Can you do a soil test? How's your soil's pH?
I would suspect they need more phosphorus and/or potassium if the roots come up so easily (or else too much nitrogen; or else too much water and/or a fungal infection). Are the leaves small, too? Phosphorus helps leaf size, roots, plant maturity, and cold tolerance; it also has a role in growth and flowering (probably in fruit size, too). Potassium helps plant and root strength, as well as fruit size, heat tolerance, water absorption, etc. Potassium strengthens plants against disease and pests, too. Nitrogen is more available when more water is present, I believe. Phosphorus is less available when it's cold. Copper is said to increase the water content of fruits, and to help protect against disease (at least some fungal disease).
This link says some other insightful stuff about phosphorus.
Do you have a picture? Do the leaves look normal?
How do the berries taste?