For the reason behind this post see this thread:
The thread "Favourite Daylilies by USDA Hardiness Zone" in Daylilies forum

Daylilies that have done well here in USDA Zone 4 and which I particularly like are (not in alphabetical order but the order from my garden map):

'Wisteria'
'Boagie'
'Skyhooks'
'Court Magician'
'Pumpkin Kid'
'Midnight Magic'
'Condilla'
'Beauty to Behold'
'Red Volunteer'
'Sandra Elizabeth'
'Orchid Corsage'
'Ezekiel'
'Trahlyta'
'Highland Lord'
'Shamrock Double Grape'
'Light of the World'
'Beautiful Edgings'
'Two Part Harmony'
'Pawprints on My Heart'

Of the above, all except the last three have been with me for many years. I've posted photos of them in the July and August blooms threads so didn't repeat here but I could if people prefer photos with lists. I think, not sure, that 'Pumpkin Kid' might have struggled through its first winter but it's been here a long time now so I included it as I particularly like the colour.

'Pawprints on My Heart' has only been here a bit over a year but had no problem with one of our longest winters for some time. 'Two Part Harmony' and 'Beautiful Edgings' only arrived last fall. I don't usually plant that late here having learned from experience not to, but both made it through the winter and bloomed this year.

I don't winter mulch and snow cover varies.

I will make a list of what has done particlarly well for me here and post it. I do have pretty consistent snow cover, since my site is very sheltered.

Here is a list of daylilies that have thrived and bloomed well for me. We are located between zone 4a and 4b, have a sheltered site, that tends to hold the snow. Snow cover leaves late here, which can be good if we have a late, hard frost after an early warm up, but it means that my garden is usually 10 days to 2 weeks late to get started in the spring.

These are all daylilies that have been in my garden for several years, with no special coddling, and have bloomed well and multiplied.
No particular order,

Majestic Move
Strutter's Ball
Prairie Blue Eyes
Garden of Gethsemane
Raspberrie Pixie
Featherdown
Close Up
Minted Halo
Caramba
Shy Maiden
Spirit World
Russian Easter
Fellow
Vera Biaglow
Christina Ann Pottmeyer
Ah Youth
Little Wine Cup (this always reblooms)
Penny's Worth (blooms very early and always reblooms)
Little Grapette
Dublin Elaine
Peggy Jeffcoat
Inwood
Carolyn Criswell
Siloam Ribbon Candy
Siloam Bye Lo
Cosmopolitan

Rich sent me Pawprints on My Heart as a sdlg to test for him before introduction, it has been a great performer here as well. Bringing color other than yellow to the early season with great branching and budcount. A few other daylilies that have been here for more than 5 years and always performed well...

Astral Voyager - the first that comes to mind when someone asks me about hardy daylilies that don't just survive zone 4, but actually thrive in zone 4.


Big George - wonderful big, bright golden yellow double that often reblooms for me.


Broadway Valentine - Bright, clean colored red on a fabulous plant.


Dragon King - another fabulous red, branching/budcount can seem low when compared to newer cultivars, but still worthy of a spot in the garden.


Elegant Candy - one of my favorites of the early "candy" series, great branching/budcount when in full sun.


Fitzasaurus - big red spider, my clump is always loaded with blooms.


Itsy Bitsy Spider - one of the first to bloom here every year. Amazing in a clump!


Mystic Pizza - simply awesome! This one can't be missed even from far away, large flowers and the color is fabulous.


Noble Lord - an older clear saturated purple-red with a white wire edge. Growing on the corner of a bed that gets afternoon shade.


Rock Solid - the color can be a bit muddy sometimes, but it is always loaded with blooms...and a great parent for bringing hardiness into those southern patterns.


Spacecoast Tiny Perfection - makes a nice clump for the front of the border.


Vanilla Gorilla - super plant habit, big cream UF blooms.


There are many others that I will add once I get a chance to go through my plant list.

It's funny how one daylily will do wonderful in someone's garden but not in others. I sold Elegant Candy because it just didn't perform well for me. Most summers it would not bloom and it was in full sun all day.

I saw 'Elegant Candy' in a local garden, also USDA Zone 4a, and it was covered in flowers, actually a bit too many especially since it wasn't being dead-headed!

This is a great idea; it's often really difficult to find what actually thrives in your zone. Here in Kitchener Ontario zone 5b I've found several that just grow like crazy; through really bad winters, snow cover and no snow cover. I don't mulch and won't keep plants I have to fuss over.
Vera Biaglow is amazing. Blooms like crazy every year, comes through multiple freeze/ thaws like a champ!

Annie Golightly is another one Ive had for years, I brought it with me from my previous zone 4 garden. She makes it through bad winters, dry hot summers, and dogs that like her a bit too much!








Ruby Spider is another daylily I will never be without. Performs beautifully in both my previous zone 4 garden and present zone 5b one. Takes dividing well, doesn't mind being crowded, partial shade, average soil, icy winds, dogs! Great plant and gorgeous color. Polys quite often too.











I should also mention Tuscawilla Tigress. A dependable, vibrant, blooming machine that takes a lick'in and keeps on tick'in!




Also Night Embers which has done really well.


There's more, but I'll add them later.