K-mag is fertilizer that make melons and fruit sweet just apply small amount twice in fruiting season the only place I've found it where blend fertilizer for pasture grass.

Watermelon grower use in area with high soil sulfur to sweeten melons.

Heh, strongly prefer thornless, eh? Yeah, we have tons of wild blackberry here, all thorned. I am convinced we have caught them in the middle of an evolutionary leap into becoming carnivorous plants. The thorns are all directioned so that you can easily reach in to get the fruit, but heaven help you getting your hand back OUT!

Only reason to let you get the bait but not get back out is if you intend on eating what you've caught, those blackberries just haven't evolved a mouth yet, but I'm keeping my eye on those buggers...

Strange thing is that I usually like sour fruits. Tart cherry is my favorite fruit. I love black currants. I love eating lemons and cranberries. But blackberries do not attract me for fresh eating when they are sour.
Olga

If you'll consider thorny, Kiowa is great - but it's one THORNY devil. Largest berries I've ever come across, and good flavor without having to wait until they're dull and ready to fall off at the slightest touch.

Kotata is also very good, but it is also thorny. I am trying several thornless trailing types to see if any of them are hardy enough. Unfortunately this last winter was too mild to test them. They are all western trailing types, I find they taste better than the erect varieties I have tried. Kotata has proved to be hardy and tasty so its the only definite positive so far; but, it is thorny (small thorns at least). I have never grown Kiowa.

Scott

Thanks for suggestions, Luckuy and Scott. I see Kiowa is offered by several nurseries. Scott, where did you get your Kotata?
Olga

Olga, I got mine from Burnt Ridge. Kotata seems like it has a touch of raspberry in the lineage, not as much as Logan or the other hybrids, but it is a bit more on the raspberry side of flavor than your standard blackberry.

Scott

Thanks a lot. Just ordered both Kiowa and Kotata ;)
Olga