WSU Extension Snohomish County Master Gardeners
SCMG Education Outreach
November GARDEN TIPS AND TASKS
SCMG Education Outreach
November GARDEN TIPS AND TASKS
SPOTLIGHTS IN THIS ISSUE
PEST MONITORING AND MANAGEMENT - Spruce aphids, oystershell scale, lecanium scale.
GENERAL OVERALL MAINTENANCE - Soil compaction, preparation of tools and watering systems for winter.
EDIBLES - Garden clean-up, mulching, freeze protection, pruning raspberries.
FLOWERS AND FOLIAGE - Mulching; winterizing beds, roses, and dahlias; planting/forcing of spring-blooming bulbs; sheet mulching to create planting beds.
LAWNS - Mowing, final fertilizing, avoiding soil compaction.
PLANT OF THE MONTH - Skimmia japonica, Japanese skimmia.
PEST MONITORING AND MANAGEMENT - Spruce aphids, oystershell scale, lecanium scale.
GENERAL OVERALL MAINTENANCE - Soil compaction, preparation of tools and watering systems for winter.
EDIBLES - Garden clean-up, mulching, freeze protection, pruning raspberries.
FLOWERS AND FOLIAGE - Mulching; winterizing beds, roses, and dahlias; planting/forcing of spring-blooming bulbs; sheet mulching to create planting beds.
LAWNS - Mowing, final fertilizing, avoiding soil compaction.
PLANT OF THE MONTH - Skimmia japonica, Japanese skimmia.
PEST MONITORING AND MANAGEMENT

Most foliage that is going to fall has left branches bare by November, so this is an ideal time to look closely at bark, branches, and twigs for problems or the potential for problems. Inspect all your plants. Closely scrutinize those plants that seemed stressed, grew very little, or looked wilted during the growing season– these could be early indicators of a problem.
- Be sure to remove all diseased or infested plant material (this includes fruit) from the ground beneath your plants as they may harbor the beginnings of new problems.
- Healthy debris is best left as “nature’s free compost material.”
- Washington State University (WSU) Extension publication; Bugs and Blights.
- Spruce aphids, which emerge from late fall to March, may be present. Start looking for damage now, but you may not see these tiny green insects (1/16 inch) until February when they increase in numbers.
- Sticky liquid may also be seen on the plant. This is called honeydew, the liquid excrement of aphids.
- Pacific Northwest Pest Management Handbooks publication; Spruce (Picea) - Spruce aphid.
- Plant resistant varieties.
- Wash plants with a strong stream of water or see Hortsense for chemical controls.
- WSU website; Hortsense; Spruce: Spruce aphid.
- Oystershell scale, a small sucking insect, may be protected beneath each hard shell.
- They may appear on fruit trees, shade and ornamental trees, and shrubs – sometimes, but rarely, on fruit.
- Lightly scrape small infestations from affected limbs.
- Prune out and destroy heavily infested twigs.
- Hang a bird feeder in the tree to encourage birds that eat insects.
- Use double-sided tape to trap crawlers, the juvenile stage, in June.
- Improve the vigor of the plant; a healthy tree is more capable of fighting off pests.
- Chemical control may be tricky as the insects are well protected from most applications, except when the crawlers are on the move in the spring. Sometimes properly applied dormant oil sprays help.
- WSU website; Hortsense; Common Insects and Mites: Oystershell Scale.
- PNW Pest Management Handbook publication; Ash (Fraxinus)-Oystershell scale.
- Photo credit: Oystershell scale; Ken Grey Insect Image Collection.

Watch for…1/4 inch, rounded bumps on limbs and twigs that look like a spot of gelatin.
- Lecanium scale, a small sucking insect, may be overwintering beneath.
- These bumps may appear on fruit trees, small fruits, dogwood, maples, roses, and cherry laurel hedges.
- Hand-wipe to control small infestations.
- Prune out and destroy heavily affected branches.
- Dormant oils may be effective if used at the proper time.
- WSU Extension publication; Insect Answers; Lecanium Scale.
- WSU website; Hortsense; Common Insects and Mites; Lecanium Scale.
- Photo credit: Lecanium scale crawler in winter: Sharon J. Collman; WSU Professor Emeritus.
- Accurately identify the pest or problem. For help you can contact the Master Gardener hotline at 425-357-6010 or send an e-mail with a photo to: [email protected]
- The Snohomish County WSU Master Gardener Office Clinic is open from 11:00 AM to 3:00 PM Monday through Thursday. Walk-ins are welcome. The clinic is located in the Administration Building at Willis D. Tucker Park, 6705 Puget Park Drive, Snohomish, WA 98296.
- If you want to do the research on your own, here’s a helpful website:
- WSU website; Hortsense.
- Thoroughly read pesticide labels to ensure safe handling. Choose the least toxic options and use them judiciously. Instead of pesticides/herbicides, consider cultural changes as well as physical or biological controls. Use chemical controls only when necessary.
- The label must state that the pesticide is for the problem you are addressing.
- Grow Smart Grow Safe website.
- The label must state that the pesticide is for the problem you are addressing.
- Be sure to take any unused pesticides to your local Household Hazardous Waste center for safe disposal.
- Washington State Department of Ecology Website; Household Hazardous Waste & Moderate Risk Waste.
GENERAL OVERALL MAINTENANCE
What to do…
- Good air circulation is important for general plant health; this is a good time to prune out dead, diseased, inward growing, or crossing branches.
- Compost piles - cover to protect from winter rains.
- Washington State University (WSU) Extension publication; Backyard Composting.
- Prior to winter storage, clean your tools with steel wool, removing all rust and soil. Sharpen edges with a stone or file, then lubricate with a silicone or oil-based spray lubricant.
- Sharpen the blades of your mower for next spring’s exuberant grass growth. Some stores will do blade sharpening, or you can buy tools that sharpen at the correct angle.
- WSU publication; Garden Tool Care and Maintenance.
- Oregon State University (OSU) 10-Minute University publication; Sharpening Garden Tools.
- A great video showing tool sharpening:
- WSU Master Gardeners of Benton and Franklin Counties Facebook page video; Tool Care Sharpening Your Clippers, Nippers & Loppers.
What to do…
- Try not to walk on garden beds and lawns, especially if there are frequent rains.
- Root growth continues in the winter and does best in loose soil.
- Compressed soil is difficult for soil microbes, worms, and insects to move through and cycle nutrients.
- Soil compaction removes air pockets that store water for non-rainy winter days.
- Designate pathways to reach specific areas of your lawn or garden.
- WSU publication; A Home Gardeners Guide to Soils and Fertilizers.
- Michigan State University Extension publication; What to do about compacted soil.
- Winterizing water systems
- Now that it is raining more frequently, you can turn off the water to the garden. Drain drip lines and hoses as well as irrigation lines. Blow out the water from your irrigation systems.
- Colorado State University Extension publication; Home Sprinkler Systems: Preparing Your Sprinkler System for Winter.
- Medford Water Commission publication; Winterizing Your Sprinkler System.
- Be sure to monitor your plants in greenhouses and cold frames. The added humidity in these enclosed spaces can encourage fungal diseases, and the warmth and shelter may increase insect populations.
- Regularly inspect your plants under eaves or in sheltered locations. Water if too dry.

EDIBLES
It’s not just temperature that affects plant growth; day length counts, too. The Persephone Period, named after the daughter of Demeter in Greek mythology, is the time we receive less than ten hours of daylight a day. For Snohomish County, the Persephone Period lasts roughly from Halloween to Valentine’s Day. Find the exact day length for any day:
Congratulations - you made it through another growing season! Unfortunately, weeds germinate and grow all winter, so go out occasionally to weed on those rare sunny days.
It’s not just temperature that affects plant growth; day length counts, too. The Persephone Period, named after the daughter of Demeter in Greek mythology, is the time we receive less than ten hours of daylight a day. For Snohomish County, the Persephone Period lasts roughly from Halloween to Valentine’s Day. Find the exact day length for any day:
- United States Navy Observatory website; Astronomical Applications Department.
Congratulations - you made it through another growing season! Unfortunately, weeds germinate and grow all winter, so go out occasionally to weed on those rare sunny days.
- Finish garden clean-up. Do not put diseased material or weed seeds in your home compost.
- Mulch your vegetable garden beds with fall leaves, burlap, straw, etc., to suppress weeds and improve tilth. You will be rewarded in the spring with fluffy soil after removing the layer of mulch.
- Washington State University (WSU) Extension publication; Guide to Mulches.
- Mulch cold-hardy plants such as winter cabbage, carrots, beets, and kale to protect against freezing.
- Protect cold-hardy plants from freezing with cold frames, greenhouses, plastic tunnels, or other covers.
- Pacific Northwest Extension publication; Winter Vegetable Production on Small Farms and Gardens West of the Cascades.
- Remove all dead or diseased canes and clean up all debris around the plants.
- Cut out thin, short, or crossing canes if you need to maintain a smaller size (in containers or raised beds).
- Summer bearing raspberries: Remove any dying floricanes at the crown to prevent disease spores from overwintering and spreading to new canes. (Floricanes are the second year canes. They have three leaflets per leaf plus shorter spaces between leaves on the cane. Primocanes have five leaflets and longer internodes).
- Bundle the remaining primocanes and tie them to the supports.
- Everbearing raspberries: Cut all dead floricanes to the crown. For the primocanes, remove the dead tips, cutting a few nodes below the dead portion.
- Oregon State University Extension publication; Growing Raspberries in Your Home Garden.
- Photo credit: Raspberries in winter, WSU Extension publication; Berry Basics Strawberry, Raspberry, Blackberry.
- Garlic can still be planted in November, though it’s too late to plant most vegetables.
- WSU Snohomish County Master Gardener Foundation publication; Tips and Tasks; October.
- Grow some herbs in a pot on your kitchen windowsill. Supplemental light is helpful for these plants.
- Harvest regularly so you don’t lose everything with a sudden change in weather.
- Bring in any pumpkins or winter squash that are still in the garden. They will rot in cool rainy weather. Store them in a cool, dry place.
FLOWERS AND FOLIAGE
Maintenance/Clean-up
- Mulch perennial beds and beneath trees with small or shredded leaves.
- Leaves add organic material as they decompose.
- Leathery or waxy leaves (think rhododendron or camellia) do not break down fast enough to make good mulch.
- Shred leaves first with a leaf shredder or mower.
- Make a pile in an out-of-the-way corner and allow it to compost into leaf litter.
- Leaves add organic material as they decompose.
- If you have older mulch on beds, add more to get about 3-4 inches.
- Winterizing perennial beds
- Most plants have started to die back or are in full “give-up” mode.
- Hostas and others like them will have turned to mush. Cut them to the ground.
- Note: Any diseased material or waxy leaves (e.g. rhododendron, magnolia) should be disposed in yard waste.
- Herbaceous perennials like hardy geraniums that have withered can be cut close to the ground.
- Plants with sturdy stems, such as phlox, the sunflower family, and Joe-pye weed, can be cut to 12-18 inches to provide shelter and nesting sites for pollinators.
- The cut stems will also mark plant locations. You won’t plant on top of a dormant plant if the stem marks the spot.
- Keep seed heads to feed overwintering birds on plants such as coneflowers, sunflowers, and ornamental grasses.
- Hostas and others like them will have turned to mush. Cut them to the ground.
- Roses
- Shorten long stems to about 3 feet; longer stems may break in a wind or under snow load. This does not apply to climbing and rambling roses!
- Major pruning happens next spring.
- Remove all leaves from the shrub and the ground to reduce incidence of black spot next spring.
- Mound 6-8 inches of mulch around the base of the plant to protect the crown.
- Washington State University (WSU) Extension publication; Growing roses in Washington state: A seasonal calendar.
- Dahlias can be cut down and, in many areas, protected from the rains with fern fronds or evergreen boughs. If you prefer to dig up the tubers, now is the time.
- To store dahlia tubers, remove the stems and layer in sawdust, shavings, perlite, etc., surrounded by moist newspapers. Do not pack in potting soil. The trick is to keep the air around the tubers moist but the tubers themselves dry, but not desiccated. Check every month and adjust the moisture; remove tubers that show any evidence of rot.
- Label the dahlia tubers by name, or at least by size and color.
- WSU Extension publication; Overwintering Dahlias.
- Hold off pruning trees and shrubs until they enter dormancy during the colder winter months. Fresh cuts are less likely to be infested by insects and disease. Dead or diseased material may be pruned out at any time.
- Michigan State University Extension publication; Winter dormancy and chilling in woody plants.
- Bulbs can still be planted if the ground has not yet frozen. They won’t do much for you sitting on the shelf in your garage! (If the ground has frozen, you may want to try to “force” the bulbs in an indoor pot, enjoy, then add to your spring garden.)
- WSU Extension publication; Community Horticulture Fact Sheet # 67 Forcing Bulbs.
- Trees and shrubs can still be added to your landscape in early November.
- Sheet mulching is a low effort approach to create a planting bed for next spring.
- King County Native Plant Guide; How to Sheet Mulch.
LAWNS
Maintenance/Clean-up/Planting
Maintenance/Clean-up/Planting
- If your lawn is still growing, make your last mowing at a height higher than usual.
- Washington State University (WSU) Extension publication; Winterizing Your Yard.
- WSU Extension publication; Home Lawns.
- Apply the final feeding of the year before mid-December, using a slow-release fertilizer. The slow release of nutrients will feed over winter.
- Spread compost thinly on top (1/4-1/2 inch) which also helps slowly feed the lawn.
- Snohomish County Washington publication; Natural Lawn Care for Western Washington.
- Walk on the grass as little as possible. Read the tip about soil compression damage above in General Overall Maintenance.

PLANT OF THE MONTH - November
Japanese Skimmia
Skimmia Japonica
(SKIM- ee- uh juh-PON-ih kuh)
Japanese skimmia is a slow-growing, low maintenance, shade-loving evergreen shrub. It is dense and mounding, with leathery dark green leaves, which have a spicy scent when crushed.
Japanese Skimmia
Skimmia Japonica
(SKIM- ee- uh juh-PON-ih kuh)
Japanese skimmia is a slow-growing, low maintenance, shade-loving evergreen shrub. It is dense and mounding, with leathery dark green leaves, which have a spicy scent when crushed.
- Native to Taiwan and Japan, it grows 3-5 feet tall and up to 5 feet wide in zones 4-9.
- Plant skimmia in acidic or neutral pH, well-drained soil. It prefers part to full shade or sun-dappled areas.
- Fragrant, creamy white flowers appear in spring with male flowers having a stronger scent.
- If a male plant nearby, female plants can produce red berries in the fall, which attract birds and are showy throughout the winter.
- This slow-growing plant is deer resistant.
- All parts of the plants are poisonous if ingested in large quantities.
- Skimmia is a fine specimen or hedge plant and works well in mass plantings.
- Prune after spring flowering to reduce size, but pruning will remove potential berries.
- In warm, dry weather it can attract spider mites.
- Washington State University (WSU) Clark County Extension publication; PNW Plants; Japanese Skimmia.
- Oregon State University publication; Landscape plants, Skimmia japonica.
- Photo credit: Japanese skimmia; WSU Clark County Extension PNW Plants.