Keeping fallen leaves on our Riverhouse property would benefit the environment.
According to The National Wildlife Foundation, instead of having all our fallen leaves taken to the landfill, we have other options.
- We can let leaves stay where they fall. They won’t hurt our lawn if they are chopped with up a mulching mower.
- We can rake leaves off the lawn to use as mulch in garden beds. For finer-textured mulch, we could shred them first. This would be instead of purchasing bark for mulch. All of the interviewed landscapers recommended mulching to help conserve water, amend our soil, and reduce the need for toxic weed control.
- We can let leaf piles decompose; the resulting leaf mold can be used as a soil amendment to improve structure and water retention.
If we combine fallen leaves with grass clippings (distributed on the bayside of the path that has previously been sprayed with Roundup), we can suppress weeds as well as build soil to better combat erosion, filter runoff into the river, retain moisture, and build a nutrient-rich soil that could support the growth of fresh seasonal vegetables.
Learn more from The National Wildlife Foundation >>
Maxine brought some Fava Beans to the Board Meeting this past week for me to plant as a cover crop. I’ve never before gardened in a location where a winter planting was possible, so I did some research for our bio-region.
In the Pacific Northwest, planting a cover crop in the fall can help to capture and recycle nutrients that would otherwise be lost by leaching throughout the winter rains. Cover crops also protect from water and wind erosion. They can help the soil absorb water more readily, suppress weeds, supply nitrogen and increase organic matter in our porous sandy island soil.
The Oregon State University Master Gardener handbook, “Sustainable Gardening” recommends fava beans as one of the choices for an Oregon cover crop.
I just planted Maxine’s Magic Beans where the pumpkins grew this past summer. Let’s see what happens? I love to watch things grow!
Learn more about cover crops from the Oregon State University Extension Service >>
According to Eric, the East Multnomah Soil and Water Conservation District representative, we do not have sumac growing on the riverbank – it’s Indigo Bush.
Indigo bush is a native prairie shrub used for soil stabilization and wildlife plantings that grows abundantly along the Columbia River around Portland. It grows only up to 13 feet tall and forms dense thickets that may deter goose infiltration into our yards.
Learn more about Indigo Bush >>
The only problem that I can see with Indigo Bush is that it can overwhelm other plants, which may mean we would want to control it in some areas while something else becomes established.
Many of our Riverhouse rhododendrons and azaleas are failing due to an infestation of lace bug.
Azaleas, rhododendrons face severe threat from lace bugs
By Kym Pokorny | For The Oregonian/OregonLive
Lace bugs usually become active in mid- to late May and early June, when they start laying eggs, but could get going earlier this year because of the mild winter. The bug is especially persistent because several generations are produced in one year, each one as hungry as the last.”
“Start looking now for eggs, which look like brown spots along the veins on the underside of evergreen azalea and rhododendron leaves. Once adults appear, you’ll see yellow dots on the surface and black feces on the underside. Eventually, foliage turns white, which is a sign the plant is not long for this world.”
Read more about lace bugs in the Northwest >>
Howard Donnelly of NW Trees says he has used Safari on Azaleas and Rhodies for 2 years without any harm to pollinators.
“With my applications, I use a soil drench method to insecticide off any blooming plants so it does not come in contact with pollinators.”
Jane volunteered to do some research on Safari for us and uncovered the information below.
Insecticide temporarily banned by Oregon Department of Agriculture after 50,000 bumblebees die in Wilsonville
Learn more >>
“To summarize, the disclosed toxin in Safari is Dinotefuran. It is a neonicontinoid which is the insecticide which caused a couple of big bee die-offs in Oregon last year and is now banned in Portland. I was told that this was the insecticide our landscape company wants to use to treat the Rhododendrons.”
Thank you, Jane, for researching this.
The Landscape Committee voted “no” to spraying Safari to control the lace bug.
However, many diseased plants have been marked with flags for removal.
In an attempt to look for other options to save our beloved rhododendrons and azaleas, John and I made a trip to the Crystal Springs Rhododendron Garden in Portland yesterday. It was a gorgeous northwest day to meander through those magical trails!
Dennis O’Malley, of the Portland Chapter of the American Rhododendron Society, was generous in sharing his anecdotal lace bug experience with us, explaining that The Crystal Springs Rhododendron Garden falls under environmental codes of the City of Portland banning many pesticides. So they had been experimenting with other solutions for dealing with the region-wide infestation of the lace bug.
The lacewing is a natural predator of the lace bug (confusing I know).
Lacewings are beautiful little green or brown insects with large lacy wings. Individual white eggs are found laid on the ends of inch-long stiff threads. It is the larvae that destroy most of the pests. They are sometimes called aphid lions for their habit of dining on aphids. They also feed on mites, other small insects and insect eggs.
Soap & Oil Sprays
The important point to remember is that the lace bugs attach to the underside of the leaves and the spray must come in direct contact with the bug to be effective. Dennis recommended the Safer brand of Insect Killing Soap. He also suggested a 1 gallon Gilmour Sprayer with a wand to help get up underneath the leaves. This has to be repeated every couple of weeks because the spray does not effect the eggs and new eggs hatch about every 14 days. He also talked about Kelp Spray which is believed to be released systemically providing extended protection.
Dennis said that he didn’t believe that removing one infected plant will have any effect on keeping others from becoming infected because it is an air-born region-wide infestation. He also said that he didn’t believe the lace bugs would kill a healthy plant. It may look a bit scraggly for a couple of years, but if you nourish it and bath it regularly in soap spray, it should pull through. That is obviously not an option on a large scale commercial level, however individual property owners may want to invest some time in nurturing a shrub they particularly love.
Another Rhododendron Society member shared her personal recipe for an organic systemic spray as we signed up for Membership. She recommended:
1 TBSP Kelp
1 TBSP Iron
1 TBSP Magnesium
1 GAL Water
Thank you Portland Rhododendron Society for so generously sharing your time, experience, and love of these northwest treasures!
I found a Safer Insect Killing Soap with Seaweed Extract that I am going to try on the rhododendrons and azalea by unit 444 that showed signs of lace bug last year.
As a Riverhouse Homeowner, what action do you propose? We welcome a discussion of the problem in the comment area below.
My Backyard Habitat Site Visit is scheduled for:
12:30 pm, Thursday 5/21/2015
444 N Hayden Bay Dr
Any one else who is interested is welcome to attend. I will be meeting with:
Backyard Habitat Technician
Backyard Habitat Certification Program
The site visit should take about one hour and is designed to provide technical resources to get us started. There are five components of the certification criteria:
- Invasive Weeds
- Native Plants
- Pesticide Reduction
- Wildlife Stewardship
- Stormwater Management
Learn more here: backyardhabitats.org/certification-criteria (expand each topic for more detailed info by clicking the blue tabs).
The link below is recommended for searchable lists of red, yellow, and green zone pesticides:
The product that we will be using on your Silver Maples is called Agri-fos. The active ingredient is mono-and di-potassium salts of Phosphorus Acid. This product contains NO neonicotinoids which is the active ingredients in the products that have been shown to kill bees. This product is applied to the trunk approximately four feet high and down to the ground. This is a safe product that is approved by the state of Oregon and the city of Portland.
I hope this helps to ease both your mind, as well as, the minds of your tenants regarding our responsible plant health care practices. We strive to act responsibly with all of our services that our company provides when it comes to the health of vegetation and the environment.”
Below are the proposed treatments to control insects.
- Azaleas & Rhodies will be treated for Lace Bugs
- Indian Hawthorne will be treated for Root Weevil
- Sarcococca will be treated for Aphids & Spider Mites
- Otto LuyKen will be treated for Leaf Beetles & Shot Hole