I KNOW IT’S hard to get booted and fleeced up and head back outside after a long summer of watering and weeding. But it’s worth it for your gardening enlightenment, as well as the health of your plants.
The big advantage of working the autumn garden is that summer mistakes are still so obvious. It’s the perfect time to assess what is working in your garden and what isn’t. Take note for next spring, when we usually develop an acute case of amnesia, especially when it comes to how many plants will fit in our gardens. Now is the time for realism and planning, when caring for our gardens during the warmest summer on record is still recent memory.
The average first frost date in the Seattle area is Nov. 11, depending on the elevation where you live and how close you are to moderating bodies of water like Lake Washington or Puget Sound. A killing frost, the kind that turns hosta leaves to mush, usually hits a bit later.
Because our climate is relatively benign there aren’t hard and fast rules on what to do when. You can prune, and plant bulbs and woody plants pretty much anytime the ground isn’t frozen. But it’s definitely time to get outside and put the garden to bed for the season. Here’s what to do and not do:
• Do pick up diseased leaves from plants like peonies and roses. Bag them up and put them in the trash rather than the compost pile so you don’t spread disease when mulching next spring.
• Cut back perennials and annuals whose leaves melt into goo with the first hard frost, like hostas, day lilies, catmint, iris and most annuals.
• It’s conventional wisdom to divide spring-blooming perennials like brunnera and iris now, but usually that job is far more palatable in earliest spring when you actually feel like gardening.
The next few weeks, when the weather is still warm and the rains have set in, is great time to plant trees and shrubs. They’ll get well watered over the winter and have a head start on root growth for spring.
• Do mulch around shrubs and more tender plants. Plants that require sharp drainage, like rosemary and Lobelia tupa, resent moisture-trapping mulch, so keep it off the crowns of perennials and away from the base of shrubs.
• Don’t cut back too much. I know an expert gardener who cuts everything way down in early November. I’m sure her spring gardening life is much easier than mine, but her winter garden doesn’t offer the delights of frost gilding spires of fading grasses and birds rustling through the leaves. The spent stalks of sunflowers, rudbeckia, taller sedum, ornamental grasses and coneflowers stay upright for months to feed birds and add height to the winter garden.
• Leave hardy fuchsias alone, even though they look like brittle, bare sticks by now. That top growth protects them through the winter. For the same reason, it’s best to leave spent flower heads on hydrangeas until March.
• Run the lawnmower over healthy-looking leaves, and rake the shreds onto the beds for mulch. With some plants, like Melianthus major and gunnera, you can mulch the plant with its own leaves after you cut it back.
• Don’t walk in garden beds when it’s been raining hard, because even the pressure of a footstep can harm the tilth of saturated soil. What a good excuse to stay indoors on a rainy day.
Valerie Easton is a Seattle freelance writer. Reach her at firstname.lastname@example.org.