The Prime series blackberries fruit once in the Fall on the new canes and once in the late Spring / early Summer on the 2nd year canes. I have 5 Prime Ark 45's which are in their second year. They fruited well in early Summer and are fruiting now. Looks like they will go until it frosts 2-3 weeks from now in my area. Your Prime Jan's seem to be much more productive. I have had probably 2 pints so far but they only started producing about 2 weeks ago. The berries are huge though, averaging between 9-13 grams.

Thanks jtburton, You are correct on the size of the berries. Mine are about 3/4 size of a golf ball, or size of a mens fat thumb. Don't take much to make a gallon with these Prime Jan variety. And I might add they are a very good tasting berry.
These canes that grew this year with the two crops, will there be new canes come up this fall for next year's berries?

Generally, the canes that are new this year and produced berries in the Fall, will fruit again next summer. You will want to prune back the top part of the canes that fruited this Fall in late winter and remove the cane entirely after the Summer fruiting. Next year, you should have a series of new canes emerge in the spring and fruit in the Fall.

I let my canes grow taller this year than last year and as a result they have grown too tall (7ft) and now require some support to keep from falling over. They are also especially susceptible to strong winds when they get this tall. Next year I'm going to prune them back mid-summer when the new canes reach about 5ft, which should make them more stable.

As for the flavor, my Prime Ark 45âÂÂs have a good, traditional blackberry flavor which ranges from mildly tart to mildly sweet depending on the amount of sunshine they get. The best thing about this variety, in my opinion, is that it allows you a good supply of fresh blackberries when no one else has any locally available in the Fall. I have also noticed that I have had zero (fingers crossed) bird problems with this Fall crop and the bugs have been generally mild too. My Fall raspberries, on the other hand, which started ripening in mid-August, were so plagued by stink bugs and birds that I just removed all of remaining fruit and blooms them for the season.

It sounds like the Prime series is a good berry. Nice about the fall fruting! Funny how things can be so fifferent in other places. i have fall raspberries, and I have only ever seen one stink bug, and the birds don't touch them. i have multiple cultivars, so who knows? I guess the scare tape, and the dog is working!

I had few stinkbugs last year and a bunch this year, so I took a calculated gamble and removed their food source at the height of the infestation (e.g. Fall raspberries). A new brood has arrived but they haven't been as destructive as the stink bugs earlier this year. I have hundreds of them though on and around my house. It has even made the news here: http://www.wcpo.com/money/consumer/dont-waste-your-money/how-to-fight-the-stink-bug-invasion