I was surprised to find this fall when I added things up that 25% of my daylilies are Ev, 25% are Sev and 50% are dormant. Thats on many, many daylilies! I have never lost anything and last winter we had temps down to -15 C (or about 0 F I think) with no snow cover for all of last March. We lost about 30 acres of Alfalfa but my daylilies were fine. They are mulched around them just to keep weeds down -nothing over top. I never look at this when I purchase them but then I only buy from northern sellers. I would hope that they only sell what does well for them. I think that is a good rule of thumb. Buy from sellers in your own zone.

I also have many evergreen daylilies. I'm in zone 6. Never had a problem with any of them over the winter.

Nina

Do you go ahead and cut back the foilage? Mine are starting to yellow, but are I'd say about half green still.
Thanks for the info! I can't wait to see them bloom.
The EV's are "Flying Tigers" and "Imperial Elegance" both from Marietta Gardens. I also have a couple of SEV's "Cosmic Courier" from Marietta, and "Bahama Butterscotch" from Oakes Daylilies.

I never cut back any foliage. Here we have had some good frosts although not for a while now. November has been pretty nice and I am afraid some things are growing again. My dormant daylilies are completely gone. The evs and sevs are pretty beat up but still have green fans showing. I was looking at my seedlings today and marking down which are dormant and which are not dormant. It is an excellent time to do this job. That's why I listed and tallied the evs and sevs of my known cultivars earlier this fall so I could compare my seedlings to them. It works great right now when the dormants are definitely gone.

Yup, my dormant's are done for the season. Only waiting on the SEV and EV's to pretend their dormant.

Same here. All dormants are done for but still green showing on the EV,SEV's. Not very cold here yet and it is already Thanksgiving.
Julia

Supposed to snow here tonight, but just a light coating. Then go down to 20's for one night this week. Maybe now, they'll get the hint lol!

I ordered from a Florida seller a few years ago (ladybug Daylilies, Dan Hansen). I mentioned my zone and he answered back that several of my choices would not do well in Zone 5. I asked if I only could order dormants and he said, no, he could pick similar- looking alternates to my list that would do well: that some EV and some EV do well in my zone. He was right, and everything he picked DID do well. Those are the ones that are still sitting out green in my garden. So I think that some EV and some SEV can be hardier than others, but it takes someone really knowledgeable to know the difference.

I grow a ton of evergreens in southern Michigan, but most of them are Munsons and I'd have to say they're doing ok, but they certainly aren't thriving. When I was busy adding all the Munsons I liked, I didn't pay any attention to whether they were evergreen or not (and most Munsons are evergreen). Now I wish I had, because many of them would definitely prefer to live elsewhere.

If I'm spending big bucks on daylilies now, I'd prefer to purchase those that are sev or dormant. I'll take a chance on the evergreens if the price has gone down. I've just lost a few too many, but I think that was because I didn't research them properly to see if they had a history of performing in my climate.

Ev or dor does't seem to make any difference regarding hardiness here. I grow many of both and some of my best performers are Ev's, others are dor's.

While I've only owned the garden since this spring, I bought an established display garden. Many of the daylilies here were planted when the garden was established in 1991. Many others were added after that. It is an open field with no mulch.

We have an average of 120 freeze/thaw cycles per winter (as opposed to Minniapolis where they average 40 such cycles),we have extreme winter drought, and infrequent snow cover.

I don't cut foliage back until spring. The theory among gardeners here is that it helps insulate from the extreme cold temps. We've already been down to 7F one weekend this month.

Evergreens are very slow to increase in my Zone 5b garden with a few exceptions. Emperor's Dragon, Key to My Heart, Pandora's Box and Passion District have done very well here.

There have been a few slow growers that are so beautiful that they are worth the wait. They are Victorian Lace, Last Snowflake and Lillian's Somewhere Between.

Edward
Timberlea, Nova Scotia

"We have an average of 120 freeze/thaw cycles per winter (as opposed to Minniapolis where they average 40 such cycles),we have extreme winter drought, and infrequent snow cover" writes berrytea4me.

I'd be very interested as to where this data is retrieved from. And how a freeze/thaw cycle is defined.

"I'd be very interested as to where this data is retrieved from. And how a freeze/thaw cycle is defined."

This is from a botanist at the Denver Botanical Gardens who wrote an article about the challenges of growing daylilies in our climate for an AHS Journal.

I've recently been reading old journals dating back to 1970. If I recall correctly that article appeared in one from the mid to late 1980s but I'll have to go find it again to quote you the exact author, journal date & page. It was in the science section of the journal.

The article did not define freeze/thaw but I can tell you from my experience living here for the past 13 years that it is soil temperature freeze/thaw. We regularly have air temperaturess ranging from low teens at night to 50s or even 60 during the day in the same 24 hour period. The only place on my lot that I ever have a prolonged ground freeze is on the north side of buildings where the sun never shines in the winter. Even there it is unusual for it to remain frozen for more than a few weeks at a time. Most areas where sun hits daily it also freeze/thaws daily.

Ah, here it is. Later edition than I remembered. It is the fall 1997 edition of the Daylily Journal. Vol 52, No. 3. page 328.

The article is titled "American Hemerocallis Society National Meeting 1996 Scientific Forum Part One An Inquiry into Hardiness" by James E. Henrich, Denver Botanic Gardens

In the speaker notes it states "James E. Henrich is Director of Horticulture at Denver Botanic Gardens. He holds a bachelor's degree in Biology and a master's in Horticulture. He has collected plants in Mexico, Nicaragua and the Republic of Korea and has published papers on the Iris family."

In the section titled "Front Range Climate" the entire quote is as follows:
"The Colorado Front Range, extending form Ft. Collins on the north to Colorado Springs on the south, is a semi-arid climatic zone and possesses some interesting environmental conditions. We receive about 14-16 inches of annual precipitaion, 320 days of sunlight per year, have USDA hardiness Zones 6-4, and experience around 120 freeze-thaw cycles per year, compared with about 40 cycles in Minneapolis-St. Paul. In this low rainfall area, humidity is inherently lower and evaporation higher."

I can appreciate the difficulty in defining the parameters of a freeze/thaw cycle. In my experience.. you can't correlate it just to an air temp chart.. this after charting actual crown temps of the plants. Actually... the temps at 1" below the soil surface... crown level. Then you have soil types.. moisture...sun exposure.. the actual temps vary a good deal.

Be interesting to plot your crown temps... but no doubt your temps are more variable than most. But at what point it the plant actually affected? IE.. at what point do ev's vs dorms start to grow and then stop growth cycles? Yet that will vary per genetics too.

I agree but I'm not sure how one would go about doing that.

If you left a thermometer poked in the ground it seems the air temp would affect the readings but the ground is frozen solid you'd never get a probe in an inch deep in the mornings (I'm thinking of one of those scientific thermometers that has a metal probe like a meat thermometer).

Maybe if you had special equipment such as a probe that could be left buried with only wires at the surface that you could connect a digital thermometer to?

Probably beyond my means. I'm sure one of the ag. colleges around here has probably done something like this though I've never seen such data.

Wow, I surely appreciate the scientific knowledge that is being shared in this thread! I agree that soil types, moisture and amount of sun along with the freeze/thaw cycles are big factors in determining survival rates.

But I think (going back to Kentstar's original question) that most Ev's will survive zone 5 just fine. It's the colder zones of 4 and 3 where a mulch covering the crowns would be helpful for winter survival.

I have not lost any Ev's, although I only have about twenty of them, the rest being Sev's and Dor's. I do not cover them, nor do I cut the foliage back in the Fall. I believe that if you plant new DLs at least 6-8 weeks before the ground freezes, they will be established well enough to survive the winter. Last winter we suffered -20° temps, and all my DLs survived.

One more tip...I noticed on D___'s Garden site where you can find hundreds of DL cultivars listed with their hardiness zones, you will see that all are hardy to at least zone 5.

Just my two cents' worth.

Julie

Julie,
You may be right that ev's may be more hardy in zone 5. I can't speak to that since this is the coldest climate that I've tried to garden in.

I also agree 6-8 weeks should give the plant enough time to settle in.

I would not trust the zone data at Dave's. It is not backed up by any significant testing of each cultivar. I noticed that for iris too. If even based on any tests at all, it is based on some generic test data for the species then broad brushed to apply to all.

Simple to check ground temp.... Take your portable drill and bore a hole 1" - 1.5" down.. insert digital meat thermometer... you have a reading in 30 seconds or less.

Do check different areas... temps will range surprisingly. Air temps mostly are meaningless to rate daylily cold hardiness... CROWN TEMPS are what the plant experiences. Snow cover.. mulches etc.. inhibit cold penetration in a major way.