I'm in 6a/5b and I don't plan to protect them at all. If they don't make it, that is fine. i don't want to have to mess with them every year. It's a great year to see what can make it.
If not I will try others or replace them with raspberries which never seem to mind the weather.
I'm not sure if what you suggest will work? the only way I could do that is with my tank sprayer, as I would not want to hook the hose up in this weather.
See what others say...

I think that blackberries that are good for zone 5 or 6 will be okay. I set out an apache and a natchez this fall and this morning we have 14 degrees..

I have a Natchez, Triple Crown, Chester, and Navaho, unprotected and it was -3 yesterday morning. i'll report back in the spring. It's going to be -10 Monday night.
I also have others and will report any problems. One is protected The Wyeberry. It's buried under straw. I left one cane exposed, just to see what happens. It's a rare plant so i decided to protect it.

So the weather didnâÂÂt cooperate with my plan. Freezing temperatures were delayed until later in the evening, so I couldnâÂÂt spray the plants with water before the deep freeze arrived. There was some rain yesterday, so hopefully it helped provide an icy cover ⦠but on the downside, the rain melted much of the snow that was protecting my trailing blackberries. At -4F now and at least -10F tonight, this should be a good test of blackberry and raspberry cold hardiness.

The low temp in my backyard so far this year was -7F. There were other temperatures locally that fell much further, but that's my lowest confirmed temp. At this time I also had sustained 20MPH winds with wind chills as low as -37F. The temperature stayed under -1F or lower for 24 consecutive hours.

Is winter kill apparent immediately after the weather event or does it require waiting until spring?

I don't know? I looked at mine, and I can't tell? I do know do not trim until late winter/early spring. If we get more the damaged part will protect the good growth. This is advice given to citrus growers. Lot's of citrus was damaged in CA this year. In areas that are marginal for citrus. We got to -14 degrees. This year is a good test. If any are not hardy I'll be glad to find out now. I will try others, and eventually root tip the hardy ones to fill all spaces. I ordered three more for spring. Yeah -14 is 4 degrees colder than my zone. Curious also to see if any raspberries will be hit. Or if buds survived on the fruit trees. The only good thing it was cold for a long time, so they were well dormant when the weather hit. IMHO in zone 7 and 8 plants die because of the swings. In my zone once cold it stays cold, no extreme winter warm-ups. Even now with expected warmer temps, it snowed this morning over an inch. High in the next few days will be 41 degrees. But back to the teens by Wednesday. Not really high enough for the plants to think of coming out of dormancy, but in zone 7 and 8, your highs may induce plants to start growing. Since we have all had lot's of chill hours. Scott and others often reported many blackberries not hardy, but I think the temp swings is the problem. Also possible the fact they are in pots, and not the ground. I expect many he said were not hardy in zone 7 to be perfectly hardy in zone 6. Again from the temp swings, and possible growing conditions (pots vs. in ground).

I should be in a good position to answer the following questions this growing season:
⢠Can you successfully grow trailing blackberries in zone 6 by covering them with row covers?
⢠Is there a particular variety of trailing blackberry that is hardier than the others?
⢠Are thorny boysenberries really cold hardy to below 0F?
⢠Are the following varieties of eastern blackberries hardy to zone 6: Triple Crown, Ouachita, Kiowa, Prime Ark 45, Osage, and Black Satin?
⢠I also have a number of raspberries that have had their hardiness claims tested.

Drew and jburton,

Please do follow up with reports on the hardiness of your blackberries this spring and summer. Your results would be helpful.

Thanks.

Looking forward to those answers! I can add Sanchez, Navaho, Chester (this is hardy no doubt), and Wyeberry.
And can answer
⢠Are thorny boysenberries really cold hardy to below -10F?
Unprotected, they are hanging on trellis. I just went and looked at it. A couple tips are wilting, but the main stem where it is not red, looks green. It looks good to me. But it's way too early to tell, damage might continue from tips.
I really do not want anything I have to protect, so if it's not hardy it's just an opportunity to plant something that is.
Berries Unlimited says -10 without protection. Even though it got to -14, it should be OK with some tip burn (less than 1 inch at this point). I doubt I'll ever feel -14 again in my lifetime. I went out there, and it was brutal!!

I would like to try Osage and Prime Ark Freedom.
Loch Ness, Apache, and Black Diamond are being added this spring.

I have a couple in low areas, and that might kill them if we have a wet spring. If they die, I will build a 1 foot raised bed in that spot and replant new ones.
I'm adding Niwot primocane black raspberry. Excited about that one! Looks like though it may not produce the first year even though primocane fruiting. It tends to fruit too late the first year. I've seen that with a red too. It fruited earlier the following year.

This post was edited by Drew51 on Fri, Jan 10, 14 at 12:28

A one-time spray with water won't do any good.

The water must keep coming as long as temps are below freezing. It's the *continuous* ice formation which releases heat from the water.

I've got Triple Crown planted 2012, made it through 2012 and 2013 winters covered with multiple layers of burlap (old coffee bean bags). I was worried about 2013-2014 since we had some very bitter cold without snowcover, but I uncovered the canes a few weeks ago, and just this week took a peek at some I was tip-rooting (trying to move them to another row since I planted 5 in same row with raspberries and now the raspberries are spreading so want the row to themselves). Roots look good, I'm leaving them covered through heavy rains and cool temps right now, but canes are starting to get leaf buds. I did cut the canes to separate from the mother plants, leaving some buds on each section.

Got a handful of berries off those 5 original plants last summer, hoping for more this year, and will keep tip-rooting to fill out the new row (not sure when/if I should move the original plants).

I want 1 row of Killarney and 1 of Encore (not spreading as much, that's in a second row with a fallbearing variety I got off Freecycle). Plus 1 of TC and maybe 1 of the fallbearing (which is spreading to the south, marked them coming up through the mulch so just plan on mounding dirt on top of them, only a couple need to be moved, the rest are coming up pretty much in a straight line).

I probably have to find a new spot, but DH pulled out a lot of the wild black raspberries when he dug out the multiflora rose from the back field. Saw post about Niwot - did you have to call Nourse to order?

My fallbearing raspberries (could be Autumn Britten, woman couldn't remember) flowered but weren't pollinated last year even though I uncovered them when I saw blossoms. Had covered with sheer curtains to try to keep the SWD out - saw a few on the Encore, was trying to pick the TC ASAP to keep ahead of them. Think there would be a problem with Niwot and SWD?