Fall Garden Cleanup

September 20, 2017

When the weather starts to change and the leaves start to fall, many of us want to get out into our gardens to tidy things up before the rain and snow come back in full force. But, even though this list may look daunting, it actually can be done quite quickly without much pruning or dump runs with bags full of leaves!

Fall “To Do” List in the Northwest garden

For your Lawn

  • Fertilize grass with an organic fertilizer. Late fertilizing encourages sugars to be stored for a quick rebound in spring.
  • Thatch if necessary, aerate (every other year), and overseed.
  • Add lime. The ideal ph for lawns is between 6.0 and 7.0. The best way to know your soil condition is to have a soil test done, however most soils in the Northwest tend to be acidic due to the high amount of rainfall and conifers in our area. Adding lime over time will make the soil more alkaline, which turfgrass prefers. Lime also makes the soil more hospitable to the microorganisms that help to break up clay soils and make nutrients available to plants.
  • Winterize your lawn mower after the last mow of the season by cleaning off grass clippings and sharpening the blade. Store in a dry place.


Container plantings

  • Freshen up containers with evergreen shrubs and perennials, grasses and fall bloomers like pansies and mums. Some of our favorite fall container plants are nandina, heather, heuchera, acorus, Algerian ivy, osmanthus, arbutus, and leucothoe.
  • If you use plants in containers that aren’t hardy for our zone and if you have the space (and the desire) remove and bring in any tender plants before the first frost, which in the Seattle area is usually mid-November (but beware that we are already seeing snow around Stevens and Snoqualmie pass so it could be sooner this year).
  • You can over-winter plants like banana, echevaria, begonia, caladium, colocasia, fuchsia, geranium, and brugmansia/datura spp (Angel’s Trumpet) in a greenhouse, basement, or garage near a window. Some plants like begonias and echivarea can be stored as houseplants. Check weekly and be sure not to let them completely dry out.
  • It’s also a good idea to bring in any containers that do not have holes drilled in the bottom or that are not freeze-proof, like terracotta, to prevent them from cracking over the winter.
Evergreen Container Planting

Evergreen Container Planting

Planting beds

  • Keep weeds pulled to avoid them going to seed. I wish there was a magic solution other than pulling but sorry to break it to you, manually pulling them is the best way to deal with pesky weeds.
  • Remove spent annuals and vegetable crops. Plant cover crops in the place of next year’s veggie garden. Cover crops reduce erosion and replace the growth of weeds and add nitrogen to the soil.
  • Divide and transplant perennials. Most perennials start to look pretty ratty as we start getting colder temps at night. They can be cut back to around 2-6” and divided to plant in other parts of the garden or to give to friends and fellow gardening geeks like us.
  • Dig up summer blooming bulbs (dahlias, cannas, and gladiolas) and store them somewhere dry for the winter.
  • Plant spring bulbs: tulips, daffodils, hyacinth, snowdrops, and crocus, as soon as night-time temps drop to around 50 degrees (and about 6 weeks before the ground freezes). Plant bulbs in a sunny location in well-drained soil in groups of 5-10. Or for even larger drifts of bulbs plant in groups of 15-30. Large bulbs should be planted 8-12” deep and smaller bulbs 4-6 “deep. If you aren’t sure which end is up, plant sideways and they will right themselves. Cover with soil and water. There’s no need to fertilize newly planted bulbs but bulbs that have been in the ground for a year or more can benefit from a layer of nutrient rich compost or mulch. You can protect against hungry squirrels by covering bulbs with chicken wire and securing in place with pieces of wire before covering with soil.
  • Root-prune large shrubs or trees that you intend to move or transplant in spring. To root prune, run a spade wide around the drip line of the tree to sever roots. This encourages new feeder roots to develop. Ideally you should leave the tree for 2-3 months up to a year before transplanting.
  • Create new planting beds. Remove areas of grass or sheet mulch large areas by putting a layer of cardboard down over grass or heavily weeded area (remove weeds if they have gone to seed) and top with a layer of mulch.
Sheet Mulching

Sheet Mulching

  • Plant new additions. Fall is the best time for planting! Plants are entering dormancy yet are still developing roots through fall and winter. With the increased rainfall and temperature drop they will get a good start on being established when warm temps return. Late blooming perennials like sedums, aster, and ornamental grasses as well as heucheras, heathers, and colorful conifers are great plants for instant fall color and texture.
  • Continue to water until rainfall starts. And don’t forget containers and plants underneath the eves that don’t get natural rainfall. Most damage occurs not because of cold but because of cold and dryness together.
  • Tidy up and cut back any unruly plants and rogue groundcovers but wait until spring to do any hard pruning of trees and shrubs, and especially roses. Pruning can make plants less cold hardy, not to mention that a hard pruning this time of year when plants are going dormant may leave your shrubs looking pretty awful. Wait until late winter/early spring to do major pruning.
  • Mulch. If you didn’t mulch in the spring you can do it now. A 1-2” layer of mulch will help to regulate soil temperatures, insulate plants, cover weed seeds, control erosion, and help keep water from splashing on leaves, which reduces fungal diseases. There are many different types of mulch: leaves, straw, hog fuel, wood chips, bark, cocoa bean hulls (don’t use if you have a dog), pine needles, wine corks, and composted nutrient-rich mulches. Choose the mulch that is appropriate in the area you are mulching (you probably wouldn’t want to mulch with hog-fuel in your front yard but it can work great in a woodland garden, side yard or less frequently seen area).
Mulching Bad and Good Photo Courtesy of Organic Plant Care LLC

Mulching Bad and Good Photo Courtesy of Organic Plant Care LLC

  • Leave the leaves in planting beds to control weeds and to enrich the soil. Leaves that have fallen on the ground are full of nutrients. The exceptions to this are leaves with diseases like rust or powdery mildew, so it’s best to rake up leaves from roses and fruit trees which are often plagued with these diseases. If you have a mulching lawn mower you can run it over your lawn (with bag attached) and then spread the leaves in your planting beds or veggie garden, or add them to your compost bin. The leaves will break down slowly and can be raked up in the spring or left to further decompose. You can also run your mower (bag off) over them and leave them right on the lawn. (Note: leaves shouldn’t be left to sit on the lawn without chopping them up.)
Mulch Mowing Leaves Photo Courtesy of Kansas State University

Mulch Mowing Leaves Photo Courtesy of Kansas State University

  • Adjust irrigation by 50%. Plan to have irrigation winterized before temperatures drop below freezing. An irrigation company can be hired to do a ‘winter shut down’ in late fall.
  • Clean, sharpen and oil tools and store in a dry place.
  • Keep a gardening journal – of what worked and what didn’t – so that you can refer to it next year. Also make notes for crop rotation for next year’s veggies.

See, it’s not too much to do! What are you waiting for?  You have (at least a little) work to do!

Have fun, and if you have any questions or comments please feel free to leave them below.  Happy gardening!

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