Crush a chartreuse leaf of the anise hyssop to get a whiff of licorice. (Morton Arboretum photo)
We often choose plants for fragrant flowers, from musky-scented roses to violets to sweet Korean spice viburnum. But leaves can also offer subtle and interesting scents, says Patrick Kelsch, horticulturist of the Fragrance Garden at The Morton Arboretum in Lisle.
Many are familiar: Basil, rosemary, oregano and thyme are as fragrant as they are flavorful. In the Fragrance Garden, Kelsch greets visitors with a bed of oregano, which has purple flowers above its scented fuzzy leaves. Further down the garden is a patch of low-growing thyme. Thyme often is planted to fill in between paving stones, he says, because it prefers sandy, gritty soil and because the scent wafts up from the leaves with every step.
Often foliage must be crushed to release a plant's scent; crumple a leaf of anise hyssop (Agastache foeniculum) to get a whiff of licorice. But the gray-green fuzzy leaves of catmint, such as Nepeta x faassenii 'Walker's Low,' are not so shy, launching their pungent aroma when you merely brush by, Kelsch says. Lesser calamint (Calamintha nepeta) has an aroma that is lighter and mintier, beneath a cloud of tiny white flowers that usually is buzzing with bees.
Many plants with strongly scented leaves, such as bee balm (Monarda didyma), are members of the mint family, Kelsch says. You can tell by feeling the stem; mint-family stems are square, not round.
Look to shrubs too. The leaves of Carolina allspice (Calycanthus floridus) have a spicy fragrance when crushed, to go along with the sweet smell of the (usually) red flowers. The arboretum has a cultivar called 'Athens' with yellow blooms. Then there's spicebush (Lindera benzoin), an aptly named, shade-tolerant native shrub.
Fragrance is not usually the first thing we think of when choosing plants. But once you realize the possibilities of seeking out fragrance as well as color in the garden, Kelsch says, "it really informs all your plant selection."
Beth Botts is a staff writer at The Morton Arboretum in Lisle (mortonarb.org).