Archive for garden tips

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. 

 

Success with Crape Myrtle in Portland Landscape Designs

Residential Landscape Design PortlandLandscaping with Crape Myrtle in Portland

I responded to a request for help from clients in Northeast Portland who were concerned their crape myrtle trees planted two years ago were not healthy because they didn’t flower. They had done their research on crape myrtle but unfortunately not from a source familiar with their trees cultural needs or growth patterns here in the Willamette Valley.

Let me knock a few myths out of the way to save you the same unease and help get our crape myrtle trees off to a good start.

  1. Crape myrtle are drought tolerant so don’t ever water them. Not so!

Latest wisdom is to water them deeply with a drip irrigation or soaker hose once every 10 days. Touch the soil with your hands down a few inches to ensure you are not over watering. It should be moist and then as you get closer to the time to water again it should be almost dry. When they have been growing for ten years in your landscape they might become very low water needs.

I like to design plant companions for the crape myrtle that have the same water needs. In this garden I have crape myrtle with Chinese Camellia – Camellia sasanqua ‘Yuletide’ and American Switch grass-Panicum virgatum ‘Shenendoah’. The clients added ground cover sedum.  None of the plants near the tree need to be watered more than once a week ever after except perhaps for their first summer. A splash of hose water once a week is not at all what I am talking about, I am talking about slowly applied water and preferably drip system or soaker hose.

  1. Fertilize if you want a lot of flowers, that’s true for all plants, right? Not so!

First off, nothing is true for all plants. There are plenty of plants that are harmed by fertilizer so tuck that behind your ear for a future conversation. We typically have fertile soil here in the Willamette Valley, so I would never fertilize crape myrtle beyond adding garden compost to the soil once a year as a top dressing. Adding fertilizer will work against your goal of having flowers.A  young crape myrtle in SE Portland landscaping.

  1. You must dead head (pinch off) all the spent flowers. No way!!

If I had to deadhead crape myrtle flowers, it would take a bazillion hours and eventually a ladder.  Nope, you don’t need to deadhead. When your tree is young, and you get a heavy crop of flowers you might want to thin out some flowers to prevent the young branches from breaking.

  1.  Flower timing will depend on our summer temperatures. True.

It’s got to be hot enough and stay warm even at night to kick off the flowering of crape myrtle here in the Willamette Valley. If we have a cool June which we do sometimes, the flowers will be delayed until it’s been warm enough for long enough. For a deeper dig into crape myrtle read what Paul Bonine says in Pacific Horticulture magazine.  He’s my expert! 

Sleep-Creep-Leap

These clients came from California, a climate where plants grow fast. They were not familiar with the saying “Sleep-Creep-Leap” which describes typical plant growth for the first three years.

A  crape myrtle in the late Portland summer. Photo by Carol LindsayOnce roots are well established many plants grow fast and then after many years, they slow their growth. Just to be perverse, some plants grow slowly when young and then after they are a decade old, they grow much faster. It depends on the genetic makeup of each plant as to its growth rate.  Generally, it takes 3 years of root growth in a plant to get to leap.

Patience in our culture is a revolutionary idea. Contact me if you have more questions on your landscaping.

Colorful Four Season Plant for Portland Residential Landscape Designs

North Portland residential landscape design for year round colorColorful Four Season Plant for Portland Residential Landscape Designs

I like to use Nandina as a colorful four season plant for my Portland landscape designs.

Advantages

The foliage is colorful year around.

Very low maintenance plants if you know the cool pruning tip.

They are easy to prune successfully so you can keep them for years.

Nandina varieties fit multiple diverse needs in the landscape because they can be small (18″ to 24” tall) or up to 8 feet tall.

They thrive in half or full day sun.  Deer don’t typically eat them.

Colorful Four Season Plant for Portland Residential Landscape DesignsDisadvantages

People prune it wrong and then it’s so ugly they remove them – this is so easy to avoid.

It’s not a successful shade plant and will look leggy and sparse in the shade.  They will look so bad they will be removed.

People think Nandina is drought tolerant and they don’t water it in the summer……….this ends badly.

Nandina (from China) doesn’t feed our native insects; therefore, overusing it limits food for our native bird population.  I like to select at least a few native plants for companions.

Is this plant overused? Some garden designers snub the Nandina plant because it is used in commercial landscapes. Nandina is useful to my Portland residential landscape design clients who want low maintenance landscapes.  With the right plant partners Nandina can sparkle in a home landscape.

North Portland residential landscape design for year round colorHow I Use Nandina in Garden Designs

Nandina domestica – Heavenly Bamboo (not related to Bamboo)

There is a variety of Nandina to fit every landscape:

  • 6 to 8 foot tall  ‘Moyers Red’ or 4 to 6 foot tall ‘Plum Passion’ dress and soften an expanse of fence, hide the hot tub or garbage area nicely
  • 2 to 4 foot tall ‘Sienna Sunrise’, ‘Moon Bay’ or ‘Firepower’ work well in foundation plantings and entry areas.

Use a tape measure on planting day, assume the size info on the plant tag is being modest and give your plant more room to grow.  Some varieties of Nandina will grow 3 to 4 feet wide.   To keep your Nandina from getting too wide, I suggest pruning out entire canes at the base of the plant once a year.  For varieties that are listed as 3 to 4 feet wide, plant it at least 30 inches off your path.

A new variety called ‘Blush’ is typically 24 inches tall and 18 inches wide. The evergreen leaves turn an intense claret red and hold their color for months, longer and redder than other Nandina. ‘Blush’ was designed for the southern United States where it is fully drought tolerant. In Portland, all varieties of  Nandina including ‘Blush’, requires irrigation in summer. Multiple articles on the net enthusiastically state ‘Blush’ is drought tolerant but they do not mean here in the NW.  In the high humidity of an Alabama summer I too am probably drought tolerant…..Mint Julep anyone?

North Portland residential landscape design for year round colorPlant Partners

I love to combine Nandina with textured or needled plants that contrast with the narrow Nandina leaves.  Dwarf conifers, (Pinus mugo ‘Sherwoods Compact’), heather  Erica carnea ‘Adrienne Duncan’ or ornamental grasses like  Opiopogon (black mondo grass)  work well.  NW native plants, like salal, sword fern and huckleberry give  contrast and good looks.  They also provide food for native insects and for our birds who must eat native insects for food.  Pairing Nandina with typical cottage garden plants disappoints my aesthetic; there isn’t enough leaf contrast.

How to prune Nandina

The key to success with Nandina is learning how to prune it which is all about thinning the multiple canes (or stems) of the shrub.  Read more in my next blog or check out this u tube video I found to get you started.

 

 

 

Tempting Red Hellebore Flowers for Winter Cheer

Popular Double Hellebore From Englands Ashwood Ashwood Garden Hybrids

Helleborus x hybridus ‘Ashwood Double BiColor Shades’ grown here in the NW by Monrovia.

Tempting Red Hellebore Flowers for Winter Cheer

Red flowered Hellebores are still the holy grail for plant geeks but they are so tough that anyone can covet these and grow them.

‘Peppermint Ice’, ‘Amethyst Gem’ and ‘Ashwood Double Bi Color Shades’ are Hellebore cultivated varieties with red to eggplant hued double flowers.  They wow us in late winter with a long vibrant flower display.

As a Portland landscape designer I like to use Hellebore in my designs.  The Helleborus x hybridus plants (which is what we are focusing on today)  can live for a hundred years, deer don’t like them, they are low water and except for a typically minor problem with aphids, and a little slug activity they are pretty pest free.

Helleborus x hybridus 'Peppermint Ice', Perfect for Portland Gardens

Peppermint Ice has a darker outline around each of the petals. Its adds a lighter touch with pink red flowers.

They are shade tolerant although I  tend to use these three in strong morning sun with dappled or full afternoon shade.

Amythest Gem comes from the famous NW Garden Nursery. Double petals with a light edge gives us drama and the constrast needed to appreciate the mass of petals.

Double flowers give us more color than the singles but the singles, with only 5 to 7 petals, are also stunning and low maintenance.  ‘Ashwood Double BiColor Shades’ have a wine red petal with a darker edge which is opposite of ‘Amethyst Gem’.

Using Hellebore as a cut flower

The flowers last a long time in the landscape but not long as a cut flower because the stems wither quickly.  Most people cut the stems off and float them in a bowl.  I’ve picked them from my NW Portland garden, knowing they would only look good for a few days.  There are techniques for making them last which involve picking them at the right time based on the age of the flower and using an alcohol solution in the vase.  Follow this link  to NW Garden Nursery and read the bottom of their culture sheet.   Now that you are bringing the flowers inside please be aware that all parts of the plant are toxic.

All Hellebore flowers tend to nod down rather than face up.  This protects the flowers from cold damage (disfigurement/freezer burn) because water drips off the flower and  is not trapped inside. Nature designed this

Hellebore foliage looks fantastic with the lacy Himalayan Maidenhair Fern (Adiantum venustum) on this wall of boulders.

plant to flower in winter.

Great Foliage Year Round

Of course, it’s not just the flowers that encourage me to use hellebores in landscape designs. The leaves are leathery, attractive and provide interesting contrast with a range of plant material including feathery fern fronds, ornamental grasses or tiny leafed boxwood.

The summer foliage of hellebores look great with many plants including Sweet Flag (Acorus gramineus).

What about aphids?

What about aphids?  My only problem with Hellebore is aphids. Some years I don’t have any noticeable aphid activity. When I do it’s so early in the year that handy predators like lacewing and lady bug are still in sleep mode or haven’t hatched yet so I’m  on my own. Dealing with them is easy.  Use a spray bottle filled with water or 1 tsp of dish soap to 1 gallon of water and spray down your plant.  Use your hose or this great gadget called the bug blaster  which you can buy at Portland Nursery. (I’ve got to get one this year to use in my veggie garden too.) Don’t use a pesticide because most of them will harm bees even if they are not present when you spray. Aphids have soft bodies and will be damaged by the force of the water or the soapy solution will invade their bodies and disable them. You will have to knock them down with water or soapy water once or twice a week to prevent the temporary cosmetic damage.   I’ve never lost a hellebore plant to anything let alone a virus but in recent years virus has spread from plant to plant by aphids.  It is only an issue for professional growers or collectors.

Check out this bowlful of hellebore beauties

Check out this bowlful of hellebore beauties

How to care for your Hellebore

How to care for your Hellebore:  I water once or twice a week its first summer and then once a week after that.  Drip irrigation would be best rather than overhead sprinklers because drip can water deep into the soil.  Established Hellebore become quite a low water needs plant and might be content with every ten days or less.  An application of mulch around the plant once or twice a year is a good practice.  If your soil is so good that they make seedlings, be aware they won’t have the same flower as your hybridized plant. I cut the old leaves off the plant in late winter so that the flowers are not visually diminished by the previous years worn foliage.

How to kill a Hellebore

Plant it in a low spot where winter rain will rot the roots. Over water it and fertilize it heavily.

Winter Color provided by Hellebore 'Peppermint Ice'

Helleborus x Hybridus ‘Peppermint Ice’ is another Winter Gem by NW Garden Nursery. It is grown by Terra Nova so is available at local garden nurseries. Photo by Terra Nova.

Helleborus x Hybridus 'Peppermint Ice' photo by Terra Nova

Helleborus x Hybridus ‘Peppermint Ice’ has double flowers that hang down but the overall effecting your winter landscape is very colorful. The flowers last a long time.

Safe Soil in the City

Portland landscape designer Carol Lindsay

Daizzie and I in my edibles garden

Safe soil in the city – smart and healthy practices for urban gardens

I love having a vegetable garden. It’s healthy, right? I love eating kale and I grow a lot of greens for smoothies year-round.  There are a few concerns about growing food in urban areas. Two concerns that apply to us all, city and suburban, are lead paint and lead exhaust from the past in our soils. Let’s be practical not scary about this.

Is my food safe to eat? What are the most important practices I can do and how can I keep it simple?  My garden is below Highway 30.  It’s an old heavily traveled highway so our soil has years of exposure to lead exhaust.

There’s no way I’d grow my food in the ground here.

My current garden practices

I’ve been assuming my food is safe to eat because:

Our community garden has raised beds with new clean soil from just three years ago.
I apply lots of compost at least three times a year.

Carol's winter kale

My garden supplies me with year round greens like kale.

I use an organic fertilizer. (OK it’s boxed Dr. Earth, not a truckload from Natures Needs because it’s very convenient and my garden is small.)  I don’t know what my NPK ratio is which makes me a bit of a lazy gardener but the food I like to grow does fine.  NPK being Nitrogen, Potassium, Phosphorous.  And yes I was trained as an advanced master gardener and yes that was a very long time ago………they teach you all about soil in the master gardener program.

I wash my produce, no nibbling right out of the garden bed. (OK once in a while a strawberry or tomato).

According to some experts I’m doing OK but I could do a lot better.

My improvements

  1. Soil areas next to old garages often have higher lead levels.

    Soil areas next to old garages often have higher lead levels.

    Reducing exposure to dust is the most effective thing you can do to reduce lead hazard in your landscape. It is typically in the first few inches of soil. This is the most important thing in the blog.  Mulch and compost applications cover your soil and protect it from dust with contaminants in it.    We want to keep the dust and soil off human skin and out of the mouth.  This is critical for babies and small children and good for the rest of us too.  Adding compost has many benefits for improving conditions for plants.  Adding compost at least twice a year can only benefit, there are no drawbacks.

  1. Here at my community garden, we could have put a barrier between our new soil and the existing ground soil. I can still do this once my winter Kale are done in March. I’ll have to get a tarp and dig out a lot of my soil so I’m going to install a metal grid and landscape fabric.  The grid is to keep the moles and gophers out of my raised bed. They may have brought some of the lead contaminated soil up into my new clean soil, and they caused a lot of havoc with the roots of my plants.  Some died or did not produce well because of the soil disturbance.
  1. I could improve the efficacy of washing my veggies by using a 1 percent vinegar solution instead of only using water. I’m thinking a large spray bottle under the sink could be used for my final wash. It’s got to be simple or I won’t do it.

Beyond these good soil management practices, I will need to do a Nutrient Analysis soil test to know what I need to add to my raised beds to improve the health and productivity of my vegetables and bind up any lead and keep it locked into my soil where it won’t cause problems for me.

Portland landscape designer in edibles garden

My garden is below Highway 30. It’s an old heavily traveled highway so our soil has years of exposure to lead exhaust.

Lead Soil Test

My client Katy had an older home in SE Portland.  I suggested a lead soil test.  She collected the soil and submitted samples for a lead test. She discovered the area where we wanted the kids play structure to go had high lead.  It was next to the neighbors’ garage.  Several inches of contaminated soil were removed.  She brought in new soil and playground chips and now has a safe play area for her toddlers.

What’s one new thing you could do this year to improve your landscape or edibles garden?  Get your soil tested.  I’m planning to collect soil from my vegetable garden and submit it to a lab for testing.  I’ll share that experience with you in another blog.