Essential herbaceous plants, list your favorites

[MaineDesigner]

I felt we needed a flip side to the "Plants You Love to Hate" thread. You can list by genus, species or cultivar but please add at least a word or two about why you like them.

My list would include:

The genus Paeonia - I've just started to explore the species peonies. Nice foliage, frequently great fragrance, longevity and nice blooms. I tend to prefer the singles, anemone/Japanese, and semi-doubles to the bomb and extremely doubled forms.

Nepetas - As far as I can the garden forms are a taxonomic mess and frequently mislabeled in the trade. 'Six Hills Giant' flops for me but 'Walker's Low', 'Blue Wonder', 'Dromore', 'Little Tich' and 'Dawn to Dusk' (huge, not a floriferous as many but still nice) have all been great. I just planted 'Candy Cat' so the jury is still out on this one. Sustained bloom and very undemanding. Does anyone here have experience with 'Joanna Reed', 'Pool Bank' or 'Sweet Dreams'?

Geraniacea - I'm not a fan of Pelargoniums but there are a ton of good plants among the true Geraniums. I love the foliage scent on many of them, it makes them a pleasure to work with. The much hyped 'Rozanne' has been a little unreliable for me here in Zone 5 but it certainly is floriferous.

Polygonums, Epimediums, Thalictrums, Iris (excluding modern TBs), grasses, sedges and ferns are all on my list too.

[Jess]

Nice idea Maine.

I will not include herbs in my choices as that would take me far too long.

My most favourite based purely on personal preference...

Zantedeschia aethiopica. Whats not to love. This has to be my personal favourite. It is tall and stately with such beautiful large glossy green leaves that fall away like a skirt at the base. The flowers (bracts) appear atop long juicy straight stems and open into pure white curled trumpets. If happy there can be 15/20 flowers on the one plant. They positively glow at dusk.

Astrantia 'hadspen blood' Beautiful colour, tidy growth, nice clump former, not too fussy on siting will grow in sun or shade.

Epimediums, any. Such pretty leaves and I love the way the new flowers curl up from under the old foliage. Again makes a good clump, will grow in dry shade even beneath a hedge and the flowers are very unusual.

Aconitum 'Sparks Variety'. Hooded dark blue and stately. Rabbits leave them alone as they are highly poisonous, slow to get going but once a good clump has established they will support themselves.

True geraniums. No garden should be without. All colours available from the purest white to the truest blue. Some with very smelly foliage, and virtually evergreen, others very dainty and suitable for a rock garden.

Crambe cordifolia. In a good year when the slugs and snails are not too rampant, the caterpillars don't turn the huge leaves to string vests and the wind doesn't blow the flowers off the minute they come out it is superb. A towering frothy mass of white scented flowers. Mine is right outside my living room window so the scent can waft in.
http://seeds.thompson-morgan.com/pix/m/seeds/7/7576.jpg