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Sustainable Gardening in Autumn
by Ann Lovejoy

Many people toss in the trowel on Labor Day. Here in the maritime Northwest, vegetable gardens can yield harvestable crops year-round and ornamental beds can remain well into winter. If yours don’t, visit some nurseries and buy something in bloom every week or so to build up your autumn borders.

Always tidy as you plant fall bulbs, but simply clear away the clutter, removing fading flowers and foliage so autumnal beauties can shine. Replace spent annuals with winter pansies, hellebores and evergreen grasses. Leave ornamental grasses standing until spring unless they are floppers. If so, reposition the plant where its seasonal cascading will be an asset.

Always divide grasses in spring, since divisions are prone to winter rots. Whenever you move, trim or divide grasses, always wear eye protection, since grass blades are full of silica. Sharp as knives, they can cut corneas like butter — a highly unpleasant experience.

Perennials that are going to seed may need a tidy session. Those that look quite attractive are the ones to buy more of, especially those alluring to birds. Goldfinches flock to feed on members of the thistle family, particularly artichokes, cardoons and blue globe thistles.

Trim unsightly perennial stems back to the best looking foliage. Take bare stems clear back to the base of the plant. Nothing looks sillier than long bare stems sticking up above a rosette of basal foliage.

Good, sharp pruners are vital. If yours mash or rip the stems, use them only for destructive tasks. Anvil pruners are called “the nurseryman’s best friend” because those raggedy cuts kill so many plants. Get by-pass or scissor-action pruners instead.

Sedums like ‘Autumn Joy’ are strong fall performers and need no trimming. Their winter silhouette is lovely and birds like their seeds. To make more, simply cut some stems and place them on the soil. By spring, young plants will sprout from every leaf node.

This is an excellent time to divide old hosta, daylily, and iris clumps. All bloom best when broken up periodically; otherwise they grow woody and bloom sparsely. Use a sturdy, square-tined garden fork to pry out the clumps; big ones may require two forks and two people to lift.

If the plants are too overgrown to be pulled apart by hand, chop them in sections with a small ax or a sharp-bladed shovel. Toss old, woody roots on the compost heap and divide big chunks into smaller crowns with two or three clusters of leaves. Place these in renewed soil, arranging them in triangles or wedges, with each piece facing the same direction. Next summer, each group will be full of bloom and healthy foliage. If you have too many, pot them up for donation to a neighborhood school, church or nursing home.

The final fall task is to spread a deep blanket of compost mulch. Rake half an inch of compost into the lawn, adding more where turf is thinnest. This will not smother the grass, but it will encourage deep rooting, which makes plants more resilient and drought tolerant. For a lovely cool-weather feed that also suppresses weed seeds, add corn gluten, spreading 20 pounds per 1,000 square feet of turf.

Give empty vegetable beds 4-6 inches, and be equally generous in the ornamental beds, taking care not to cover up resting crowns of dormant perennials. Feather the compost mulch lightly, adding perhaps half an inch at the base of evergreen perennials and grasses as well as shrubs and trees. Increase the depth as you approach the driplines, home of most feeder roots. The feeder root zone extends beyond the dripline for as much as a foot for perennials and even further for shrubs and trees, so be lavish with the compost. Your reward will come next season, when your plants look happy with less help than ever.

Ann Lovejoy is the author of many books, including The Handbook of Northwest Gardening: Natural; Sustainable; Organic (Sasquatch Books, 2003, 402 pages, $27.95).

©2007 Caliope Publishing Company