Gardens: a window sill plant that will fragrance your room for months

Not many plants look as ordinary as the one that grows in a small pot on my kitchen’s sunny window sill. Pressed to describe it, I could only say that its flowers aren’t particularly showy, its foliage isn’t especially handsome, nor is it possessed of an unusually attractive growth habit. But if I crushed a few of its leaves gently between my fingers and then waved them beneath your nostrils, I’d put money on you swiftly assuming a sweetly beatific expression similar to that of a small child given a large bagful of lemon bon-bons.Because scented geraniums – or scented leaf pelargoniums as they are properly known – have that sort of effect on people.

Depending on the particular species or variety (many of which have been in cultivation for hundreds of years), their intensely perfumed, evergreen foliage can conjure up memories of fistfuls of rose-flavoured Turkish delight, mint humbugs, zingy cola bottles or lemon sherbert. Others have leaves that smell strongly of orange, apple, strawberry, peach, apricot, lime, coconut, ginger, cinnamon or nutmeg.

Almost all are delightful when used in a pot-pourri , a herb pillow, or a bouquet, or to perfume bathwater, shampoos and massage oils. Some also play an important role in aromatherapy and perfumery; the foliage is so strongly scented that just a small group of plants is often enough to lightly perfume a room.

Plus, truth be told, I’m being a bit unkind about their flowers; although the variety that grows on my kitchen window doesn’t have especially decorative blooms, there are plenty, such as Pelargonium ‘Orsett’, that do. Better again is the fact that the aromatic foliage of many species/varieties (the important exception is Pelargonium crispum) can be translated into flavours in the kitchen and used to transform pies, puddings, soufflés, sorbets, breads, cakes and muffins.

They’ll also add punch to a fruit salad, zing to a homemade jam or jelly, and will richly infuse custard, ice cream, butter, sugar, punches, spirits (vodka, gin) or even vinegar with their fruity, floral or spicy tones. Some can be also be used to make a delicious herbal tea. Typically the fragrant leaves are used whole and then removed at a late stage in the cooking process after they’ve fully imparted their flavour, but some chefs are happy to use the youngest, most tender leaves, chopped very finely, as a permanent ingredient.

The variety that grows on my window sill, Pelargonium ‘Citriodorum’, is also known as ‘Queen of Lemons’ on account of its intensely aromatic, citrus-perfumed leaves. These are commonly used to add flavour to jellies, sorbets, ice creams, cakes (you can line baking tins with their leaves) or to make delicious lemonade. Its small pink flowers, which are also edible, appear in summer.

It’s just one of many scented geraniums with lemon-scented foliage; another excellent variety is ‘Mabel Grey’, a favourite of many pelargonium-loving gardeners, with deeply scented grey-green leaves and mauve flowers.

Of the many different rose-scented geraniums available, I grow Pelargonium graveolens, a large upright plant (up to one metre in height and spread) with pale pink summer flowers and rose-perfumed leaves that are widely used in cookery. But other rose-scented varieties well worth seeking out are Pelargonium ‘Attar of Roses’, and P ‘Lady Plymouth’ which has variegated foliage. Both are more compact than P graveolens, with an average height and spread of 30-60cm. For foliage with an intensely minty kick, grow the white-flowering Pelargonium tomentosum.

All of these scented-leaf pelargoniums, or scented geraniums as they are commonly known (despite its popular usage, the latter term is misleading as these plants aren't related to the true garden geraniums), will grow quite happily outdoors during the summer months as long as you give the plants a sunny, sheltered position and a free-draining compost. But come October and the threat of frost, they need to be brought under cover. If that sounds like too much fuss and bother, then these frost-tender semi-woody plants, which are of complex, often confused parentage but originate mainly from South Africa, are quite happy to spend their entire lives indoors.

Either way, to successfully overwinter them, you should give the plants a spot in a bright but not too warm room (near a south/west facing window is perfect), or in a frost-free glasshouse, porch or conservatory. Space them widely apart and only water sparsely over the winter months so that the compost is kept barely moist. Gently but regularly removing any yellowing leaves also helps keep plants healthy.

Come early spring, your scented geraniums will start back into growth, at which point you should trim them back, re-pot where required, and gradually increase watering. Once flowers appear in late spring, start giving the plants a weekly potash-rich liquid feed, regularly removing any blooms as they fade.

Nipping back growing tips in early summer will give you strong, bushy plants, which is exactly what's required, as once you get a taste for their deliciously scented foliage, every leaf will count.(For the widest selection of varieties, check out the specialist online nursery scentedgeraniums.co.uk, which delivers to Ireland. )