Cut them back, plant them deeper than they were and don't worry about the roots being cool. That is a myth. What they meant was moist. Not cool. Moist.

Get a liquid fertilizer with a high middle number. The one I have is 4-10-3. The middle number is for root development. Follow directions on the package and wait.

Aside from that, do you have room for eight jackmaniis? Do you really want all 8 of them when there are so many gorgeous and interesting clematis? If you are going to try to raise 8 of one type, you might as well try other varieties too:

There' Mme Julia Correvon
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=574

Comtesse de Bouchaud
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=130

Barbara Harrington
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=2946

Huldine
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=20

Duchass of Albany
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=30

Hagley Hybrid
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=196

Justa
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=2085

General Sikorski
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=19

Venosa Violacae
http://www.clematis.hull.ac.uk/new-clemdetail.cfm?dbkey=585

:-)

If your weekend is like mine, it's near freezing this morning, so planting as suggested (trimmed back, a little lower than you got them) is going to be fine. I would not fertilize just yet, though. I'd wait until there was some growth - I've had bad luck fertilizing new clematis transplants which stimulates too much grow, which the roots can't quite seem to handle yet.

Just my experience. Otherwise, enjoy!

Wow Michael, near freezing at this time of year. Yikes!! Send it south with some rain please. I do agree that if you have temps like Michael has, just plant the root balls, water them in well, and wait and see what happens. Once you see growth, then you could always fertilize them with, as Janet suggested, a slow release fertilizer with a higher middle number since that is the phosphorus content that stimulates root growth and eventually flowering.

Actually, Miguel I suggested a liquid fertilizer with a P number, and low N&K number.

If I had 8 of the same plant, I'd do an experiment:
On 2 of the plants - use what I suggested
One 2 more - no fertilizer
One 2 more - use a slow release granular
One the final 2 - something else.

Then monitor the results each month. I know there would be too many variables in a normal garden unless you could have them all in a row, receiving the same amount of sun, but it would be interesting. I wouldn't be surprised, though, if they all looked the after 3 years, :-)

So, my newest questions... which is better, morning or afternoon sun? and.. How much deeper than before? is one inch enough? or should I go deeper?

My plan is to put four across the front of the house... two on each side of the front door. Those will be in the sun most of the day.
Then the other four, I will put on the sides of the house where it wraps around to the deck-- which doesn't get as much sun as the front, but is still sunny-- but only morning or afternoon depending on which side of the house you're on.

I plan to pick the four biggest for the front because those have the best chance.
Then the next two strongest looking ones will go on whichever side of the house is best for them. (when I get some advice)
The last ones will go in the least favorable spot--- and then I'll baby them.

I also got four rose bushes, and a box of hostas so I have a lot of work ahead of me today.