Yes, it will grow from seed.
No, it will not need staking.
It does not take up much space so a group of three will fit in under 2 sq. feet. Grow smaller plants around it. I believe I had blanket flower and crocosmia nearby. The one thing I found is that it did not transplant well in the fall.

It's one of the GREAT plants of the summer garden. Fabulous leaves even when it's not in bloom and architecturally stunning. Everyone who sees it asks about it. BTW, I have one plant that takes up three square feet all by itself.

George,

I put in 3 Bluestone plants two seasons ago. I was afraid they'd be whipped into submission by our strong coastal winds so I planted them up against the house...not an ideal position. They sat doing not much with just one or two flowers per plant their first two years. This spring, they have taken off & are stunning even without flowers yet. The leaves are at least a foot long & 6-7" wide...frosty blue in color...much bluer than, say, h. 'Blue Angel'. I've already learned from just the few flowers they threw last year that staking will not be necessary nor do they need to be planted up against the house for protection from the wind. I'll be moving mine come next spring. They are great plants & I agree about a mature plant taking up about 3 s.f. I'll have DH take pictures today & will post later on this afternoon.

Oh, mine are planted in a full sun position & are growing in a lasagne bed so the soil is quite rich. They are not water hogs, however, when making that lasagne bed we used a little peat so the soil holds water well. I do not fertilize any of my perennials....just top dressed with leaf moulde & manure in the spring.

I can't answer the seeding question as mine have only thrown 3-4 flowers in their previous seasons. This year will be a good test as I expect dozens of flowers & will leave the seed heads stand for winter interest & the birds.

Tricia

Thank you for replies.
I ask about selfseeding since in their native ranges they grow along the roads and I was affraid it might be somewhat invasive in a more hospitable environment.

Here a picture of mine, George. They're about 5' tall now & in bud.

Tricia

Here is a link that might be useful: Rudbeckia Maxima

I really like mine too. The leaves are a really pretty color and the flowers are cool too. I haven't had any trouble with it seeding around.
Jen

Mine seed around, but not invasively so. Mine also need staking, but maybe that's because they are planted in pretty rich soil.

I grew mine in clay soil in Meriden, CT and it was happy. I recently moved here to OH and it is fantastically happy, but id doesn't really seed alot, nor does it wander. Very tidy and a great impact plant. It wasn't grown much in Meriden, (or here for that matter) and the blue green leaves are fantastic. Drought tolerant too! It does like full sun though.

Great plant, but I have had trouble with slug damage to the leaves. If they start getting holes, put out bait.

I must stake mine as they grow 7 ft tall and flop over otherwise