Any clematis growers out there? [View all]

I rooted several cuttings using this method: http://lodgelanenursery.blogspot.com/2011/06/how-to-take-clematis-cuttings.html

I rooted them about eight weeks ago in tall 4" pots filled with sterile "seed starting" medium and using rooting powder. I covered them with old gallon vinegar jugs with the bottoms cut out and the top cracked open to keep them moist. Then I placed them on the ledge of the porch where they got good light, but no direct sun.

And, I am pleased to say, they all rooted. The leaves are looking a little tired, but still green.

Now that they are rooted, I'm thinking they might need a bit more in the way of nutrients to keep growing. Should I re-pot them in larger containers with organic potting soil + some worm poop?

I can't seem to find satisfactory info on the interwebs about the next step. Most say to overwinter them indoors and plant out in Spring, but nothing about when/if to re-pot in the meantime.


FYI, the cuttings were from a Clematis Jackmanii like these: