Not that touch screen thing in your pocket!
Rubus fruticosus aggregate
hardy in zones 5-10
Blackberries are a perennial, some growing to 10' high and up to 10' wide when mature if they have room and plenty of nutrition. They require full sun to partial shade. And while the plant lives from year to year, they will lose their leaves in the cold of winter.
Blackberries can be either erect cane plants or trailing types. The thornless cultivars are mostly considered erect cane types, but some still benefit from a sturdy trellis for support. For example, Navajo needs no support but Natchez is clearly a trailing vine.
Blackberries can be easy to grow if you get their micro climate right.
They prefer rich soil with plenty of organic matter, good air circulation and good water drainage. Optimal soil pH is 6.0 to 7.0, but blackberries can adapt well to most any kind of soil pH. Plant at least 2' apart, though more like 6-8' will give room to mature plus extra room for air circulation.
Do not select a site where potatoes, tomatoes, peppers, eggplant, other caneberries, or strawberries have been grown within the past 3 years. Avoid planting where vegetables have been grown the previous year.
Plant far away from any existing raspberry plants too. The reason is blackberries and raspberries can both be susceptible to verticillium wilt, a fungi associated with those plants. So the idea of keeping them separate is to avoid spreading the disease if one or the other gets it.
If you use mulch, choose something like sawdust or hay, so that you don't encourage fungi to grow under the plants. Eucalyptus mulch would also be an excellent choice.
Trim canes to encourage new growth. Fruit will form on 2yr old canes, and then those canes die at the end of the season. So trim the older canes after harvesting fruit so new canes will shoot right away. New canes will also shoot up from the roots as well.
Just like with peach trees, if you choose multiple cultivars to plant, you can extend your harvest season. It is possible to harvest from July to even November. The following are all thornless blackberries that work well in zones 8 & 9:
Navajo is a mid season blackberry (late July) for zones 6a-10b with exceptional flavor. I would go so far as to say it may be the number one blackberry to plant in this area because of flavor, production and especially ease of care of a bush-shaped plant. Plants average 4-5' high and wide and are highly resistant to disease.
At 11-12% sweetness, Navajo blackberries are one of the sweetest thornless blackberries compared to 9-10% on most of the other cultivars. And while sources say it needs 800-900 chill hours for optimum fruiting, it thrives and fruits very well in all of zone 9 in Florida where the chill hours range from 300-650.
Navaho ripens over a long period of about 5-6 weeks, and produces berries up to 1" in length. It's seeds are so small that some vendors have called it "seedless". It was a 1989 patented variety from the University of Arkansas.
Natchez is an early to mid-season blackberry (June to July). Its semi-erect, thornless canes produce long vines that require some type of support: either a fence or trellis. Average height is 4-5', with canes as long as 8'.
It produces very large flavorful berries with a sugar content of about 9.5-10%. Very high yields.
Some sources say it requires 400-500 chill hours for maximum production, but it does very well in all of zone 9. It has excellent disease resistance overall. Another University of Arkansas release (patented 2007) for zones 5b-9.
Quachita is another early to mid-season blackberry, with a longer ripening season than Natchez: about 5 weeks. Vigorous, upright thornless canes attain an average size of 3-4' height and width, but still benefit from a trellis. It is a heavy producer of very sweet berries: Soluble sugar content is similiar to Navajo at 10-11%.
At 300-400 chill hours for maximum productivity, Quachita is one of the lowest chill hour thornless blackberries. A University of Arkansas patented release from 2003.
we have large Navajo at present 2g/$15ea