Loads of rain here recently, following on a month-long drought. Such is the weather for a gardener... never perfect, never quite what we would want it to be. At least I'm not watering by hand and sprinkler now, a tiresome and well-draining activity I try to confine to items planted within the last year; anything that's been in the ground longer is on its own. The ample moisture has refreshed and renewed many plants that looked on the verge of demise, including the toasted lawn, plumping up flagging stems and leaves, triggering everything to put on fresh turgid growth in a botanical sigh of relief.
All this exuberance is especially noticeable on the largest and most heavily textured plants, those we need for bold effects, the unapologetically oversized plants all experienced gardeners instinctively turn to for accents and focal points, and to avoid monotony in a planting scheme. Tropical annuals, of course, are perfect for providing the scale and impact needed, and I couldn't garden without Cannas, Cardoons, and my beloved (and deadly poisonous) Castor Beans. But they are a lot of trouble to raise from seed every year, or carry over as bulbs, or buy again every season.
What I'm appreciating most right now are the perennials that provide that tropical look with less effort on my part, those that reliably return every year to make the late summer garden, beyond the flowery fuss of May and June, a satisfying essay in texture and form. Here then, a baker's dozen of these big, bold beauties, some of which you probably already grow, and some new ones you may want to try.
One of my top ten favorite perennials, Ligularia japonica thrives in damp shade and builds up into magnificent clumps of rich green, deeply divided foliage that gives a distinctly tropical effect. In midsummer the flowering stems shoot up head high or more, and though I'm not so fond of the shaggy golden yellow blooms, I love the seed heads that follow: tufts of golden brown that hold well into the winter before shattering.
I'm not sure why this plant is so hard to find in nurseries because it comes easily from seed... in fact I pull out dozens every spring that sprout in places I don't need it... so if any of you want a start, email me and we'll get a list going for next year!
Darmera peltata, commonly called Indian Rhubarb, is technically an American native, just not to our area. It hails from wooded streamsides in Oregon and northern California, but grows very well here in the Hudson Valley as long as it's given a spot in shade that never dries out. The thick, rhizomatous roots, lying just on the surface of the soil, make it an ideal plant for stabilizing the bank of a stream or the edge of a shaded pond.
The flowers are more curious than beautiful, naked stalks topped with a ball of pale pink blooms that poke up very early in the season, before the leaves expand. It's those leaves that are the main attraction, and why we grow the plant: scalloped discs more than a foot in diameter, held shoulder-high in a wet year like this one. They take on rich shades of bronze, gold and red in the autumn, then disappear with the first snow, leaving only the conspicuous rhizomes to mark their place until the following spring. Darmera increases gradually and steadily, never overly aggressive like Petasites japonicus, a plant often recommended for similar conditions.
Aralia cordata is a great large-scale perennial native to Japan, where its young shoots are eaten like asparagus. 'Sun King' is a golden-leaved version that was reportedly discovered there in a department store nursery by plant explorer Barry Yinger, and brought back to the U.S. where it's recently become a hot perennial. I've been growing it for about five years now, and continue to be impressed... it flattens to the ground every winter but returns faithfully in spring, quickly making a dense mound of foliage 6 ft. tall and wide.
The sprays of delicate greenish white flowers in late summer are attractive, followed by black berries that the birds relish. But it's the foliage color that makes this plant truly distinctive: it seems to have some sort of inner phosphorescence that makes it glow in the late evening light like no other golden plant. Or maybe that's just the martinis.
Miscanthus have been the most popular ornamental grasses for twenty years or more, but they're undergoing something of a reevaluation because many of the varieties can reseed invasively, particularly in Zone 6 and southward. Most nurseries are now required to put scary labels on all their Miscanthus, even the varieties that aren't a threat. One that's perfectly safe to plant here in our area, because it blooms too late to set seed, is Miscanthus x giganteus, a hybrid of unknown origin. It's also the largest of the genus by far, towering ten or twelve feet in ideal conditions.
The effect is close to that of a Bamboo, without the running propensities... a clump of Miscanthus x giganteus will gradually increase every year but never enough to cause terror and panic. After first frost, it turns beautiful shades of tawny gold until the leaves shatter in late winter. Give it space, full sun and adequate moisture and enjoy the drama that ensues!
Like an Astilbe on steroids, Persicaria polymorpha is a shrub-sized perennial that really looks great at the back of a border, or in a meadow style planting. It's related to the much hated and horribly invasive plant known locally as Japanese Bamboo (not a Bamboo at all, but equally uncontrollable). But Persicaria polymorpha doesn't run rampant, just makes a nice polite clump that increases slowly every year. Its common name is supposed to be Mountain Fleece but I've never heard anyone call it that. It's valuable for its scale, boldly textured leaves, and long-lasting plumes of flowers that age from greenish white to a pleasing tan.
Prefers full sun and average to moist soil, and as I mentioned it's strong enough to hold its own in a meadow, growing 5-6 ft. tall and able to compete with grasses, Asters, Goldenrods and other such plants. Takes its time to emerge in the spring but the hollow, persistent stalks are very distinctive so you'll be able to find it during late winter cleanup. Persicaria is a genus of plants that has been switched around a lot in recent years by botanists (damn them) but although the name Persicaria polymorpha is officially listed as "unresolved", most likely you'll find it being sold and referenced under that name... at least for the time being!
Rodgersias are substantial perennials that make a bold foliage statement. There are several species and cultivars that will grow here, including Rodgersia aesculifolia, Rodgersia pinnata and Rodgersia podophylla. The one I grow was bought as R. pinnata 'Superba', but I'm not entirely sure it was labeled correctly. Never mind, they are all beautiful, dramatic and worth the patience it takes for the painfully slow crowns to establish and build up.
In England and northern Europe they can be grown in full sun, but here they need some shade from scorching afternoon heat, and reliable moisture in the ground. Distant cousins to Astilbes, which is evident when they throw their plumes of white or pink flowers, which are attractive but nothing in comparison to the visual impact of the leaves.
Astilboides tabularis used to be called a Rodgersia until it was hived off into its own genus by the ever-annoying botanists. Culturally, it has the same requirements as Rodgersia and takes just as long to establish and really get going, but it's well worth the wait.
The platter-sized discs of fuzzy mid-green, held aloft on strong stems, contrast dramatically with other more delicate shade lovers like ferns, Thalictrums or Actaeas. Astilboides is a great feature at Margaret Roach's garden in nearby Copake Falls, NY, always eliciting lots of questions and comments on her Open Days.
With most of us trying to grow fewer Miscanthus, we're all looking around for other large, substantial grasses. Panicum virgatum, also known as Switch Grass, is a native American species with several selections that fit the bill. One of the largest and most dramatic is 'Cloud Nine'. It forms a graceful fountain of slightly bluish foliage that erupts in late summer into an enormous cumulus cloud of delicate bloom.
The whole thing ages to a pale gold by September and persists until we have a really flattening wet snow. Other good alternatives to Miscanthus are Sporobolus wrightii 'Windbreaker', Molinia caerulea 'Transparent', Andropogon gerardii 'Red October', Panicum virgatum 'Northwind' and Spodiopogon sibericus.
I know Hostas don't need any promotion... you've probably got more than enough of them already if you've been gardening for a while. But there's just something so satisfying about the large, blue-leaved cultivars that I couldn't leave them out of this list. If you can get around the deer, Hostas are incredibly reliable and one of the very few bold-foliaged plants that will survive in dry shade. I prefer most Hostas used in masses, but I love these large blues set apart as specimens, underplanted with something low and lacy, like Sweet Woodruff, so they can show off their size and texture and lovely vase-shaped form. The classic old-time variety is Hosta sieboldiana var. elegans, still a great plant after more than a century in the nursery trade, but there are lots of newer big blue cultivars to try as well, like 'Blue Angel', 'Humpback Whale', 'Blue Umbrellas' and 'Empress Wu'. Just promise me you won't become a collector.
Although it's not a true perennial, the Korean Angelica, Angelica gigas, is a very reliable biennial, meaning it needs two years to complete its life span from seedling to bloom. You may need to buy the plant two years in a row to get it going on the proper cycle, but it's worth the trouble. Handsome compound leaves, almost like an Acanthus, held on sturdy 5-6 ft. stalks, topped by striking domes of deepest red-purple. The flower color is particularly rich, and the whole plant is suffused with shadings of wine-red that make it a standout among other more ordinary greens.
Blooms in late summer, and like many umbellifers, it's a great pollinator plant. The seed heads persist into fall in an attractive way before dropping to begin the next year's seeding cycle. Best on evenly moist ground with some shade from the hottest afternoon sun, but adaptable to an average border setting as long as the soil is fertile.
Goldie's Fern (named for Scottish botanist John Goldie, not Goldie Hawn) is the largest of the native Wood Ferns, genus Dryopteris. Although one doesn't usually think of ferns as bold plants, the sheer scale of this beauty puts it in a class by itself, a well-established crown easily reaching 4 ft. tall with an equal spread on boggy soil. In our climate only the Royal Fern, Osmunda regalis, can compete, but its fronds look completely different. Dryopteris goldiana has the classic twice-compound fronds of many other ferns, just at an impressive size. Plus it has the leathery texture of all Wood Ferns that enables them to remain attractive throughout the growing season, instead of browning out in dry spells like some with more delicate fronds.
Comfreys are notoriously invasive, but this variegated type, Symphytum uplandicum 'Axminster Gold', is very well-behaved. I've had it for more than ten years and the clump increases only modestly every year, just enough to share with friends. My Vermont garden designer friend, Donald Corken, pointed out that it's unusual to find a plant with this coloring that grows in full sun, an astute observation.
Like all Comfreys, the deep, strong roots will enable the plant to regenerate quickly, so after flowering I cut the whole business right to the ground and in a week or so there's a fresh flush of new foliage. Average to moist soil is recommended by most references, but I have mine in a raised bed with light, sandy soil and it's done very well.
Something you may not have thought of using as an ornamental is common Rhubarb, Rheum rhabarbarum. If you look at it with an unbiased eye, it has everything you'd want in a bold perennial: handsome large-scale foliage, tall sprays of milk-white or pinkish flowers, adaptability and bone-hardiness. The stems can still be harvested for early use in the kitchen and the plants will regenerate plenty of new leaves to carry through the summer.
Once established, the substantial rootstock will live for many, many years, as evidenced by their continued presence around old farmsteads. Richly manured soil will yield the largest leaves, but they will grow well in ordinary garden soil as long as it's not too hot and dry. If you want to get fancier, there's a non-edible Eurasian version, Rheum tanguticum, with jagged leaves suffused with red, and deep pink flowers. Very handsome!
You may have noticed that many of the plants I've suggested require some shade, and at least consistent moisture if not downright boggy soil. That's simply a matter of evolution... large leaves can collect more sunlight in dim conditions, and reliable moisture in the soil is a requisite for maintaining full, lush growth. If your garden conditions tend towards hot, dry and sunny, you probably won't be able to grow all of these, but it's worth trying to find a spot where you might succeed with some of them... the north side of a building, in the drip of the eaves, would be a likely place.
There are other choices not covered here, of course... Inulas are wonderful, and a great feature at James Golden's garden in western New Jersey, Federal Twist (see photo below). But I've never grown them, so I hesitate to write about them. Another obvious choice for dramatic effect is the Japanese Butterbur, Petasites japonicus, but it's so fearsomely aggressive that I couldn't recommend it to anyone who has a garden smaller than Central Park.
Those on the list above are reliable here in USDA Zone 5, adaptable and extremely valuable for adding something refreshingly audacious to your garden. Look at your plantings with a critical eye, and you're sure to find somewhere that needs more punch, more boldness, more vitality, more of a horticultural extrovert!
Inulas at Federal Twist, an inspiring garden in a lovely corner of New Jersey, well worth a visit on the Garden Conservancy's Open Days.
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Welcome to Sempervivum, an opinionated, sometimes informed and completely unqualified journal of gardens, plants and plantings by artist-gardener Robert Clyde Anderson.