Archive for Garden Pests

Designers List of Shade Plants for Root Weevil Resistance

NE Portland Hostas with Root Weevil Damage

Root weevil damage distracts from an otherwise beautiful collection of shade loving plants.  

Designers List of Shade Plants for Root Weevil Resistance

I wanted to write a blog about shade plants for root weevil resistance. Root weevil disfigure so many shade garden plants and can make a garden look ravaged. It’s disappointing to see hosta and other plant leaves looking all chewed up. Can we design a shade garden with beauty and style without using root weevil favorite snack plants?

“Well HELL that’s not much of a shade garden” is what I said when I thought about eliminating all the plants root weevil like to eat. I was disappointed in the tiny number of plants that would work and wandered off to write about something different, something a bit cheerier!!!! However, I’ve been thinking about it and yes, we have some great plants we can use. 

Evergreen Shrubs  

Fatsia japonica Spider's Web in SE Portland Residential Landscape Design

Sometimes choosing an interesting variegated leaf, such as this Fatsia japonica ‘Spider’s Web’ can hide the notching caused by Root Weevil (look close!)

Aucuba, Daphne and Fatsia are not root weevil favorites and if you select the variegated forms the notching doesn’t show as much. To be specific, Daphne odora ‘Marginata’,  Fatsia japonica ‘Spider’s Web’, and Aucuba japonica ‘ Gold Dust’ are varieties that I recommend.

I have never seen much leaf damage on our Native Huckleberry (Vaccinium ovatum) probably because the leaves are so tiny.  

Three Root Weevil Resistant Rhododendron for Part Shade 

Grant Park Garden Design Rhododendron with Root Weevil resistance

The fuzziness on the bottom of the leaves on some Rhododendrons reduce Root Weevil damage.

I’ve found the official lists less than helpful since most Rhododendron listed are sun lovers. Root weevil prefer part shade to shade. 

Rhododendron ‘Clipiense’ is my best weevil resistant compact rhododendron for shadier situations. This rhody has fine hairs on the leaves so root weevil rarely bother it. It’s a slower growing variety and can take more shade than the other two I have listed but not deep shade.

Rhododendron ‘Fred Peste’ is a compact red rhododendron.  Fred does well in morning sun and afternoon shade, although he can take more sun than average.  

Rhododendron ‘Blue Diamond’ can take full sun but does well in full am sun and afternoon shade. It can get taller than wide.

Perennials   

NW Portland Sword Fern and Hardy Geranium in Residential Landscape Design

Sword fern (Polystichum munitum) and Hardy Geranium (Geranium macrorrhizum) do not show Root Weevil damage.

Sword fern (Polystichum munitum)  has a fuzzy frond (leaf) and root weevil don’t eat fuzzy leaves typically. Most fuzzy fronded ferns will be root weevil resistant and are an important player in a root weevil free planting. 

Hellebore argutifolius is perfect for NW Portland Landscape Designs

Helleborus argutifolius photo credit: Great Plant Picks

Hellebores are typically safe from weevil once they are mature plants. When the soft and munchable new leaves unfurl in February the root weevil have not hatched yet (here in Portland) so are not present until late April or May. The harder leafed hellebores like Helleborus argutifolius seem particularly impervious. 

Groundcover Plants   

Oregon Oxalis (Oxalis oregana) doesn’t seem to get a lot of weevil attention in my gardens and it is fun to add to salads. Same with our native piggy back plant Tolmiea menziesii. It has hairy leaves and is great for shade. For Saxifraga varieties, use the hairy leaved varieties for weevil resistance, the smoother ones are on the weevil munch list. Hardy geranium varieties that smell like cedar and have a fuzzy leaf are 100% weevil resistant – Geranium macrorrhizum for deep to moderate shade and Geranium x cantabrigiense for part sun areas. Another good bet is Sweet woodruff (Galium odoratum)

Last but not least, Euphorbia Rob’s spurge (Euphorbia amygdaloides var. robbiae) is a tough evergreen ground covering shade plant. I consider it a thug but it’s great to use in gardens where I have a path that doubles as barrier to their creeping roots. This plants roots must be contained or it will march right over your hostas. I’ve never seen any root weevil damage on this plant.

 Know Thy Enemy?   

Root Weevil have no natural predator here in the Pacific Northwest so it’s rare to find a shade garden without them.  We can cut the population of root weevil down to tolerable numbers and thus get our beautiful shade garden back. Read my blog “Attack of the Root Weevils”  to learn what can be done to reduce their population in your garden. 

 

Resistance is Futile-Plants that take over your landscape

Resistance is Futile-Plants that take over your landscape.

 

This blog is about attractive plants that take over your landscape.  They are tempting and for sale at most garden centers.

Star Trek The Next Generation came out 20+ years ago but I was busy building my landscape design practice and raising a stepdaughter so I missed the whole thing.

Maybe I’m just going to seed as I recently watched all seven seasons in short order. I encountered the Borg and was impressed with their ability to take over a universe. The Borg remind me of certain plants that will happily assimilate your entire garden and need to be avoided. 

Here’s a list of plants that are as devastating as the Borg and good at propagating their own kind without any assistance. They have an aggressive spreading growth habit and yet they are still sold at most nurseries and garden centers in spite of their thuggish nature. Be warned.

Foliage of houttynia 'Chamelon', is an aggressive spreader in Portland Oregon gardens.

Houttuynia cordata ‘Chameleon’ Photo Source

Here is a beauty of a beast: Houttuynia

Houttuynia cordata ‘Chameleon’ –  I’ve never known anyone who (once it was planted ever managed to get rid of it. It is famous for aggressive roots that will grow through other plants and overpower them. It can seed although it hasn’t in any of my clients gardens because I never use it.  Look at how cute the variegated leaf  is!

Aggressive Japanese Bloodgrass in Portlands' Raleigh Hills residential landscape design

Japanese Bloodgrass, Imperata cylindrica ‘Red Baron’, can spread indefinitely

Japanese Bloodgrass Spreads

Imperata cylindrica ‘Red Baron’ or ‘Rubra’- Japanese blood grass is a spreader but it can be dug out and eventually (as in years of work later) be banished but don’t sacrifice your time to this plant…you will be sorry!!

Aggressive Ribbon Grass in NW Portland parking lot is well contained by boulders.

Ribbon Grass, Phalaris arundinacea

Ribbon Grass is on the Fence

Ribbon Grass, Phalaris arundinacea, is a plant that can be very difficult to eradicate but if a designer suggests it for a contained area that doesn’t mean they are a newbie.  It is planted in a parking lot that I frequent. It’s been trapped there over 9 years and has not escaped. I myself have never used it in a design but it is very very low maintenance.   Here is an article regarding success in killing the ribbon grass. 

Front yard of North Portland Row House is lost to Aspens aggressive growth habit.

This stand of Aspens (Populus tremuloides) started out as one trunk!

Aspen Trees

Aspen trees, Populus tremuloides, are beautiful in a forest but not good for tiny city plotsOne tree will become many and fill your soil space with invasive roots that lift walkways, invade foundations and water lines and leave companion plants with no water or nutrition. See this great article from designer pal Beth Goodnight regarding the evils of aspen and some alternative suggestions.

Keep Mint in a Pot

If mint gets away from you – you will never get rid of it. Some people plant it in a pot and keep it on a concrete patio. The roots can escape from the pot and once it spreads in your soil you will have it forever so I never set my pot of mint into a planting bed. I like having mint for soups but it is strictly a container plant. 

Japanese Anemone in Portlands' Grant Park neighborhood in low maintenance residential garden design.

Japanese Anemone is beautiful but travels fast

Japanese Anemone and Bishops Weed in the Right Spot Only

Japanese anemone, Anemone sp., should only be used by experts. This one is very very seductive and over the top beautiful. It travels by root which is the problem. I like to use it in very low maintenance planting plans/landscape designs and in parking strips where it is easily contained. It doesn’t seem to invade the lawn so I’ve used it in plant borders too.

Bishops weed, Aegopodium podagraria, should be planted by people who know exactly what they are in for. It can be contained in the parking strip or a low maintenance planting where you have nothing but shrubs. Large shrubs with bishops weed as a ground cover can be a functional landscape choice. If I use it I have a rule:  You are not allowed to ever give a start of it to a friend.      

There are, of course, many plants besides my short list that should be avoided or used with caution. These plants are the stars of this blog because they are so attractive, tempting and readily available at your local garden center.

Warning: Roundup is on Trial

Tips to Keep Yourself Safe When Using Roundup in Your Dog-Friendly Garden

The first law suit claiming Roundup causes non-Hodgkin’s lymphoma started June 17th in San Francisco. There is new research indicating glyphosate, the primary ingredient in Roundup is a serious carcinogen and may cause other health problems. They (Monsanto) are accused of hiding the truth about the risks and paying industry influencers to help them do so.

It’s no use complaining that everything you read (even a note from your garden designer) says something is causing cancer. There are facts to work with and being cautious is logical. I will be following this trial and the science closely and will share what I glean.

Using Roundup?

Here is a very good tip: buy it pre-mixed so you don’t spill the concentrated form on your garage floor or on your skin while mixing it up. Read that long label. Wear protective gear, including appropriate gloves. Protect your skin from any contact so no shorts or flip flops. Make sure the cap is on tight when you buy it. I had a bottle slosh all over me at Fred Meyer.Dog on playground slide dog friendly landscape in Portland Oregon

How long do I keep people and pets away from treated areas?

Read the label. The old rule was the area you treated had to be completely dry. Who knows what we may learn but remember dogs will eat grass while the Roundup is still inside the blades regardless of whether it is still wet or not. The product is now inside my dog. I’m not a chemist or a licensed pesticide applicator but I am sure I don’t want my dog eating treated grass and I don’t want the wet product on my skin or on my dog.

Why use it at all? Protecting our natural areas from invasive weeds!

Glyphosate has been extremely helpful where we are struggling to protect our native plants. Here in Portland the volunteers who protect Forest Park were using glyphosate to remove english ivy which threatens Forest Park. As usual, a black and white answer, while simple to comprehend, often does not address the complexity of life.

I promised if news came out that I felt was important to my clients lives, I would say so. Here is an article from August 2018, which reports “Monsanto, the maker of Roundup, was found liable in a lawsuit filed by a school groundskeeper who said the company’s weedkillers caused his cancer.” My goal is to inform, not to scare. If you use Roundup please do so with a healthy dose of caution and the right protection.

I want to keep us in touch and keep you informed. I publish tidbits to Facebook and photos to my Houzz page as well as monthly blog posts. Contact me through the websiteemail or call 503-223-2426. It always great to hear from new and old clients.

 

Natural Slug and Snail Control In Your Portland Landscape

California Brown Snail in Portland, OR

Slugs and snails do a lot of damage in Portland gardens.

Slugs and Snails in your Portland Landscape

My history with slugs in the garden

I was never thrilled with my options for dealing with slugs and snails.  In the 80’s we had the typical little gray French slugs and snails in our gardens and they were pesty enough.   I had often just hand picked them and kept the numbers down.  Then in the 90’s we started seeing California Brown Snail and they added significantly to the total damage.  It was too much for me to manage organically.  The beer bait didn’t work for my garden on a city sidewalk in NW Portland’s Nob Hill District.  Dogs would drink the beer which is NOT good for them and the traps looked tacky too. Using the snails for escargot doesn’t work as a pest management practice since the typical serving is six 1 ½” snails per person.  My family would  never go for Escargot anyway.  They are not adventurous diners.

 

Slug Bait Problems

NW Native banana slug does not damage living leaves

The banana slugs only eat leaves that are decaying or broken. They also pollinate native spring flowering plants on the forest floor. I did not like leading them to slaughter.

I started using the “pet safe” iron phosphate slug bait.  It was an easy method to cut down the population compared to beer baiting or hand picking them. The problem with slug bait is that it does not discriminate. It would lure innocent NW native banana slugs to their death along with the real culprits that did the damage to my plants.

Another problem with slug bait is it doesn’t protect your plants immediately.  Slug bait lures the slugs to the bait but does not kill them right away.  They have time to do a lot of damage before they sicken, stop feeding and then die.

Worms die from iron poisoning

The major issue is the iron phosphate remains in the slug’s body and breaks down and ends up in the soil.  This iron residue left behind in the soil created a toxic environment for worms, the creatures who keep our soil healthy.

I didn’t notice it myself until I got raised beds in my community garden.  I noticed a steady decline in the population of worms in my beds.

Copper wire around vegetable bed deters slugs

Daizzie inspecting the copper wire which keeps slugs out of my veggies by producing an electric shock.

 

There is an inert ingredient in the pet safe slug bait that combines with an active ingredient to kill earthworms.  They die from iron poisoning.  The combination was also causing harm to wildlife and to small domestic animals so it was time for me to make a big change.

Slug Bait Alternative-Natural Slug Control

Ann Lovejoy is a trusted resource and treasure for Pacific NW Gardeners.  She is the one that made the connection between the iron phosphate “pet safe” slug bait and the harm it was doing.   Read more about how slug bait kills worms. 

She made several suggestions for what to use instead of slug bait.  My favorite is using liquid caffeinated coffee sprayed onto plants as a repellent.  I tested it this past fall to great success.  I was able to protect my kale crop from slugs.  I purposely sprayed coffee on only half the plants as a test.  The plants I did not spray were missing half their foliage.  The plants I sprayed had no holes or missing foliage.   I sprayed at least once a week during the fall rains.  Ann says a direct spray of coffee will kill the slugs but I could not tell if this was a success.   I sprayed the coffee directly on slugs but when I came back the next day the sprayed slugs were no where to be seen.  They may have crawled off and quietly expired but I was not sure. Maybe my coffee wasn’t strong enough. I will do more testing now that the soil has warmed up enough for new slugs and snails to hatch. I’ll post again and share what strength of coffee it takes for an obvious demise.

I can’t wait to share this with my landscape design clients.  Many clients have pets.  The fact that pet safe slug bait is toxic needs to be shared.

Scrub copper wire with wire brush – slugs can cross the wire if it’s oxidized or dirty.

Use Copper Wire for Raised Beds and Containers

Another option to deal with slugs in raised beds is to line the edge of the bed with copper.  I used a copper ground wire but you can use sticky copper tape available at most garden centers and it will last maybe one garden season if you are lucky.  It is easy to buy and apply to your raised beds, pottery and containers.

Slug or Snail?

What’s the difference between slugs and snails?  Slugs and snails are pretty much the same animals according to Robin Rosetta, Associate Professor at OSU.  Over time slugs evolved out of a hard shell so they could move through cramped spaces and allow them to get down into the soil to find food and protection.  Apparently, there is still sort of a shell under their hump like mantle.  Snails still have a shell and so are restricted to above ground activities.  They use their shells to survive inclement weather and are protected from some enemies and predators.

Bad News about Slug Bait and Winter Garden Care Tips

Slugs at NE Portland Landscape Design in a Day

Slugs on a Honeydew Melon Date

Winter is just around the corner here in Portland.   Here are 5 timely tips to help you care for your landscape right now.

Slugs Last chance to knock out slugs! Control your slug population now in late fall.  They lay thousands of eggs that will hatch in spring.  I’ve got bad news about using the so called pet safe slug baits. New science says it kills your earthworms and can sicken your pets and other animals.  Control your slugs with beer traps or even better an instant coffee spray.  Yup coffee! Fill a spray bottle with strong instant coffee or any coffee except de-caf.  Spray the leaves of plants they prefer and any slugs or snails you see.

I grow lots of winter greens here in NW Portland so I’ve been out there spraying down the leaves of my beautiful Dinosaur Kale plants to protect them now.  Spraying coffee once a week in fall and early winter makes a big difference in the spring hatch of slugs.   Read more about why slug bait harms worms.

Coffee bag

Its the caffeine that kills slugs or snails. Instant coffee works well.

Mulch.  If you only do one thing to improve your soil and care for your plants, mulching is the biggie.  Schedule your winter mulch application for the last week of November to mid-December or hire someone to blow in your mulch.  Companies such as Bark Blowers will blow in mulch including the newer “living” mulch products that I prefer.  One company that provides mulch inoculated with beneficial bacteria is Natures Needs, a product called  Recology Compost.  McFarlane Bark, Mt Scott Fuel and Grimms Fuel supply basic mulch products.   Did you mulch just 2 inches deep?  Great!  Now go and unbury the crowns of your plants so they don’t die from rot during our wet winter. Burying plants with mulch might be a good practice in Vermont or Montana but not here.

Iron gate design with snow

Landscape Design in a Day client’s custom gate.

Protect your plants from winter temperatures

The best cold protection for plants in the winter isn’t something that naturally occurs to most people.  Over watering and over fertilizing done in summer can cause plants to not go dormant.  When cold weather comes, they are not prepared.  Read more: Protecting Plants from Winter Cold Starts in Summer 

Pruning knowledge  There are many plants that should not be cut back in the fall and winter.  There are many perennials and grasses that can be cut back to create a more attractive winter landscape. This is a case by case basis which drives new gardeners crazy. Consider consulting with your garden designer who can teach you what to do to your plants and when.  It feels good when you know what to do.

Protect your pottery  The best winter protection for your pottery is proper drainage and location.  Make sure water drains through the pots hole and doesn’t back up.  If water sits in the bottom and it freezes, good bye pot.  I have had Vietnamese high fired pottery outside and intact for over 15 years.  I always put drainage material in the bottom of the pot and a piece of flagstone under the pot or I use those little pottery feet.

If I have expensive pots where they will get east winter wind, the kind of wind that freezes rain to ice on the power line, I would move them into a protected area for winter right now. I hate to even think about that kind of weather but we get our share here in Portland Oregon, especially in January.   Its hard to pay attention to the weather report, and besides who wants to move heavy pots around when its icy cold out?  Not me.