You may want to investigate the Seattle Public Utilities SEA street program for some possible planting solutions. The SEA street program was designed to reduce runoff and protect nearby salmon spawning streams but it could certainly be applied to any drainage ditch situation. The drainage ditches have been enlarged and converted to swales or natural runoff recepticles, but the plantings have been utilized to absorb or divert the majority of the runoff before it reaches the storm sewers and eventually the streams. The plantings are primarily native in origin.

Take the virtual tour with the link - it's pretty interesting. Or better yet, drive or walk through the neighborhood to see firsthand. It's the Pipers Creek watershed in north Seattle and has been expanded to include several more blocks than the original progarm included.....a testament to the success of the program!

ps. I grow an evergreen groundcover honeysuckle myself (Lonicera crassifolia - assume it to be the same one SWGB refers to) and it would not be my first choice for this situation. And it's not an easy to locate plant, either.

Here is a link that might be useful: SEA streets