Just a few suggestions:
On dark nights try a dark rattling jig. I've done well with a black/red 3/4oz jig with rattles and a full sized black/red brush hog for a trailer.
On lite nights with a nearly full moon, try a jig/trailer combo in Pumpkinseed or brown/orange without the rattles.
Have you tried looking for rockpiles in or near your hydrilla patches? These can be the spot on the spot.
As a last suggestion, try to find a swimbait type jig head that has the line tie right at the nose, so it'll shed weeds. Use it with a large Big Hammer, Fish Trap or other quality swimbait and swim it right over the tops of the hydrilla with really long casts. This is for a slightly more agressive bite than you're likely to find in these temps.
Tight lines,
Wade