No, nothing special I can think of, after having both for many years. Both are totally undemanding, as far as I can see.
I've got the original knautias I grew from seed, and have let them self-seed as they wish for many years, and have never seen any need to divide a plant in however many years. A mature clump gets to about 12" across at the base, but spreads upwards, and reaches close to 5' tall. I usually start out making a feeble attempt at deadheading some of the more visible plants out front - each plant produces multitudes of flowering stems, each consisting of a triple cyme of which the central bud opens first - I deadhead the spent central flowers for a while.... though I very quickly tire of that effort ;) They bloom heavily, though with small flowers, all season through, as you seem to have seen already.
Your Helenium hoopsii should bloom next spring - it's an early bloomer, usually with the tulips. (This sets it apart from the fall-blooming heleniums.) The plant itself only gets to about 6-8" tall with rather recumbent leaves, and the yellow daisy flowers stand about 18" off the ground. It is naturally a single bloomer, though since I don't bother deadheading, I don't know if it could be induced to rebloom. (I'm happy to allow it its natural behavior.) Can't say I've ever had to divide one of these either - though I did divide one in the course of moving it.
Both prefer full sun...which reminds me that I have a couple of H. hoopsii that have become too shaded and need to be moved...
Hope that helps...
Lori

Funny you mention it Pudge, I went out to do some fall clean up and noticed that each of my scrawny little Knautia had one proud little blossom on it! What a shock! These were plants started from seed late this spring (I tried winter sowing them but nothing came up so re-seeded and voila!)

Good to hear about their growth habit here in Calgary, Lori. I got the seeds from my mother-in-law in B.C., hers grow HUGE.

~GC

Oops, thanks for the correct spelling of "hoopesii", Pudge! (I realized I've been spelling it wrong, mentally at least, forever...since sometime pre-1999, when I grew it from seed - have it correctly spelled in my list now, at last, LOL!)
Also to answer the question more clearly, the knautia starts blooming around the beginning of July.

GC, I had no luck WS Knautia macedonica either, maybe thats the key to start them later in the spring. Anyone have any spare seed for little ol' me. LOL, ok, I'm begging ;)

I too will not see any blooms till next year on the Helenium hoopesii, these one WS very well...I will have to take a look tomorrow to see if there is any red leaves in mine.

Sharon

Thanks for the info Lori. I didn't realize the Knautia would get that tall, nor that the Helenium bloomed that early, so good to know.

I don't recall any particular problems starting the Knautia but then I don't wintersow, except for what occurs naturally, and I did start them late because it was my second order (the half price one) from Gardens North so they were probably started in mid-April. Those seedlings all limped along until I planted them in the holding bed at which time I promptly forgot about and ignored them, and then they just exploded.

Sorry Sharon, I have no seed left over but hopefully will have some next year.

WOW- thats a tall knautia!
I have one that is 2 summers old that the blooms only reached up to maybe 20" tall- but boy does it pump out flowers! Even in the part sun area I have it in. I am still getting new blooms daily, even after a few frosts have ended this seasons growth of several plants.
Mine in zone 4 started early in June to bloom- and the WS seedlings that I started in March this year were blooming come early August. I was quite thrilled by that! Although the germ rate was only about 60 percent of all the seeds winter sown-
I was a little suprised that my WS seedlings display a darker, fuller, more round flower, and are a little taller already than the more mature plant... I didn't think there could be so much variance with this plant.
Thanks for discribing your findings about this plant- I will have to add moving it twords the back of the bed instead of front and center like it is now- to my spring to do list!
It is a favorite of mine- and one I will always have in my gardens- I am glad that others have found it hardy and a reliable boomer- even when left to fend for itself as it has to in my gardens-
Julie

Julie, did you possibly plant a "dwarf" selection such as 'Mars Midget'? If not, then the huge sizes are probably due to maturity and siting (full sun, ample space). Anyway, I've also had the Knautia since pre-1999, and the many very tall specimens I have seem pretty normal.

:busily adding knautia to my Wants List: :)

Hmmmm..... Could be-
I have no idea what cultivar I planted- it came to me from a swap and was only labeled knautia macedonica. I had no idea what I picked up when I grabbed it- I just thought the name sounded interesting- and no-one else seemed to want it- poor thing-
I picked up a "dragon flower" that way too- (obedient plant) and have been removing it ever since!
Julie