In summer, one of the joys of my garden is sitting on the front steps at dusk, watching the sphinx moths. Resembling hummingbirds in size and motion, these crepuscular insects are drawn to the garden by a heady jasminelike perfume, a scent produced within the white, tubular blossoms of flowering tobacco (Nicotiana alata). I watch the moths as they dart from bloom to bloom, hovering at the mouth of each flower just long enough to sip its sweet nectar. As darkness settles over the garden, the tobacco flowers glow, releasing the last of the day’s warm light, and the sphinx moths become flitting shadows in the gloaming.

I walk through the garden surrounded by hundreds of white flowers, some clustered at the tips of waist-high stems arching over the garden path, their long sticky leaves brushing against my bare legs, others borne on shorter, thinner stems that twist upward through the branches of red-ozier dogwoods and between clumps of day lilies and violets. All of these plants can trace their origin to a small planting made years ago, a dozen plants purchased at the local garden center. Seeds produced by those first plants were scattered by wind and water throughout the garden and now, after many years, all I have are rogue seedlings growing where I don’t want them, leaving the rest to entertain the sphinx moths and me.

There are several species of exuberant self-sowing annuals that, like flowering tobacco, will return to the garden each summer from seed scattered the previous fall (see sidebar for a few of my favorites). You can start self-sowing annuals in your garden from either plants or seeds. I like the idea of starting from seed planted in late fall, waiting until after several frosts so that the seed will remain dormant until spring. There seems to be more time for such chores in the fall and the soil conditions are often better for seed sowing in late October than they are in April. But if you are in a hurry to get started, you can purchase seed or plants of many self-sowing annuals for planting this spring, after the water recedes.

Self-sowing annuals are ideal for gardeners who, like myself, enjoy managed chaos in the garden. Sure, there are the permanent bones of the garden, the trees, shrubs, vines, and herbaceous perennials that I have planted over the years. But the garden comes alive in summer with the colorful flowers and intoxicating smells of annuals that move about from year to year, filling the garden’s voids with unplanned color and fragrance. The most provocative combinations of color and texture arise from this approach to gardening and, when such accidental associations attract the attention of visitors, I am pleased to accept the credit. After all, I gave a nod to the sharing of that space.

Send queries to Gardening Questions, 116 N. Main St., Orono 04473, or e-mail rmanley@adelphia.net. Include name, address and telephone number.

Some self-sowing annuals for spring or fall planting

Calendula officinalis (Pot Marigold). Flowers up to 4 inches wide in a variety of colors from orange to apricot, cream, and bright yellow.

Cleome hasslerana (Spider Flower). Eight-inch balls of pink, spiderlike blossoms on stems 3 to 5 feet tall.

Cosmos bipinnatus (Cosmos Daisies). Tall stems with large daisylike flowers, each with a yellow center surrounded by pink, red, crimson, or white petals.

Nigella damascena (Love-in-a-mist). Light blue flowers hovering above a tangle of fernlike foliage.