I do not use them as companion plants with the hosta. My hosta are in containers.

And, we've had a great amount of rain this summer.

Two plants you did not mention which I have are
perennial salvia. I like the lavender or deep blue bloomers.

daylilies. I like the short ones, in the nature of the Stella d'Oros. But I guess if you have mature Empress Wu, you could use some Yellow Mammoths!

Like you, I love mondo grass/orphiopigon dwarf or not, and liriope, which is evergreen here. I have it in the wide blade and the common blade, but some of mine gets to be at least 18 inches tall and blooms prolifically.

My ajuga is growing like crazy down the Hosta Allee, the narrow strip between the Teahouse and the privacy fence. Some of the wild violets are blooming now, which I had no idea could happen this late in the season.

What do you think about lambs ears? With their wooly gray blue texture I think they would look good with some big blue hosta.

Also, I like artimisia, or Dusty Miller if it is the wider gray leaves. The Powis Castle is very lacy leafed though, still a soft gray green. It will come back if mulched nicely over the winter.

You might even have a chance to plant some low growing herbs--but not rosemary which likes to stay on the dry side, and might keel over if you water regularly. I have a row of rosemary with my Italian cypress, boxwood, and bush roses, and it takes lots of heat and is close to 3 feet tall and wide, lovely smell when you brush by it....but not for a hosta companion.

I love my different sedum... I don't have a collection.. just a few basics and they are extremely hardy...
I have some dianthus in really well draining soil that does poor... but in heavy clay its doing extremely well...
I have ajuga in clay thats looks perfect.. but my ajuga in my good soil has dried up...
I have fantasy roses, as annoying as they are... they look fantastic...
Of course you mentioned all the liriopes and vinca vines..ivy vines as well..
I found out the hard way this year that heuchera would rather be dry lol...
My firepokers and my variegated yucca do well regardless...
My bearded iris foliage all still looks fresh..

On another note... I'm planning on doing away with lots of my sun loving stuff... mostly everything not on the above list lol.... so if anybody wants any huge divisions of daylillies and lives close to southern kentucky.. shoot me an email... I'm really getting to where I don't like taking care of them anymore lol.. free to a good home..
John

I have Happy Returns daylily in a bed with hosta that I thought got enough sun but it doesn't. Blooms poorly so that daylily isn't a good candidate. (I think some daylilies will do OK with some shade but HR isn't one of them.) And I've planted hosta (plain green NOIDS) in another bed where vinca minor is established and the hosta just barely hang on, getting smaller every year. Trying one more time with an Earth Angel and making an effort to keep the vinca from encroaching on the hosta (which I haven't done with previous efforts.)

Don't have any heucheras but was reading somewhere that they'd rather be dry than wet so I'm going to try one or two of them if I can find some inexpensive ones. (I've never grown them.)

Planted ajuga in a confined bed about 10 years ago. It escaped in no time so I quickly got rid of it. Was still finding an occasional ajuga plant as late as last year! None so far this year but, needless to say, it's been dry.

Lamium does pretty good, hanging on in the drought. Downside is that it's a magnet for red spider mites.

Two thumbs up on lily of the valley.

I love liriope and grew it when I lived in Oklahoma. Don't think it is reliably hardy here but I might try some anyway.

Most of the very large liriope that I have came from Plant Delights Nursery in NC. You can check their catalog for the hardiness. Or, check something like Aztec grass which is another ground cover and clumping lilyturf sort of plant.
This is a picture of some of my large liriope with hosta so you can get an idea.

One plant that comes to mind right away is hakone grass. Still looks great without extra water.

I don't have a lot of experience with companions. I have spent hours trying to clear my gardens of other peoples introductions of Snow on the Mountain, vinca and Ajuga. However, I do have a large hosta bed with a border of sedum and it does well in sun or shade, wet or dry. Another that look great with large hostas are hardy geraniums. In the same large garden I have both the Great Solomons Seal and Variegated Solomons Seal.

In Theresa's Angel Garden under my black walnut I have Hemerocallis, Heuchera and hardy Geranium that don't seem affected by the juglone. Of the three the daylilly seem most affected by lack of water, but only in that some of the leaves brown and are shed when it gets really dry when planted in a lot of direct sun. Under the walnut, which is very deep rooted, they stay green. The geranium is like the famed battery that just keep going and going. I have a very nice looking bunch in the corner of my roadside ditch that I have never watered once in the 8 years I have lived here and it never suffers from drought.

Les

I would think native plants are probably the best drought resistant plants. Link below of listing found for Minnesota and shade.

Paul

Here is a link that might be useful: MN DNR : Selected species for native shade gardens

Sandy-One very attractive and virtually totally insensitive to drought in the Missouri/Arkansas mountain areas is Lantana. It is a perennial but may not be hardy in your area where you tend to feel the effects of the wind whistling in from Kansas. With things heating up I'd had some survive the winters in Mountain Home but not in our coldest winters. Mtn.Home is in its own mini-zone due to being surrounded my the two huge reservoirs of Bull Shoals Lake and Lake Norfork. They tend to keep the air a bit warmer in the winter. Lantana blooms best when it is very dry.

Les

It's very interesting to read how everyone's experiences differ. In my garden, daylilies refuse to bloom in the shade, perennial salvias only grow well in full sun, and lantana is an annual here. It dries up and dies if it doesn't get water, and won't grow in the shade anyway. Hakone grass is wonderful but sooooo sloooow if you don't get a big clump to start with.

The artemesias as a family grow well in the sunny herb garden, but crap out in the shade. Rosemary isn't hardy for me, I keep mine in a huge pot on the patio. Dianthus is going great guns in the herb garden and rock gardens in the sun, but dies in shade.

I have four members of the Solomon's seal family, from the little variegated Japanese fairy bells, the false and true Solomon's seal, and the giant variegated, and they all do well with no supplimental water.

There are five varieties of lirope here, and all doing great with the drought. Tho one is an invasive monster that is not allowed in the polite company of other plants and makes a circle in rocky soil under a tree where I can keep it confined.

A couple of other plants that do well in dry shade for me are the wild petunia, ruellia, which blooms most of the summer from June on, and a little dwarf goatsbeard that appears to be unfazed by the drought. This one is new for me this year so I'm looking forward to see how it does next year.

The hosta beds are packed with early spring ephemerals and bulbs, that are pretty much gone by the time the hostas get going well.

I just think with the changing climate I will have to change the way I garden, and with what. I realize I can't depend on the "normal" summers of the past, a lesson I have definitely learned from the past two years!

I love reading about everyone's ideas and experiences. There is always something new to learn!

Sandy