Archive for Shade groundcovers

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. 

 

Deep Shade Plants Tried and True

 

Garden Design Northwest Portland Fatsia Japonica, 'Spiders Web'

Large leaves of Fatsia Japonica capture the available sunlight efficiently.

Think about it……………big leaves are like big hands.  The more surface area the more light the plants can access.  Having said that……this is a perfect example of the rule about how there are no steadfast rules.  Our native huckleberry, Vaccium Ovatum has tiny but highly reflective leaves, ( such a rule breaker!)  and it grows very well in a lot of shade.  Sigh………..plants are tricky.

Maurice Horn of Joy Creek Nursery and Lucy Hardiman of Perennial Partners presented a program for designers through The Association of NW Landcape Designers.  I have been a happy  member for nearly 20 years.  Maurice and Lucy added plants to my shade plant palette and reminded me of plants that had slipped off my list over time. I will share just a handful of these plants with you.

Lets look at just 5 plants:  one tree, some shrubs and 2 groundcolor plants.  Most of these plants can take a little sun but my point is, they  thrive in deep shade which is a difficult  area for many homeowners to select plants for.

Tree

Plant this beautiful Snake Bark Maple under your fir trees………Acer Tegmentosum “Joe Witt”  Manchurian Snake Bark Maple  This one is new to me.

Shrubs

Fatsia Japonica  (also called Japanese Aralia)  This is beautiful planted as under story to larger trees.  It is also my 3 Labrador dog yard plant so very tough and can take a fair amount of morning sun.   Mahonia Nervosa and Vaccinium Ovatum are both shrubs native to the Northwest.

The Vaccinium, a huckleberry plant will be more shade tolerant if you buy it from Boskey Dell Natives and ask for one that was dug out of deep shade.   I have native huckleberry at my home on the Puget sound and it seeded itself and  grows in full sun.  The truth is the offspring of my plant (little rulebreakers) will prefer a sunnier location than if planted in full shade.  This is all about natural selection.

The Mahonia, (also called Oregon Grape) a favorite of hummingbirds,  can get a little ratty looking at the end of winter, wait til the hummingbirds have gotten their fill of the flowers and then cut the plant back to about 12″ tall every year.  There won’t be berries for birds  if you do this but you can keep the plant front yard attractive.  http://www.greatplantpicks.org/plantlists/view/980

Here is a highly textural  native fern called Adiantum Aleuticum, Northern Maidenhair Fern. This one has previously escaped my radar. I use a lot of different ferns so nice to have another native one to use.

Ground cover

Last of all (for now) is an evergreen  ground cover ……..Beesia Deltophylla, I first met this plant at the famous Heronswood Garden in Kingston, Washington.  It is slow to bulk up but is such a low maintenance plant.  It would be great to have more access to this plant. I found it recently at Portland Nursery and snapped up a dozen for a client.  It won’t flower well in deep shade but the glossy leaves reflect light and are a huge asset in a deep shade setting.

Carol Lindsay, Designer and Garden Coach   503 223 2426