What about perennials? It usually takes a hard freeze to kill off the herbaceous (those that die down in the fall) perennials. My fall perennial clean-up is more selective. I've cut back top growth on tarragon, lemon balm, wormwood and oregano. This older growth was unsightly and there's fresh growth in a rosette at the base if I need any fresh. I'll continue around, doing the same for mints, catmint, feverfew, etc. Some things I just leave alone in the fall-
- Woody-stemmed herbs like thyme, sage, lavender. No cutting allows foliage to provide some protection for the crown of the plant since it doesn't die back to the ground
- Coneflower and other plants that provide seed for birds over the winter
- Cold tolerant plants that look good and continue to produce - snaps are blooming again, parsley and sorrel look great and continue to provide harvest fresh or for drying, chives and burnet which will eventually freeze but often provide green foliage throughout the winter (sometimes even under snow)
The best trip was a visit to Mt. Gretna where we grew up. We walked all the paths we used every day and it amazed me how things had grown up. Places I remember being fairly clear were quite overgrown. Some paths were narrow and looked unused. I guess even in Mt. Gretna people drive everywhere.