Page Dickey recommends several poppy species for a self-seeding garden. Shown are Shirley poppies (Papaver rhoeas) and California poppies (Eschscholzia californica).

“The first spring at Church House, I was struck by the absence of any flowers that had escaped their proper place to seed about. I felt somewhat destitute…without these serendipitous seedings and went about insuring we would have them in the future.” 

— Page Dickey, “Uprooted: A Gardener Reflects on Beginning Again,” 2020

In a chapter titled “Self-seeding,” author and landscape designer Page Dickey tells us about her long-standing affection for gravel, in particular pea gravel that she uses for garden pathways. She enthuses, “I love the crunch of it, the fact that it’s porous, that it doesn’t cost a lot, and that it looks natural. … ”

Dickey recommends using ¼-inch pea gravel that’s a mixture of off-whites, soft tans and grays. Another advantage of pea gravel, Dickey says, is that it suppresses weeds but doesn’t prevent flowers from reseeding themselves.

I’ve seen this interesting aspect of gravel first-hand. We used pea gravel around our trailer at the coast to reduce the proliferation of a vigorous, self-seeding perennial called false dandelion (Hypochoeris radicata). When we arrived for our summer vacation this year, I was pleased to see that the gravel had, indeed, prevented the false dandelion from growing. A few clumps of grass that had made it through the gravel were easily removed.

I was also pleasantly surprised that more than a hundred native irises, Iris douglasiana, had successfully pushed their grass-like foliage through the pea gravel. The whole graveled area became a propagation nursery from which I could lift the young irises and transplant them elsewhere.

Like my native irises, there are many plants — annuals and perennials — that are welcome to self-seed in the garden. Annuals tend to be enthusiastic self-seeders because they produce flowers, and seeds, for long periods of time. It’s usually short-lived perennials that are the most robust self-sowers, especially those with soft, feathery seedheads (milkweed, goldenrod and vervain come to mind).

I agree with Dickey that allowing unexpected flowering to take place in the garden adds charm and informality, as well as a bit of intrigue, to our growing spaces. It’s also a low-labor and cost-effective way to multiply the number of plants we have growing in our garden.

Here are Dickey’s picks for self-seeding flowering plants. She gardens in Connecticut, but all of the listed plants can be grown in our USDA hardiness zone (Zone 8a and 8b). Check specific plants for recommended sun, moisture and soil conditions. I’ve also included a couple of hearty self-seeding plants I grow in my garden and a list of self-seeding Oregon natives.

• Golden columbine (Aquilegia chrysantha) — perennial; blooms in spring, may rebloom in fall

• Glory of the snow (Chiondoxa forbesii, C. luciliae) — perennial bulb; blooms in late winter

• Fumewort (Corydalis lutea, C. ochroleuca) — perennial; blooms in late spring to fall

• Cosmos (C. spp.) — annual; blooms in summer to fall

• Woodland crocus (C. tommasinianus — perennial bulb; blooms in early spring

• Bleeding heart (Dicentra spectabilis) — perennial; blooms in late spring

• Small yellow foxglove (Digitalis lutea) — perennial; blooms late spring to summer

• Winter aconite (Eranthus hyemalis) — perennial bulb; blooms in late winter

• Giant sea holly (Eryngium giganteum ‘Miss Wilmott’s Ghost’) — perennial; blooms in summer

• Bells of Ireland (Moluccella laevis) — annual; blooms in spring

• Flowering tobacco (Nicotiana langsdorffii) — annual; blooms in late spring to fall

• Atlas poppy (Papaver atlanticum) — perennial; blooms in late spring to fall

• Ladybird poppy (Papaver commutatum) — annual; blooms in late spring

• Oriental poppy (Papaver orientale) — perennial; blooms in late spring

• Shirley poppy ‘Angel’s Choir’ (Papaver rhoeas) — annual; blooms in spring

• Opium poppy ‘Lauren’s Grape’ (Papaver somniferum) — annual; blooms in summer

• Kiss-me-over-the-garden-gate (Persicaria orientalis) — annual; blooms summer to fall

• Cream pincushion (Scabiosa ochroleuca) — perennial; blooms late spring to fall

• Scilla (S. siberica) — perennial bulb; blooms in early spring

• Feverfew (Tanacetum parthenium) — perennial; blooms in summer to fall

• Purple mullein, white mullein (Verbascum phoeniceum, V. lychnitis) — perennials; bloom in summer

• Johnny Jump-up (Viola tricolor) — annual or perennial; blooms spring through fall

• Zinnia ‘Aztec Sunset’ and ‘Persian Carpet’ — annual; blooms in summer to fall

From my garden, I would add to the list:

• Red valerian (Centranthus ruber) — perennial; blooms in late spring through fall

• Tickseed (Coreopsis spp.) — perennial; blooms summer through fall

Oregon natives that self-seed readily:

• Western red columbine (Aquilegia formosa) — perennial; blooms in summer

• Douglas’ aster (A. subspicatus) — perennial; blooms in late summer to fall

• Camas (Camassia leichtlinii) — perennial bulb; blooms in spring

• Farewell-to-spring (Clarkia amoena) — annual; blooms in summer

• Western bleeding heart (Dicentra Formosa) — perennial; blooms in spring

• California poppy (Eschscholzia californica) — annual/perennial; blooms in spring to early summer

• Globe gilia (Gillia capitata) — annual; blooms in late spring to early summer

• Cascade penstemon (P. serrulatus) — perennial; blooms in summer

• Checker-mallow (Sidalcea ssp.) — perennial; blooms in late spring

• Blue-eyed grass (Sisyrinchium bellum) — perennial; blooms in summer

• Fringecup (Tellima grandiflora) — perennial; blooms in late spring to early summer