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Species Roses
by Karlton Holmes
When I was first assigned to work in the Arnold Arboretum's rose garden, I thought, "Karl, you're in trouble now." I began to read about rose care (just to brush up, mind you), and I came across material that would have been the envy of the great alchemists of the Middle Ages, including images of blackspot, crown gall, powdery mildew and fire blight. It seemed rose care had a mystique that would confound me at every turn.
Rosa setigera. Unlike hybrid roses, species roses have simple
flowers, generally with five wide-open petals.
Photo © Stephen Scanniello
That was ages ago now. What had seemed an impossible task is actually a fairly simple one because I found myself in charge of a rose garden that specializes as a collection of species roses—plants that had originally been wild and then were transplanted into a garden setting. With few exceptions, no plants are easier to tend than those that have evolved in the wild; they take care of themselves.
Species roses are the simplest and purest form of roses—essentially the living ancestors of all other roses. It is through breeding, cross-breeding and other genetic manipulation that we have come by the fancier rose forms that are prevalent at flower shops and in many gardens.
What to Look for in Species Roses
Like their hybrid progeny, species roses come in a variety of flower colors, from the subtlest and most creamy orange to the sexiest of class="border"llo pinks. There are the whites in Rosa rugosa alba, the yellows in Rosa primula and Rosa ecae and, of course, the pinks and near-reds that dominate the spectrum of species roses. But, much more than color, what sets a species rose apart is the actual form of the flower. Bearing little or no resemblance to their long-stem hybrid counterparts sold on Valentine's Day, species roses have simple, unpretentious flowers—generally five petals open wide, borne singly or in clusters. But even though the form of the flower is less complex than that of many hybrids, the species rose offers year-round interest that many of the hybrids cannot.
The flowers of Rosa x hibernica wouldn't be nearly as effective
without the dark, creamy green foliage.
Photo © Stephen Scanniello
In choosing a species rose, first I'll want a good flower whose color matches the overall scheme that I want to develop. After that, though, I begin to look for other qualities, such as foliage color, texture, scent, fruit (the rose hips) and overall branching pattern. (You'll know you're a true gardener when you become obsessed with how your plants look even in the dead of winter!) Almost every species rose has several of these qualities, enabling me to enjoy the plant long after it has stopped flowering.
When it comes to species roses, I am a foliage freak. All roses retain at least part of their foliage even in the winter, since rose prickles are technically a type of modified leaf. Species rose prickles come in all different sizes, shapes and colors; they can give the stems a soft, furry appearance, or they can lend the plant a fearsome and fiery aspect. As a professional gardener, I'm outside year round, including in winter, when the translucent ruby prickles of Rosa sericea pteracantha catch the orange light of the setting sun in the winter and give the plant a fire-like glow at the end of the day.
Other more obvious forms of foliage give the species rose interest throughout the growing season. Rosa glauca has a pinkish cast to its otherwise wintergreen foliage. Rosa rugosa has rough, almost hairy foliage, and Rosa spinosissima has a light, delicate, almost ferny foliage. And this is just in the summer. In autumn the foliage on species roses turns every fall color from yellow to purple. What's more, the foliage on some plants has a fragrance more luxuriant than the flowers themselves. The new leaves on Rosa bracteata and R. inodora have a lingering apple scent that fills the garden on a wet or humid day. These are definitely plants that I would choose for my garden.
Like their close relative the apple, roses develop a fruit (called a hip) that starts off green and changes color as it ripens. Hips have an ornamental quality of their own and keep the party going all summer and into the winter after the foliage is gone. Their colors range from a pale limey green to bright pumpkin orange and burgundy. Crack them open when they're ripe for a tasty treat, or pick them off right before the winter and use them in holiday floral arrangements.
When it comes right down to it, a species rose is a great plant in either the designed or natural setting. Their flowers are simple and their forms unassuming. They look great, smell good and have a branching pattern that gives the plants presence year round. Even better, they're a snap to care for.
Planting and Maintaning Your Species Roses
Last August, I found myself in a traffic snarl-up on Boston's Southeast Expressway, where the ambient temperature was about 120¡F. Looking around, I spotted Rosa rugosa, thriving in between two rows of New Jersey barriers in a hideously hostile environment. That one glance wiped out every preconceived notion about the difficulty of rose maintenance. If those roses can not only survive but flourish under such extreme conditions, then they can probably do well just about anywhere. Look on the roadside in June and you'll see pink Rosa virginiana climbing up into just about anything it can get a purchase on. You'll find Rosa palustris in swampy meadows and Rosa rugosa not only in median strips, but growing along the sand dunes on the beach. (In fact, one non-native species rose, Rosa multiflora, is such a rampant grower that in many areas it has become an invasive pest, outcompeting the indigenous vegetation.)
The most important thing to keep in mind about growing species roses: They all do best in the sun. There is one thing that you can do right off the bat that will affect the way your rose looks and how it performs for its entire lifetime—site it properly. Your species rose will do fairly well in a wide range of circumstances, but what you want in your garden isn't just any old shrub, but a plant of heretofore unequaled terrestrial splendor. So you've got to find a sunny spot. The soil should be well drained and loamy. A good gauge for this is whether or not grass grows well there. It if does, or could, then you're in luck.
Plant, prune and feed your species rose as you would other roses. As for disease, you're in luck: Species roses are relatively disease resistant. This is the major advantage to using unhybridized plants; several millennia of evolution have produced fit and hardy roses. Which isn't to say that all hybrid roses are disease infested—not at all. But species roses do have the genetic cards stacked in their favor in this regard; they may get some of the same diseases that the hybrids get, but it's more likely that they'll survive them without any chemical treatment.
What about Japanese beetles? Again, you're in luck. Japanese beetles don't mature into voracious adult micro-monsters until mid-summer. By this time, most of the species roses have stopped blooming and are producing hips. Japanese beetles are more likely to go where the pickin's are better—like your neighbors' hybrids, which are still in bloom and providing a more succulent meal.
Favorite Species Roses
Following is a list of favorite species roses. Some of these are forms of species roses, and some are crosses between two different species, but any lack in purity is more than made up for by garden versatility.
Small shrubs (2-4 feet tall)
Rosa spinosissima—Super flower, foliage and hip producers, with rich green, delicate foliage. Any of its forms or hybrids are worth a try. My favorite is R. spinosissima altaica, which at 5 to 6 feet is a bit taller than others of its species, with larger flowers. Altaica is packed with white flowers on prominent yellow stems. It's an earlier bloomer, flowering in mid-May and lasting for about three weeks. It then produces beautiful round burgundy hips that are unlike anything else in the late summer and fall garden. All spinosissimas (also known as pimpinellifolias) have a pretty, rich, green and delicate foliage.
Rosa woodsii—For those of you with a passion for native North American plants, here's one for you. Rosa woodsii is a full shrub, growing to 3 to 4 feet; flowers are blue-pink with a sweet scent. The hips of the woods rose are small and glossy, and the petals are perfect as a garnish on any mid-summer omelette.
Rosa rugosa—For anyone who grew up on the coast, this plant is bound to evoke nostalgia and memories of sand in your shoes. This Japanese native has been used so often that, at least in New England, many people think it's a native. It has rough, dark-green leaves and large dark-pink flowers. The scent is sweet, rich and pure. There is a white form called Rosa rugosa alba, and the petals of both the pink and white look great as a garnish for your after-dinner finger bowls. My favorite rugosa is Rosa rugosa 'Hansa', a large-flowered bloom with a scent that will dominate the area it's planted in.
Medium shrubs (4-6 feet tall)
Rosa pendulina—This plant has it all: beautiful, rich pink flowers; elongated cherry-red hips; and cinnamon-red and yellow stems in the winter. Maximum winter display requires extra pruning in the fall—leave only those canes that look best. This is a labor of love that will satisfy you during those months of dormancy when you normally wouldn't have high expectations for your roses. Underplanting this with Helleborus foetidus creates a composition that will never quit.
Rosa x malyi—I choose this rose on account of its flowers, with their candy-apple petals, white interiors, and bumble-bee yellow stamens. Rosa x malyi flowers in mid-May, just as spring is driving its hardest back-to-life bargain. This isn't a subtle rose; though it's a one-act show, the smiles it brings are worth everything.
Rosa x hibernica—This rose is the child of Rosa spinosissima and Rosa canina. It's also a rose chosen for its flowers, but the flowers wouldn't be nearly as effective without the foliage—a dark and creamy green that backs up dusty pink flowers with a parchment-white interior and yellow stamens.
Rosa glauca—Previously named Rosa rubrifolia (and for good reason: rubri meaning red and folia meaning leaf), this American native rose with its wintergreen leaves tinted red is a great foil for any garden featuring dusty or variegated foliage. The flowers are bright pink with white centers, relatively small, and short-lived. The hips, however, start off a pale whitish pink and then turn to orange, a perfect color in the late-summer garden.
Tall shrubs (6-15 feet tall)
Rosa pomifera—As the botanical name implies, the hips on this rose are like small crab apples. Inconspicuous in flower and almost puritan in winter form, this rose is a big late-summer and early-autumn performer. The hips are almost the size of a quarter and pumpkin yellow in color. Its appearance in the garden is like a broad and bold wash of orange by a painter's brush, totally on the mark.
Rosa beggeriana—It's not the flowers, hips or scent on this one, but its sheer size. This rose is a monster. Free standing it measures around 13 to 15 feet tall. Few gardens can or will want to support a giant such as this. Size-wise it pushes every limit, while maintaining its presence as a flowering shrub to be admired.
Rosa setigera—Maybe it's the flowers that come late in the species rose blooming cycle; maybe it's the arching branch form resembling that of a tumbleweed in the winter; maybe it's the pink flowers, borne in clusters, fading to an almost white as they age. Whatever it is, I love this plant. It is vigorous, forthright and unstoppable.
Karl Holmes is a horticultural consultant, garden designer and gardener. He is the former Rose Care Specialist at Harvard University's Arnold Arboretum.