Cabbage Planted last year

Cabbage Planted last year that overwintered and came back better than last year since it is bug free. The aphids really did damage to the cabbage last year. For some reason there are no aphids this year. A couple of thoughts for less aphids: the great number of lady bugs I’ve seen every where including the garden in the city, or maybe having Comfrey planted between and around the cabbage. Good bugs like comfrey like to overwinter in Comfrey so maybe that has helped as well.