What should you be doing (or not doing) in the garden this Fall to help your plants survive the Winter and thrive next Spring? How do you protect bird nesting and pollinator habitats or get a jump-start on pest control? Here is a detailed Fall to-do list to help you “put the garden to bed.”
1. Leave the Leaves
Wildlife experts and conservation groups urge us to NOT rake up or remove our fallen leaves. In many cases, this is great advice and will benefit lots of bees, butterflies, and other pollinators and beneficial insects, as well as birds that depend on them for food. Here are some tips on how to best handle those messy leaves for various situations in your landscape:
- In shrub beds and landscapes areas, rake leaves into beds and underneath shrubs as mulch—allow to break down over time (takes about 6–9 months for most leaves to decompose). You can also collect and compost leaves to use later as mulch once they are broken down. Avoid piling wet leaves around Winter Pansies to reduce fungal issues.
- If you can’t see your plants underneath the leaves, it is probably wise to pull them back. Some plants have extremely waxy or slow-to-decompose leaves, such as Evergreen Magnolias, English Laurels, and Rhododendrons. If possible, keep these leaves underneath the plant they fell from and let them break down slowly in place.
- Do not leave a thick blanket of leaves on top of turf grass or lawn areas—only a fine layer of chopped or shredded leaves should cover grass to avoid damage. Large leaves can be mowed or shredded to make smaller, but avoid doing this unless absolutely necessary—shredding can damage insect larvae and changes natural texture and composition.
2. Mulch & Protect
Get ready to mulch and protect tender plants and garden beds. Use about 3–4 inches depth of compost, straw, wood chips, or fallen leaves to cover the soil. Mulch helps protect the soil from compaction, suppresses weed growth, reduces soil moisture evaporation, and adds slow-release nutrients as the material decomposes.
- Since mulch insulates soil, it is best to wait until we have had one or two killing frosts before mulching— Thanksgiving is a great time to mulch and work off some extra calories!
- Avoid smothering evergreen perennials and tree/shrub trunks—keep mulch 4–6 inches away from the plant’s base; it’s okay to cover a dormant plant as long as it is uncovered in Spring.
- Scatter slug bait in perennial beds and vegetable beds underneath mulch every three weeks during mild, wet weather (Monterey’s Sluggo and Bonide’s Slug Magic are animal-safe).
For extra Winter protection, keep blankets, sheets, or frost cloth accessible. Move tender and tropical plants to protected locations for Winter. If you intend to keep a Citrus plant outside, move it to a sheltered area and place stakes or tomato cage in the pot to help support frost cloth, or cover during low temperatures. Only water when soil looks dry, maybe once per month.
Many plants that struggled with pests or diseases can be treated with a dormant spray while they are leafless to improve health next Spring. Fruit Trees, Dogwoods, Lilacs, Roses, and many other edible or ornamental plants can be sprayed with a copper spray for diseases or an oil spray for insects. Spray applications should be done two or three times while the plant is dormant—Thanksgiving, New Year’s, and Valentine’s or Presidents’ Day are ideal application target dates.
3. Plant or Transplant
Fall is the perfect time to plant or transplant! With milder air temperatures, warm soils, and ample rainfall, Fall planting allows roots to become established for successful growth the following year. Our average first frost in the Portland Metro area usually arrives in mid to late November, which means there is still plenty of time to plant, transplant, or divide many landscape plants.
Learn more about planting during Fall by following our blog Fall Is for Planting!
4. Cut Back & Prune
Cut back: Hybrid Tea and Floribunda Roses to chest or waist-high to minimize Winter wind damage. Secure Climbing Rose canes to a support structure.
Prune now: Only as needed—damaged tree limbs or those that may cause damage in wind or ice storms. Provide stakes to newly planted trees in high-wind areas, but remove after the first year.
Do not prune: Rhododendron, Azaleas, and Spring-blooming trees and shrubs—pruning now may remove next season’s flower buds and cause the plant to not bloom—these plants are best pruned after they flower in Spring.
Prune in early to mid February: Japanese Maples, Blueberries, and Most fruit trees. Cut back old foliage on Hellebores, Epimediums, and Sword Ferns just before new growth or flowers emerge.
Prune in mid-February: Most Hybrid Tea and Floribunda Roses, Summer-Flowering Clematis, Winter-Dormant Ornamental Grasses (if not cut back in Fall), and Hardy Fuchsia (cut back to new growth as Spring leaf buds begin to swell).
5. Prepare & Winterize
- Irrigation: Drain above-ground irrigation lines and blow out or winterize irrigation systems.
- Hoses: Pull hoses into garden shed or garage for storage.
- Gardening Tools: Collect, clean, sharpen, and oil tools before storing for Winter.