My favorites are Clarkia and Corydalis sempervirens. The Corydalis is a dainty little thing, not real showy, but it does really well and is very adaptable. Annual poppies will self-sow like crazy.

Foxgloves here. The prettiest pink one decided to grow up through my hebe with purple and white flowers, it looks really good.

I'm hoping the alyssum I planted this spring will self-seed; I've had it do so in other gardens before.

Foxglove, shasta daisy, lupin, nastursum, pansy, johnny jumpup, lady's mantel, cosmos,

Opium poppies are one of the most common here. "Weedy" will vary with the site and the gardener, so already some listed are highly debatable. Probably millions of foxgloves are growing on western Washington stump ranches at the moment, spectacular but not part of the local ecology.

Jacobson, WILD PLANTS OF GREATER SEATTLE is a good book to look at to find out what pops up on its own here and to what extent. Anything growing wild was included, not just native plants.

A couple more: Lychnis coronaria, Alstroemeria, Aquilegia, Erythronium, Grape Hyacinth, Cyclamen neapolitanum, Cyclamen coum. Erythroniums and Cyclamens are in part shade.

If you want plants to self-sow, you need to keep the slugs under control.

...hardy geraniums, Hellebores, pacific coast iris, pulmonaria, phlomis, hesperis, Milium effusum 'Aureum'-Bowles' golden Grass, Persicaria amplexicaulis'Firetail', Potentilla nepalensis, various Campanulas--but watch out for peachleaf it can be invasive, Euphorbias, Tovara virginiana-aka Persicaria, Aquilegias....

Columbine, love-in-a-mist, sweet william --it's a jungle out there!

Sweet woodruff, creeping jenny, lamium. Set em and forget em they'll flourish for years. Feverfew, like a white chrysanthemum, reseeds like a labrador. OH and some horrible low, small form of verbena that you can't even pull up without a stabbing metal implement, one inch at a time.

I guess I am thinking invasive, rather than re seeding. I would second Nigella, and alyssum as more desireable ones.

Plantknitter, backing up to your mention of peachleaf campanula: is that a very low, ground-hugging spreader? Mabye 6 inches high max, medium blue flowers?

Poochella
the peachleaf -- Campanula persicifolia has a tall,~2+ foot flower stem with blue or white or other inbetween colored flowers on cultivars.

The low growing Campanulas may be C. posharskyana--Serbian bellflower, or C. portenschlagiana.
Are you saying your low growing ones reseed alot?

Hi Plantknitter- no, the low one just spreads at an annoying pace (to me) by runner, I think. I've dug and tried to eradicate much of it, but still a patch will emerge or intertwine among taller neighbors where it's difficult to remove. It is c. pocharskyana. Thanks!

Calendula, forget me nots, echinacea, snapdragons

I forgot Viola labradorica! It would self-sow on Mars. Trees: Styrax japonica, Koelreuteria paniculata.

The purpeleaf Viola labradorica hort. (of gardens) is correctly V. riviniana 'Purpurea'. The true V. labradorica is a tiny far nothern species that may not be cultivated much, if at all. 'Purpurea' may pop up anywhere conditions suit it. The typical greenleaf, rosey flowered V. riviniana is even a lawn weed in this area. A neighbor of mine had a carpet of them develop, producing an alpine lawn effect.

Biennials do well here because they fit into the wet/dry season. They start growing with the fall rains then overwinter and bloom in early spring, making seed before things dry out in summer. Some that do well in my yard-
Forget-me-nots, which are invasive,

Money plant, Lunaria, which comes in purple or white and makes those lovely dry translucent floral arrangements,

I'm trying Collinsia, Chinese Houses, but haven't got them sown in fall yet to see how they do.

Thanks for all the good information. I'm going to keep trying. I think the problem in my garden is that I don't put out slug bait early enough, or often enough, and my volunteers get eaten. Thanks, lilydude, for the tip.

I do have some unusual volunteers that I THINK are Daphne! Had little, pale green flowers this spring. Is this possible?

This year I had reseed Nigella, Lady's Mantle, Feverfew, Celosia, Johnny Jumps Ups, Pansies, One Petunia!, Possibly coreopsis..seem to have a lot more this year than last, Campanula persificola, Forget-Me-Nots, Columbines, annual Candy Tuft, foxgloves, Balsam, Sweet Peas and Rose Campion. Whewwww...I didn't know there were so many until I started listing. And I would imagine I forgot a few. BTW, I am near you..out here in Graham area. I work in Tacoma.

Thanks again, everyone, for the good information.

Now that it's spring, anyone want to add anything?
Daphne in Tacoma

Malva mauritania Bibor Fehlo - tall majestic hollyhock cousins with rich plummy flowers - all over the garden

Most prolific is feverfew

DO NOT grow alstromeria - you will never, never never get rid of them and they spread and choke neighbors

Nigella, Echinacea, Calendula - very reliable reseeders

Larkspur is good, also very good is Fennel, including the bronze - which also are good butterfly larva plants

Some hardy geraniums reseed. I like the Sanguinums, they make a lovely mound of blooms in spring, but there is a geranium with a larger leaf that is quite a pest and has a woody root that is hard to eradicate. I'm not sure which geranium it was that started these plants, I bought several that year.

The self-seeders I have are:

Foxgloves, hollyhocks, forget-me-nots, candytuft, alyssum, nasturtium, monkey flower, rose campion, love-in-a-mist, love-lies-bleeding and Papaver Somniferum. These have come back reliably for the last two years. :o)

The self seeders that come to mind right now are, Meconopsis cambrica, Welsh Poppies, my garden is a sea of yellow in amongst all the other plants right now, lovely if you like yellow. Another yellow, Corydalis lutea pops up all over the garden, I pull it out where I don't want it. I also like the foxgloves and columbine that have placed themselves here and there. The other plant that has self seeded in my garden is Lithodora 'Grace Ward'.

A......

Right now (mid-April) I've got babies coming up all over from 2 perennial salvia ("Caradonna") I planted late last summer. This is very cool as I LOVE this plant!