i want to see pictures of your unruly tangle ... mine have chosen to work their way up into a 5' bonanza peach ... not what had been intended ... but perhaps acceptable ...
Usually you don't trellis blackberry canes. They are erect.
With an eastern facing exposure I wouldn't worry about any damage to roots. I would consider it ideal for the summer.
Mulch, mulch, mulch!
If the base is exposed paint them with 50% white latex paint solution---this will make IDing the dead floricanes (post 2nd year) for removal at pruning time easier too.
I am guessing the lack of annual pruning has led to the bending of your blackberry canes into a tangled mess by letting them get too tall as primocanes without pruning them for year two rather than you have a non-erect variety that (as far as I know) doesn't do well here. But I would be happy to find out I am wrong especially if you know the cultivar's name you have.
Growing Blackberries in the Low Desert (PDF) AZ Coop Ext
Well, this is about ones years worth of growth as it was planted last year about this time and it had some small twig that has since died. This is all new growth through the last year.
I have no idea of the variety got it from the AZRFG and the gentleman said, "I have no idea what kind this is but I get blackberries off of it every year as big as my thumb" while holding up a giant set of hands and a thumb the size of a small cucumber.
Maricopa has specifics about caining types of blackberries and this is not caining so I'm at a bit of a loss. I mostly disregard anything non-phoenix specific for gardening as "full sun" is full death here.
I might consider trellising then if it won't scorch. Thoughts on a trellis? I should add this AZRFG had it apaprently on a chain link fence which he stated got some unusual shade from surrounding trees.
AZRFG had Rosborough blackberry plants this year. The man I spoke with said that's the type they recommend for Phoenix, so it's probably what you have. I bought one, but my dog ate it. I've since planted a Ouachita I bought at Baker Nursery -- it's a stick!
Wow, if it was from the AZRFG greenhouse then it was either a Rosborough or Brison (which are cane types) as those are the only two cultivars they have. If it was from one of their plant sales were members bring in and sell their own it could be a trailing; which is what I suspect given the seller's comment. It will actually be wonderful if it does produce well here. You say it has thorns so that narrows it down. It is doing quite well too other than crawling along the ground. Nice area...mulch and gutter drainage. Does it get 6-8 hours of sun---seems like a western and other facing wall too besides the eastern one?
If nobody else comments about trellising then I would go with my first link above. Notice in the cartoon diagram they train the new floricanes onto the trellis and the new primocanes are run out parallel on the ground. Makes it easy to remove after fruiting is over and then moving the next floricanes onto position. I will see if I can fine a better description as I have seen it somewhere.
edit: found it
someones yard, not greenhouse so it's a totaly mystery. The gentleman didn't himself know the variety which is fine, but plays directly into my own neorosis.
The picture has me facing south. It gets sun until around noon daily so roughly 6 hours if one counts the first hour. more in the summer as the sun is higher in the sky.
I'll trellis this shortly then. Should I await until Juneish (when it's blazing hot?) in order to allow canes to produce fruit or trellis asap? some of these canes are wound wonky like and won't appreciate trellising. I do like the two wire trellis idea although I admit with the thorns this job has me a little nervous. I just trimmed my fan palm and my hands are cut up, and now this?!
Do you want to wait until June when its blazing hot? Yeah, me neither.
I love that you have mulch all over your bare ground!!! Yeah mulch!
My rosborough plants fromt he AZ rare fruit growers plant sale, also seem to creep along the ground... they haven't grown as much as yours because they don't get hardly any sun, but they are still alive, and I haven't had sucess putting them in a place where they get lots of sun. I don't see why you couldn't trellis them...try it and see what happens.
Nice! It looks as if we have similar trellising arrangements. This photo was taken at the end of March:
The one in the foreground still looks pretty much the same now. It's a Rosborough I got at last year's VPA plant sale. I had two, but one died. It's kind of scrawny, and hasn't produced a damn thing. But it has a little 8" or so floricane popping up now.
The one farther away is also a Rosborough. I bought it at Root Phoenix (I think the seller was the same AZRFG guy) in March, to replace the other one that I bought from the VPA plant sale that died.
Now, it has a floricane on it that's about hip high. I'll cut it down to 48" next month. It has exactly one berry on it. I also need to get some more mulch.
Brian: Would you be interested in selling some canes that I could root?
I have had ZERO luck with blackberries.
If you'd like, email me directly: ernie 85017 at cox dot net.