Hey Val.

In our neck of the woods I would probably not got below a 3-4 fan clump. Some multiply like rabbits and others just seem to sit there. I've got several that are 2 years in the garden and still at the same number of fans as when they arrived. One day I'll get the beds "planned" and revamp, bring in compost etc to nudge them along.

Where are you in MA? My plants and I are presently in Providence, RI.

I really think it depends on the particular daylily. I have several clumps that are nearly 2' across and bloom wildly. Hyperion and Woodside Ruby are two such DL's.
I also had Duke of Durham which I was ready to get rid of because of the low bloom count and poor blooms. I removed half the clump and fed, them boom... it was spectacular this summer.
Let the daylilies talk to you, and be sure to listen.
Nina

There really isn't a perfect size to look for, as growth rate can vary greatly. My dips seem to multiply faster than most tets. Just in the next day or two I must divide giant clumps of HEAVENLY CURLS and KAREN'S CURLS. They have become so gigantic that bloom production was down this season. Each clump is probably at least 40 fans. Good thing I've sold pieces of both! Many others will get divided too over the next week or so.

Some clumps in the display garden I purchased are probably 15 years or more since last division, huge 3 foot across at least, and still blooming like mad. Others are much smaller, obviously divided more recently, and barely bloomed.

I think it just depends on the cultivar, your soil composition, nutrient conditions, water, etc.

It makes sense. The density of roots vary greatly by cultivar so if they are so bound up that they can no longer reach the nutrition they need to thrive, they will show you by declining in bloom.

Thanks everyone.
I do have some that haven't been divided forever and still seem to bloom well and I try to divide when the production is down. I have a problem with lack of space so I want to keep the clumps big enough to make a statement, but not so big that there isn't room for anything new.
Of course then there's the problem with the ones that resent division and sulk for a while--a definite flaw as far as I'm concerned.
Val

In general I draw the line at 30 fans. Trying to divide a clump that has more than 30 fans is way too much work. I find that I get optimum performance with between 10 and 30 fans.

Edward

Val - I was just thinking of the ones that resent division,
I have a couple of those. I also have 2 different ones that sulked all season and all I did was move them. These
naughties are BITSY and AFTER ALL, two of my best blooming
plants. I hope they recover by next year.

I have Duke of Durham and it blooms quite well but doesn't
increase at all, guess I'll try your idea.

Kay/phal

This discussion has made me decide to watch some of the ones I divided this year to see whether the ones that are hard to divide take longer to recover than the ones that divide easily. I know some don't seem to miss a beat and some sulk, but I've never noticed if it has naytbning to do with how easily they divide. Has anyone else noticed?