Hesperis (Dame's Rocket) would be perfect for the conditions! :) but that's for late spring / early summer bloom in zone 5. I don't know how easy/hard it is to yank though... I've never tried to yank mine, except when they were seedlings.

Corydalis lutea prefers shade, self-seeds, is easy to pull out. It has small yellow flowers from May until Frost and always looks neat and clean. Find someone who has it, they will give you plenty for free.

I grew Rose Milkweed in a partly shady location (under pine trees) - maybe you could try that. That self-seeds. And it will also attract butterflies.

Wow, they are beautiful. The gov calls them invasive, but they look almost like a lilac. I could think of worse things to be "invaded" by.

Here is a link that might be useful: Rose Milkweed

I have a spot like that, shady garden but in summer gets brutal afternoon sun over a break in the roofline of the house. I am experimenting, but so far phlox David is doing quite well and blooming. It is first year plant. I am also thinking I will add a dwarf red leaved barbary of some sort. Strawberries and begonias do NOT like these conditions :)
You can also try echinacea and geum.

Daylilies should work for you in that spot. Calendula might be all right there, too.

Tracy

Thanks everybody -- I think I have enough to go on. I never thought of milkweed as a garden plant. Uh, is this the same kind that's out in the farmer's fields? Has anybody ever cut it as a vase flower? The reason I ask is because I would never want it to go to seed (is that right? It's invasive because it self sows? Or underground runners?) and using it as a cut flower sort of guarantees it won't be around to set seed.

Anyway, thanks a million for the ideas..
Lime

Lime,

Since the area is on a slope, and you don't want to water more than twice a summer, have you considered native wildflowers, native grasses or some kind of groundcover native to your zone?

As far as specifics, I try to pay close attention to what the highway dept. plants in medians and along the highway. That's usually a pretty good indicator of what will thrive in your area with minimal care.

Marilyn

You're so funny, Marilyn.. this is Indiana -- the highway dept grows grass where it's flat and crown vetch where it's steeply sloped. That's it. Ladybird did your state a huge favor in the 60s, believe me!

We get a lot more rain than you get, so it's not like it will be *that* dry. I just didn't want somebody to say hostas or something. I want it to look like the pictures here on the forum, but I have a feeling their cottage gardens are more well-planned than they let on... Maybe white hesperis, cleome, and milkweed. That would be awfully pretty in pink and white. A little scent from the hesperis will be nice, too.

Is white hesperis seed I should look for in the seed exchange or bite the bullet and order it?

Lime