Unless you consider them very unsightly right now, there's no reason not to let them stay green as long as possible. You can cut them back after they have frozen and died, or even cut them back in spring. They will naturally die down all the way to the ground when they do go dormant. The stems should basically fall out on their own or you can cut them down to 1-2 inches. They may be established well enough survive winter whether you cut them or not, but you'll certainly improve your chances even more if you leave them green as long as possible. September-planted mums sometimes make it and sometimes they don't. But the green leaves will allow the roots to continue getting deeper.

Did you trim the flowers after they finished blooming? If not now is a good time. Below is an exerpt from a newsletter I receive from a local lavender farm...dated 12/4/08 3. Garden Note: Prune Your Lavender Now Pruning lavender is essential to good plant growth and flowering. As a general rule, lavender should be pruned to shape at the end of the first growing season. After the second and following years, plants should be cut back by one-quarter to one-third. It is important to remember not to cut the plants too short. Leave at least one inch of leafy stem on each branch, as there is little assurance that bare stems will sprout new growth. We encourage fall pruning for several reasons. First, fall pruning allows the gardener an opportunity to identify and cut out dead wood. Second, fall pruning will minimize the chances of branches being broken under a heavy snowfall. Finally, fall pruning eliminates the possibility of accidentally cutting off new growth -- on which blossoms are formed -- in the spring. ----------------------------- 4. Winter Care of Herbs (Indoor Plants) Some professional growers claim that more indoor plants are killed by over-watering than under-watering. This is often the case with herbs; they simply do not like wet feet. So water them when they are dry -- usually not more than once a week. And -- this is important -- don't let the pots sit in saucers full of water. About an hour after you water your plants, empty those saucers and let the roots breath. Fertilization requirements vary by plant. Generally, plants that are largely dormant in the winter, e.g., lemon verbena, rosemary, and scented geraniums, should be fertilized no more than once a month. Actively growing plants such as that basil you treasure should be fertilized every 2-3 weeks. Basil requires lots of light (14-16 hours a day) and warm temperatures (at least 60 degrees at night). It loves a sun-filled room, but don't place it too close to windows where night-time temperatures may drop down to 45-50 degrees. Rosemary is an impressive indoor plant, but it can sometimes be difficult. Start by thinning out the plant to allow good air circulation. Rosemary wants all the light it can get and prefers cooler temperatures in winter. A drafty south window is a perfect spot for it. Do not over water! And remember that most rosemary is hardy down to 15 or 20 degrees; don't bring it in too early. Bertha Reppert of The Rosemary House once said that rosemary should be brought in after Thanksgiving, moved back to the garden in March, and taken for a walk on nice days in winter. If you're still bringing plants inside, remember to properly prepare them. Plants that have been in the ground need to be dug up and potted. Plants already in pots need to be checked to see if they are root bound. Repot any that are. Wash the soil off the roots and prune any broken or oversized ones. You should also prune the branches taking special care to open up the middle of the plant to allow good air circulation and let in light. As a rule of thumb, both the roots and branches should be cut back by about one third. Give your plant a serious shower to wash off as many insects, larvae, and eggs as possible. And remember that most insecticides kill only adult insects -- not larva or eggs. In order to insure that you've gotten them all, spray your plants with insecticidal soap every 5 days for two weeks before bringing them indoors.

Spanish lavender does tend to be a bit more of a sprawling plant than the more common (and hardy) English lavender. Cutting it back now in a zone 8 climate will not hurt it and can encourage stronger, more upright growth, a bushier habit and more profuse blooming next season. Be careful not to overdo, however - do not cut into the woody portions but trim back lightly and you can remove some of the more floppy stems. Also growing it in very lean, almost poor soil and not fertilizing or overwatering will help its growth habit. Interesting you should remark on its fragrance - Spanish lavender is generally considered one of the least fragrant of the lavender species, with an almost piney, antiseptic aroma concentrated in the foliage and not the flower bracts. It was used as a room "freshener" in olden days.

hi -- if you're in a new yard, you'll probably have a better idea in the spring of what method works best for the conditions you have. personally, by late fall i've pretty much lost the motivation to do much yard work. -- the messy look of the dead/dying leaves doesn't bother me, so i don't do a thing to my hostas and let the leaves turn to compost on their own. i gather up what ever is left of the old leaves in the spring when i have more enthusiasm and when the new growth is emerging. in contrast though, my mother always does a major fall clean-up. in her zone (5) and her yard conditions (shadier and wetter than mine), if she doesn't get the dead leaves up before winter, her garden becomes not only the wet slimy mess that you describe, but, as a result, also a MAJOR slug party. the only way for her to stay ahead of the slug invasion is to clean the beds out in the fall. lucky for me, i don't have a severe slug problem, so i don't have those worries. in general, if leaves are still green, they're still producing food, and so best to leave them alone til they turn.