Sourwood (Oxydendrum arboreum) silhouetted against River Birch (Betula nigra). Miss KIm Lilac and Golden Child English Ivy in the forground. Photo by: I. Hemiingway

Fall Foliage Color: Mother Nature’s “Last Hoorah!” 

There’s no question that autumn in New England is a beautiful time of year.  At its best, the foliar show is spectacular.  In most years, mild, dry days, and cool, crisp nights yield a world radiant with hues of golden yellow, sun orange, and fiery red leaves, silhouetted against the cool green of evergreen and lawn and a cloudless, azure sky.  Wet years, like the current one, can mute and delay fall color, but are still lovely. 

In the Northeast U.S., including my home here on Cape Cod, woody, deciduous trees, shrubs and vines, and herbaceous perennials provide the lion’s share of the autumn show.  As the days shorten and temperatures become cooler, these plants begin to prepare for winter by withdrawing nutrients from their leaves to be stored in the roots or bark. Then, through the process of abscission (leaf drop), the flow of water and nutrients (sap) between the root and the leaf is cut off.  Specialized cells in the abscission zone swell, damming the vascular tissue and stopping the flow of sap.  In woody plants, the abscission zone is located where the leaf petiole meets the stem; in most herbaceous perennials, it is located where the leaf meets the crown of the plant.

Orange-red Japanese Maple ( Acer palmatum 'Oshio beni') really "sings" in the fall when contrasted with American Beech and Cosmopolitan Miscanthus. Photo by: I. Hemingway

Chlorophyll, the photosynthetic chemical responsible for the green color of leaves, is unstable and must be consistently replenished during the growing season. When the supply of nutrients is cut off in the fall, the chlorophyll that remains in the leaf begins to break down, and the green color of the leaf gradually disappears.  Carotenoids, which are pigments that are responsible for yellow, orange, and brown leaf color, are more stable. While carotenoids are present in the leaf during the growing season, they are partially, or fully, hidden by the chlorophyll, and only become fully visible once the chlorophyll is gone.  Anthocyanin, the pigment that produces purple and red colors, forms when concentrated sugar is trapped in abscising leaves, and is then exposed to bright sunlight and cool temperatures.   As light, moisture, temperature, and nutrient levels vary, the intensity and quality of fall color will likewise vary from year to year, from location to location, within a species, or even within an individual plant.

When designing your home landscape, it is easy to overlook the contribution that plants with good fall foliage color can make.  Flower color has a tendency to dominate ones thinking.  But setting aside a portion of your home landscape for plants that produce fall color will give you years of pleasure in a season when flower color is minimal. When designing a home landscape, a good rule of thumb is to use about one half to two thirds evergreen plants (a combination of both broadleaved and needled), and one third to one half deciduous and perennial flowering plants with fall color potential.  The following list includes some of the best plants for fall foliage color for your consideration.

Trees:  Red Maple (Acer rubrum), Sugar Maple (Acer saccharum), Japanese maple (Acer palmatum), American Beech (Fagus sylvatica), Heritage River Birch (Betula nigra ‘Heritage’), Whitespire Birch (Betula populifolia ‘Whitespire’), Franklinia (Franklinia alatamaha), Gingko (Ginko biloba), Carolina Silverbell (Halesia carolina),  Smoketree (Cotinus coggygria), Katsura (Cercidiphyllum japonicium),  Redbud (Cercis canadensis ), Serviceberry or Shadblow (Amelanchier canadensis), Black Tupelo (Nyssa sylvatica), Flowering Dogwood (Cornus florida),  Kousa Dogwood (Cornus kousa),  Sourwood (Oxydendrum arboreum), Bradford pear (Pyrus calleryana ‘Bradford’),  Red Oak (Quercus rubra), Scarlet Oak (Quercus coccinea), Sassafras (Sassafras albidum),  Japanese Stewartia (Stewartia pseudocamellia), Sweetgum (Liquidambar styraciflua), Japanese Zelkova  (Zelkova serrata).

Shrubs:  Red Chokeberry (Aronia arbutifolia), Bloodtwig Dogwood (Cornus sanguinea), Vernal Witchhazel (Hamamelis vernalis), Virginia Sweetspire (Itea virginica), Purple-leaf sand cherry (Prunus x cistena), Dwarf Fothergilla (Fothergilla gardenii), Fothergilla (Fothergilla major), Oakleaf hydrangea (Hydrangea quercifolia), Staghorn Sumac (Rhus typhina), Spirea (Spirea spp.), Lowbush blueberry (Vaccinium angustifolium), Highbush blueberry (Vaccinium corymbosum), Arrowwood viburnum (Viburnum dentatum), and Blackhaw Viburnum (Viburnum prunifolium).  Note:  Burning Bush, aka Winged Euonymus (Euonymus alatus), likely the best known and most widely sold shrub for its fall foliage color, is now on the Mass. Invasive Plant Species List and is illegal to distribute or sell in this state.  Birds feed on the red fruit and have spread the plant throughout natural areas, where it is out-competing important native plants. Two great native substitutes, which have exceptional fall foliage color, are Highbush Blueberry and Virginia Sweetspire.  

Leaves of Japanese Stewartia (Stewartia pseudocamellia) in autumn. Photo by: I. Hemingway

Vines:  American bittersweet (Celastrus scandens), Virginia Creeper (woodbine) (Parthenoccissus quinquefolia), Boston Ivy (Parthenocissus tricuspidatus), and Purple-leaf Grape (Vitis vinifera ‘Purpurea’).

Herbaceous Perennials:  Blue Star (Amsonia), Balloon Flower (Platycodon), Hardy Cranesbill (Geranium), Leadwort (Ceratostigma plumbaginoides), Stonecrop (Sedum), woodland shade ferns: (Athyrium spp.), Cinnamon Fern  (Osmunda cinnamomea),  Bracken Fern (Pteridium aquilinum), Sensitive Fern (Onoclea sensibilis),  and Royal Fern (Osmunda regalis), Barrenwort (Epimedium spp.),  Plantain Lily (Hosta), Monkshood (Aconitum),  Peonies (Paeonia),  Bloddy Cranesbill (Geranium sanguineum),  ornamental grasses:  Switchgrass cultivars (Panicum),  Flame Grass (Miscanthus sinensis var. purpurescens),Maiden Grass cultivars  (Miscanthus sinensis ’Adagio’ and ‘Gracillimus’,  Indian grass (Sorghastrum nutans), Little Bluestem (Schizachyrium scoparium), and Dwarf Fountain Grass (Pennisetum alopecuroides ‘Hameln’,  ’Coral Bells (Heuchera).

"Enjoy Autumn while it lasts". Winter on at our Cape Cod home. Photo by: T. Hemingway

I hope that you include some of these wonderful plants in your home landscape and increase your enjoyment of Mother Natures “last hoorah” before the winter season sets in.