Only 1 has sprouted leaves - and very beautiful, healthy leaves too!

I got the roots from Raintree Nursery online. They looked great. I planted them about 4" deep in big 18 gal rubbermade bins (w/lots of drainage holes on sides & bottom) outside (I'm in NW NJ zone 6) - filled with: some leaf mold on the bottom, some bagged garden soil, and then about 12" of bagged composted manure.

I planted them horizontally instead of vertically. They didn't get a lot of water the first 5 days, but then I watered & mulched & it's rained alot.

Any thoughts as to whether something's wrong w/the other 3 roots & what I should do something about it or whether to change something?

Thanks & all the best, Tree