Lee Valley & Veritas Gardening
Lee Valley 35 Years  
  Volume 8, Issue 5 - May 2013    
The Sweet Smell of Garden Success
The sweet-smelling rose
There are few garden scents that can compare to that of a rose. (Photo by E.K. Bowell)
When selecting scented plants, it's important to think beyond just bloom fragrance. Other plant parts can also provide lasting aroma, such as foliage (lavender), bark (sassafras), roots (wild ginger) and berries (bayberry shrub). Some plants boast a combination of scents. Carolina allspice (Calycanthus floridus), for example, has strawberry-scented flowers and allspice-scented foliage and bark. As scent preference is strictly personal, I have avoided describing the fragrances of suggested plants; instead, I leave it to the reader to decide. Keep in mind that floral scent varies according to the time of day, weather and condition of the plant.

Situating Scented Plants
Aromatic plants make the strongest impression when placed strategically in the garden. Consider planting a fragrant shrub along the front walkway to provide a pleasant welcome to visitors and home dwellers alike. I like Carol Mackie daphne (Daphne burkwoodii 'Carol Mackie'), Oregon grape (Mahonia aquifolium), Korean spice viburnum (Viburnum carlesii) or Snowbelle mock orange (Philadelphus 'Snowbelle'). At the front entrance, a sweetly scented, hardy vine, such as variegated kiwi vine (Actinidia kolomikta), trained to a wall or porch post provides a lovely fragrant greeting. If you like to enjoy outdoor fragrance inside the house, place a scented plant next to your home's foundation below a window that can be opened. To add cheer to a shady, damp or confined side yard, I've used large clumps of the very fragrant autumn lily (Hosta plantaginea) combined with shield ferns (Dryopteris spp.) for foliage and blue camas (Camassia spp.) for color. Also, a notably fragrant tree placed in a side yard makes a good focal or pivot plant. Some to try are fringe trees (Chionanthus virginicus), Red Jade crabapples (Malus 'Red Jade') and star magnolias (Magnolia stellata).
Highly fragrant hyacinthHighly fragrant hyacinth
The scent of highly fragrant hyacinths is pleasurable to many but overwhelming to some.
Naturalized along pathways, fragrant hyacinths, dwarf irises (Iris reticulata), muscari, striped squills (Puschkinia scilloides) and cyclamineus daffodils are charming. Furthermore, low-growing plants such as thyme (Thymus spp.), sweet woodruff (Galium odoratum), sweet alyssum and Roman chamomile (Anthemis nobilis) emit scent when crushed by the foot traffic. Plants that release scent when their foliage is brushed against further contribute to the garden experience. Examples include wormwood (Artemisia spp.), sage (Salvia spp.), yarrow (Achillea spp.) and lavender. In perennial and mixed borders, well-established roses such as Father Hugo (Rosa hugonis) and the newer Austin roses both work well. I also favor edging and filler shrubs such as slender deutzia (Deutzia gracilis) and lilacs (Syringa vulgaris). The popular and highly dependable scented daylilies 'Hyperion', 'Stella d' Oro', 'Silent Star', 'Fragrant Treasure' and oriental lilies 'Stargazer' and 'Starfighter' along with 'Sarah Bernhardt' peonies all make their presence smelt when placed in a border.

Woodland gardens offer many opportunities to incorporate aromatic trees, shrubs and wildflowers. Enjoy the subtle fragrance of winter hazels (Corylopsis pauciflora) and Chinese witch hazels (Hamamelis mollis) in early spring, followed by fothergilla species, with their fragrant, white bottle-brush-like flowers and summersweet shrubs (Clethra alnifolia) later in the summer. The spectacular, scented Northern Lights azaleas used as accents in part shade along path edges and at entrances and exits are lovely. Also consider woodland phlox (Phlox divaricata), fall-blooming bugbanes (Actaea spp.) and vines such as climbing hydrangea trained on tree trunks.
Sweet autumn clematisSweet autumn clematisSweet autumn clematis
As its name implies, sweet autumn clematis emits a charming scent.
The confined nature of courtyards, walled gardens, patios, porches and balconies creates reflected heat and light, thereby intensifying plant aroma. Fragrant vines such as honeysuckle (Lonicera spp.), chocolate vine (Akebia quinata), wisteria and various clematis can be trained on surrounding trellises, lattices and pergolas. Scented standards such as Miss Kim dwarf lilac (Syringa pubescens subsp. patula `Miss Kim'), along with planters and hanging baskets filled with aromatic herbs, heliotropes, marigolds and nasturtiums, can be moved around for best effect. Scented night-blooming plants can make a sitting area into a romantic retreat. Try night-scented phlox, pale evening primrose (Oenothera pallida), flowering tobacco (Nicotiana alata) and scented white and purple petunias

Additional Benefits
The foliage and nectar-rich flowers of fragrant plants attract both butterflies and bees to the garden. Butterflies are particularly attracted to lilacs, spicebush (Lindera benzoin) and Dutchman's pipe vine (Aristolochia durior). Add in some parsley, dill, sage and fennel to provide a smorgasbord for butterflies. Aromatic, nectar-rich plants include butterfly bush (Buddleja spp.), honeysuckle and swamp milkweed (Asclepias incarnata). Annuals and perennials with good landing-strip-type petals are coneflowers (Echinacea spp.), wallflowers (Cheiranthus spp.), dame's rocket (Hesperis matronalis), phlox (Phlox spp.) and bee balm (Monarda didyma). Additionally, many of the night-blooming plants are moth pollinated.
Swallowtail butterflySwallowtail butterflySwallowtail butterfly
A nectar-seeking swallowtail butterfly is attracted to the lovely lilac flowers.
Selecting Scented Plants
Before purchasing scented plants, determine when they are likely to bloom in your area, for how long and at what intensity. This will help you determine what you need to maintain a fragrant garden throughout the growing season. Determine each plant's ideal habitat and required maintenance for its optimal health and persistence. Some fragrant plants, such as marigolds, sweet pea and heliotrope, benefit from deadheading (the removal of spent flowers) to preclude seed formation and to prompt repeated blooming. To avoid disappointment, study the plant labels to ensure the cultivar or hybrid you are buying is the scented one. If possible, buy plants when they are in full bloom so that you can confirm their fragrance. Also, knowing when to prune fragrant shrubs is vital to avoid removing flower buds. Generally, shrubs that bloom in the spring flower on the previous year's wood and are best pruned after they flower. Later summer and fall-blooming shrubs that flower on the current year's wood are best pruned in early spring.

Depending on your selections, some plants are better planted alone rather than in combination with others as mixed scents can be unsettling. Also, plants such as woodland phlox are so delicately scented to my nose that I have to rely on large clump plantings to be able to detect the fragrance. Others just have an unpleasant smell. The seed pods of the female maidenhair tree (Ginkgo biloba), for example, have a rather fetid odor when stepped on. The simple solution is to buy the male seedless clones. Others that evoke turned-up noses from some are the sweet scents of hyacinths and paperwhites, and the somewhat pungent foliage of stinking hellebore (Helleborus foetidus), skunk cabbage (Symplocarpus foetidus), ornamental onions (Allium spp.) and boxwoods. Keep in mind that some of the highly scented plants are poisonous, so awareness and careful siting is of utmost importance.

Scented plants offer many benefits to both gardeners and pollinators. They can also add a new and exciting dimension to your garden. Try a few and enjoy the fragrance all season long.

Text by Frank Kershaw

Photos by Marnie Wright

Frank Kershaw is an award-winning horticulturist with thirty-five years' experience. He teaches garden design and horticultural courses at George Brown College in Toronto, Ontario, and at the Toronto Botanical Garden. Frank is also a presenter at the Lee Valley Tools seminars at the Toronto stores.

Marnie Wright (gardenwright@muskoka.com) is a lifelong gardener, writer and passionate garden photographer. Her Rocksborough Garden, developed over thirty years, is located in Bracebridge, Ontario.
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