Thornless Blackberries are probably the easiest fruit crop that I have ever grown, and the rate of return is phenomenal.
Flowers in spring
Immature fruit
Daily fruit harvest when fruit matures in mid Summer
Care and maintenance for thornless blackberries is extremely easy: provide supplemental irrigation during dry periods, fertilize once a year with a balanced slow release formula like 10-10-10 and mulch around the plants to reduce weed competition (and keep tidy). I have experienced no pest or disease issues, which is remarkable considering this is Florida (I love this state, but it is literally a hotbed for pests and disease vectors).
Pruning advice was confusing when I researched it online, so I did my own thing and it worked out pretty well for me. The plants were put in the ground in the fall of the first year, the plant had numerous shorter canes or branches, and a couple of longer ones, I believe these are referred to as primacanes. I left them as is when the plant went dormant through the winter. In the early spring new foliage emerged and flowering occured shortly thereafter. The flowering was sparse, but all the blooms were pollinated and a decent berry harvest took place mid summer. Within a few months of the fruiting being complete, the old canes began to die and new incredibly long canes emerged which I believe are called floracanes. Therefore I pruned off the old primacanes and trellised the new long floracanes. These then went dormant in the winter and followed the same path of leafing, flowering and fruiting the following year. Simple and easy.
The research on pruning wasn't entirely in vain, I did learn that trellising the canes will make it easier for pollination and fruit harvest. The thornless varieties do not grow dense and bushy like the thorny blackberries you find growing in the wild. Looking at the 5' and 6' long floracanes my plants were producing just laying on the ground getting stepped on and broken convinced me there was merit to the trellising tactic. So all six of my blackberries are trellised on coated wire attached to 6' t posts.
This summer was our first real harvest from the canes, last year the fruit from the primacanes was somewhat meager. The canes this year produced so many flowers that I did not truly believe that they would ALL produce fruit. Happily I was wrong. The plants produced so much fruit that we were at a loss of what to do with it all and finally ended up letting the birds take it. Next year I will be better prepared and am already getting the hang of homemade wine making!