Poppies

Most poppy varieties (Papaver spp.) naturally self-sow when their flowers fade, and their curiously shaped seed pods dry out. These include corn poppies, Iceland poppies, and breadseed poppies, as long as you don’t mulch around them too deeply.

Cosmos

Most cosmos are annuals that die off when the weather gets chilly in the fall. If you allow cosmos flowers to dry on their stems, they’ll naturally drop seeds and save you the trouble of sowing new plants next spring.

Bee Balm

Bee balm (Monarda spp.) is a native plant that grows perennially in many areas throughout North America and should return each spring without you needing to replant it. However, bee balm also naturally spreads via runners and seeds. Just a few bee balm plants can turn into a lush patch of bee balm in a few years if you don't remove the spent flowers.

Black-Eyed Susan

Like bee balm, black-eyed Susan (Rudbeckia spp.) is a native perennial that naturally survives winters in Zones 3 and up. You can count on these prolific self-sowers to spread over time if you leave their flower heads in place through winter and wild birds don’t gobble up all the seeds before spring.

Calendula

Calendula may grow as a tender perennial in mild climates, but it’s usually treated as an annual and replaced each spring. That said, these plants also self-seed when their flowers are left intact, and they can provide you with lots of volunteer calendula plants for free. Wait until the volunteer calendula seedlings are a few inches tall and have true leaves, then thin them out so they’re spaced at least 6 inches apart.

Borage

Often grown as a companion plant for vegetables, borage (Borago officinalis) is a hardy annual with periwinkle blue flowers that attract pollinators and other beneficial insects. Many gardeners start new borage plants from seed each year, but that’s often not needed as borage is a rapid self-sower. To increase the chances of borage spreading by seed, only apply mulch and compost to your garden in thin layers in the fall and mark the area so you’ll know where to look for borage sprouts in spring!

Columbine

There are between 25 and 30 native species of columbines (Aquilegia spp.) in North America, and most of them are short-lived perennials that self-sow easily. Look for native columbines, like Eastern red columbine or the mountain columbine, and steer clear of hybrid varieties; they may self-sow too, but they usually don’t grow true to type and may not resemble the parent plant.

Larkspur

Larkspur (Consolida ajacis) is a hardy annual that typically flowers from spring through mid-summer in showy shades of pink, purple, blue, and white. After the flowers fade, allow the petals to turn brown on the stems and then wait for the papery seed pods that follow; they will crack open naturally and self-seed.

Lupine

A favorite spring-time bloomer, lupines (Lupinus spp.) spread and form colonies via rhizomes, as well as their “explosive” seed pods that can shoot seeds several feet away from the parent plant. Big-leaf lupines are considered to be invasive in the Northeastern United States and parts of Canada, and they may not be well-suited for every garden. If you live in these areas, look for native varieties of lupines, such as the sundial lupine, which also self-sow and offer more benefits to native pollinators.

Nigella

Also known as love-in-the-mist, nigella is a striking plant with bluish-purple flowers and airy foliage, which adds fun texture to any bed you grow it in. When left to self-sow, these annuals typically drop seeds when the seed pods turn papery in late summer to early autumn. As long as the area isn’t thickly covered with mulch, you can expect the seeds to sprout in spring and flower about 8 to 12 weeks after that.

Lunaria

Also known as the money plant or honesty, lunaria (Lunaria annua) is an intriguing biennial that produces clusters of purple flowers during the first year of growth and silver, paper-like seed pods the second year, then dies. After the seed pods form, lunaria plants naturally die back, but if you don’t remove the pods, they’ll drop their seeds and provide you with new plants the following year.

Feverfew

Feverfew (Tanacetum parthenium) is a perennial that stands out with its bright yellow and white, daisy-like flowers, which appeal to pollinators and were traditionally used as a medicinal herb. If you leave the flowers in place at the end of the season, feverfew will spread over time, and you may find volunteer plants cropping up in unexpected places. If you need to relocate some of these volunteers, choose a sunny and well-draining spot, which is where feverfew does best.