I am back with some additional notes. The plants that were planted in winter that hadn't reached maturity yet (Still a cutting, able to be removed and replanted without destruction of bush), and the plants that were planted in spring both retained their traits. The bushes I had that lost their traits were already in their second stage of growth during winter n' went into dormancy. It may be due to the dormancy during winter, but this is only one data point.
I will also try to report whether or not the bushes lose their traits come next spring on my world, as it would really suck if the dormancy just killed the traits of fully established non-wild bushes too.
Edit: Wording Clarification