William Shakespeare brought out the romantic in us all, but actually there are practical reasons why plants smell glorious.
When you are rooted to the ground like a plant, emitting scent is a clever way of communicating.
A fragrance can often be noticed long before we see the plant.
Plants have evolved to co-exist with insects and other animals. Scent is one method they use to improve their chances of survival.
Many different plant parts may be scented.
Most noticeable to us are flowers and foliage.
However, fruit, fruit skin (lemon), bark (cinnamon), roots (ginger), flower buds (cloves) and seeds (mustard) may also be fragrant.
Flowers are colourful and fragrant to attract the attention of pollinators such as birds and bees.
Leaves contain aromatic compounds that may either encourage visitors to pollinate flowers and help with seed dispersal or else repel potential browsers.
Plants create fragrance by producing volatile organic compounds in specialised structures.
Potent essential oils may be contained in minute glands on or within the plant. Fragrant plants are displayed en masse in the lower botanic garden theme gardens.
Oil glands can easily be seen on plants from the Rutaceae or rue family. Plants in the rue family include citrus, lemon, grapefruit, oranges, ornamental Mexican orange blossom (Choisya ternata) and New Zealand native mairehau (Leionema nudum).
Nocturnal pale or white flowers heavy with fragrance attract moths at night. Plant names may indicate those which will oblige your sense of smell as well as sight, for example names which include "citriodora", "fragrans", "odoratus" and "fragrantissima".
In warm calm conditions the air around the fragrant border is heavy with perfume.
Plenty of seating and formal lawns create a perfect summer picnic spot.
Marianne Groothuis is curator of the camellia and theme collection at Dunedin Botanic Garden.
