A couple of weeks ago I bought a Reuben Blackberry plant and I noticed strange red spots on it. Now the leaves are beginning to turn yellow and dry. I used Natural Peat for this plant (local gardeners recommendation).
The simplest explanation for the yellowing leaves is transplant shock, which is very common in the first few months after transplanting:
The red spots could be caused by Blackberry Purple Blotch, a disease caused by Septoria fungi, especially if the spots are/were present on the stems as well:
http://whatcom.wsu.edu/ipm/manual/black/purple_blotch.html
Alternatively, the symptoms for Anthracnose might also match for the spots:
https://plantdiseasehandbook.tamu.edu/food-crops/fruit-crops/blackberry-dewberry-and-boysenberry/
What is the best fertilizer to use on thornless blackberry bushes? I planted several varieties of thornless blackberry bushes five years ago. The first two years I had tons of huge berries. The past two years they have not developed any blossoms. There isn't any sign of virus or disease. I have cut the canes way back every year and the bushes fill in beautifully. I have garden fabric around them with bark on top. The only other plants in the area are raspberries and blueberries.
Here are links to refresh you on the care requirements and pruning practices.
https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberries-not-fruiting.htm
https://www.gardeningknowhow.com/edible/fruits/blackberries/growing-blackberry-bushes.htm
https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberry-pruning.htm
http://ohioline.osu.edu/hyg-fact/1000/1431.html
https://content.ces.ncsu.edu/pruning-and-training-thornless-blackberries/
I read about problems with blackberry bush not producing. Mine is over 6 years old and never has bloomed or produced fruit. It has put out new plants and spreading. Maybe it is the soil. Should I try and transplant next spring to better spot? The rest of my garden is fine. Get plenty of vegetables. I live in southern New Mexico.
If the site is generally good in terms of the light levels and other characteristics, you can try to amend the soil to the correct pH and nutrient levels for blackberries. A soil test can help you decide what to do.
Otherwise, you can replant to a site which you believe has better conditions. This article has advice on site selection and soil conditions for blackberries:
I planted 2 blackberry bushes that vine out this past spring and they grew great but, of course, no berries yet. I have only seen how to prune them after they have had berries. How do I cut them back this first year?
I would leave the Blackberries for now and prune them in the early spring.
Make sure you identify the type of berries that you have planted.
Here are links for you.
https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberry-pruning.htm
http://extension.oregonstate.edu/gardening/help-cane-berries-bear-more-fruit
http://www.fruit.cornell.edu/berry/production/pdfs/rasppruning.pdf
I trimmed my blackberry vines back and they started to bleed a lot of juice out of the stem. Is that clean water or what coming out? These vines are about 1 inch thick down to 1/2 inch thick. It looks like clean water to me. I was just wondering if I could taste it safely. Thanks
Pruning is generally done when the plants are dormant.
Your plants are producing sap from the pruning cuts since the plants are not dormant.
This article has proper pruning techniques.
https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberry-pruning.htm
Bought a house this year that had a blackberry bush. Do I need to cut it back for fall/winter? Had a new cane that grew up and the old came I cut down. The new one was tipped at the top at about 4 feet. Now I have long branch offs from this. Just not certain if I need to cut them, as some are over 6 ft in length. Just want some proper guidance. Would love to send a picture. Thank you!
These articles will answer your questions:
https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberry-pruning.htm
http://www.lsuagcenter.com/topics/lawn_garden/home_gardening/landscaping/lsu-agcenter-horticulturist-explains-importance-of-summer-pruning-of-blackberries
Having been unwell for about 22 months, some wild blackberry plants have set up in my garden. How can I remove them with none returning?
These articles will help you control the blackberry infestation:
http://extension.oregonstate.edu/gardening/node/580
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7434.html