Look Down for Fall Color

It’s been a slow and stately progression through the season here in the Hudson Valley; the weather and the leaves have changed gradually but surely, and we finally had a real killing frost here just last week. Always a beautiful time around here, and many people claim it as their favorite season, despite the danger of being run down by busloads of eager leaf-peepers on the back roads of New York and New England.
 
The trees are so spectacular that no one really grouses about the lack of flowers in the garden, although there are a few hangers-on… Asters, Chrysanthemums and Aconitums are three that come to mind. But it’s not about flowers just now. The perennial garden is taking its turn towards being a study in texture and monochrome… the gradual annual transition from a painting to an etching.
 
Still, there’s abundant color among herbaceous plants that we can note for future exploitation… why not plant for appeal at this time of year, as well as for the peak bloom periods? We’re often advised to choose trees and shrubs for more than one season of interest, so why not perennials too? If, for example, out of twenty similar pink Astilbe cultivars on the market, one of them has outstanding fall color, why would I not choose that one?

Case in point is this Astilbe cultivar, ‘Delft Lace’, which bears delicate, somewhat open sprays of warm pink flowers in June and clean, deep green foliage all summer in the ferny texture that Astilbes are known for. If that’s not enough, it’s deer-proof and fairly weed suppressing once established. Then for an added bonus, when temperatures cool it takes on mottled shades of pink, red, gold and coral, varying somewhat every year. Now that’s a perennial that pays its way.

Another Astilbe for multi-season interest is this dark foliaged variety, ‘Chocolate Shogun’… it holds the deep maroon color all season and the flowers are a pleasing creamy blush that blends well with everything, then age to these beautiful bronze seed heads.

Most years it turns glowing shades of red in autumn. One note of caution:  I have several plants from three different sources and they aren’t all the same. They all have the deep purple foliage but those that bloom with creamy flowers (not a definite pink) are the only ones that bear the bronze seed heads.

The true, or hardy Geraniums are a vast tribe that includes many types that color up nicely in fall. This is the unpronounceable Geranium wlassovianum, the Siberian Cranesbill, a workhorse for damp soil in sun or semi-shade.

Siberian Cranesbill blooms pinkish lilac on trailing stems that grow rapidly from a central crown to weave among other perennials in an attractive way, and as its origin suggests, it’s absolutely bone hardy.

Another Geranium workhorse that has reliable fall color is the unbeatable groundcover Geranium macrorrhizum, the Bigroot Geranium. There are several forms with flower color ranging from white to magenta… this is ‘Ingwersen’s Variety’, an oldie but goodie with flowers of a nice strong bubblegum pink.

Still flowering here as late as last week is the almost ever-blooming Geranium hybrid ‘Rozanne’, shown here weaving herself among the foamy pink inflorences of the Purple Love Grass, Eragrostis spectabilis. It’s a native grass that’s common on roadsides around here, and it’s being incorporated into plantings more and more often. Not much to look at in the foliage department, but the clouds of pinkish purple bloom are stunning when they have the right setting.

Another small scale grass that ends the season with style is the Japanese Forest Grass, Hakonechloa macra. All its varieties are graceful and elegant throughout the year, but some of them have particularly nice fall color, like ‘Nicolas’, shown above.

The lime green variety, Hakonechloa macra ‘All Gold’, is the fastest growing cultivar (that’s relative) and bleaches to a pleasing shade as the season winds down, while still retaining its pendant, willowy form.

At the other end of the scale are some very large, sculptural grasses that color up well. Molinia caerulea, the Purple Moor Grass, has an upright vase-shaped form that lends itself to being used as an eyecatching feature in mixed perennial plantings. There are several good cultivars on the market, and I particularly like ‘Skyracer’ for its height and see-through habit. Add to that a lovely greeny-gold autumn hue and you have a real winner.

Even larger is the Giant Sacaton, Sporobolus wrightii  ‘Windbreaker’. This selection of the southwestern states native is hardy here in Zone 5 and makes a graceful mound of foliage topped in late summer by 6-8 foot plumes that age to tawny gold.

One of the best pairings for larger grasses is with the Arkansas Blue Star, Amsonia hubrichtii. It’s a terrific plant, native to the Oachita Mountains of Arkansas but perfectly reliable here in the northeast, providing one of the best displays of fall color by any perennial. As frost approaches, the finely textured foliage takes on shades of lime green, coral and violet.

Then it becomes a dramatic mass of bright golden yellow that’s unequalled among herbaceous plants.

The fall color is enough to warrant growing it, but it’s equally fascinating in May, as the curious clusters of sky blue flowers unfurl like some undersea creatures.

Stems and stalks can provide fall color just as well as leaves, as in these pinkish purplish branches of the Marsh Spurge, Euphorbia palustris. It’s another plant I like to use alongside large grasses to provide a foliar contrast in average to moist soils.

I love its refreshing blast of acid yellow flowers in late spring, an antidote to all the pink and lilac that’s everywhere that time of year.

In summer, the Marsh Spurge features interestingly textural seed heads and mounds of clean, medium green, deer-proof foliage that makes unobtrusive filler as other plants take the spotlight.

And making the case that it’s a four-season performer, the desiccated winter stems curl inward to form an intricate, wiry sculptural sphere.

Another Euphorbia that’s colorful all year is the much smaller Euphorbia polychroma ‘Bonfire’. A bit tricky to establish, and often not a permanent resident, but if you can succeed with it you’ll be rewarded by season-long shades of burgundy and ruby red, and as the frost comes, subtle overtones of lavender and violet.

Epimediums are one of my favorite groups of perennials. I love them for their dainty early spring flowers and their beautiful foliage that smothers most all weeds. Not all of them color well in the fall, but I’m gradually learning which ones do… like ‘Purple Prince’ (above), which mutates through shades of caramel and peach as autumn progresses. 

Two more good choices are Epimedium rubrum (left), sporting fresh pink flowers in spring, and the hybrid ‘Freckles’ (right) with dappled leaves that turn a solid bright orange.

Lavender and purple aren’t colors I usually associate with fall, but this Agastache ‘Blue Fortune’ was, I thought, quite decorative after being touched by a couple of light frosts.

More lavender and silvery grey shadings in these seedheads of Liatris ‘Floristan White’, the beautiful Korean Feather Reed Grass (Calamagrostis brachytricha) and the towering domes of Eutrochium dubium ‘Baby Joe’, a trio that thrives in full sun and damp to wet soil.

Don’t forget that green is a color too, and like pines and hemlocks growing among flaming oaks and maples, the deep green of Hellebores provides a satisfying counterpoint to the brighter colors of surrounding perennials and grasses.

Sometimes the lowliest plants can offer a real color blast as temperatures turn chilly. This Sedum rupestre ‘Angelina’ sports chartreuse foliage all summer that flames into shades of gold and orange in the fall.

So why lament the lack of flowers in October and November when there’s so much color and texture to hold our attention?… not only from our spectacular tree foliage but from ordinary garden perennials, if we only care to observe. Above, clockwise from upper left, Cinnamon Fern, Coreopsis tripteris, Persicaria ‘Firetail’ and Gillenia trifoliata all make a contribution to the fall garden.
 
Observe, appreciate, rethink. Allow the plants to be plants, and savor the full cycle of growth, maturity, decline and decay. As snow arrives this week, I’m enjoying the garden in the moment, but already starting to dream ahead to another year of renewal and replenishment. I hope I’ve given you some ideas for plants that generously offer more than a fleeting moment of beauty. And I hope you’ll try some of them, next year and in seasons to come.