thornless blackberries

I planted thornless blacberrirs last year. The canes grew about 7 feet tall. This spring the canes look dead but there is new growth at the base so plants look alive. Do I cut off canes above new growth?
Thanks

*Most* blackberries are biennials, and floricane bearing; they behave like summer-bearing(floricane bearing) raspberries; in year 1, a cane grows; in year 2, that cane will grow offshoots, which will then fruit, and another cane grows to do the same in year 3.

In fall/winter of year 2, after they've fruited, the canes which grew in year one will die, and can be removed if you like.

There are some primocane bearing blackberry cultivars, but that doesn't change the fact that canes will die after their second fall.


If these canes grew from the ground last year, and aren't sending out offshoots this spring, they may have been killed by an overly cold winter; where are you located?

Thanks
In Wisconsin on edge of zone 4/5. We had cold and little snow to insulate.

Does sound like it could be winter damage then. I recalled reading that zone 5 was about the limit of blackberries, but a quick google shows that this is highly cultivar dependent, with some cultivars apparently feasible down to zone 3! So, if this particular cultivar can't hack it, there's probably one that can. Good luck!

I have some thornless black berrys aka Brambles aka muire. They are great I was getting 10kg plus from one plant at my old allotment
I grow them left and right alturnate years . Last year being the first year here at La Ravardiere I grew them and tied them to the wall to the left of the plant I got no berrys it being the first year . This year I will tie the new growth to the right and harvest on the left . After the harvest or at latest 29th September I will cut off all the growth on the left ready for the new growth next year . Most important never let the ends of the growth touch the ground unless you want a new plant .
Legend has it that when the devil was cast out of heaven on the 29th Sept and he fell to earth and landed on some brambles which hurt so he cursed the bramble so all the fruit after the 29th Sept will be bitter . Doubt me if you will but the later fruit is always bitter so this must be true

David

gary reif wrote:Thanks
In Wisconsin on edge of zone 4/5. We had cold and little snow to insulate.

Thornless blackberry cultivars are less hardy than most of the ones with thorns.  I live in the Southern Tier of NY in the hills, effectively zone 4b.  If you like blackberries, it's worth a few thorns IMHO.

Thornless blackberries are not as cold hardy as wild brambles.  You can tip layer them by just sticking a growing tip into soil.  Pin it down with a rock or a metal pin made for that purpose if you need to.  They root easily.  Once they start sending up a new shoot, cut the branch near the new plant that came from the mother plant.  Best to prune out any dead growth to just clear the space to make picking easier.  They do get rather large.  Keep mulched to conserve moisture and moderate temperature extremes.    They are a fungal dominant plant so love wood chips or leaves.  Use plenty of compost for optimum berry taste and size.  We also put a trace mineral mix plus cal/Phos and a tiny bit of wood ash on ours.  

David Livingston wrote:I have some thornless black berries
I grow them left and right alternate years . Last year being the first year here at La Ravardiere I grew them and tied them to the wall to the left of the plant I got no berries it being the first year .  This year I will tie the new growth to the right and harvest on the left .

David

I use a variation of this that may be helpful where the winter is severe.   I train them to an upper and lower wire.  New canes are trained to the lower wire and then covered with hay for the winter and the canes that have finished fruiting removed.  In the spring the new canes are moved to the upper wire and the process repeated.  During the winter some cane tips will have grown to the ground and rooted which can be transplanted to increase your patch or offered for sale or trade.