I have a Thorntons thornless black berry ..
I'm happy to take 10 or so cuttings right now to pot grow them for next year
propagation this time of the year is so simple , take some new fresh growth tip about 10 inches long and dip it in some rooting compound at the root end of the cutting
Poke it in a deep pot so about 4 inches is above the surface or put it direct in to weed free ground inthe same manner .
method two tip and layer , best done in spring
Find a growing tip nick it just behind a leaf stem to make a spur when it's bent
scrape some soil loose peg it down into the soil with a j hook made of old wire cover the spur with a little more soil and then place half a brick over the spur . It will make new roots at the spur , come late summer sever the new plant and transplant.
How to grow them ... over the years I've found it's best use the fan method
( currently our thornless plant is growing in a 100 litre patio tub & are is not yet set in a fan . )
Set up two stout posts about 10 feet apart & 7 foot above the ground using anchoring & straining points to keep them steady in a wind when there is a lot of growth on the wires as they act like sails . Put three or four taut wires betweem them .
Plant the plant give it a decent capping of well composted manure & straw in January as the new creepers start growing , take them to the left side of the middle of the growing frame and tie them on loosely in a fan shape with binder band to the cross wires so that all this years rods are now on the left, these will bear fruit in August next year .
Next year any new growth is now tied in a fan to the right side . You harvest the left and once it's winter you cut the old dying wood out again always manure the plant each January . fromthen on it's simply follow the harvesting & pruning cycle
The plants can last 10 or more years , to stop the plants sending out suckers beyond the size of the footprint that you decide to have , dig an 18 inch deep trench a four feet in diameter round each plant to sever & kill off any underground sucker roots . you can mix the back fill with manure if you so choose.