Annual flowering plants grow vigorously and bloom profusely during their growing season. They fill in the gaps between your perennials, adding color, texture, and lush beauty. They may also provide frequent armloads of blooms for indoor displays. Many old-fashioned favorites can enthusiastically self-seed, volunteering new growth season after season, creating colorful bloom flushes and a natural, informal appearance in your garden. Without any assistance from the usually delighted gardener, seedlings of these self-sowers often appear in surprising locations, providing drama, excitement, and sometimes new and fabulous, never-before-considered plant combinations. Some of these classic favorites include:
- Borage (Borago officinalis, annual)
- Poppies (Papaver rhoeas, annual)
- Love-in-a-mist (Nigella damascena, annual)
- Nasturtiums (Tropaeolum and cvs.,annual)
- Four o’clocks (Mirabilis jalapa, Zones 9–11)
- Sweet peas (Lathyrus odoratus, annual)
- Sunflowers (Helianthus annuus, annual)
The best self-sowing annuals are those that produce abundant healthy seedlings, but not so many that they overwhelm the garden or become a dandelion-like chore to remove. If you are looking for something beyond the go-to self-seeding annuals listed above, check out one of these unique favorites.
Growing 2 feet high and wide, blue honeywort (Cerinthe major ‘Purpurascens’, annual) is a Mediterranean native that is happiest in full sun and well-drained soil with minimal water requirements. It flowers almost constantly and can give you up to four generations of extraordinary blooms in a single growing year! The fascinating flowers are carried on the tips of arching, branching stems clothed in beautiful, mottled blue-green foliage.
‘Marshmallow’ flowering tobacco
Looking as lovely in a bouquet as it does towering over the garden, this elegant Brazilian plant reaches 5 feet tall and is topped by an airy cloud of tubular white, pink, and rosy blooms, with all the colors appearing at the same time. These flowers float high above the lush, bright green foliage. ‘Marshmallow’ flowering tobacco (Nicotiana mutabilis ‘Marshmallow’, Zones 10–11) blooms all year long in frost-free areas and reliably and profusely self-sows elsewhere. ‘Marshmallow’ is happiest in sun to bright shade, in rich soil, and regular watering. Plus, it’s a hummingbird favorite!
‘Blue Bedder’ viper’s bugloss
Honeybees adore the mounding mass of nectar-filled, cup-shaped, gentian-blue blooms. ‘Blue Bedder’ viper’s bugloss (Echium plantagineum ‘Blue Bedder’, annual) grows to 20 inches tall and 20 inches wide. Easy to grow, pest resistant, and drought resistant, this long-blooming annual hails from the Mediterranean, has low water needs, and does best grown in full sun. Though said to prefer rich soil, it has happily reseeded in gravel pathways in my garden!
‘Solar Fire’ ursinia ‘
Solar Fire’ ursinia (Ursinia anthemoides ‘Solar Fire’, annual) is easy to grow, a happy reseeder, and fast to flower! Plant this South African beauty in rich, well-drained soil and full sun any time of year in frost-free areas (early spring through late summer elsewhere) and watch as 16-inch-tall-and-wide mounds of ferny foliage quickly become blanketed with an eye-catching mass of long-lasting, orange-gold blooms. This annual works as beautifully in containers as it does in the border and has average to low water requirements.
Too many plants? If your self-sowing annuals seed too enthusiastically or plant themselves where you really wish they had not, they will be very forgiving if you simply transplant them to more suitable locations.
—Fionuala Campion is the owner and manager of Cottage Gardens of Petaluma in Petaluma, California.
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