Head of Horticulture, Sally Petitt, writes:
The appeal of a garden can vary greatly from one person to another. Keen horticulturists will be interested in individual plants; artists in the visual appeal; and casual visitors may be drawn to a calming atmosphere. But a good garden relies on much more than one individual aspect, and when combined, the senses of sight, touch, sound, taste and smell add much to a garden. For me it is hard to spend time in a garden without looking at the individual shapes, forms and colours and the resulting combination; running my hands through tactile swathes of grasses; listening to the gentle rustling of leaves in a breeze; taking a sneaky taste of freshly picked peas; or sticking my nose in a bloom for a fragrant hit. For many though, scent is the key to adding value to the garden, and while appealing to our senses it also helps attract a range of pollinating insects.
Why do flowers produce scent and why do some not?
Floral scent is tool used by many plants to attract pollinators or to deter predators, but not all flowers rely on scent for reproduction. Some, such as grasses and many trees, are wind-pollinated, so they don’t invest energy in making scent. Others attract pollinators using visual cues like colour, shape, or nectar guides. In some cultivated plants, human breeding for traits like bigger blooms has reduced or eliminated scent – especially in some modern roses and lilies.
While floral fragrance can be a delightful bonus when choosing garden plants, scent isn’t always appealing to humans. However, we’ve long enjoyed its benefits. Many plants, especially those from the Mediterranean have scented leaves and stems, and while this scent can be attractive to us, it can be a deterrent to animals which might otherwise regard the plant as a food source. When crushed, plants such as lavender, mint and thyme release a scent, which can also be released in rain and in hot weather to fill the air.
Some plants rely on floral fragrance to attract insects to ensure pollination and the production of seed. Roses are perhaps the most familiar scented flower with many varieties producing appealing fragrances including fruity, tea, myrrh and musk, but a range of trees, shrubs, perennials, annuals and climbers also produce scented flowers. Some plants have adapted to ensure that their peak of appeal is greatest when a specific pollinator is likely to be present. In its native range of Asia, Jasminum officinale (Jasmine) produces scented flowers in the evening to ensure it attracts hawk moth pollinators. Many co-dependencies exist between plants and animals, with one of the most well-known relationships of this kind existing between Darwin’s orchid (Angraecum sesquipedale), whose flowers only release a scent at night to attract a particular hawkmoth (Xanthopan morganii var. praedicta) to pollinate the flower while feeding on the nectar. And of course, some plants, such as our celebrated titan arum (Amorphophallus titanium), smell particularly unpleasant to us, but highly desirable to pollinating gnats and flies.
Adding scent to your garden
It can be easy to bring scent to your garden, and while you may not wish to have a dedicated Scented Garden as we do here at the Botanic Garden, careful selection can provide a succession of fragrance through the year.
Scented plants such as Daphne bholua ‘Jacqueline Postill’ add scent as well as welcome flower during the winter. In summer a mixed planting of herbaceous perennials and roses can bring a romantic look to the garden, but add scented roses such as Rosa ‘Madame Hardy’ or ‘Dannahue’ and your garden will be transformed to a completely different level. A single lavender (Lavandula) beside a path can fill the air with fragrance if brushed as you walk past it, and tobacco plants (Nicotiana sylvestris) will pump out evening fragrance. Additionally, scented plants such as geraniums Pelargonium ‘Pink Capitatum’ , P. tomentosum or scented blooms of Dianthus ‘Mrs Sinkins’, will attract a diverse range of beneficial insects including butterflies, moths and bees to your garden.
As well as successional planting to ensure year-round fragrance, clever design can enhance the impact of scent in a garden. Here at the Botanic Garden, our Scented Garden is set in a gentle hollow to trap and concentrate fragrance, with raised beds to allow visitors to appreciate the plantings at close hand. At home, consider positioning scented plants around patios, doorways or seating areas where their fragrance can be easily enjoyed as you relax or entertain.
No matter how large or small your garden there is always space for a touch of fragrance!
Top scented plants
- Lavandula ‘Hidcote’: A bushy dwarf shrub with fragrant silver-grey foliage and spikes of purple flowers. A must-have for a hot, sunny spot.
- Sarcococca confusa (sweet box):an evergreen shrub reaching 2m in height whose cream-white flowers fill the air with fragrance in the New Year.
- Lonicera periclymenum ‘Serotina’ (honeysuckle): a climbing plant which will scramble over fences and arches and produce highly fragrant, pink and red, tubular flowers.
- Lathyrus odoratus cultivars (sweet peas): highly fragrant annual climbers with pea-like flowers in a range of pastel shades, requiring regular picking to encourage new flowers.
- Nicotiana alata (flowering tobacco plant): an easy annual suitable for borders and pots whose flowers will fill the evening air with heady fragrance.
Gardening jobs for July
- Continue deadheading perennials and roses, but also tender perennials such as Dahlias and annuals to encourage flowering.
- Keep container plants and new plantings watered with water from a water butt or grey water, but don’t worry about your lawn – it will recover.
- Cut back and feed hardy geraniums after the first flush of flower – this will encourage another flush of flower later in summer.
- Keep harvesting early vegetable crops to enjoy yourself, but also to encourage further cropping.
This piece was originally written for Cambridge Edition magazine.
