I am so glad i saw this topic as i was about to start one about what plants grow like they are out for world domination in your garden. Daylily that is.
I have grown Mary's Gold and Strutters Ball for about 7 years in my garden. The former i have divided once and the latter at least twice. In fact Strutters Ball will be divided again this year and possible Mary's Gold.
Another one is Scapes From Hell, i have two large clumps of this and one has to go. Magic Carpet Ride is a beautiful red with and grows like its a weed. It gets big sturdy fans and scapes and i think it works out while i am at work. Godzilla vs. Magic Carpet Ride, who would win?
Mango Time i divided last year from 2 clumps into 6 clumps and my total scape count this year is in the 50"s.
Fooled Me from Lowes garden center 4 years ago is begging to be divided about 4 ways.
I have others that have benefited so greatly just by moving them to better location or soil that you would swear are not the same plant.
They are Chicago Apache has went from wimp to body builder just by moving into a partial shade location.
Always Afternoon, small clump with 13 scapes. May need my calculator to count buds on this one.
And finally the category of large clumped ones that stay large but probably need divided to really take off.
They are: Illini Jackpot
Laughing Out Loud
Hot Wire
Mighty Chestnut
Tooth
Just to name a few.