Being that I garden in a cold climate area - and considering that my 'early' daylilies (ie, species) usally begin flowering in mid to later June and a 'few' registered daylilies will begin blooming either the very last few days of June or start in the first few days of July... I consider my midseason to be late July and first week or two of August.

Until recently (as I have added many more registered daylilies as well as seedlings), daylilies blooming into September were rare and only Moussaka bloomed into October.

So to judge 'season' ... when Explosion in the Paint Factory (listed in the database as a late season daylily) has its first buds showing the start of colour on the 20th of August... what would be the range of seasons for daylily blooms?

I suppose anything before July would likely be 'extra early', first half of July might be 'early' ... mid July to mid August is the majority of daylily blooms, so midseason (?). Anything around the end of August into September would be late season... and anything into October would just be crazy? Oops, I mean extra-late...?

Or is there some specific time frame for how long each bloom season 'should' last?

Any time after third week of August, we start hitting cold nights and could have frost at any point / any night... so from that point onwards, the daylilies blooming are definitely competing with cold weather ... yet still put out blooms for up to six or more weeks. Is that considered 'normal'?

Seedling of 'Sultry' continued blooming after the second week of September...


Wish I had not been so sick on return from Italy ... there were several daylilies still budded and blooming the second week of October, including Explosion in the Paint Factory, Moussaka, Fully Charged and Sharply Focused (and some of the seedlings). I just could not get outdoors to record and evaluate the bud & bloom counts or be sure how many other daylilies were also still producing buds.

@admmad
And is there any particular designation for daylilies that will persist in blooming 'after' they are being hit by repeated frost...? If no, it seems like there should be.

I use a 4 week mid-season split on either side of ~25 May here in TX. I based this on FFO counts one year. Peak shifts somewhat based on how cold Winter was. Two more weeks each way for early & late and any outliers are v. early & v. late respectively. Rebloom doesn't count. Still have DL's blooming into fall. About 2 months later in MI although that is an estimate as I am not there all summer.

@adknative "And is there any particular designation for daylilies that will persist in blooming 'after' they are being hit by repeated frost...? If no, it seems like there should be."

I don't think so. For some perennials there are a few mentions of "root hardy", "stem hardy", "flower bud hardy", etc. However, they are usually for specific plant species that are known to have problems. For example, some Forsythia cultivars are leaf and stem hardy to lower temperatures than they are flower bud hardy. In some locations those Forsythia will grow apparently well but never flower.

I agree, "flower bud hardy" designations for daylilies might be useful perhaps especially so for extra early (EE) or very late (VL) cultivars. Hmmm, why aren't those registration classifications symmetrical/parallel? as extra early (EE) and extra late (EL) cultivars or very early (VE) and very late (VL) cultivars?

Around here, in Stoneham MA, the breakdown looks like this

EE- 2nd and third week of June
E- third and fourth week of June
EM- end of June, first week of July
M- first three weeks of July
ML- last two weeks of July, first week of August
L- second and third week of August
VL- third week of August through September

I have lots of things blooming until frost and past a few light frosts but they are usually reblooming by then and get cut off by a hard frost.

I kind of study this for my garden. I'm trying to extend my daylily season by acquiring and hybridizing more EE, E, L and VL cultivars, One thing I've learned is, you can't see a beautiful daylily created in Florida, and assume it will bloom EE in a Northern garden just because it was registered EE.

That means I can't count on the how a plant is registered. I have to track how it blooms in my garden. In my garden, I label whether a plant is EE, E, etc based on this calendar for its first bloom.

EE On or before Jun 15
E Jun 16 x Jun 25
EM Jun 26 x Jul 5
M Jul 6 x Jul 20
ML Jul 21 x Jul 30
L Jul 31 x Aug 9
VL On or after Aug 10

It looks like you might have to slide that scale back a couple weeks. I was questioning my methodology of using First Flower Open day, but it's so confusing when you try to add in Last Flower Open date into the equation. Especially since I've been introduced to several plants recently that start M or ML, but build buds way past some of my VL plants.

If you are interested, for EE plants, Olallie Gardens has a seedling they sell called Early Bird VT that starts really, really early, and is unconcerned with frost and late snows. Always has the earliest scapes and blooms for me. While I can't get a lot of EE registered plants to bloom EE on my scale, I do have good luck with the Skinner's "Earlybird" EE plants, available from Manatawny Creek Farm. Not to be confused with the box store ones, Cardinal and Oriole. These are like Earlybird Sunshine and Earlybird Orangeade. These are full sized, Tet plants that bloom well before Stella de Oro for me in Zone 5 (ish? - don't get me started).

And then for VL, some that seems to resist frost for me (as apposed to fully tolerating frost), Genesta and After a While Crocodile are VL's that don't shut down on the first mild frost. And recently I've added Pee Wee's Big Adventure, Final Exam, and Tree Turtles which all start before VL's per my scale, but are among the latest blooming plants in my garden thanks to bud building.

From the AHS FAQ

"Extra Early (EE) – These daylilies are the first to bloom, and vary from March or April in the extreme South, to May or June in the North.
Early (E) – These daylilies bloom three to five weeks prior to the mass of bloom at midseason.
Early Midseason (EM) – These daylilies bloom one to three weeks before the height of bloom of most cultivars.
Midseason (M) – These daylilies bloom at the peak of the daylily bloom in your own garden. This ranges from May in the South to July in the North.
Late Midseason (LM) – These daylilies bloom one to three weeks after the height or peak of bloom in your garden.
Late (L) – These daylilies bloom when most others have finished blooming, usually four to six weeks after the peak of the season.
Very Late (VL) – These daylilies are the last to bloom, often late in the summer in the South, fall in the North."

There was an article by Carol McNamara in the Hemerocallis (now Daylily) Journal Vol 26 No. 1 March 1972 titled Bloom Sequence. It was updated as chapter 3 in the Daylily Encyclopedia by Steve Webber in 1988.

If one uses the date that the first flower opens to determine to what bloom sequence category a cultivar is in then the number of fans that the cultivar has can affect the FFO date. The more fans, the earlier the potential first flower open may be.

Also, the spread in the dates that flowers open for a cultivar may affect the sequencing.


Cultivar number 1 will have an earlier FFO than cultivar number 2 but both cultivars have the same average flower opening dates.

Such a great topic and one that I've struggled with figuring out here. I guess my bloom season follows something like Zoia's and Tim's. I was told by the folks that used to run a daylily farm here that peak season in our southwestern Indiana area was the last week of June and the first week of July. But there are so many variables at work. I wish it could be more cut and dried, because I've ordered what I thought would be late or very late and they were more mid than late.

Weather conditions can shift my bloom season by several weeks. I have one daylily, 'Cyber Zone', that is registered as EE and it usually begins blooming the last week of May. However, in 2012 we had such an early hot summer that it bloomed on April 30th, a full month ahead. And btw, that was the only year we watered all the daylilies every day for a few weeks because of drought.

I have noticed that daylilies planted up against the south side of my house seem to bloom earlier than others. 'Cyber Zone' is on the south side of my house. Would it bloom later if I put it on the north side of my house? I might be moving it this year since it went into decline, so maybe I will put that to the test.

'Yellow Ducky', 'It Is Finshed', and 'Worth It All' are all planted up against the south side of the house with 'Yellow Ducky' being on the southeast corner. 'Yellow Ducky' is registered as ML, yet peak bloom for it is always the 2nd or 3rd week of June, which I would consider mid-season. However, 'It Is Finished' is right next to 'Yellow Ducky' and is registered as EM and usually begins blooming the last week of May. 'Worth It All' is registered as M and usually begins blooming the first week of June. Would all of these bloom later if I moved them to the north side of the house?

I moved 'Petticoat Frills' from the west side of the house to the south side either in late 2013 or early 2014. It is registered as M and while on the west side, it began blooming the second week of June in 2010 and 2011, the 3rd week of May in 2012 (drought year), and the 3rd week of June in 2013. After moving to the south side of the house, it bloomed the second week of June in 2014 and 2015, but since 2016 it has consistently bloomed the first week of June.

Just throwing this supposition out there: With the description Sue furnished from the AHS FAQ (Thanks, Sue!), do hybridizers look at their own gardens to see when a daylily blooms in relation to the rest of their garden and register it according to that? Someone working on EE's may have a ton of EE's in their garden and if a seedling blooms later than those, they may register it as EM or even M. Just wondering.

Is it possible that there is confusion as to what season to register a daylily? Based on first bloom or peak season? For instance, a Florida seedling begins blooming as an EE on April 1, but the hybridizer registers it as an E or M based on peak bloom?

Oh my, sorry for the long post. I got started researching and didn't realize how long-winded I was getting.

Good question as I have no records on "peak" bloom whatever that means, only FFO. Is "peak bloom" most cultivars blooming or most FFO or most flowers open? Not necessarily the same dates.

Also think about the number of plants a hybridizer grows and how that would affect the registration of bloom period.
For example if the hybridizer only grows a dozen daylilies there might or might not be a relevant difference from the peak bloom and the EE and VL bloom periods. But if the hybridizer grows several thousand daylilies there would probably be a very long period between mid season and EE and VL.
So how those plants are registered as to bloom period by the hybridizer might be very different than how they would be rated by you in your garden.

Vickie, I have noticed here that the amount of shade affects bloom time. I have Purple De Oro planted in several locations. Two in same patio area but different locations. The one in the sunniest location blooms first, The one that's up against a fence that blocks late morning/ early afternoon sun starts blooming about one or two weeks later. The one in the most sun finishes blooming before the one by the fence does. Length of bloom time is about the same. Same plant, similar size.
Here are pics, sunny one first, then fence one:





The third one is planted in a shady location. Planted among hostas and Heurcheras. It doesn't get as many blooms as the first two posted but considering in it's in a shady location, it does well.



Based on my observations, the amount of sun effects the timing of the bloom. Too much shade effects the amount of blooms too. Purple De Oro happens to be a cultivar that here tolerates shade well. I have another cultivar, Becky Lynn that's in the same garden as the last shady Purple De Oro but where Becky Lynn is planted, it's in more sun than the Purple De Oro. It didn't bloom this year. I suspect it's because the trees in the woods have grown to shade more of this garden area and Becky Lynn is a cultivar that does not tolerate too much shade. It otherwise looks healthy and is of a size that it should have bloomed.

This season I'm going to leave Becky Lynn where it is and see if it blooms. If not the following year I will plant in more sun. This year I'll also write down the actual dates and sun time of these in order to have more accurate information. I have other daylilies that also do this. South Seas, I have two clumps. The one that recieves about an hour more sun a day, blooms about a week before the other. The amount of blooms are otherwise not affected. It's in half sun/half shade locations. Morning and late shade, sun all afternoon.

I have that situation with two clumps of Asian Appliqué. The sunnier clump blooms at least a week earlier than the shady clump. The shadier one blooms at least a week later. The amount of time they are in bloom is the same, just offset.

Dave, I only do FFO too and that is in the form of a picture. I try to take pictures of each FFO no matter how awful the bloom is, then use the "Date Taken" in my photos as my record of each FFO for that year.

That is very true, Larry. So many variables!

Great information on the shade factor with the same daylily in different locations, K and Zoia.

Great feedback from everyone, thanks so much to all. Sue, great information, that does help. And @Lyshack - Tim, totally helpful. I do think (based on your garden seasons) mine would slide a couple of weeks further along, but similar.

I checked out the growers you've suggested for earlier bloomers (sold out on Early Bird VT but one I will watch for... and Genesta also sounds like a winner, too). So hard to stretch the bloom time here, there are so few plants that bloom early (even bulbs ... excepting daffodils and hyacinths ... tend to die after just a few seasons). If I could bring in some earlier daylilies, it would help a lot.

Yes, I am also debating bloom seasons on some of my (better) seedlings ... but do have to say, few of mine have to worry about shade, most get sun from early morning (5 or 6 am) right thru at least 3 or 4 pm, so I would say 'full sun' for the day.

The only ones being shaded out are now near the oak trees I planted 20+ years ago along my driveway ... which finally started producing acorns only in the past several years. And those slightly shaded daylilies I have been moving to sunnier locations. So I do think the 'seasons' for daylily bloom times is more affected by weather... this past summer, 'everything' in the gardens ran at least a full week later than generally.

Again, thanks for all the suggestions (and specs on particular daylilies).