When you've only had an inch of rain in the months of June and July, it's pretty easy to figure out which plants can take a tough summer and still perform. We have about two acres of gardens, all of which have to be watered by hand during a drought, so even if I drag hoses on a daily basis I can't get to it all. And I don't, so most of it has been on the edge of collapse, or worse, all summer. We've lost a few plants, and some look as though they wish they'd died, and didn't. So when I plan a garden for the fall, heat and drought tolerance are definitely a factor. For this article, bloom is my primary consideration, but there are other plants which can be spectacular with no flowers in sight. Foliage and berries are definitely important, too.
When people tell me that they've nothing in bloom in their garden after the spring, I know that they're once-a-year shoppers. They come into the nursery in May and buy whatever looks nice. Then they hit the golf courses and go off on vacation, and wonder why their garden is so dull the rest of the year. Now I'll be the first to admit that spring is an exciting time in the garden, but if you plan it right, September and October can be much better. The soil is warm, the nights are cool, rainfall is adequate, the weeding is mostly done, and you might even find time to sit and enjoy the garden. Cooler temperatures intensify the colors, so blues deepen, reds clarify, and whites simply sparkle.
There are many, many plants which start blooming in spring or summer and keep going well into the fall, but it is a dwindling sort of bloom, and by then they are looking tired. Corydalis, Viola, Dicentra, Coreopsis, Rudbeckia and Echinacea are a few examples of perennials that do this, often until frost. A few shrubs are Caryopteris, Buddleia, Hibiscus, and Hydrangea. But my favorite plants for fall bloom are those which have worked and saved the whole growing season toward their own spectacular finish, looking as fresh as the plants that bloom in the spring. Asters, goldenrods and many of the sunny meadow plants could qualify, but frequently they only remind us of how dry the summer was- the foliage blackened, mildewed or both. And I'm not into mums - "hardy" or not. Planting an annual that only blooms for a few weeks before the frost gets it is not my idea of gardening. I like things that I can count on, that I don't have to fuss with and coddle, and I think I've grown a few for some different types of gardens.
So what do I love the most? In the autumn, all brilliant with golden light and blazing foliage, I love blue and white. Nothing can compare to the cool clarity of Aconitum, Gentians, Boltonia, Clematis and Anemone, when you're overwhelmed with scarlet and gold trees and burnt orange and rust Chrysanthemums. And I've always been a foliage person, so if it's still looking tidy in the fall it, too, can go on my list.
Many of the plants I have chosen prefer to be planted in rich, leafy soil in partial shade, so it always surprises me when people complain that they have nothing in bloom in their shady gardens after the spring. One of my favorite plants for the fall is the white form of Anemone x hybrida, either 'Alba' or 'Honorine Jobert'. It is an elegant thing with handsome foliage, spreading slowly into colonies. Its pristine white blossoms are held on tall stems, up to 4-5 feet if it's really happy. The flowers are long-lasting cut flowers if they are cut when they first begin to open. Otherwise they shatter rather quickly. It is a little bit slow to get established, and doesn't make much of a show its first year, but the patient gardener will be richly rewarded with a long-lived, long-blooming, easy, beautiful and tough perennial.
Another beautiful, tough plant for the shady garden is Kirengeshoma, either palmata or koreana. Both are shrub-like herbaceous plants to 3-4 feet with handsome maple-like leaves, dark stems and waxy yellow flowers in Sept. The flowers of koreana are a bit more upright so show up better, not getting quite so lost in the foliage. We have one very large plant which has grown happily under a swamp maple for about ten years, so it must be quite tolerant of root competition, but this year it suffered from the drought and dropped most of its inner leaves. It was nicely budded in August, though, so the blooms don't seem to be affected. Maybe it'll make it easier to see them!
The Tricyrtis clan is a bit weird, but admirable. It is a very large, mixed up genus with many species and hybrids which bloom in the fall. The flowers are orchid-like, waxy, and frequently strangely spotted, and certainly not what I would consider beautiful. But you have to give credit to a plant that carries itself with as much grace as this one does, and then tops it off with these strange blossoms. Tricyrtis hirta is the most commonly offered variety, with arching stems growing up to 2 feet in moist, loamy soil in partial shade. It blooms in September; with smallish white flowers heavily spotted in maroon and pink. All Tricyrtis varieties need to be planted where they can be seen up close, for they are easily overlooked. My favorite varieties are the pure white 'Shirohotogisu', with no spots, and the species T. macrantha. This one has large waxy yellow bells on pendant stems, best planted where it can be seen from below. All of the Tricytris would prefer moist soils, but perform nicely even in our dry summers.
An amazing, underused and underappreciated native plant is Chelone obliqua, or Turtlehead. Although it prefers to grow by water, we have it growing in our shady woodland garden where it was watered only once this summer, and the foliage is beautiful, dark shiny green, unmarred by any insect or critter. The flowers reflect its common name- a cluster of turtle's heads atop 2-3 foot stems, pink in the species and white in the cultivar 'Alba'. Neither are spectacular, but they're nice, and definitely worth growing for the foliage alone.
In the sunny rock garden, which holds a special place in my heart, there really is very little that blooms after June, much less in September and October. But there are a couple of outstanding plants that are small enough for the rock garden, with nice neat foliage that holds up well throughout the summer. Serratula seoanii makes a dark green mound of finely dissected foliage, almost like a fine Astilbe, and is topped by small clusters of purplish-pink thistles on one foot stems in September. It's not a show-stopper, but it's neat, it blooms late, and it doesn't self sow. In fact, it's probably available only from specialty nurseries, as the only way to propagate it is by division- not a nurseryman's dream! But a great plant for late color in the rock garden.
Alliums are another genus of not-very-showy-but-definitely-worth-growing plants in the rock garden for their late color. Small enough for a trough garden at only about 4", we have grown one as Allium thunbergi 'Ozawa' but there seems to be quite a bit of disagreement on the name. It has shiny green, twisted, grass-like foliage, and sturdy heads of pinkish-purple flowers in September and October. There is also a wonderful white form if you don't like the former.
A larger, sturdier Allium, suitable not only in the rock garden but also in the front of the border, is Allium senescens 'Glaucum'. This is another plant I would grow even if it didn't bloom, for it makes beautiful clumps of blue-green twisted foliage up to about 10" by late summer. In September, pink heads on 1' stems top it off. A neat, easy, handsome plant for well-drained soil. No watering needed!
Sedums are a familiar genus to rock gardeners, and Sedum cauticola is a really good one for the smaller garden. Its fleshy, circular, blue-green leaves make it another plant worth growing even without flowers, so its bright pink flowers on 4" stems in September are an added bonus. A great plant!
Another wonderful Sedum I love for its foliage is S. sieboldii. It is a bit more upright, but again with beautiful turquoise foliage that makes it a perfect plant for a specimen or for pot culture. Clear pink flowers in late September and early October give it the common name "October Daphne". Its only drawback is that it won't tolerate winter wet, so must be given extra drainage.
Before we leave the rock plants, there's one fabulous plant that I just have to mention, even though it doesn't start to bloom until late October. Gentiana scabra is a plant for the larger rock garden or the edge of the woodland garden. We have it planted in the Winter Garden at the edge of the dry stream bed, and it is so happy there that it blooms for two months and gives us no end of trouble trying to keep it in stock. Its brilliant, dark blue flowers on 12-16" trailing stems are a beacon in the fall garden. When the rest of the world is all aglo, it shocks us with the depth and intensity of its deep blue bells, clustered at the tips and along the stems. It likes a richer soil than most rock plants, and doesn't like full sun. Given a spot where it's happy, it will knock your socks off, and self-sow to boot. There is also a white form, not as vigorous, and a pink form, nowhere near as beautiful. Gentiana scabra ends the year for us with a bang, and starts off the winter season with a glorious show, not to be missed.
In the perennial garden, most people have given up by the time September rolls around, but there are some wonderful, effortless plants that we shouldn't forget. Boltonia asteroides 'Snowbank' is another fine, underused native plant. It has strong stems to 3-4' that never need staking; narrow, handsome, blue-gray foliage, and is topped with masses of airy white daisies in September. The cultivar 'Pink Beauty' is said to bloom much longer, from August into October, but somehow I still prefer 'Snowbank'. It's something about that gray and white combination that is so restful in the fall, amidst all those other hot colors! It is easy to grow in sun or partial shade, but it has a statelier presence in the sun.
Another fine, upright accent plant for the late garden is Panicum 'Heavy Metal', a Switch Grass. Although a grass, not technically a perennial, I use it in the perennial border as a upright accent of cool blue foliage and delicate sprays of airy flowers that are held all winter. Its foliage is outstanding, it never needs staking or dividing, and it doesn't spread rampantly into its neighbors (unlike some other less well-behaved grasses for the fall!).
Foliage freak that I am, I can't help but mention another fine native perennial, Amsonia hubrechtii. It is one of the blue milkweeds, with clusters of pale blue, almost insignificant flowers in late spring. It is a handsome foliage plant all summer, but its time of glory comes in the fall. 3' sturdy clumps of upright, airy stems clothed in narrow, shiny foliage turn bright yellow and last for weeks. It is a truly outstanding plant that should be in every garden.
Of course, everyone is familiar with Sedum 'Autumn Joy', but I can't help but mention it, for it is truly one of the finest, easiest, four-season perennials there is. No garden should be without it in any season, but certainly not in Sept. and Oct. Enough said!
Besides these perennials, I'd love to talk about Heptacodium miconoides, a large shrub newly introduced from China, blooming in September with fragrant white flowers followed by showy red sepals that persist for weeks, and attractive exfoliating bark. And Franklinia alatamaha, a small tree with white camellia-like blossoms against its brilliant scarlet foliage in the fall. Oxydendrum arboreum looks like it's still blooming in October, with pendant racemes of white seed pods against brilliant scarlet foliage. Clematis paniculata, invasive but glorious, fragrant, vigorous. And I haven't even mentioned the hardy annuals that peak in Sept. and Oct. Maybe that's next years' article...
