I guess by "sapling" you mean "cane".

I defy anyone to prevent a blackberry from doing what most plants are programmed to do: make seed. One cane with a good root system or even a rooted tip will produce a fully-functioning plant.

It's true you will not get fruit from a first-year cane (unless it's one of the newer varieties), but that doesn't mean you won't grow a plant that will ultimately produce berries.

If you want your own patch, dig up one of those suckers, plant it, mulch it, and water it. It's that simple.

okay thanks for the feedback.

Literally gave my friend at work one 12" tip rooted cane and he now has 3 new canes coming up . It will definitely produce a full bush.