Fragrance in plants is the quality that excites the nose, creating an even greater interest in plants and adding a new dimension to growing them. However, the purpose of scent in plants is not to attract human admirers but to encourage the presence of pollinating insects.
Nature and Scents
Scent plays an important role in attracting insects to flowers to carry out pollination, but it is not the only way in which plants attract pollinators. Subtle variations in petal color, which we may not even notice, frequently attract specific insects.
There is different sensitivity to colors. For instance, blue strains of Delphiniums in Britain are pollinated by bees, whereas in North America red Delphiniums are pollinated by humming birds.
But scent is of importance in attracting insects to flowers, and some insects, such as moths, have an acute sense of smell. For instance, some moths can detect Honeysuckle at several hundred yards, and honey bees can detect a wide range of odors. In tests it has been shown that they are able to distinguish certain scents from forty or more others.
Although color is an important guide to a flower, it is the scent which is useful in enabling a bee, when flying among many flowers of a similar color, to alight on the one it wishes to visit.
The appeal of a particular scent to a bee is often only temporary, because the bee needs to pass on to the next group of plants in bloom — and is attracted by a different scent as the seasons change.
Scented Patio Walls
During warm summer afternoons and evenings, fragrant plants will create an exciting dimension to patios. The climbers such as Honeysuckle, Jasmine and the Mountain Clematis (Clematis montana) are superb for clothing trellises around patios. And Wisteria brings a rich vanilla aroma.
Many climbing or rambling roses soon smother walls with scent and color, and on a warm south— or west-facing patio the pineapple-scented Cytisus battandieri creates a wonderful display of yellow flowers.
Window-boxes under windows can be made to create a mixture of day and night scents by planting them with a combination of the Night-scented Stock and Virginian Stock. The fragrant Tobacco Plant and the musk-scented Common Mignonette (Reseda odorata) will also help to drench the air with rich and delightful scents.
Types of Flowers — the Insects They Attract
The reproductive parts of many flowers show that the evolution of insects and flowers, especially in those flowers that are a source of honey, must have occurred simultaneously.
As well as scent and colour, the shape of a flower influences the type of insect that pollinates it. Insects such as butterflies and moths, which have long tongues, can reach nectar deep in the tubes of certain flowers — as in Aquilegias for example.
Night flying pollinators are especially attracted by scent. The Moss Campion (Silene acaulis) is visited by butterflies, whereas the highly fragrant night-flowering Bladder Campion (Silene vulgaris) attracts night-flying moths and long-tongued bees. Other sweetly-scented and night-flowering plants include Night-scented Stocks (Matthioki bicornis), Evening Primroses and Tobacco Plants.
Fragrant Plants for Indoors and Conservatories
- Cape Jasmine (Gardenia jasminoides) bears white, waxen flowers with a heavy and sweet scent from mid to late summer.
- Cyclamen (Cyclamen persicum) creates delicate and sweet fragrances from late autumn to early spring.
- Common Hyacinth (Hyacinthus orientalis) has sweet flowers from midwinter to late spring.
- Persian Violet (Exacum affine) has flowers with a Lily-of-the-Valley scent from mid to late summer.
- String of beads (Senecio rowleyanus) is a trailing plant that bears sweetly-scented white flowers from late summer to early winter.
- Wax Plant (Hoya camosa) is a climber with penetratingly sweet flowers from late spring to late summer.
- Miniature Wax Plant (Hoya be/la) I&a miniature climber that bears sweet flowers from spring to late summer.
- When growing roses in tubs always choose a specimen with a rich fragrance.
- Madagascar Jasmine (Stephanotis floribunda) is a climber that reveals strongly sweet flowers from late spring to early autumn.
- Pink Jasmine (Jasminum polyanthum) is a climber with sweet-smelling flowers that blossom from mid-winter through to spring.
Scented Plants for Window-Boxes and Tubs
- Wallflowers (Cheiranthus cheiri) have a sweet scent from April to June.
- Sweet William (Dianthus barbatus) flowers during June and July.
- Siberian Wallflower
- (Erysimum x allionii) with sweetly-scented flowers from May to July.
- Bulbous Iris (Iris dandordiae) has a honey-like scent. I. Reticulata is violet-scented.
- Grape Hyacinth (Muscari armeniacum) creates a wealth of deep blue flowers during April and May.
- Roses of all kinds are loved for their perfume.
- Sweet Alyssum (Lobularia maritima) has white flowers with a scent like new-mown hay, June to September.
- Night-scented Stocks (Matthiola bicornis) bears dull lilac-colored flowers with a heavy and sweet bouquet during July and August.
- Ten-week Stocks (Matthiola incana) has clove-scented flowers from July to September.
- Tobacco Plant (Nicotiana) has highly fragrant flowers which bloom throughout the summer.
