There are a lot of fragrant annuals but a few stand out as capable of adding a strong perfume to your garden or patio. Here is a list of strongly-scented flowers, some of which are perennials in the higher growing zones in North America:
List of Fragrant Annuals
Mignonette (Reseda odorata) – Strong scent of vanilla-raspberry from small slightly yellow flowers. Mignonette has the added benefit of attracting beneficial insects to your garden. Direct sow in early spring.
Petunia (Petunia) – The old-fashioned purple or white vining petunias have a strong lily-like scent at dusk, unlike their more modern hybrids.
Evening stock (M. longipetala) – Small lilac flowers with strong lily-like perfume. Evening stock are an excellent candidate for patio containers and window boxes.
Fragrant amaryllis (Clidanthus fragrans) – Yellow flowers resembling crocus bloom in mid-summer with a strongly sweet scent (perennial bulb in Zones 9-11).
Heliotrope (Heliotropium arborescens) – Large white or violet blossoms with a very appealing cherry-vanilla fragrance.
Flowering tobaccos (N. sylvestris, Nicotiana alata, N. suaveolens) – Tubular white flowers that are fragrant primarily in evening and at night. The hybrid bedding plant varieties, for the most part, have little fragrance.
Virginian stock (Malcolmia maritima) – Small purple or red blooms with a strong scent. Virginia stock prefers cool weather over the heat of the most southern states.
Night phlox (Zaluzianskya ovata) – As their name suggests, Night phlox are strongly fragrant at night and have unusual snowflake-shaped flowers.
Peruvian daffodil (Hymenocallis species) – Yellow or white spidery flowers bloom in summer, perennial in zones 8-10. The hybrid ‘Sulfur Queen’ is especially fragrant.
Four-O’clock (M. longiflora, Mirabilis jalapa) – Four-O’clocks are very popular because they are floriferous and fragrant trumpet shaped flowers. Mirabilis longiflora, in particular, is recommended for its white flowers and orange-blossom scent.
Stock (Matthiola incana) – These strongly clove-scented flowers are recommended for cut flowers and thrive in cooler weather.
Wallflowers (E. perofskianum, Erysimum asperum) – Yellow to salmon to copper- colored flowers on short spikes with a pleasant scent.
Sweet alyssum (Lobularia maritima) – These white flowers have a honey-like fragrance that attracts beneficial insects. Often used as ground cover.
Tuberose (Polianthes tuberosa) These strongly-scented white flower spikes bloom in late summer, and are perennial bulbs in Zones 8-10 (grows as an annual in cooler climates).