllus – silver; silver leaved
- asper – rough; asperifolius – rough leaved
- caesius – bluish gray, light gray
- cadicans – white, woolly
- cineraceus – ash colored, covered with gray hair; cinerariaefolius – with woolly leaves
- comosus – with long hair, hairy
- eri, erio – woolly
- floccosus – woolly, like matted wool
- glaucous, glaucifolius – dull greyish-green or blue color, with leaves that are gray, gray-green
- griseus – gray
- incana, incanus – hoary, light gray
- hirtus, hirsutus, hirsutulus – hairy; with hairy stalks or stems; covered with coarse hairs
- laevis – smooth; free from hairs or roughness
- lanatus, lanosus, lanuginosus – woolly, or downy
- leuc – signifying white, (from the Greek leukos, white and phyllos meaning leaf) as in Leucophyllum minus, Big Bend Barometer Bush)
- polio, poliofolius – with white or gray leaves
- subcanus – somewhat hoary or grayish white
- tomentosus, tomentosa – tomentose, densely woolly
- trychophyllus – hairy leaved
(From Gardener's Latin, a Lexicon by Bill Neal, Algonquin Books of Chapel Hill, 1992)
Fifty Shades of Gray
Luckily for us gardeners living at the gateway of the Southwest on the windswept plains with copious hours of solar radiation and minimal cloud cover, gray and silver leaved plants thrive well in our compost-poor, yet mineral sufficient soils. Low water and low maintenance will keep these lighter colored plants not just surviving, but thriving. Here are Fifty Shades of Gray, more or less, that will shine in your gardens, in sun or moonlight.
Acantholimon hohenakeri, prickly dianthus, evergreen blue-green foliage, pink flowers in spring. Low growing, compact and mounded form, prickly, not for the front of borders, up to 8-12” tall. A rock garden plant.
Achillea ageratifolia, Greek yarrow, light gray-green ever-gray foliage, low growing white, daisy-like spring blooming flower.
Achillea serbica, Serbian yarrow, gray-green evergray, low growing white daisy-like spring blooming flower to 6”T. Forms a low, spreading mat for hot and dry areas.
Achillea x 'Moonshine', yarrow, silver-gray foliage with lemon yellow flowering late spring to summer, drought tolerant 18'W x 24”T.
Agastache ruprestris, hyssop, light gray green leaves, orange flowering mid-summer to fall to 36”T, water every other week.
Agave parryi, Parry's agave. Gray green thick smooth succulent leaves that form a rosette up to 2 ½ feet. Cold hardy to Zone 6 .
Alyssum wulfenianum, Wulfen's Madwort, low growing gray leaved with yellow spring flowers to 6” tall.
Argemone albiflora, white prickly poppy, bluestem prickly poppy. Southern native, silver blue leaves, white blooms spring into summer. Argemone polyanthemos, silver blue leaves, crested white prickly poppy, native, white flowers in late spring.
Artemisia filifolia, Sand Sage, Western native, grow on the dry side for better appearance. 3-6' tall.
Artemisia frigida, Fringed Sage. Low growing 1.5’ x 1.5’ silvery shrub grows from 3000’ – 11,000’. SW native.
Artemesia ludoviciana, white sagebrush, silver foliage, native to most of the US, any soil/condition nearly.
Artemisia x Powis Castle, large mounding perennial with ferny silver leaves. Forms large rounded mound 3'T x 4'W.
Artemisia schmidtiana 'Silver Mound', small mounding silver with silver leaves, about 12” x 12”.
Artemisia stelleriana, Dusty Miller, Old Woman, Beach Wormwood. Perennial native to Japan and Kamchatka has naturalized along the Atlantic coast. Silver white leaves with pale yellow flowers. 'Silver Brocade' is a named variety often planted.
Artemisia versicolor 'Seafoam'. Curlicue sage, yellow flowers with unusual silver foliage. Mounding shrub 18-24”T x 3' W.
Atriplex canescens, Four-wing Salt Bush, Chamiso, 1-6' x 4-8', saline, heat and drought tolerant. Treat lean. SW native shrub.
Atriplex confertifolia, Shadscale, silver gray semi-evergreen leaves. 2 x 2', suited to the garden but grows well under extreme conditions. SW native shrub.
Baileya multiradiata, desert marigold, annual or re-seeding annual. SW native with silver leaves and yellow daisy like flowers.
Berberis trifoliata (Mahonia trifoliata), Agarita, or B. haematocarpa, also called Algerita. Western native shrub, gray blue evergreen leaves and prickly, grows to 8 feet. Makes a good screen.
Bukiniczia cabulica, formerly Aeoniopsis cabulica, small rock garden plant biennial that reseeds. Drought tolerant. Blue-green rosettes with mottled leaves, small pink flowers the second year. Unusual with a fun name.
Cerastium tomentosa columnae, Snow-in-summer, small white daisy-like flowers, summer blooming, low growing and spreading.
Chrysothamus nauseosus nauseosus, Dwarf Chamisa, Silver green leaves and stems, 2 ft. tall, pale yellow flowers in summer. SW native shrub.
Echinicereus reichenbachii albispinus, white spined lace cactus, attractive clumping columnar cactus with bright pink flowers. White spines are so dense as to make the cactus look white.
Eriogonum umbellatum, sulfur flower, gray green foliage with showy sulfur yellow flowers in late spring to early summer. SW native.
Eschscholzia californica, California poppy, annual; reseeding annual. Finely laced blue gray leaves. Yellow cupped spring blooming flowers.
Heterotheca canescens, Gray golden aster, silver foliage, yellow native wild flower, mid summer to fall blooming.
Krascheninnikovia lanata, (previously Ceratoides lanata), Winterfat, 1-3' x 2-4', beautiful winter interest. Native shrub to SW and Western US.
Lavendula, Lavenders. Several species and many varieties grow in well drained soil, medium water-use. Light gray green leaves with white blue, purple and pink flowers, depending on the variety. Spanish lavender (Lavendula stoechas) is usually not cold hardy in the Texas Panhandle.
Leucophyllum minus, Big Bend Barometer bush, 3'T x 2'W, summer flowering after rain, Silver gray leaves. May be the only Leucophyllum reliably cold hardy for the Texas Panhandle.
Nepeta x faassenii 'Select Blue' & 'Walkers Low', blue catmint, gray-green leaves, late spring to fall blooming, low water-use, mounding.
Oenothera caespitosa, White tufted evening primrose, drought tolerant, gray green foliage, white blooms. SW native. Oenothera macrocarpa ssp. incana, Silver edged Missouri evening primrose, native summer with silver-blue leaves, long yellow, chalice shaped blooms.
Orostachys iwarenge, Dunce caps. Succulent from Japan, small, low growing glaucous gray rosettes, dunce caps in late summer.
Perovskia atriplicifolia, Russian sage, blue gray leaves, blue summer flowering shrub, low water-use. Spreading shrub 3-3 ½ 'T x 3'4'W at maturity.
Poliomintha incana, Mint bush, gray frosted mint or hoary rosemary mint. Southwest native shrub with blue gray leaves, lavender white flowers in spring. Grows to 3 ½ – 3 foot tall and wide.
Psilostrophe tagetina, paper flower, perennial herbaceous native, gray green foliage with yellow blooms spring and summer.
Ruschia pulvinaris, shrubby ice plant. Small low growing and mounding with blue gray succulent leaves, tiny magenta flowers to 6”. Attractive for the rock garden.
Salvia argentea, silver sage, biennial foliage plant with silver-green leaves with annoying sticky dirty white flowers on stalk. Leaves look tough like lambs ear but tear easily and are easily damaged by hail.
Salvia chamaedroides, New Mexican sage, Beautiful shrub with gray-green leaves with blue summer flowering, 2' x 2'. Native to the upper Chihuahuan deserts.
Salvia daghestanica, Dwarf silver leafed sage. Xeric, 10” x 12”, violet blue, flowers for 3 – 4 weeks, late spring.
Salvia dorrii, small, xeric, 12” x 12”, silver leaves with purple flowers. SW native.
Salvia officinalis, the herb sage. Gray green leaves with blue flowers in spring. Low water-use.
Salvia pachyphylla, Mohave Sage, xeric, 30” x 30”, unusual sage, Silver leaves with stunning purple sticky flowers.
Santolina chamaecyparissus, gray santolina with small yellow flowers. Gray foliage, mounding and spreading. To control growth, trim back after flowering.
Senecio cineraria, (now Jacobaea maritima) Dusty Miller or silver ragwort. Perennial subshrub native to the Mediterranean region with yellow daisy like flowers, whitish silver leaved plant grown as an annual. Cold-hardy in Zones 8-10. Senecio flaccidus, Threadleaf groundsel, native perennial, silvery blue green leaves with yellow daisy-like flower, can grow to 2'T x 2'W.
Shepherdia argentea, Silver Buffaloberry, grows to 6-18’T x 4-15’W. Gray green leaves. Cold hardy to -30. The flowers are inconspicuous, but in July the female shrubs are filled with red fruits.
Sphaeralcea angustifolia, globe mallow, light gray green foliage, light pink flowers throughout summer and fall, native to the Davis Mountains. Sphaeralcea coccinea, caliche globe mallow, silvery gray foliage, spring blooming orange and orange red flowers, local native perennial. (Also S. ambigua and Sphaeralcea grossulariifolia, gooseberryleaf globemallow, red, native to SW, xeric.)
Stachys byzantina, (formerly Stachys lanata) lambs ears and 'Helen von Stein' 'Silver Carpet' et al, lambs ears, tough but soft, gray tomentose leaves with pink fragrant flowers.
Tanacetum niveum, white bouquet tansy, silver gray leaves, small white daisy-like flowers late spring.
Teucrium aroanium, gray creeping germander, gray green evergreen foliage, deep lavender pink fragrant flowers summer long.
Thymus pseudolanguginosus, woolly thyme, small gray leaves, a low to the ground ground cover. Rarely flowers.
Veronica incana, silver speedwell, silver gray leaves with blue flowers on spikes summer long.
Veronica pectinata, woolly creeping speedwell, woolly grayish green evergreen leaves, blue flowers, drought tolerant ground cover.
Originally published as a GardenNotes. Angie Hanna, October 17, 2013