The wonderful garden aroma

In the Garden
Ralph Purkhiser, Purdue University Master Gardener

     Scientists say the sense of smell is closely connected with the part of the brain where memories are stored.  That plays a big part in the way we experience our gardens through the sense of smell.  I have had numerous people who have asked me where to get starts of specific roses that their mothers or grandmothers grew.  At Sandhill Gardens, I have a pink old-fashioned shrub rose that has an intoxicating scent.  That rose was planted by my grandmother, Bertha Hooten, in the 1920’s.  Nearly all of my cousins have taken starts from that rose over the years, as it is a direct connection with their childhood memories.
     No scent is more prominent in the garden than the scent of lilacs.  I still have four old syringus vulgaris, or common lilacs, which my grandmother planted here nearly a century ago.  However, the scent of the other lilacs that I have added over the decades is very similar.  By having so many different species and varieties, I can make that scent and its connected memories linger for a couple of months.
     I also have a garden scent that connects me with my other grandmother.  Ada Purkhiser was not one to grow many flowers, but her spice cakes were legendary.  While visiting the Louisville Zoo several years ago, I caught the scent of a spice cake.  Actually, it was the blooms of the Korean spice viburnum.  I knew right then that I had to add that scent to my garden.  It is one of the earliest scented shrubs of the spring and the blooms and scent lasts for about three weeks.
     There are many other trees, shrubs and herbaceous plants which bear scented flowers, each triggering its own memories.  Peonies, daffodils, magnolias, mock oranges and all spice keep the scents going in the garden.  As with the pleasure of different textures, these scents stimulate the olfactory receptors of my blind friends, allowing them to enjoy yet another aspect of my garden.
     Of course, the real reason that flowers have scents is to attract their specific pollinators.  The scents guide the insects, birds and bats to the nectar, and the process results in the transfer of pollen to other blooms.  Some of the sweetest scents are stronger at night in order to attract bats and moths.  Not all scents are necessarily pleasant to most humans.  Some plants are pollinated by flies and emit the scent of rotting flesh to attract the flies.  I usually plant such specimens in out-of-the-way locations, but, I must admit, I have had a lot of amusement in getting visitors to sniff the offensive scent of the giant dragon arum flowers.  
     Not all garden scents come from flowers.  Many plants have foliage that holds scents.  The native spice bush leaves release a spicy smell when disturbed.  Many herbs also release essential oils when touched.  It is important to place such plants in areas where they will be touched, if only just brushed as we pass through the garden.  I cannot help myself when I pass rosemary plants.  I have to rub my hands on the foliage to get one of my favorite scents, and the oils linger on my hands for hours thereafter.
     Of course, there are many other scents that are experienced in a garden.  Soil will yield a scent when disturbed, especially when wet.  Freshly-mowed grass is a scent that evokes a lot of memories.  Even the scent of fertilizers may trigger some memories.  Another of my favorite scents is the smell that lingers after a thunderstorm.  That scent is caused by ozone produced by lightning, and makes one think of something that is very clean.  Good or bad, the scents are part of the total experience of the garden.  A gardener should make a conscious effort to ensure the scent of the garden welcomes visitors.