Some petunias make good scents Sometimes the sweetest flower scents are found in unexpected blossoms. Petunias might not be first on the list when considering scented flowers; at best, many petunias have only a slight musky scent that wouldn’t be considered true flower fragrance. But some deeply perfumed petunias have been unexpectedly popping up in greenhouses and, be assured, your nose is not fooling you. Decades of petunia hybridizing has resulted in plants with a wide colour spectrum and diverse features – vivid bicolours, double-frilled petals, spreading ground covers, cascading waves for containers and neat mounds for edging. But no mention of scented petunias, especially those with enough perfume to be described as intoxicating. Yet sniffing your way down the greenhouse petunia aisle, you may find a petunia selection puffing out enough deep vanilla scent to cause swooning. What is this about? Early in the previous century, native white Petunia axillaris was selected from Argentinian highlands plants and bred with another native specie, violet P. integrifolia. Both species produce substantial amounts of volatile benzenoid chemicals that synthesize perfume in petals. Scent is a primary function of reproduction in flowers and P. axillaris uses its deep vanilla perfume to attract night-flying hawk moths; while P. integrifolia uses scent to attract pollinator bees in sunlight. Twenty-first century petunias are developed for their colour and form choices, with little focus on petal scent. But genes from those original Argentinian species are still floating around in modern petunias and causing some delicious perfumes to unexpectedly cast a cloud of vanilla through your patio and garden spaces. Any scented flower has its lowest scent potential in bright midday sun. But in cool morning hours and from late afternoon into darkness, petunias are sending their scent messages out to potential pollinators – and that could include you! When cruising garden centre aisles in cool mornings, it’s worthwhile taking a deep sniff of any petunias with dark purple, pale purple with dark veining, mauve, bicolours with white, and pure white flowers. These are the most likely to still retain errant perfume genes and you can look for them as box plants. Named varieties known to be scented are ‘Scentsation’, ‘Daddy Blue’, ‘Blue Storm’, ‘Madness Plum Crazy’ and ‘Prism Sunshine’. These are also available as seed and are easy to start indoors in late winter. Almost every form of petunia is adaptable to container planting, requiring a sunny location and consistent watering. Fertilize every two weeks for a full summer of beautiful flowers and, hopefully, dizzying scents. Gardening CSANews | SUMMER 2024 | 45
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