Oh gosh, too many to list...

Great pic of your balloon flower - it really captures the gorgeous color of them. Its hard to find the non-dwarf ones around here - if/when I stumble on one, I'm grabbing it and running! I have plenty of Sentimental Blue, which is lovely in its own right, but not the same graceful habit of the taller ones - of which I only have one, sadly.

I also have "Ice Dance" sedge (Carex) - it's bulletproof and agree it is zero maintenance, other than needing to divide every couple years.

I’ll mention Agastache ‘Kudo’s Yellow’. It is smaller than usual for an Agastache, but much more vigorous in a good way. The flowers are a soft yellow that blends beautifully with everything and seem to bloom from late spring to late fall. it needs no maintenance except to shear it in late season to get a repeat bloom, but it will still send up secondary bloom stalks if it isn’t sheared or deadheaded. I wish I had bought a ‘Kudo’s Red’ to try.

The old standby Sedum ‘Autumn Joy’ needs zero attention during the growing season. It is a pretty mint green including its flower buds for a lengthy period. This lasts until those flower buds start to color up and go through such pleasing color changes, from pink and darker pink etc until they become bronze brown. I think they look good all winter too, until they need to be cut back in spring.

In my GA Zone 7b garden, Walkers Low catmint & Royal Candles Veronica only need to be cut back once for a second flush. Also Wedding Gown hydrangea has been very unfusy for me.

Vernonia 'Iron Butterfly' is a soft, fluffy mound similar to amsonia hubrichtii but a bit smaller. Plant it in a rain garden, it tolerates standing water. Plant it in a hot, dry spot, it doesn't mind being parched. It's beginning to bloom this week and the pollinators are swarming. I trim it back in spring: that's the only human attention it receives.

I’ll mention Agastache ‘Kudo’s Yellow’.

I gotta try Agastache. Lovely colour foliage and flower and a definite pollinator attractor. But I thought I have read that it doesnt reliably return each season. I wonder if it is more problematic in my CDN zone 6. (Having said that, by coincidence I was at a friends\s garden on Sunday and she had an Agastache that was doing just fine and had survived its first winter last season) .

echolane, how tall are your "Kudo's Yellow"? Could you share a picture or two?

Jen, cecily...excellent plants you have listed. I am learning lots.

Angela sedum. Electric blue penstemon. Bloody cranesbill. Prairie winecups.

Golden Oregano is a great mention. I still havent been able to reliably source it.

I love kniphofia but it is totally unreliable in my hardiness zone :(.

Astilbe is a 'no go' for me as reliable moisture is crucial for its success in flowering.

Great lists. Yes rouge all the Ornamental grasses I grow fit with this theme.

A few more that have not been mentioned - Persicaria polymorpha, Rodgersia, Allium senescens and many of the Sanguisorba my favorite being S. o. 'Tanna'. I am sure I will think of more.

cecily I will be watching for Vernonia 'Iron Butterfly'. Does it seed about? I have Vernonia crinita 'Mammuth' and I really like it but it reseeds if I don't get it deadheaded.

Yes, Iron Butterfly seeds and the babies are taller with coarser foliage. I dig the babies (get 'em while they're young before the roots go deep) and transplant them to a meadow. I tried the Chelsea chop on several babies this year: still waiting on the results.

Thank you cecily! I will still look for it since it is such a lovely plant. Even baby V. c. 'Mammuth' seedlings have a deep root so hopefully Iron Butterfly will be somewhat less daunting. I have been trying to deadhead in a more timely fashion, but it doesn't always happen.

Since the foliage of this plant is similar in appearance I will give full marks to Amsonia hubrichtii for zero maintenance.

Joe Pye Weed (Eupatorium)

Geranium macrorrhizum

Aralia 'Sun King'

Geranium sanguineum

Culver's root

native ferns

all of the above are ignored and do well.

Rouge -- re: golden oregano: Have you checked the herb section at your local nurseries? That is where I found mine around here.

That is genius mxk3. There is a well known herb nursery not far from me and on a lark I just did a search in their online catalogue for "Golden Oregano":

GOLDEN OREGANO at Richter's Herb

I havent called re availability so late in the summer but it looks like then I might have a source for it next spring.

YAY! I accidentally stumbled on it when I was looking for some other herbs, I didn't even know it existed LOL! You will love it, it really lights up semi-shady areas. It does spread quickly if it's happy, so no need to go overboard and buy a lot of it. I started with two plants and divided them both in half the second spring they were in the ground.

I know member Frozebudd raves about it also.

It shows it as zone 6 to 9. But I am thinking it is lots hardier than this.

I assume it can easily take full sun.

Any pictures of it you could post?

No pics of it from last summer -- that entire bed was dismantled. DH isn't home right now, and I need his phone to snap a pic -- I'll try to remember to do that this weekend for you.

Got an email from Richters re GO. It is sold out for this season so of course check back next year.

(Thanks again mxk3 for the great idea)

I’m happy to send GO to anyone having a hard time finding it. ridiculously easy to propagate. I’d be glad to set up a trade or send for postage.

Here's a pic from today -- they don't look like much here, but keep in mind these are divisions from first-year small plants that I planted last year, they'll eventually spread to form a carpet of brightness.

They do spread!! I just dug out two 3’x3’ patches started from a 4” pot two years ago. I kept one small piece in case I wanted to do it again. They do make the most wonderful bright yellow display in the garden, and really they are fairly easy to contain if you give them room and keep an eye on them before they start mingling with their neighbors.

echolane, how tall are your "Kudo's Yellow"? Could you share a picture or two?

So sorry, I haven’t responded because I can’t seem to get a decent photo! I go outside with the intention of taking a photo and the sun is way too bright and washes out their pretty yellow color. Or I’ve waited too long and the light is too dim to show off their beautiful soft yellow color. We also had a major hot spell which hastened the end of their first bloom cycle. At this point I can shear them or just let them rebloom without shearing. I think they still look pretty unsheared, but I think they rebloom much more quickly if I shear them. They rebloom with amazing rapidity.

They are about 20“-22” tall and very bushy.

I would recommend hellebores..mine are effortless except cutting tattered foliage off in the spring..

So true nicholsworth!

Calamintha is so effortless that I don't think about it. It blooms all summer with no irrigation in a very hot, dry spot and the bees love it. I'm planning to add several more as a bee friendly edging for a new bed this fall. Calamintha, nepeta and oregano would be a nice combo.

Calamintha, nepeta and oregano would be a nice combo.

For sure!

(And I know Calamintha is a bee magnet)

Coincidentally, I don't remember seeing Calamintha at nurseries here and had always ignored that category for seeds. I didn't know anything about it. This weekend I finally investigated and decided to put it on the winter sowing list. It seems like a great plant that deserves more attention!

So many to list, but I'll just give you a few that haven't been mentioned. Russian sage is very easy. Just plant in full sun and it will not disappoint. Might have to water if you're experiencing a drought in your area but other than that very easy. Monarda is also very easy. Just make sure it gets plenty of water and sun and it will do well. They occasionally get mildew on the leaves but this is mostly a cosmetic problem. Phlox, buddleia, and peonies are also very easy. Again just keep them watered and give them plenty of sun and they'll do fine. And of course just about all plants appreciate a little compost every so often if you have a pile.

Update: a local nursery had herbs on clearance so I obtained one calamintha and two Greek oregano at half price. Of course they were encrusted with bees at the nursery and gently removing the bees before placing the plants into my car was a challenge.

Interesting question, rouge. Of course, the tastes and styles of individual perennial gardeners are obviously relevant to their answer. I'm with Dillybeansown above in being an inveterate deadheader. When the deadheading is not required for horticultural purposes, I still deadhead for aesthetic ones. Balloon flowers seem an obvious example of "don't need to deadhead" but "will look more attractive if you do". Deadheading (or otherwise tidying up) perennials for aesthetic purposes can be quite time-consuming.

Don’t know if anyone mentioned this but I have to say liriope muscari requires no care and does very well. I have some under the canopies of a red maple and a Norway maple and they established very well with very little watering. I guess their roots move even in dry soil.

Heres mine from last week