Monday, December 8, 2008

Fall and Winter Garden Tasks

It may seem like gardening season is over now that the weather has cooled and rain is starting to fall regularly, but fall and winter are actually the best time of year to accomplish many garden chores.

Fallen Leaves: A Gold Mine!
Yes, that's right- the leaves that are piled up in your yard are a great asset to your garden. Here are a few ways they can be used:
1) Rake the small or medium size leaves directly into your landscape beds. Leaves add many nutrients to the soil as they slowly decompose, and will protect your soil and plant roots from heavy winter rain and erosion. Pile the leaves very lightly around the crowns of perennials and roses to protect them from freeze damage, but do not smother them with a thick layer. If you have a Big-leaf Maple or another plant with huge leaves, the leaves should definitely be chopped up into smaller pieces so that you do not end up with a matted mulch that sheds water and smothers plants.
2) Winterize your vegetable beds with a 2-3 inch layer of leaves, to protect soil nutrients from being washed away by our heavy winter rains, and prevent winter weed seeds from invading. Keep the leaves from being blown away by pinning some bird netting, burlap coffee bags, or other "breathable" material over the top of the leaves.
3) If you have an outdoor wooden worm bin, fall is a great time to harvest the finished compost and re-bed the worm bin with moist, fallen leaves. And remember to save a few garbage bags fun of leaves for the next time you'll need to re-bed it, which will probably be spring or summer when dry leaves won't be available. Fallen leaves are the natural habitat for red-wiggler worms, and make the very best bedding for outdoor bins in my opinion.
4) Add leaves of all sizes to your yard waste compost bin(s), or rake them into a big pile in an inconspicuous corner of your property. Keep the pile damp but not soggy, and within a year or so they will have decomposed into the finest compost you can imagine. Spread the finished compost on your ornamental or vegetable beds.
5) Leaves are a great ingredient for sheet-mulching, which is an easy method of turning part of your lawn into garden beds. The first layer of newspaper or cardboard goes on top of the lawn (cut the grass super short first). Then pile on a 6-8 inch layer of leaves, a 1-2 inch layer of finished compost, and top it all off with a 3 inch layer of wood chips to hold everything down and prevent winter weeds from invading. An easy way to stretch your compost- buying dollars. Fall is the very best time of year to get a sheet-mulching project going, as moist soil conditions will speed the decomposition of the dying grass underneath the mulch.

Look for Tent Caterpillar Egg Cases

We haven't had a bad outbreak of tent caterpillars since around 2004, but it's still a good idea to take a look at the bare branches of your trees and shrubs at least once during winter, to see if there are any egg cases attached. The egg cases look like dirty gray, plastic foam-like bands and masses, and are usually attached to the smaller shoots and twigs. Some of their favorite targets are fruit trees (including Crab Apple), Raspberry and other cane fruit, Alder, Cascara, Birch, Hawthorn, Rose, Spiraea, Potentilla, and even English Laurel. Beneficial insects that prey on the caterpillar larvae began to catch up with the caterpillar invasion after the first year of a bad outbreak, but that first year can do a lot of damage, especially to young trees. The egg cases can be peeled off very easily with your fingernail, even though I know this sounds yucky. They're actually very dry little discs so you won't get gooey I promise! It's much much easier than spraying with a dormant oil spray and doesn't harm beneficials, it doesn't cost a cent, and will pay off in much fewer problems on your plants during an outbreak. The common belief is that tent caterpillar outbreaks are on a 7 year cycle, but it doesn't necessarily happen that way.

Remove Deadwood from Evergreen Shrubs

This is a great time to examine your Rhododendron, Azalea, Camellias, Pieris, Ceanothus, and other broadleaf evergreens for deadwood. It's normal for some dead branchlets to accumulate over time on the interior of broadleaf shrubs, as it's usually just a result of an increasing amounts of shade in the center of their leaf canopy. However, deadwood that builds up in large amounts can itself block a significant amount of sunlight, cause overly-humid conditions, and eventually contribute to a decline in overall health. The good news is that it's easy to see deadwood in a broadleaf evergreen, and easy to remove it. For dead branchlets that are pencil-sized or smaller, you may not even need your pruners- try reaching in with a little pinch and twist to snap them off cleanly. But always use your pruners or pruning saw for anything bigger. It's kind of fun to do this kind of cleanup, and you'll be surprised how much better your shrubs will look too! One important note though- don't remove 100% of the deadwood! Why not, you ask? Well the answer is for your fine feathered friends, the birds. Many perching birds, especially hummingbirds, prefer to roost and preen on deadwood rather than live branches. And getting to have their beauty adorn your garden far outweighs the unsightliness of a handful of deadwood!

Assess Deciduous Trees and Shrubs for Pruning Needs
Without their leaf canopy, the branch structure of deciduous trees and shrubs is much easier to assess. Winter is a great time to reduce or eliminate diseased or crossing branches, and improve the gracefulness of the branching structure. Thinning cuts are almost always a much better choice than a heading cut. Thinning cuts are made at the outside edge of the branch collar, at around a 45 degree angle from the trunk. Always use a sharp bypass pruners or a pruning saw, and go slow. Making a sharp, clean cut allows the plant to compartmentalize the cut, and seal out pests and disease.

However, not all trees and shrubs do well with winter pruning. Plum, Cherry, and other stone fruit trees have a tendency to become susceptible to diseases, and/or to put out water sprouts or sucker growth if they are pruned during the dormant season. These plants do much better with summer pruning, done in July or early August. Japanese Maple and many other Maples also do well with summer pruning, as they have a tendency to "bleed" sap excessively when pruned during our mild winters here in the Pacific Northwest. Even if you do need to delay your pruning until summer, winter is a great time to tie a colored ribbon or string around the branches you need to remove, so you'll save time and error when sumer rolls around.

No matter what time of year you prune, never remove more than 30% of the total live canopy of any tree. In fact, I advise clients to try to stay within 15-20% whenever possible. Removing too much live wood can cause trees and shrubs to go into shock from the disruption to their food-making capacity. They can begin a cycle of unsightly water spouting and root suckering, limbs that are usually not well attached to the tree, and increased susceptibility to pests and disease.

If you'd like to learn more about pruning your own trees and shrubs (and you live in Seattle), set up an appointment with me for a hands-on pruning lesson to get the knowledge and confidence to do it yourself. Check out my website at for more information.

Tool Maintenance

High-quality tools can last many years, especially with a little care. After using them, do a quick exam and cleaning of your tools as you put them away. First scrape off any loose dirt or mud, give a quick scrub with a nylon brush or cotton rag, then be sure to dry them off- tools put away wet will rust, making the surface rough and much harder to dig or cut with.

Check the blade edge of shovels for any big nicks, and use a flat mill file to re-bevel the blade to match the original manufacturing if needed. Also check for rust, which can be cleaned up with a wire brush, sandpaper, or steel wool. Hanging them up instead of propping them against a garage wall protects their blades from rust and keeps the surrounding area safer too.

It's amazing how much easier pruners are to use when they're sharp, and how much cleaner the cuts are on your plants. You can take these to most small hardware stores to be sharpened for a reasonable price, or do it yourself (and be careful). Find the original sharpening angle used by the manufacturer, and use an oiled whetstone only in one direction, not back and forth. One of my New Year's resolutions in 2004 was to sharpen my pruners more often, and I can tell you it's been well worth the time every year for the 5 years since then. If you schedule a pruning lesson with me, I'll be glad to show you some quick and easy tips during our session.

If you're storing any tool for winter, put a heavy coating of WD-40 or machine oil on the blade. A little furniture oil on wood handles is good too. If you're heading back to the garden soon, put a light coat on and wipe any excess off before using.

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