Garden Tips 'n' Tasks  
September
WSU Extension Snohomish County Master Gardeners
SCMG Education Outreach    
September GARDEN TIPS AND TASKS​
                                                 SPOTLIGHTS IN THIS ISSUE
​​                                              
​PEST MONITORING AND MANAGEMENT - Slugs, juniper twig blight, English ivy, protecting beneficial insects.
GENERAL OVERALL MAINTENANCE - Watering, drought, assessing plants, lighting.
EDIBLES - Powdery mildew, extending growing season, cover crops, garlic, harvesting late summer crops.
FLOWERS AND FOLIAGE - Staking, mulching, conifer flagging, hedges, dividing, propagating, planting spring bulbs.
LAWNS - Creating new lawns, rehabilitating existing lawns.
PLANT OF THE MONTH - Rudbeckia hirta, Black-eyed Susan/Gloriosa Daisy.
                                        PEST MONITORING AND MANAGEMENT
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Slugs
Watch for…
  • Plants with shredded leaves or nearby slime trails.  
    • Western Washington is an ideal environment most of the year for slugs as it usually provides a wet climate that creates the moisture slugs need to survive and lots of plants to eat.
What to do…
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Juniper twig blight
Watch for…
  • Yellow to red, or dead foliage on branches. 
    • New growth is highly susceptible to the fungal growth that causes juniper twig blight.  
What to do…
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English ivy
Once a desired groundcover, English ivy readily grows outside its bounds and is categorized as a noxious weed in Washington.  It is a threat to native forest land.  If allowed to climb trees, its weight can cause trees to topple in high winds.  After heavy rains, slopes may fall away from beneath the ivy because it is a poor soil stabilizer.  Watch for… 
  • Unwanted seedlings, ivy starting to climb or form seeds.
  • Remove unwanted seedlings, root and all.
  • Cut ivy stems at ground level and remove as much of the vertical growth as possible.  Portions too high to reach will wither and die.
What to do…
If you still desire to have a controlled patch in your yard, now is a good time to establish your dominance!
  • Keep edges of garden ivy trimmed and contained.
  • Cut off flower heads to avoid seed spread.
  • Do not allow it to climb trees!
  • Photo credit: English ivy vines climbing trees; B.M. Johnson; WSU.
Protect our beneficials!  Okay, Miss Muffet, you can stay on your tuffet.  It’s time to get past thinking a spider is scary… ​Keep in mind…
  • Accurately identify the pest or problem.  For help you can contact the Master Gardener hotline at 425-357-6010 or send an e-mail and photo to: snocomg@gmail.com.
  • If you want to do the research on your own, here’s a helpful website:
  • 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.   
  • Be sure to take any unused pesticides to your local Household Hazardous Waste center for safe disposal.
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                                                GENERAL OVERALL MAINTENANCE
​                                                 Enjoy the warm and sun, the bounty,
​                                                     and bug/slug squishing chores,
​                                           because soon enough will be gray days
                                                    chasing you back indoors!
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Coping with Drought
Irrigation is a choice between saving on your water bill vs. saving your valuable plants.
For detailed advice, see below: Watch for…
  • Increased insect and other wildlife damage. During droughts, these creatures will use your plants for their needs.  
  • Spider mite webs.  Mites may hide on dust-covered leaves.
  • Undersized and off-flavored fruit and vegetables.
  • Branch dieback, diminished hardiness, increased disease susceptibility, root death, or plant death.  All of these are long-term results of drought.
What to do…
  • Spray water to remove accumulated dust from foliage.
  • Avoid adding fertilizers and pesticides which can burn plants.
  • Keep turf 2 feet from tree trunks and add mulch if not already present.  Removing ground covers from tree bases will reduce competition for water.
  • Shade plants where possible to reduce evaporation.  Floating row covers, latticed pergolas, or canopies may lower temperatures and reduce desiccation.
  • Avoid watering plants, especially annuals, that have passed their prime or are diseased.  Remove them instead.
  • Water deeply, but less frequently, as trees, shrubs, and perennials prepare for the colder months ahead.  
  • Add mulch where needed. It can reduce evaporation by as much as 50%.
  • Assessing the garden
  • Consider which chronically stressed plants to move when fall becomes cooler and the rains are more regular.
  • Group plants according to their light and water needs.  Hydrozoning will reduce water usage.
  • Tag, map or photograph the plants that had plant disease or insect attack and plan to remove their mulch and dropped leaves at autumn’s end.  Add new mulch to those areas. Overwintering disease spores and insects are down there waiting to re-attack!
  • Research your plant ailments for how and when to treat.  For help, consult Master Gardener Office clinicians.  ​For contact information, see the Pest Monitoring and Management section above.
Lighting 
Consider enhancing the garden for evening strolls.
  • Safe landscape lighting (12 volt, LED, or solar) is a great way to illuminate your garden.  
  • Path lights add safety; up-lighting a shrub or an interesting tree trunk makes a beautiful statement.  If you have a pond, shine a light on the water.  
  • Plants for night gardens:
  • Night-scented flowers such as nicotiana, jasmine, evening-scented phlox (Zaluzianskya ovata), petunias, or angel’s trumpet (Brugmansia) will captivate your senses. These and others may still be available at local nurseries. 
  • For nightly glow, add white-flowered plants like hydrangea or silver-leaved plants such as Senecio that reflect moonlight.
  • Photo Credit: Nicotiana and white jasmine; Sheryl Kelly; WSU Snohomish County Master Gardener.
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                                                                          EDIBLES
Maintenance / Clean-up    
  • Rain and damp weather in the fall may bring on diseases like powdery mildew.  Such problems can often be tolerated until the end of the season. If the problem is overwhelming, simply pull out and destroy affected plants.
  • Clean-up now can prevent disease and pests from overwintering in your garden. 
    • Keep weeds from going to seed. It will save you time and effort next year.  
    • Many plants in the garden are ready to go into the compost bin after they are through producing.
    • Do not put weed seeds into your compost.  
    • It’s ok to put them into commercial yard waste containers since it is heated enough to kill weed seeds
    • Do not compost diseased plants. 
    • For a complete guide to composting, see:
  • Swelling or galls near the base of raspberry canes may indicate crown borers are present.  Remove infected canes and crowns and destroy.
  • Photo credit: Raspberry crown borer larvae and damage; E.P. Breakey.
  • September is a good month to assess what was successful and what was not. Keep notes for next year.
Extending the season Garlic Cover crops
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 Cover crops Harvesting
  • Corn can be harvested when the silks turn brown and kernels are milky.
  • Harvest potatoes when the tops die down. Store them in a dark location. 
  • Pick green tomatoes and ripen them indoors if frost or blight threatens. 
  • Photo credit:  Protection for tomatoes from rain and dew; Vicki Sorg; WSU Snohomish County Master Gardener
  • Leave winter squash and pumpkins in the field to ripen. 
    • Harvest when they are fully mature and the skin is hard and waxy. Cut the stem a few inches away from the fruit to protect the area where it joins the squash.
    • Do not leave them in the field if weather remains wet. These conditions encourage rot and mildew.
  • Harvest dry beans, such as black beans or cranberry beans, which are grown to dry and store for later use.
    • If the garden stays mostly dry, allow beans to hang on the vines until the pods are dry and open easily, then gather.
      • Lay them in a single layer on porous material, such as cardboard or a screen, in a well ventilated area to finish drying.
    • If the garden is wet before the beans are ready, mold can be a problem.  
      • Protecting the plants with a plastic ”roof” may prevent mold.
      • Harvest the beans after the pods have stopped growing and are plump (and hopefully have started to dry).
        • Lay these beans in a well ventilated area to finish drying.
    • Dry beans can be left in the pods for weeks or months before shelling. If the beans are shelled before the pods dry, they will need extra drying time to store without mold or rotting. 
  • Some late summer vegetables can be left in the garden to mature slowly as the weather cools. Watch crops like late cabbage to see that they remain healthy-looking and cut them while the heads are still solid.
  • Pears should be harvested before they are mature.
  • The best general source for vegetable gardening in Western Washington is:
  • If you have a super-abundance of any edibles, remember your local food bank. Check to see when they accept donations.
​FLOWERS AND FOLIAGE
Maintenance/Clean-Up
  • Stake tall flowers to keep them upright during autumn winds.
  • Dig, clean, and store tuberous plants such as begonias if frost threatens.
  • Continue deadheading most plants to extend their flowering season.  However, avoid deadheading roses in late summer, which could encourage growth that’s vulnerable to winter damage.
  • If you cut back the spring blossoming perennials to get a second bloom, that second bloom may be spent.  It’s time to cut back or shear them again.  This time, shape the plant at the size and configuration you desire.
    • On woody perennials, do not cut into the wood section when shaping.  
      • Lavender can be cut back to a few leaf clusters above the woody stems, but no farther.  Shape as desired.  If this is not done every year, the plant flops open.
  • Mulch:  Resist the impulse to rake up all fallen leaves, twigs, and other plant debris from garden beds.  This natural mulch provides a habitat for beneficial insects and fungi, and recycles organic matter back into the soil.
    • However, if the plant had insect or disease issues this year, remove the fallen debris and mulch and replace with fresh mulch.  You don’t want to assist overwintering spores or insects.
      • Pfeiffer, Christina and Mary Robson, Month-By-Month Gardening in the Pacific Northwest, Cool Springs Press, 2017.
    • Recycle disease-free plant material into compost.
  • Conifer flagging: Don’t despair if you see some discoloration and loss of foliage in certain conifers, particularly western redcedar and some pines. This is a natural process called “flagging,” where the tree is prioritizing its resources. This is a normal part of conifer growth.
Planting/Propagation
This a good time to install new trees and shrubs.
  • For information on how to plant, stake, fertilize, and water newly planted trees and shrubs, see:
  • If your garden lacks privacy, consider adding a living screen or hedge to your landscape.  A living screen will block an unsightly view, reduce noise and dust, provide a buffer against the wind, and give shelter to wildlife.
  • It’s also a good time to refresh those tired containers.
    • Add colorful fall accents, such as violas, mums, asters, kale, and purple fountain grass.
    • Consider planting a small evergreen tree or shrub surrounded with winter favorites such as pansies, sedums, or heathers.
Dividing
  • Divide spring-blooming perennials, such as daylilies, hardy geraniums, salvias (not woody), garden phlox, iris, peonies, bleeding heart, and Veronica.
  • It’s the start of spring bulb planting time!  Snowdrops, crocus, daffodils, tulips, hyacinth, etc. will reward you with fabulous color from late winter through the end of spring.  
    • Choose firm, plump bulbs free of disease and decay.
    • Plant as soon as possible after purchase; or store bulbs in mesh or paper bags in a dark, dry place until ready to plant.
    • Generally, plant to a depth of two to three times the height of the bulb.  
    • Bulbs have their own energy stores; there’s no need to fertilize when initially planted. 
    • Plant in well-draining soil in the garden or in pots.  Bulbs can be staggered in layers in the soil, so they will blend together when emerging.  For example, plant large bulbs such as hyacinth deeper, with daffodils above, and crocus above those.
    • After placing bulbs, cover with soil and top with mulch.  Water well if rain is not imminent.
​                                                                        LAWNS
Maintenance/Clean-up/Planting
​Now that temperatures are cooler and rain may be on the way, it could be time to reseed an existing lawn or even start a new one.  It’s still warm enough for seeds to start growing before cool weather slows everything down, and the coming rains mean that you won’t have to worry so much about keeping up with watering. 
  • Creating a new lawn:
    • Prepare a new seedbed by tilling in 2-3 inches of compost before fertilizing, seeding, and watering.
    • Use a lawn mix that is labeled as suitable for Western Washington.  
    • Once sown, sprinkle the lawn mix with a light dusting of compost to hold in moisture and protect seeds from birds.
    • Water lightly but regularly. Newly planted or reseeded lawns must be kept moist.
    • Explore options for ecolawns as an alternative to grass. 
  • Rehabilitating an existing lawn:
    • First, control any broadleaf weeds.  This can be done manually or by using an herbicide labeled for lawn use.
    • Use an aerator to improve drainage.  By removing small plugs of soil, aeration increases the flow of water and air into the root zone, improving root health.  Leave the plugs on the lawn to naturally decompose, adding nutrients to the soil.
    • Dethatching can be done at this time if needed.  Thatch is a dense layer of stems and roots which can keep water and air from reaching roots. 
    • Apply fertilizers suitable for fall.  It’s advisable to do a soil test before adding fertilizer.  
    • Look for “slow-release” on the label.  Slow-release fertilizers provide nutrients over an extended period of time and can prevent fertilizer runoff.
  • Acidic soils typical of Western Washington may also benefit from an application of lime in the fall.
  • Top dress with 1/4 to 1/2 inch compost, gently raking it into the turf.
  • Overseed with seed suitable for Western Washington.  Water in well, then cover with compost.
  • For more lawn care tips and advice:
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                                       PLANT OF THE MONTH - September
                                         Black-eyed Susan, Gloriosa Daisy  
                                                   Rudbeckia hirta
                                            (rud BEK ee ah HER tah)​
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  • Looking for a plant to brighten up your garden?  Rudbeckia offers vibrant daisy-like flowers from early summer to frost.  It may still be available at a garden center near you.  Or perhaps a friend has starts or seeds to share; it is easy to start from seed either now or next spring.
  • Native to the eastern United States, this prairie/meadow flower has become widespread throughout North America.
  • Supported by a sturdy stem, the 2–3 inch wide bloom has a dark chocolate-brown dome (though it can also be green) surrounded by rays of gold, orange, or a combination of the two. Some varieties add burgundy to the mix!  
  • Deadheading will promote continued bloom.  Cut flowers are long lasting in arrangements.
  • The stems and 3-6 inch, oval leaves are green and have hairy bristles, making them distasteful to deer.
  • This short-lived, deciduous perennial grows 2-4 feet tall, forming clumps 1-2 feet wide.  Rudbeckia will readily self-sow or spread by underground rhizomes, re-establishing itself and gracing the garden for many years.
  • Hardy in zones 3-9, this sun-loving plant also does well in partial shade. Its water and fertility needs are moderate, and it is tolerant of most soils, neglect, and some drought.
  • Bees, butterflies, and other pollinators love this plant, but it is resistant to most insect pests and diseases.  It is relatively problem free; it even tolerates salt.
  • For more information:
  • Photo credit: Rudbeckia hirta; Vicki Sorg; Snohomish County Master Gardener
                                            
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