Who sells local/Maryland Blackberries
We built our house just over 3 years ago and cleared a batch of the wild to create a yard. We left as many blackberries as possible on the perimeter. We have what I am thinking are two varieties based on the size and taste of the berries -- nope, no idea what varieties. The wild is fairly homogenous and the trees are all very young. It might have been a farm field a decade ago. I want to get a bigger berry and generally I want to add to the gene pool; I don't mind the blending of my new berries with the originals. I want to stay thorny though. While I have you guys, how would I contain the runners in a field? I am not really interested in losing the yard and I noticed mowing the upshoots still leaves a happy stubble with stickers to step on.
Blackberries are a native plant and have been cultivated and selected for so many centuries that one would need DNA testing to determine whether a plant was "wild". Within the species, there is some natural variation, as you have noticed. But to plant blackberries that will do well in Maryland (which are basically selected versions of the wild ones you already have), you can simply order them from a catalog such as Stark or online. We have a short list of recommended thorny varieties in our online pub, "Getting Started with Small Fruit": http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG68_Getting%20Start... These should be bigger and tastier than your current plants, which were probably planted by birds.
In our website's Grow It Eat It section, there is also lots of helpful info on how to grow and harvest blackberries.
Thornless blackberries do not have runners, incidentally. Thorny ones do. This is a major way that they propagate themselves. To control their spread, you can lay heavy landscape fabric (the kind that allows water to get through) around a berry bed. You'll need a wide swatch. Commercial landscape grade will hold up to sunlight and not degrade quickly like most landscape fabric. Read the label carefully.
Another option is to use the tough black plastic edging that comes in rolls and you insert vertically into the soil to block the roots.
Most folks simply mow around the berry bed on a regular basis during the growingseason since the stubble is minor.