When is the best time for me to transplant Blackberry plants? I live in Anderson SC 29625. -
The best time for transplanting is in early spring, followed by early fall if this planting date is missed. Select a transplant site that provides full sun, air circulation and is well draining. Here is an article that you may find helpful: https://www.gardeningknowhow.com/edible/fruits/blackberries/growing-blackberry-bushes.htm
This article will help you to avoid transplant shock, which is what kills the majority of plants that are not moved carefully:
Even here in Arizona I have been doing well with growing blackberries. What I have are thornless and ever-bearing. The only problem is that the berries are very tart. In preparing some berries for wine a test, they showed no sugar content. What can I do to make the berries grow sweeter?
Most berries will grow tart if there is some nutrient lacking in the soil. Have your soil tested and then amend the soil according to what the soil tests say is lacking. Normally, your local extension service will do a soil test for free or for a small fee.
Some of my canes are 10 feet long or tall. Do I need to cut them back, and if so, how tall should I leave them? They are tied to trellises, but I have trained them to the wires.
Here is an article that you may find helpful: https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberry-pruning.htm
Your advice suggests not planting raspberry plants within 300 feet of wild blackberries. What makes wild ones different than new ones planted? How about blueberries?
Wild blackberries can carry fungus and viruses that can make your raspberries sterile (more information here: https://www.gardeningknowhow.com/edible/fruits/blackberries/blackberries-not-fruiting.htm. Ones you buy from the store should be certified virus and fungus free. This problem does not affect blueberries.
When should I plant my blackberry plants? I live in Zone 9 in north central Florida.
Early spring or fall is the best time to plant them.
I planted some new black berries last Summer. They didn't produce last year, only the cane grew. I didn't prune them at all in the summer nor winter, How much should I prune off now? The canes are about 12 ft long. Thanks
Blackberries only produce on 2 year old canes, so that is why you did not get any last year. You can do tip pruning right now, but do not remove the whole cane. This article will have more information:
What is the best time to plant blackberry bushes in Helena, Montana?
In the spring, after any chance of frost has passed, is the best time. Early fall is the next best time.