Birthday
HydrangeasTo us a fragrance feels like a gift, but for a plant it is a working tool. A flower cannot move, so it calls pollinators with scent, colour and nectar. Here is what floral scent is made of, and why some flowers smell by day, others at night and some not like flowers at all.
Fragrant bouquets delivered: peony-style roses and peony bouquets.
What scent is made of
A floral scent is a blend of volatile organic compounds — dozens, sometimes more than a hundred, in a single flower. The main groups are terpenoids (such as linalool and geraniol), benzenoid and phenylpropanoid compounds (2-phenylethanol in roses, methyl benzoate in snapdragons and petunias) and fatty-acid derivatives. What makes each scent unique is the balance of components, not one “key” molecule.
Petals are usually the main source: the compounds are made in their cells and evaporate from the surface. Evaporation is faster in warmth, which is why a flower bed smells stronger on a hot day than on a cool one.
Why plants produce scent
The main job is to attract pollinators. Bees learn a scent and link it to nectar, so they return to flowers of the same species. Many flowers release most scent when their pollinators are active: snapdragons by day for bumblebees; jasmine, tuberose, night-scented stock and flowering tobacco in the evening and at night for moths. After pollination, scent emission drops noticeably in some species, such as petunias — the invitation is no longer needed.
Not every flower smells pleasant to us. Titan arum and rafflesia smell of rotting meat to attract flies and beetles looking for somewhere to lay eggs. Scent compounds can also deter plant-eating insects and hold back microbes.
Why many roses smell less
Many cut-flower rose varieties have little fragrance. For a long time breeding focused on looks, bud strength and vase life, and scent was often lost along the way. Breeders are now bringing fragrant varieties back, especially among garden and English-style roses.
We have gathered the most fragrant plants for bouquets and gardens in the most fragrant flowers. If you put flowers on a dining table, choose lightly scented ones — see table flower decorations.
FAQ
Why does the same flower smell different to different people?
Smell perception is individual: it depends on each person’s set of olfactory receptors, experience and even how used they are to the scent.
Why does a garden smell stronger in the evening?
Many moth-pollinated plants release more scent at dusk, and still evening air holds the fragrance longer.
Are there flowers with no scent at all?
Yes. Plants pollinated by wind or birds have no need for a strong fragrance.
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Author: Maria Svitlovir
Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.
