Scents and Sensibilities
ON QUIET FALL AFTERNOONS as Scott LaFleur works in his office at the New England Wildflower Society, he enjoys the sweet scent of trumpet honeysuckle (Lonicera sempervirens) through his open window. “Not only is the fragrance wonderful, the plants are magnets for hummingbirds, so I watch the little birds up close and personal,” says the society’s horticulture director.
While we often consider spring and summer months as the time to “stop and smell the roses,” the truth is fall provides an overlooked opportunity to enjoy the fragrance of the native garden. We asked experts in different locales to chime in on what native plants bring scent to their regions come fall. In Massachusetts, New England blazing star (Liatris scariosa var. novae-angliae) and black cohosh (Actaea racemosa) make the list. In the South: fragrant ladies tresses (Spiranthes odorata) shares its aroma, as well as Joe-Pye weed (Eupatoriadelphus spp.), with its fragrant blooms and vanilla-scented foliage. Texans have thorn-apples (Datura spp.), shrubby boneset (Ageratina havanensis) and chocolate daisies (Berlandiera lyrata) to thank for nice scents when temperatures finally fall.
Each time the Wildflower Center’s director of horticulture, Andrea DeLong-Amaya, gets a whiff of chocolate daisies blooming in fall at the Wildflower Center, she thinks of the “experience as a cheap, fat-free substitute for eating dessert.” Although it is true that there aren’t as many aromatic bloomers in autumn, there are still quite a few plants that offer a burst of fragrance, adds DeLong-Amaya. “Shrubby boneset (Ageratina havanensis), for instance, has musky-scented flowers, and daturas have a clean, tangy fragrance.”
When it comes to scent, natives are powerhouses. “Compared to non-native hybrids that are bred for traits like floral color and larger flowers, natives offer you a full fragrance experience,” says Pati Vitt, curator of the Dixon National Tall Grass Prairie Seed Bank at the Chicago Botanic Garden. “The prairie dropseed (Sporobolus heterolepis), for example, is a native grass that comes to seed in the fall, forming beautiful reddish-brown tussocks that smell like sweet kettle corn. The aroma is so strong it makes you hungry.”
Considering their powerful fragrance potential, incorporating aromatic natives into the garden adds an unforgettable dimension to the autumn landscape. “Fragrance in the native garden has the benefit of creating a full sensory experience,” says LaFleur. “Sight, touch and smell all come together to tap into emotions and trigger memories.” He is particularly fond of New England blazing star, which is loved for its open, airy appearance and light fragrance, and rudbeckias that have a light scent that smells like meadows. “Black cohosh is a beautiful architectural plant with white blooms and a deep musky aroma, and asters give some of the best late-season fragrance,” LaFleur says.
Aroma is often thought of as coming from flowers, but scent also originates in leaves, bark, fruit, seeds and roots. “Fragrance is more often the result of the plethora of chemicals found in the vegetative portions of the plant,” says Anne Lindsey, president of the North Carolina Botanical Garden’s Foundation Board.
Plant oils evaporate and the molecules are released into the air, which is what causes scent. There are many different essential oils found in the plant kingdom, and each plant has a mixture of compounds that make up its unique fragrance.
A wide variety of natives in the fall landscape have aromatic foliage such as Autumn sage (Salvia greggii) and Damianita (Chrysactinia mexicana). Damianita has a pungent odor up close that gets sweeter as you move away. There are minty-smelling plants such as mountainmint (Pycnanthemum spp.) and coyote mint (Monardella villosa). Lemon-scented selections include lemonscent (Pectis angustifolia) and lemon horsemint (Monarda citriodora). Other monardas known for their pleasing aromas are wild bergamot (M. fistulosa) and bee balm (M. didyma). And sweet goldenrod (Solidago odora) is known for its licorice-scented leaves. (Visit www.wildflower.org/plants to learn about the native range of these plants.)
In California, sages add a wide variety of fragrant foliage to the fall garden, says Stephen Morgan, curator of the University of California, Riverside Botanic Gardens. “All of the salvias are especially aromatic, including Salvia ‘Allen Chickering’ (Salvia clevelandii x S. leucophylla) and white sage (S. apiana).”
So that visitors can experience their scent, Morgan says, “During fall school tours of the botanic garden, we instruct children to bruise leaves of fragrant California natives such as the Catalina perfume (Ribes viburnifolium) and in small doses the California bay laurel (Umbellularia californica), the scent of which can be overpowering and give one a headache, especially on a hot day.”
Fragrant fall bloomers also serve wildlife. Scent attracts important pollinators like bees and butterflies that might not otherwise make it into the garden.
Solidago species are important to migrating butterflies, and the white turtlehead (Chelone glabra), with its mild perfume fragrance, is critical to the life cycle of the Baltimore checkerspot. Birds also benefit.
Considering the great number of creatures depending on your fragrant garden, it’s important to treat it well. “Understand that many of your fragrant plants are food sources, so don’t fight with the creatures that rely on them for life, but embrace and nurture them,” says LaFleur. “Avoid using pesticides and other chemical-smelling industrial products that will detract from the fragrance and kill the important pollinators they attract.”
Maximize fragrance in your garden by using drip irrigation rather than overhead watering so that the plants will be dry by morning, which is the time when nectar is released. Place plants in high-traffic areas where they will be brushed up against and touched unintentionally. Or position them at nose level close enough so that you can take a quick whiff, readily rub a leaf, or pluck a sprig or flower.
Allow fragrance to collect and linger by planting in courtyards, patios, atriums, outside of operable windows and near outdoor living areas. Also keep time of day in mind and realize that some plants, like daturas, have virtually no scent during daylight but emit their fragrant aromas come nighttime. Weather also will make a difference. Hot rays from the sun will heat up the volatile oils in plants like sage and perfume the outdoors. And the air inversion that occurs when the cooler air of nightfall hits the warmth from the day also can wake up some fragrances in the yard.
For best results, balance and layer. Avoid planting every fragrant fall native you can get your hands on, because the results can be overpowering and some scents don’t mix well. Combine plants with a high note scent with lower-key varieties. Some plants are so strong that you only need one in the landscape, while others are more subtle and require planting several in order to get a noticeable aroma.
“Sometimes it is not just picking one plant for its fragrance but understanding that a symphony of flora will produce a tingling of the senses that you may not be able to pinpoint but will create the sensory mood of autumn,” says LaFleur. “Meadows are a great example of this. Here on the East Coast, the asters, grasses, raspberries and milkweeds all come together to make a New England autumn. As you get into late fall and the leaves begin to drop and degrade, the smell is very intoxicating – emitting an earthy, natural fragrance that signifies the last blast before the sterile stillness of winter sets in.”
Author Julie Bawden Davis is a master gardener in California.