Silver, Polished

After yet another zinger of a winter storm and no near prospect of seeing bare ground again, things are getting really boring around here. I figured that it was time to take a break from the photography series and find some other excuse for rifling through my image archives, so I thought I’d indulge in another color-theme post. Right now, there’s only one predominant color: white. Well, let’s say four colors: white, black, gray, and silver. (Remember, you should be able to see larger versions of all of these images by clicking on them once or twice.)

We’ve had snow, then ice…

…and most recently, lots more snow.

The boys are really not amused. I have to shovel paths for them because the snow is higher than their tummies.

But when the paths freeze at night, they turn to ice, and tiny feet on a rather top-heavy animal are not designed for ice.

Anyway, you get the idea about the snow and ice as the primary palette right now. As I’ve already twice tackled white as a topic (Just White here and I Don’t Like White back at Gardening Gone Wild), I figured I’d go for silver and shades of gray this time.

Normally, colors in plants come from various pigments within the foliage or flowers. Silvers, grays, gray-blues, and the like, on the other hand, are usually “structural colors”: due to materials on the surface of the leaf.  In many cases, various densities and lengths of hairs cause the silvery to nearly white appearance. That’s true for many herbs, for instance, such as lavenders (Lavandula)…

…culinary sage (Salvia officinalis), including the straight species above and ‘Berggarten’ below…

…woolly thyme (Thymus pseudolanuginosus), below…

..and lavender cotton (Santolina chamaecyparissus) below.

The more dense the hairs, the brighter the silvery appearance. Sometimes, the silver-white appearance is relatively consistent through the growing season, as with the lavender cotton. On other plants, such as shredded umbrella plant (Syneilesis aconitifolia), the silver is very obvious in spring and disappears as the summer progresses.

Many “silver” plants have very silvery young leaves and stems. Then, as the leaves expand, the hairs are less dense and more of the green leaf surface is visible, giving the older leaves and stems more of a grayish green to pale green cast. Some plants in this category include silver spurflower (Plectranthus argentatus)…

…rose campion (Lychnis coronaria), below…

…and common mullein (Verbascum thapsus), below.

Air spaces in the hairs reflect light, which explains why “silver” plants can vary quite a bit in how silvery they look at any given time, depending on the amount and angle of sunlight. ‘Powis Castle’ wormwood (Artemisia), for instance, is almost white in bright sun, gray in bright but overcast weather…

…and almost blue in shade or very cloudy weather.

The silvery appearance of hairy leaves is also much less noticeable when the leaves are wet but brightens again as the hairs dry and reflect light again.

Another type of structural color comes from a powdery or waxy coating on the leaf.  Depending on how thick the coating is, as well as the pigmented color of the leaf itself, the resulting effect can range from near white to gray-white, as on ‘Silver Drop’ eucalyptus (Eucalyptus gunnii)…

…bright gray, as on Sedum clavatum…

…blue-gray, as on Echeveria ‘Silver Spoons’, below…

…to powder blue, as on ornamental cabbage, below…

…pale blue to blue-green, as on sea kale (Crambe maritima)…

…and gray-green, as on Allium karataviense, below…

…and ‘Immortality’ bearded iris.

Just as herbs are a great go-to group of plants for silvery foliage, many veggies—especially allium- and cabbage-family plants—are wonderful for adding grays, gray-greens, and blue-grays to the garden.  Think of cabbages…

[Believe it or not, the images above and below are both of ‘Ruby Ball’.]

…Brussels sprouts (this is ‘Jade Cross’), below…

…kales…

[That’s ‘Red Russian’/’Russian Red’ above and ‘Nero di Toscana’/’Lacinato’ below.]

…spigarello (also known as Italian leaf broccoli ), below…

…couve tronchuda (also known as Portuguese cabbage), below…

…and leeks (Allium ampelopasum), below.

For more blues and grays, consider some hardy ornamental grasses, such as ‘The Blues’ little bluestem (Schizachyrium scoparium), below with Rudbeckia fulgida var. fulgida…

…’Dallas Blues’ switch grass (Panicum virgatum), below with Leucanthemum ‘Becky’…

…and blue wheatgrass (Elymus magellanicus), below with Geranium  ‘Jolly Bee’.

Succulents, too, offer a wealth of wonderful grays and blues. There are loads of elegant echeverias, such as Echeveria glauca (below with Sedum rubrotinctum)… 

…Echeveria ‘Blue Atoll’ (below with Crassula ovata ‘Baby Jade’)…

…Chinese dunce cap (Orostachys iwarenge), below with ‘Elfin’ thyme…

…blue chalk sticks (Senecio mandraliscae), below…

…’Forest Frost’ hens-and-chicks (Sempervivum tectorum), below…

…and lots of sedums, including Corsican stonecrop (Sedum dasyphyllum ‘Major’), below…

…and ‘Autumn Fire’ stonecrop (below with Sedum rupestre ‘Angelina’).

One thing that’s handy to keep in mind about plants with waxy and powdery coatings is that the “bloom” can wash or rub off over time or if they get touched too much, so try to handle them as little as possible. Horticultural oil sprays can remove the coatings too, so it’s best to choose other options if you need to control pests on or around plants with these sorts of leaves. (If you do forget and end up turning your blue hosta or blue spruce into a green one, it’s not a tragedy; the new growth will be blue again.)

Another sort of silvering in leaves comes from inside the foliage: air spaces under the leaf surface, which reflect light and block the appearance of the green chorophyll (or other pigments) lower in the leaf. A couple of examples here include the marking on lungworts (Pulmonaria)…

…spotted deadnettle (Lamium maculatum)…

…and ‘Looking Glass’ Siberian bugloss (Brunnera macrophylla), below with ‘Kwanso Variegated’ tawny daylily (Hemerocallis fulva).

If you’re interested in learning more about structural coloring in leaves, check out Color in Plants or Structural Coloration. I also recommend the article Structural Color for some interesting insights as to why  some plants create these sorts of adaptations. For instance, I remember learning that leaves develop hairs or waxy coatings to reduce water loss, but according to this article, these modifications actually serve a variety of other roles.

Of course, you don’t need to know the hows and whys to enjoy silvers, grays, and blue-greens in your garden. Some of my personal favorites (besides those I’ve already shown) include some nasturtiums (Tropaeolum majus)…

(Above is ‘Black Velvet’; below is ‘Empress of India’ with ‘Inky Fingers’ coleus.)

…giant coneflower (Rudbeckia maxima), below…

…ghost bramble (Rubus thibetanus), below…

…’Berggarten’ sage (Salvia officinalis)…

…silver sage (Salvia argentea), below…

…Lysimachia atropurpurea, below…

…’Purple Emperor’ sedum, below…

…’Silver Falls’ silver ponyfoot (Dichondra argentea), below…

…milk thistle (Silybum marianum), below…

…dusty meadow rue (Thalictrum flavum subsp. glaucum), below…

…silver willow (Salix alba var. sericea), below…

…Russian sage (Perovskia), below…

…honeywort (Cerinthe major), below…

…tree tobacco (Nicotiana glauca), below…

…Euphorbia nicaaensis, below…

…and Euphorbia ‘Excalibur, below’.

To finish, an assortment of silvers and grays in combination with other colors of flowers and foliage, starting with some pairings for shade.

Above is ‘Halcyon’ hosta with golden meadowsweet (Filipendula ulmaria ‘Aurea’). Below is wandering Jew (Tradescantia zebrina) with ‘Ravenswing’ cow parsley (Anthriscus sylvestris).

Above is Japanese painted fern (Athyrium niponicum var. pictum) with Cryptotaenia japonica f. atropurpurea. Below is ‘Pewter Lace’ Japanese painted fern with featherleaf rodgersia (Rodgersia pinnata).

Above is ‘Krossa Regal’ hosta with Cryptotaenia japonica f. atropurpurea. Below is ‘Blue Cadet’ hosta with variegated sweet iris (Iris pallida ‘Variegata’).

Some herby silvery, gray, and blue combos for sun, starting above with silver sage (Salvia argentea), rue (Ruta graveolens), ‘Big Ears’ lamb’s ears (Stachys byzantina), and ‘Cora White’ rose periwinkle (Catharanthus roseus). Below is ‘Powis Castle’ artemisia, ‘Pesto Perpetuo’ basil, ‘Black Adder’ agastache, English lavender (Lavandula angustifolia), ‘Hot and Spicy’ oregano, lady’s mantle (Alchemilla mollis), and silver thyme (Thymus x citriodorus ‘Argentatus’).

‘Berggarten’ sage (Salvia officinalis): above with ‘Kwanso Variegated’ tawny daylily (Hemerocallis fulva) and below with English lavender (Lavandula angustifolia) and ‘Grey Lady Plymouth’ scented geranium (Pelargonium graveolens).

Above, dwarf curry plant (Helichrysum italicum subsp. microphyllum) against black mondo grass (Ophiopogon planiscapus ‘Nigrescens’). Below is woolly thyme (Thymus pseudolanuginosus) with ‘Snow Flurry’ heath aster (Symphyotrichum ericoides).

This grassy grouping features ‘The Blues’ little bluestem (Schizachyrium scoparium), ‘Dewey Blue’ bitter panic grass (Panicum amarum), and ‘Karl Foerster’ feather reed grass (Calamagrostis x acutiflora). In the above photo (mid-July of 2010), they’re with purple coneflower (Echinacea purpurea), spike gayfeather (Liatris spicata), and ‘Temptation’ Culver’s root (Veronicastrum). Below (in late July of 2012), they’re with orange coneflower (Rudbeckia fulgida var. fulgida).

Above, ‘Heavy Metal’ switch grass (Panicum virgatum) with mounds of geum foliage and the flowers of shrimp plant (Justicia brandegeana). Below is ‘Dallas Blues’ switch grass with teasel (Dipsacum fullonum).

And some succulents…above, Chinese dunce cap (Orostachys iwarenge) with silver thyme (Thymus x citriodorus ‘Argenteus’). Below is ‘Autumn Fire’ sedum with ‘Spring Green’ tulip and the leaves of white Japanese burnet (Sanguisorba tenuifolia ‘Alba’).

Below, Echeveria glauca and ‘Silver Spoons’ with jade plant (Crassula).

Some miscellaneous perennials…above, Allium karataviense ‘Ivory Queen’ with dwarf white fan columbine (Aquilegia flabellata ‘Nana Alba’), ‘Marcus’ salvia, ‘Frosty Fire’ dianthus, ‘Silver Brocade’ artemisia, and ‘Brookside’ geranium. Below, silver sage (Salvia argentea)—which is actually a biennial—with white-variegated sweet iris (Iris pallida ‘Argentea Variegata’) and ‘Caradonna’ salvia.

Of course, you can’t talk about silver plants without including lamb’s ears (Stachys byzantina). Above is the straight species with creeping thyme (Thymus praecox Coccineus Group) and Spanish stonecrop (Sedum hispanicum).  And below, the selection ‘Big Ears’, which can range in appearance from near white to silver to sage green, depending on the time of year and the growing conditions. Here it’s with Arkansas bluestar (Amsonia hubrichtii) and the finished flowerheads of Invincibelle Spirit hydrangea (Hydrangea arborescens ‘NCHA1’).

Above is ‘Big Ears’ with dwarf fleeceflower (Persicaria affinis), rhubarb (Rheum rhabarbarum), Diabolo ninebark (Physocarpus opulifolius ‘Monlo’), Korean feather reed grass (Calamagrostis brachytricha), and Japanese maple (Acer palmatum). Below, it’s with Japanese blood grass (Imperata cylindrica ‘Rubra’).

Oh, one more: the flower stalks of regular lamb’s ears with common chives (Allium schoenoprasum).

Moving on…above, silvery common mullein (Verbascum thapsus) with ‘Toffee Twist’ sedge (Carex flagellifera). Below, gray-green ‘Walker’s Low’ catmint (Nepeta) with love-lies-bleeding (Amaranthus caudatus) and ‘Amora’ coleus.

Above, ‘Powis Castle’ wormwood (Artemisia) with ‘Snow Fairy’ bluebeard (Caryopteris divaricata), white South African foxglove (Ceratotheca triloba ‘Alba’), and Browallia americana. Below, budded ‘Autumn Fire’ sedum with white Japanese burnet (Sanguisorba tenuifolia ‘Alba’), ‘Heavy Metal’ switch grass (Panicum virgatum), and—in the wagon—young plants of Solanum quitoense.

And below, one more perennial combo in this color group: sea kale (Crambe maritima), lamb’s ears (Stachys byzantina), ‘Sarastro’ bellflower (Campanula), and Loraine Sunshine oxeye (Heliopsis helianthoides ‘Helhan’).

If you want to experiment with some silvers without committing to perennials, there are lots you can easily grow from seed or buy as annual transplants. Below is one: silver spurflower (Plectranthus argentatus), here with ’Silver Drop’ eucalyptus (Eucalyptus gunnii).

‘Silver Falls’ silver ponyfoot (Dichondra argentea) is one I make a point of starting every year. It usually also produces some self-sown seedlings. Above it’s mingling with ‘Mezoo Trailing Red’ aptenia (Dorotheanus bellidiformis); below, it’s pooled around ‘Obsidian’ heuchera.

Above, ‘Ruby Perfection’ cabbage with ‘Walker’s Low’ catmint (Nepeta) and ‘Silver and Gold’ yellow-twig dogwood (Cornus sericea). Below, ‘Red Russian’ (‘Russian Red’) kale with purple coneflower (Echinacea purpurea).

Above, ‘Lacinato’ (or ‘Nero di Toscana’) kale with Tiger Eyes sumac (Rhus typhina ‘Bailtiger’). Below, couve tronchuda (Portuguese kale) with ‘Goodness Grows’ spike speedwell (Veronica spicata) and ‘Silver Posie’ thyme (Thymus vulgaris). 

Sometimes I can get cardoon (Cynara cardunculus) to overwinter, but not often. Still, it can form a substantial foliage display as an annual from an early spring sowing. Below, it’s with ‘Cora White’ rose periwinkle (Catharanthus roseus), ‘Little Bunny’ fountain grass (Pennisetum alopecuroides), and ‘Powis Castle’ wormwood (Artemisia).

And finally, a few woody plants. Above, the sub-shrub Russian sage (Perovskia) with ‘Hella Lacy’ New England aster (Symphyotrichum novae-angliae); below, blueleaf rose (Rosa glauca) with ‘Carin’ Joe-Pye weed (Eutrochium maculatum).

Below, wickedly spiny but stunningly silvery ghost bramble (Rubus thibetanus) in mid-July with drumstick chives (Allium sphaerocephalon) and Dakota Goldcharm spirea (Spiraea ‘Mertyann’).

Last, but in no way least, silver willow (Salix alba var. sericea), below with smooth hydrangeas (Hydrangea arborescens), Mexican feather grass (Stipa tenuissima), and giant fleeceflower (Persicaria polymorpha).

Well, that all made seeing silver a bit more enjoyable, though I’d still rather see it from foliage than from ice. Speaking of ice…if you’d like to file your own official “Airing of Grievance” against winter—or too much rain, or not enough rain, or anything else, for that matter—I highly recommend checking out Formal Notices: Fifty Fill-in-the-Blank Forms for Everyday Correspondence. You can also see a sampling of the forms at Bureau of Communication; they’re absolutely brilliant.