That's all I ever do with brambles.If there are some roots,I make a cut about three to four inches,put in a pot and treat like a new plant.Sometimes they get started by cuttings and mist the leaves,until roots form. Brady

Typically, in milder climates, you can just let the tip rootings overwinter in place; by spring they are easily cut off and replanted. I cut them off the original plant leaving up to a foot of cane and leaves on the new roots.

I would bet you could do all this much earlier in the process, say when there are multiple 1" new roots.

Most caneberries, once lateral growth has stopped, will tip root into any exposed somewhat soft soil, no need to bury; perhaps just staple down in the desired spot.

If it has any roots, it should take as a new vine. I usually discard them, as evey plant I don't want to tip root does, and the one i want fails, unreal! I tried to tip root a wyeberry last season and the darn cane just died! I inspected the cane, no borers, nothing!??
I'm not sure what happened? I think I did it too early. I'm going to take some cuttings in late winter and try to root them, and if they do not work, tip root at the end of the season. My black raspberries are really easy to tip root too!
Each plant manages to get a few rooted canes every year even though I remove them, and try to keep the canes from doing it. Every year some sneak past me somehow so I shorten the cane pull the roots out and toss!

My Allen black raspberry threw out 11 primocanes from the crown. Wow! I removed 2 weaker ones. The nine remaining are huge canes! This one plant will produce hundreds of black raspberries next year. Nice and neat too, the lateral branches are all at the top of the plant. So easy to trellis them. The canes are 7 foot tall. They need no support, they grew straight up into the air. Laterals formed at between 5 and 6 feet. many went to the ground and rooted. I cut them, removed roots and tied them to the trellis. Some laterals are 6 feet long. It well may produce 1000 berries. Hard to tell? Last year three canes produced about 100 each, and now I have 9! A very impressive plant!

I know one person wants a wyeberry, if any others do, let me know now so i know how many plants I need to make.

I have a Boysenberry too! That's Burbanks cultivar right?
I have "Burbank's white" blackberry too. It still rather young.
I should get some fruit next year.
I heard Marionberry is better, I have one of those too, I just obtained one this fall. Hope it makes it!

Here is one cane of Allen. It has clusters of berries with at least 7 berries in each cluster, and I can see about 13 clusters, so that's 91 berries there. Some clusters have 10 or more berries. If you go to photobucket and expand the picture (click on image) you can see a lot better. Looks like at least 15 clusters. The plant is going to have 1000 berries easy next year with 9 canes! Maybe even as many as 1500. One plant, very nice!
Where the heck next years promocanes will have room on the crown is beyond me? Maybe it will only throw out three canes next year, we will see how it goes.
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Here's another cane running to the right across a sea of red raspberry canes. Notice the blueberry at the bottom. Easier to see on photobucket. Yes it was a good year for raspberries here! Sorry a little off subject, but these plants tip root too, so just thought I would show you guys. I had about 7 tip rooted laterals I pulled of the ground on this plant this year.
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The buries tips need water to set roots. They should set roots over winter.

I have a number of trailing blackberries, including boysenberry, and they tend to tip root (tip layer) easily. They do set root easier when the soil is moist and after they have started to slow down in growth. If you gently pull on the cane and it stays in the ground, you have a viable new plant. Just cut the cane a few inches above the end of the rooted cane and then transplant. You can dig it up after cutting the cane or wait until spring - either way works.

The blackberry variety Boysen was found in an experimental berry patch once tended by a Mr. Boysen around a hundred years ago. There were no precise field notes taken, so the parentage has been guessed at.

Mr. Boysen may have known Mr. Burbank.

Once it starts to come up from the "mound" you can cut it, remove the old appendage (nurse) stub which is upside down and dig it up. If you want to wait until 5th leaf might not be a bad idea though roots will start to become established pretty early.

Tip rooting Boysenberries turned out to be dead simple. No reason to over think the process at all.