Q.watering blackberry and raspberry plants
Once blackberries and raspberry plants have been trimmed for the fall, do we still need to water them?

Generally when the plants are done fruiting they will need less moisture.
Continue to make sure your watering if the soil conditions are dry. Do this until they are dormant.
https://www.gardeningknowhow.com/edible/fruits/blackberries/growing-blackberry-bushes.htm
https://www.gardeningknowhow.com/edible/fruits/raspberry/care-of-raspberry-plants.htm