In the world of horticulture, there have been many giants – landscape designers, plant breeders and teachers.   I am grateful for meeting my 'giant' in horticulture – Dr. Linda Chalker-Scott – during her April visit to Thunder Bay.   As I've worked in my garden this season, I've reflected on and applied the advice she shared with gardeners in my community.

I want to report on a technique that Dr. Chalker-Scott champions – the bare root transplanting of shrubs and trees.  

Many landscapers will consider this controversial, but I think it is beneficial.  I've tried it with newly-purchased potted shrubs and with a shrub that needed to be moved.  From what I can see, these plants are doing well, thanks to lots of rain, cool days and this transplanting method.

I needed to relocate my dwarf willow (Salix integra ‘Hakuro-nishiki Dappled Willow’) to a shadier, more moist location.  I dug up the willow and was shocked to see the root ball looked exactly the same as it did when I planted it a year ago.  The root mass was the shape of the pot it had come in; they had not spread into the soil at all.  How I wish I had a picture to share!  

Here's how I used the bare root transplanting method to remedy the situation. 

I placed the shrub in my wheelbarrow and gently washed the soil from the roots.  I checked the roots for structure and health.  I pruned away some of the bound up roots and untangled the rest.  I dug a shallow hole in the new location, and without amending the soil at all, I arranged the shrub with its roots radiating out like the spokes on a wheel.  I covered everything with soil, taking care that the shrub was planted at the same level as before, then watered well. 

To my amazement, the willow has shown no signs of stress; instead, there is plenty of new growth.  I know that below ground, my willow is well-supported and its roots have ample opportunity to draw nutrients from the soil.  I am keen to see how it progresses this season and beyond.

On to the planting of newly-purchased shrubs. 

My neighbour asked me to help with the placement of three new shrubs.  Armed with my new experience, I felt pretty confident we should use the bare root method.  As we removed the purple-leaf sand cherry (Prunus × cistena) from its pot, I could see that the roots had already begun to curl and harden within the pot – not a good sign.  Left as is, the woody, curled root would likely continue to grow in a circular direction around the root ball.  This is how shrubs and trees can be girdled by their own roots. 

I pruned back this circling root and proceeded as before – planting in a shallow hole, watering in with the water left from the root baring process, and covering over with soil to the correct depth.  Voila, a happy shrub!

You can review the bare root method in more
detail in Dr. Chalker-Scott's excellent slideshare,
"Take It All Off" (file download below).

Dr. Chalker-Scott, the Extension Urban Horticulturist at Washington State University, was a delightful guest.  We toured some of our northern sights. 

Fortunately for gardeners this talented teacher shares her advice freely on her website, The Informed Gardener, and in her books.  As well, you can find her among the horticulturists at The Garden Professors.  Her useful perspective on landscape plants will get you doing things differently.  There's still time to plant a shrub or two this season.

Gardeners in the northwest are gathering this weekend – not to plant, but to listen and learn.  Dr. Linda Chalker-Scott – one of horticulture's best 'myth busters' – will be speaking in Thunder Bay  this Saturday, April 30.

Dr. Chalker-Scott, Associate Professor of Horticulture at Washington State University (WSU), is a champion of the real science behind good gardening practices.  And in explaining the science, she busts a lot of myths about fertilizers, mulches, planting practices and how plants work.  There are dozens of gardening topics and the associated myths listed on her webpage, Horticultural Myths, at WSU.  Each short article will leave you wiser for the reading.

For example, The Myth of Wilting Leaves, addresses the commonly-held belief that leaf wilt is "an indicator to increase water application."   In reality, says Dr. Chalker-Scott, watering wilted plants can make things worse "if lack of soil moisture is not the underlying cause of wilt." 

Stands to reason, right?  But why?

The fact is, reports Dr. Chalker-Scott, "Leaf wilt can result from a number of stresses in the soil environment, many of which lead directly or indirectly to water deficits in the leaf.  A common cause of leaf wilt in urban environments, especially sites with compacted, poorly drained soils, is root anoxia.  Soils without sufficient pore space are deficient in oxygen which severely impacts root function.  Roots, like any other living tissues, require oxygen for survival; since they are not photosynthetic they rely on oxygen from the soil or from above-ground parts of the plant. Excess water will fill soil pores and eliminate gas exchange.  Without enough oxygen, root function shuts down and water uptake ceases.  Leaf transpiration, however, continues and eventually leaves will wilt as their water content decreases. Ironically, the leaves suffer from drought stress even though soil moisture is more than adequate!"  I encourage you to read more detail in the article. 

I love the way this scientist ends her articles with "The Bottom Line" – a summary that gives the remedy and/or practical advice.  For wiliting leaves in plants, trees and shrubs, the summary points include:

• Be sure to assess soil conditions before irrigating wilted plants.
• If soil is wet, try to aerate through the root zone.
• If soil is chronically wet, consider installing a French drain or other passive means of drainage. [A French drain is a trench filled with gravel or rock or containing a perforated pipe that redirects surface water and groundwater away from an area.]
• Alternatively, select trees and shrubs adapted to wet conditions.

There's another "bottom line", I'd say. The science behind good gardening practices should guide our gardening efforts.  Fortunately for us, explaining the science is Dr. Chalker-Scott’s passion.

Winter has well and truly come to Northwestern Ontario.  The harsh temperatures have me hunkered down indoors, using my computer as a window on gardens that bloom online.

I am amazed at where a few judicious links can take an avid reader-about-all-things-horticultural.  And, I'm equally grateful for the talented landscape designers and plantsmen who tend a weblog as well as a garden or two. 

I've selected three sites – each exceptional in my view – that offer views (and lovely vistas) related to naturalist planting. I invite you to dip into the writing on these sites.

Noel's Garden Blog
Noel Kingbury is a noted UK educator and researcher who has collaborated on many excellent gardening books. His blog is an excellent window on horticulture in Britain and the EU.

Thomas Rainer's Grounded Design
Provocative posts highlight trends and shifting thinking in landscape design, particularly in the US.  Find out about 'intermingling' – the latest trend in landscaping – and the broader movement to naturalize our landscapes.

The New Perennialist
Toronto-based garden writer Tony Spencer offers his views on landscape design in his weblog about perennial plantings.

There now. Didn't that soften the bite of winter?  Visit these sites in the cold weeks ahead and warm to new ideas in plant selection and design.