There are some Begonias that will be hardy in your area such as B. grandis that you might look at. I don't know anything about them, but I've noticed them when browsing the Plant Delights. There are also hardy Fuschia for your area, but I also have no experience with them.

You probably won't find many perennials that have the same flowering season length as your annual Begonias, so consider also looking for plants that have leaf color, size, and texture that provides contrast to the Hostas so that even when there aren't flowers, the area is ornamental. They don't have to be variegated like the hostas, but could echo one of the Hosta leaf colors to keep things from looking too busy while contrasting leaf shape and size along with a shorter flowering season.

I won't make specific Heuchera recommendations since my growing conditions are so different from yours, but I do grow an old-fashioned (I've had it more than 20 years) Heuchera that blooms red on 2' stems for well over a month. I got it at a plant sale at the Arnold Arboretum without a label, but it is one of my favorite plants. The hummingbirds love it, so I would definitely recommend that you check out varieties for your area. Tiarella is a closely related genus that has some varieties bred for flowers (Spring Symphony is one I have) and some for foliage. There are also Heucherellas that are a cross between the two, but most of them seem to be foliage selections.

Not long-blooming, but Iris has contrasting foliage for the Hostas, both in shape and color. I grow Iris cristata in full shade and I. siberica in part shade, so you could check out these Irises. You could also check out the group of Irises and their hybrids commonly referred to as Louisiana irises (Iris fulva, Iris hexagona, Iris brevicaulis, Iris giganticaerulea, and Iris nelsonii according to Wikipedia) to see if they would be happy there.

I don't know if Geranium 'Rozanne' will do well in your area in general, but it will put on quite a bloom show without having full sun, and is one of the longest blooming perennials I know. You do have to be OK with the plant's growth style which is loose stems that wander around other plants from the central growing point. It isn't a spreader.

One shade plant that I grow with gold Hostas is Leucosceptrum 'Gold Angel' which is 3' tall with charteuse to gold foliage and cream fall flower spikes that the pollinators like. Another plant with multiseason appeal is Mukdenia which has maple-shaped leaves, white spring flowers, and turns a lovely cranberry red in the fall.

Check out as well Epimediums, spring bloomers, some of which are evergreen. Some are clumpers and some spreaders, and some have ornamental leaves for a short time when they are emerging. Another shade tolerant genus with evergreen foliage that has winter blooms is Hellebores which would add interest when the Hostas have died back.

I'd also look into bulbs. Some of them are adapted for locations that get spring sun and then since the foliage dies back around the time the Hostas emerge, the summer shade won't be an issue.

You also may find some smaller shrubs that will work such as some of the new repeat blooming Hydrangea macrophyllas like 'Tiny Tough Stuff' or some of the smaller evergreen Rhododendrons and Azaleas which will only have spring bloom, but will have the evergreen foliage you are interested in.

I don't have a clue about pet safety on these - my cats only ever chewed on rodents and grass so I never worried about it.

I share a similar zone but definitely not a similar climate!! My go-to heucheras for flowering (I mostly grow them for their foliage and cut off the bloom stalks before flowering) are 'Firefly' and 'Rave On'. 'Firefly', although a hybrid, is much like the old fashioned H. sanguineum with an abundance of bright red, hummingbird-attracting flowers over a long period. 'Rave On' offers the attractive patterned/veined foliage of the newer hybrids with lots of hot pink flowers, again over a long period of time. I can't say how either will perform in a high summer heat, high humidity situation but they are great long blooming selections here in the PNW.

And I'd like to second peren.all's recommendation on the bowman's root, Gillenia trifoliata. A wonderful and much underused native perennial that makes a statement in the perennial border. And gets some great fall foliage color before going dormant!

Wow, thanks so much NHBabs, peren.all & gardengal48! I'll explore all of those suggestions - a quick glance & I see several that look GREAT. Peren.all, thanks for suggesting that I post in this forum & what beautiful pics. NHBabs, I often admire pics of your beautiful gardens & wide open spaces. Gardengal48, I know that you are a pro & appreciate your expertise. Very grateful for the advice, everyone, thanks again!

I like peren.all's suggestion of Dicentra eximia (of which 'Luxurient') is one. Mine seeds around some, but it blooms from when the daffodils are blooming right through the summer here, and is fine from full sun to part shade, so I think would be a good choice for your conditions. Nice foliage contrast as well.

NHBabs, thanks, Dicentra eximia 'Luxurient' looks very pretty. The long bloom season would be great as well as the variety of light.

I don't know if it would bloom during the hottest months for you, though it does here.

Firefly, though leaves are plain, is a long and reliable bloomer for me. Bright rich pink. It really glows. Smallish leaves. Nowhere near as picky as fancier leaved heucheras.

Thanks, linnea & NHBabs. Lots of great ideas, thanks SO MUCH, everyone, for all your suggestions. My space is small so it may take me several years of experimenting with 1 type of plant per year.

Gardengal & linnea, you recommend H. Firefly & I see seeds readily available, tho' the online sellers with the best reputations show red blooms & the sellers w/ less than the best rep show the pinkish-red that I want. Hmm. Swallowtail shows reddish blooms & says "full sun in the North and part shade in the South." I hope to try it & see if I have enough sun in my shade garden.

NHBabs & peren.all, I like your rec of H. sanguinea species or the old-fashioned sanguinea but online sellers seem to offer the newer named varieties. I do see seeds of a pink 'Bressingham hybrid,' which sellers claim was created using an old-fashioned one & claim is one of the few hybrids that will grow true from seed. Similar question about light - I will have to try it. The seller that I see with the best rep is Garden Harvest Supply on the link below.

NHBabs, I LOVE your idea of finding a perennial that provides contrast with the hostas in color, size & texture, yet echoes one of the hosta leaf colors to keep things from looking too busy. Great idea - to be worked on. Thanks, everyone, appreciate your help!

Seed for pink H. Bressingham hybrid at Garden Harvest Supply

http://www.gardenharvestsupply.com/productcart/pc/bressingham-hybrid-heuchera-seeds-for-sale-p6016.htm

Walters says "full sun or partial shade" for Bressingham, will have to see if I have enough light

http://www.perennials.com/plants/heuchera-bressingham-hybrids.html

Firefly at Swallowtail Garden Seeds (Ruby Bells is first, scroll down to Firefly)

http://www.swallowtailgardenseeds.com/perennials/coral_bells.html#gsc.tab=0

This is from only trying Heuchera twice (Sweet Tea and Georgia Peach), both of which are rated well for the South. My heucheras play the funny game of getting smaller and smaller, then vanishing without a trace. I think I give up. My planting areas were rife with organic matter, and well watered through the season. Pretty much everything else thrives for me...but Heucheras should flee for their lives. My advise, don't go big...try one and hope.

I have seen the Firefly blooms described as “red” numerous
times. I would suspect that they are all the same color, which is really deep
pink. Hot saturated deep pink.

I have at least 3. I have seen them at nurseries provided by
different growers. The tags have all stated “red”. But I “know” they are pink,
so I don’t mind, because I know it will go with my heuchera/hosta color scheme,
even if they are a tad bright for what I would prefer.

Pink and red are on a continuum. Cool reds have a purple
cast. Warm reds have an orange cast. A cool red is going to look more pink.

When you think of the “red” for Firefly, just don’t imagine “tomato”
or “fire engine”. Those are warm reds.

In the nursery trade, calling flowers truly accurate color
names doesn’t seem to happen often. For example, I grow lot of lilies. I am
always looking for red. I have ordered numerous lilies described as “red.” When
they bloom, they turn out to be the “Cool” red, which has a magenta cast to me.
Not what I am looking for in the beds were I grow them. Ditto with hibiscus.
The “red” I planted turned out to be magenta.

I don’t know about growing conditions in your zone. Here the
fancier leaved heucheras fizzle out after a season or 2, even though I am
giving them exactly what they should like. I know some gardeners here who have great luck
winter sowing heucheras from seed. I don’t know how far south that can be done,
though.

I had some H. Fireflies for a bit and I would describe the color as rich pink rather than red. Unfortunately, the voles liked them. The thing I liked least about them was the short stems, though others may like that. I prefer the taller ones since the flowers seem to float above the foliage and the hummingbirds love them.

Thanks dbarron, linnea & NHBabs. dbarron, good idea - think I'll "go small" with Firefly seeds that are readily available online. Big help to hear that Firefly will go with my color scheme in that area, very grateful. Hope to give you an update next year!

Sometimes with masses (aka seeds), you'll find a few like your conditions...so this may be quite the best way. Good Luck!

dbarron, thanks for info & support. I have just ordered Firefly seeds at Swallowtail Garden Seeds. 500 seeds for $2.99. $4.99 shipping on whole order - don't know how many seed packs you could get in as I'm always 'way below max. I like to order as early as possible as companies get sold out or get so busy that it takes forever to get an order. As you mention, out of a mass of seeds I'm hoping for a few seedlings that like my conditions. With 500 seeds I can experiment for several years! Thanks again.