Author: Linda Chalker-Scott

Dr. Linda Chalker-Scott has a Ph.D. in Horticulture from Oregon State University and is an ISA certified arborist and an ASCA consulting arborist. She is WSU’s Extension Urban Horticulturist and a Professor in the Department of Horticulture, and holds two affiliate associate professor positions at University of Washington. She conducts research in applied plant and soil sciences, publishing the results in scientific articles and university Extension fact sheets. Linda also is the award-winning author of five books: the horticultural myth-busting The Informed Gardener (2008) and The Informed Gardener Blooms Again (2010) from the University of Washington Press and Sustainable Landscapes and Gardens: Good Science – Practical Application (2009) from GFG Publishing, Inc., and How Plants Work: The Science Behind the Amazing Things Plants Do from Timber Press (2015). Her latest effort is an update of Art Kruckeberg’s Gardening with Native Plants of the Pacific Northwest from UW Press (2019). In 2018 Linda was featured in a video series – The Science of Gardening – produced by The Great Courses. She also is one of the Garden Professors – a group of academic colleagues who educate and entertain through their blog and Facebook pages. Linda’s contribution to gardeners was recognized in 2017 by the Association for Garden Communicators as the first recipient of their Cynthia Westcott Scientific Writing Award. "The Garden Professors" Facebook page - www.facebook.com/TheGardenProfessors "The Garden Professors" Facebook group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com

An unusual company

This week I’m in Charlotte, NC as a guest of Bartlett Tree Experts.  In addition to providing tree services, this company also maintains the Bartlett Tree Research Laboratories and Arboretum. The latter includes over 300 acres of tree collections and ongoing research trials.  Here’s a sampling of the tree research we had a chance to observe:


Demonstration espalier pruning…


…and pleaching


Comparison of root barrier materials.  This area was covered with a sidewalk for a number of years and then exposed to observe tree rooting patterns.  The purpose of the research was to find which barriers were most likely to prevent sidewalk lifting and cracking.


A control – no barrier, lots of roots!


Black plastic – lack of rigidity allows roots to grow over (and through) the plastic, then under the sidewalk.


18″ rigid root barrier.  One of the more effective means of keeping roots out.


Removing circling roots before planting


A tree whose roots had been corrected before planting.  I think this had been planted in 2007, then lifted a few weeks ago.


A tree without root correction.  It didn’t grow any better than the corrected tree, and those circling roots are well on their way to becoming girdling roots.

This company employs a number of PhDs whose research is routinely published in arboricultural and horticultural journals.  It was fun to finally meet these researchers whose work I’ve been following for years.

Wouldn’t it be great if more companies put this much effort towards research?

Podcast #8 – Water Works

We’ve finally gotten our summer here in the Pacific NW and it’s been pretty hot for a few weeks. The plants weren’t really prepared for this, so we’ve had to irrigate quite a bit to keep all that lush foliage happy. So the topic of this podcast is Water Works – focusing on how water moves in the soil and through plants.

One of the more interesting tidbits I found this week is a recent USDA study on growing more potatoes with less water. Sound impossible? Listen to find out the one single, simple thing that increased water use efficiency by 12% and reduced fertilizer runoff as well.

I also debunk the common myth about using drainage material in container plants. Research from 100 years ago demonstrated that water won’t cross textural barriers – so putting gravel in the bottom of the pot will actually create a bathtub effect rather than helping drainage.

The interview this week is with my garden – primarily the sunny south-facing side. I thought I’d take you on a tour to see what’s happened in the last 11 years. The photos below will help you visualize the interview.


The front yard in 2003. We’ve started taking out the turf and moving around trees and shrubs.

The front yard in 2003 from another angle. We’ve removed the second driveway and covered the area in wood chips. By the garage you can see two of the roses I dug up from the shady back yard and moved to the sunny front.

The new front yard, with fencing, more plants, a pond, and no turf.

The rhody-hydrangea corner in front of the arbor vitae hedge

The new street garden, with a new retaining wall to hold back the soil that used to wash into the street.  Everything not covered in plants is covered with wood chips.

This is the last podcast of the first “season” of The Informed Gardener. We’re going to take off for about a month before starting the next series. If you’ve got ideas about future topics, you can email me or post a comment here. In the meantime, you can listen to archived podcasts found on this blog; just click on “podcasts” on the right-hand menu.

Podcast #7 – Better Red Than Dead

This week’s podcast is dedicated to anthocyanins – those pigments that give plants red, blue, and purple colors. Anthocyanins are also powerful antioxidants, important visual signals for pollinators, and often deadly to insect pests. The myth of the week explains why red leaves aren’t usually a sign of phosphorus deficiency, but instead an indicator that anthocyanins can help plants survive many environmental stresses.

My interview this week is with Cass Turnbull, founder of PlantAmnesty, a Seattle organization dedicated to “ending the senseless torture and mutilation of trees and shrubs.”  My son Jack took the interview photos, and Cass supplied the others from the PlantAmnesty photo archive.  You’ll love the way she combines her educational message with humor!


Cass on her “throne”

One of the nonbotanical garden residents

A selection of PlantAmnesty humor

Please let me know what you think of the podcast; you can email me directly or post a comment on the blog. Suggestions for future podcasts are most welcome!

Podcast #6 – Garden Hocus Pocus

Forgive my tardy posting – I spent yesterday traveling from Indianapolis back to Seattle.  I was in Indianapolis for the Garden Writers Association annual meeting and gave a talk on “evidence based garden information.”  It was encouraging to see how many garden writers DO want reliable sources of good gardening science.  And I got to meet Joseph Tychonievich, a frequent commenter on this blog and a PhD student at Michigan State.

Anyway, on to this week’s podcast. The theme is “Garden Hocus Pocus” which just opens the door for so many topics!  I settled on opening with the ancient Greek Doctrine of Signatures and how it’s being used today.  Then I discuss the function of plant alkaloids a bit, since they have historical use in magic and witchcraft.  And the myth of the week is quite similar to the talk I gave at GWA – specifically, how to separate the science from the snake oil.

My interview this week is with plantsman Riz Reyes, who works at the UW Center for Urban Horticulture and collects plants and has a landscaping business and blogs….and he’s not even 30 yet!  My daughter Charlotte came along and took some great photos of Riz’s garden.  (Thanks, Riz, for identifying all the plants here!)


Riz with Cardiocrinum giganteum var. yunnanense at Kew Gardens


Dahlia ‘Weston Spanish Dancer’


Left to Right: Lilium ‘Miss Lucy’, Petasites x hybridus, and Ulmus glabra ‘Camperdownii’


Lilium ‘Magic Star’


Dahlia ‘Bishop of York’


Linda interviewing Riz out of the rain

Please let me know what you think of the podcast; you can email me directly or post a comment on the blog. Suggestions for future podcasts are most welcome!

Podcast #5 – Selling Sustainability

Everyone (including me) hates how the word “sustainability” has been overused and misused. Yet there are some good concepts associated with the word that can help gardeners make rational decisions about products and practices. This week’s podcast deconstructs sustainability into specific actions that gardeners can easily follow:

  • Discovering and nurturing the natural processes that keep your gardens and landscapes healthy and functional
  • Choosing plants and products wisely to conserve natural resources
  • Creating gardens and landscapes that don’t require constant inputs of packaged fertilizers and pesticides

The podcast illustrates each of these points.  First, there’s a research article that demonstrates the benefits of polyculture in growing vegetables.  Next, there’s a critical look at a website presenting a “Sustainable Garden Starter Kit: 10 Must-Have Products for the New Green Grower.” Lastly I dispel the myth of “instant landscaping”, which is code for “long term disaster.”

The interview this week is on building your own garden pond. Dr. Jim Scott (PhD in horticulture), turns his talents to the plumbing, electrical work, and aesthetic disguises needed to build a really great garden water feature. Lucky for me, he also happens to be my spouse!


Jim and Linda try to figure out how many years it took to do a week long project

Decks…

…cleverly disguise pump system…

…and filter system

Seasonal guests

Permanent residents (the little orange guys in water)

Please let me know what you think of the podcast; you can email me directly or post a comment on the blog. Suggestions for future podcasts are most welcome!

Podcast #4 – Going Native

Another one in the can! This week the podcast focuses on native plants; I’ve got an interesting research item about using mixtures of native grasses for lawns.  You’ll also hear why sometimes native plants might not be the best choice, whether the goal is attracting fruit-eating birds or creating a sustainable urban landscape.

And you will love this week’s interview with Lacia Bailey – Seattle gardener and urban dairy goat maven. Once again I enlisted my son Jack to capture the moment on film:


“I’ll bet that camera is edible, too!”

Lacia and Dalli (the goat who thinks she’s a lap dog)

The goats make short work of most garden and yard waste

My podcasting producer Tina makes some new friends

Chickens are part of the system, too. They eat bugs from the used goat bedding.

Lacia setting up the milking station

Please let me know what you think of the podcast; you can email me directly or post a comment on the blog. Suggestions for future podcasts are most welcome!

Podcast #3 – Plants, Drugs and Rock and Roll

I’m starting to have fun with these!  This week the podcast has some fun items about the wide world of plant secondary compounds, which are all those interesting chemicals that aren’t related to the basic building blocks of life (the carbohydrates, proteins, lipids, and nucleic acids).  Plus there’s a myth segment on how music affects plants – is “acid rock” as bad for plants as it is for young developing brains?

And the highlight is my interview with Robin Haglund – Seattle gardener and urban beekeeper.  Both she and Corky Luster, owner of Ballard Bees, describe what it takes to open a bee hotel on a small urban lot.  My son Jack took some great photos of Robin’s garden, some of which are below:


Linda, Robin and Corky

Bee fountain

Bee heaven – nectar and lots of water

Corky opens the hive

Bees and honey!

Art and the garden

Please let me know what you think of the podcast; you can email me directly or post a comment on the blog. Suggestions for future podcasts are most welcome!