I cannot emphasize enough that the form and shape of the plant and the texture and colour of its leaves are as important as the colour of its flowers.
Beth Chatto, The Green Tapestry
Most of us yearn for wondrous floral displays in some part of our gardens. The true measure of a good garden, however, is its foliage. Foliage provides not only a background for flowers, but is an intrinsic feature of any garden design. If foliage were the sole element of a garden, combinations and variations could be as subtle or as dramatic as that seen in any flower border in high summer.
These are my thoughts and observations on foliage, based on more than twenty years of gardening in a mostly shady garden in Victoria, British Columbia (Sunset zone 5, USDA zone 8). By many, this region at the southern tip of Vancouver Island is considered the most northerly extent of the mediterranean climate region of the West Coast. Our winters are cool and wet, while our summers are reliably warm and dry. (As I write this, however, we are experiencing an unusually dry winter, which has forced water restrictions on all of us for the spring and summer of 2001.)
Visual Texture in Foliage
Laciness can be found in a number of plants whose tiny leaves are arranged in distinct and regular patterns. Combining plants offering a lacy texture with other foliage types can produce a successful and pleasing planting scheme of great visual depth. The shiny, dark, green leaves of boxleaf azara (Azara microphylla) provide a wonderful contrast to Rubus henryi, a climbing vine with slender, trifoliate, bamboo-like leaves. Both plants are evergreen and provide yearlong foliar value in the garden. A choice evergreen fern for the ultimate in laciness is Himalayan maidenhair (Adiantum venustum). Dicentra ‘Langtrees’ and ‘Stuart Boothman’, hybrid bleeding hearts, offer both a lacy texture and a blue green, glaucous color—a great foil for deep green hostas. Cimicifuga simplex var. simplex ‘Brunette’, a selection of the Kamchatka bugbane, adds deep purple to its lacy leaves to give contrast in color and texture to gold-leafed plants, such as the golden form of box honeysuckle (Lonicera nitida ‘Baggesen’s Gold’) or a golden sedge (Carex elata ‘Bowles Golden’). Another personal favorite is Hebe pimeleoides ‘Quicksilver’ whose tiny, glaucous leaves are the ultimate in blue green laciness. A particularly fine, lacy, gray-leafed plant is Anthemis punctata ssp. cupaniana, with foliage showy well beyond its display of white daisies. An excellent, lacy, white-leafed shrub is Centaurea cineraria (also known as C. gymnocarpa), one of the dusty millers well worth some winter protection in gardens subject to cold winters.
Interweaving a variety of foliage textures adds interest to a garden without a dependence on flowers. One especially good combination I chanced upon was a painted fern (Athyrium otophorum), Euphorbia dulcis ‘Chameleon’, and Hosta ‘Abiqua Recluse’ with an edging of golden Japanese forest grass (Hakonechloa macra ‘Aureola’). The fern’s purple rachis echoes the purple of the euphorbia, while the golden chartreuse green of the hosta perfectly sets off the golden grass. This composition is compelling throughout the growing season.
Variety in Shape and Surface
The shape and feel of individual leaves is equally worth considering in composing a garden. An especially appealing plant is Rubus lineatus for its exquisite, trifoliate, pleated leaves; each leaf is frosted white underneath. The large, fuzzy, apple green leaves of Hydrangea aspera are worthy of any semi-shaded border. For shininess, I enjoy Farfugium japonicum (formerly Ligularia tussilaginea), particularly ‘Ferris Wheel’, a much improved selection over the common spotted one. Geranium nodosum is a woodland geranium that should be used more, as its new spring foliage is a fresh glossy green long before, and long after, its flowers have made their brief appearance. Inside-out flower (Vancouveria planipetala), a California native, makes a lovely evergreen ground cover with shiny leaves. When space permits, Ampelopsis megalophylla is a handsome vine with large, shiny, crinkled, pinnate leaves. For a sheltered spot or as a pot plant, common myrtle (Myrtus communis) is a fine shrub offering small, shiny, dark, evergreen leaves. The bright shiny evergreen leaves of Asplenium scolopendrium ‘Crispum’ have rippled edges and seem to reflect the light at all seasons of the year. Another worthwhile fern for its waxy, evergreen fronds is long-eared holly fern (Polystichum neolobatum); its sheen calls out to be touched to prove it’s not made of plastic. An attractive umbellifer with tripartite leaves of a superb sheen is Angelica pachycarpum, which is easily grown from seed.
Varying the size of leaves is another way to add interest and drama to the foliage palette. For sheer boldness, consider the West Coast native umbrella plant (Darmera peltata); it needs good moisture and rich soil, but even in a large pot its nearly round, lobed leaves have a strong presence. Ornamental rhubarbs (Rheum spp.) are another group to add “wow” to a garden, but they take up a good deal of space. In early spring, the unfolding, dark purple, crinkled leaves are truly worth the sacrifice of space. Another large and dramatic plant is cardoon (Cynara cardunculus), an ornamental artichoke with steely gray leaves and purple or green flower heads that provides year long interest—even in the depths of winter. The giant thistles (Onopordon spp.) are great exclamation points for the back of a sunny border; these biennials will self-sow prodigiously and need judicious editing and controlling yearly. Rodgersias are among my favorite foliage plants; two are especially good for their early bronze foliage: Rodgersia pinnata ‘Superba’ and R. podophylla.
Other plants to seek for interest provided by the shape and size of their leaves include the podophyllums (flowers below the leaves) and diphylleias (flowers above the leaves). One especially stunning species is Podophyllum pleianthum with large, shiny, peltate leaves. Diphylleia cymosa has equally impressive leaves with red stems topped by blue mahonia-like berries in late summer. Among the best of the bold-leafed hostas is ‘Sum and Substance’; not only is the chartreuse leaf large and puckered, but it is sun-tolerant and slug-resistant. Smaller in size, yet just as interesting, is Mukdenia rossii with glossy round leaves, notched on the margins. Two aroids worth considering just for their dramatic foliage are Arisaema taiwanensis with mottled stems and leaf segments with elongated drip tips, and the glossy trifoliate Arisaema ringens. For sheer weirdness, Syneilesis aconitifolia takes first prize. In early spring, the gray furry leaves are clasped tightly like folded umbrellas; then they unfurl into rounded, deeply lobed, peltate leaves—like a shredded umbrella—with a curious rubbery texture.
Spiky or sword-shaped leaves have great impact in the garden. Two particularly good plants for this are the evergreen foetid iris (Iris foetidissima) and giant water dock (Rumex hydrolapathum). The latter is a large, upright, bright green, moisture-loving perennial, grown easily from seed; it is sturdy enough to not need staking. Astelia chathamica, restricted to the Chatham Islands and known as silver spear for its slender, silvery, pleated leaves, can be most effective in a sheltered, well-drained border; it also does nicely in a pot.
A Splash of Foliage Color
Foliage color other than green is always welcome in a garden. For variety one can’t be without elderberries (Sambucus). Sambucus nigra ‘Guincho Purple’ never fails to thrill me in the early spring with its deep purple leaves. Sambucus racemosa ‘Sutherland Gold’ is slower growing but garden worthy with its clear golden color throughout the season. Among other plants with golden foliage, the golden selection of mock orange (Philadelphus coronarius ‘Aureus’) offers long-lasting color if given shade, whereas the golden selection of common ninebark (Physocarpus opulifolius ‘Dart’s Gold’) is a good counterpart for full sun. Shade is an easier condition for many golden-leafed plants such as hostas; two of my favorites are ‘Golden Oriole’, with bright yellow leaves, and ‘Zounds’ with large, puckered, golden leaves. In addition to the golden appeal of Hakonechloa mentioned earlier, Acorus gramineus ‘Ogon’ serves as an excellent accent plant for the front of a border. The golden-leafed form of Saxifraga stolonifera called ‘Harvest Moon’ makes a fine ground cover in a shaded situation.
Purple, albeit somber by itself, is a great color for contrasting gold or green foliage. Apart from Sambucus ‘Guincho Purple’ and Cimicufuga ‘Brunette’, noted above, some worthy equals are the purple-leafed Cercis canadensis ‘Forest Pansy’ and Physocarpus opulifolius ‘Diabolo’. Given full sun and good drainage, both will reward with good purple leaves that will not fade to green as the season progresses. Eucomis comosa ‘Sparkling Burgundy’ is a selection of the curious pineapple lily, whose upright leaves remain a striking deep purple, especially if grown in full sun.
I’ve often seen Clematis recta purpurea listed in catalogs and lately a selection has appeared called ‘Lime Close’. This species varies considerably in the degree of purple in its foliage, and I’ve been misled repeatedly by glowing catalog descriptions. I now have three plants, but none has ever lived up to its billing. (Perhaps I’m just not growing it correctly.) I strongly urge picking out these clematis, as well as selections of bugbane (Cimicifuga), when in full leaf to be certain of getting a good purple.
My favorite purple-leafed heuchera is Bressingham Bronze for its dependably glossy leaves. A few purple-leafed perennials that I have found easy to grow and that assort well with other plants include Cryptotaenia japonica f. atropurpurea, Geranium ‘Chocolate Candy’, white snakeroot (Eupatorium rugosum ‘Chocolate’), Aster lateriflorus ‘Prince’ and ‘Lady in Black’. Cryptotaenia is an herb and a wonderful filler for contrast in texture and color. The geranium forms a robust clump and its leaves live up to the name, as is true for the snakeroot. The two asters have deep, purple black, lacy leaves prior to their late summer flower.
Glaucous, gray blue foliage is a fine complement to just about any shade of green or purple. Rosa glauca (formerly R. rubrifolia) is the best rose for glaucous leaves. A good climbing rose is ‘Wickwar’ with bluish gray green leaves. The steely blue leaves of Hosta ‘Hadspen Blue’ are superb in any garden setting; the color seems to intensify in more sunlight. For full sun, Mertensia maritima and Parahebe perfoliata perform well. The gray-leafed Salix repens var. argentea is a lovely, low-growing willow for the edge of a border. Othonna cheirifolia, a fleshy gray-leafed composite, revels in full sun and a well-drained site. The ultimate in a blue gray grass is Elymus magellanicus, but a close second would be blue oat grass (Helictotrichon sempervirens). Panicum virgatum ‘Prairie Sky’ is a taller growing grass (four feet or more) displaying good blue gray tones. Bush germander (Teucrium fruticans), Phlomis tuberosa, Buddleja fallowiana, and Dorycnium hirsutum (syn. Lotus hirsutus) are all handsome and dependable gray-leafed shrubs for full sun. Lower growing Anaphalis ‘Moe’s Silver’ and Euphorbia rigida will also thrive in full sun and will tolerate some drought. With nearly white leaves, bee sage (Salvia apiana) should be coddled through our cool, wet winters, if only to enjoy in a pot; it is much better adapted to Southern California where it is native.
Here is where restraint is often abandoned and one quickly amasses a wacky jumble of patterns and splotches. I follow the philosophy that just because a plant has variegated leaves doesn’t necessarily make it garden worthy. Beauty is in the eye of the gardener.
I favor leaves with a clean or regular variegation. I would not be without Hosta ‘Patriot’, Brunnera macrophylla ‘Variegata’ or Iris foetidissima ‘Variegata’ as each will be consistently green with a clean white variegation. Other good variegated plants for me are Azara microphylla ‘Variegata’, Sambucus nigra ‘Aureomarginata’, Scrophularia auriculata ‘Variegata’, and Phlox paniculata ‘Nora Leigh’. Phlox paniculata ‘Harlequin’ is a new variegated cultivar that I like for its darker variegated foliage and deeper purple flowers. Two selections of Pittosporum that I find pleasing in their variegation are ‘Garnetii’, edged not only in white but often tinged pink, and P. tenuifolium ‘Gold Star’, with golden-striped green leaves. One often overlooked, small, hardy evergreen shrub with excellent small, white-edged leaves is the variegated form of Coprosma x kirkii. Some good grasses for bright white variegation are variegated giant reed (Arundo donax ‘Variegata’), needing winter protection for us but potentially invasive in warmer climes, and Miscanthus sinensis var. condensatus ‘Cabaret’ and ‘Cosmopolitan’.
Most variegated plants look better with a bit of shade, and they are effective at lightening dark corners. One that is striking all summer for me is Lysimachia punctata ‘Alexander’, a loosestrife with creamy white variegated leaves and yellow flowers. Many of the lungworts (Pulmonaria) have leaves spotted or streaked with cream, white, or silver. I enjoy P. ‘Excalibur’ with pewtered leaves and P. ‘Spilled Milk’ with large silver-splashed leaves. Among the bulbs, the variegated Italian arum (Arum italicum ‘Pictum’) never fails to provide shiny, white-veined leaves throughout the winter.
Some variegated plants can be difficult to place. I have found the gold-spotted Farfugium japonica ‘Aureomaculatum’ a challenge except when completely surrounding by green. On the other hand, the cream variegation of its cousin, F. japonica ‘Argenteum’, lends a richness to almost any foliage composition. Some especially pleasing patterns can be found among the evergreen shrubs, such as Griselinia littoralis ‘Variegata’ and Viburnum tinus ‘Variegata’. Both these shrubs could be great choices for planters as they need some winter protection in our area. Other creamy yellow, variegated plants that I find attractive are bold-leafed Hosta ‘Sagae’ and grassy Carex phyllocephala ‘Sparkler’.
For variegated vines, who does not salivate over Actinidia kolomitka in early summer with its pink, white, and silver marked leaves. Just as attractive but smaller-leafed is Actinidia pilosula; each leaf tip is dipped in silver. New to me is a star jasmine relative, Trachelospermum asiaticum ‘Variegatum’, which I plan to grow cautiously in a pot, as I doubt that it could manage our cool wet Victorian winters; the variegation is a rich cream and white.
Plants with splotched foliage may sound unappealing—even sickly—yet many can be effectively used for echoing the colors in leaves of neighboring plants. As examples, Geranium phaeum ‘Samobor’ and G. x oxonianum ‘Katherine Adele’ have purplish blotches and are both worthy of placement near other purple-leafed plants. The distinct purple markings of some of the foamflowers (Tiarella spp.), such as ‘Skeleton Key’, make this an attractive addition to a semi-shaded border.
The Rest of the Story
Stems, twigs, and bark provide another non-floral facet of plants to consider in composing the foliage garden. The rippled leaves and black stems of Pittosporum tenuifolium are worthwhile growing in a sheltered spot this far north. Hostas ‘Torchlight’ and ‘Cherry Berry’ are attractive if planted at eye level where their rhubarb-tinted stems can be appreciated. A selection of white mugwort with deep burgundy stems (Artemisia lactiflora ‘Guizho’) is a good herbaceous perennial for either full sun or dappled shade. Black stems are always striking. Hydrangea macrophylla ‘Nigra is a newly available selection with black stems. The much admired black bamboo (Phyllostachys nigra) needs careful siting and containment in concrete or sheet metal collars to keep it from spreading throughout the garden (as it did for me). Two worthy shrubs with ruby-tinted stems are pepper tree (Drimys lanceolata) and Chinese photinia (Photinia serratifolia), both requiring some shelter in our area but well adapted further south.