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 an Emerita Professor in the Department of Horticulture. 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 group - www.facebook.com/groups/GardenProfessors Books: http://www.sustainablelandscapesandgardens.com

Proposed phosphate fertilizer ban – a dissection of the criticisms

A few brave souls gave Friday’s homework assignment a good shot.  Ryan did a nice critique of the bullet points; Kenny did a little digging on WFFF, the organization behind the email; and Tom chimed in with the fact that Israel managed to do this a long time ago without impairing plant health.  Gold stars for all!

Here’s my initial analysis of the statements made, based on reading the bill (which you should do if you haven’t yet; it’s neither long nor difficult to understand):

WFFF: 1) The intent section contains scientifically inaccurate statements, creating a false precedent that turf fertilizer is a significant surface water pollutant and is not necessary for a healthy lawn.… Continue reading this article “Proposed phosphate fertilizer ban – a dissection of the criticisms”

Proposed phosphate fertilizer ban

Today I received an email alerting members of Washington Friends of Farms and Forests to a proposed ban on phosphate-containing fertilizers in the state of Washington.  Here’s part of the text of the email (I’ve removed underlining, bolding, highlighting etc. so this reads as objectively as possible):

“Concerns with the HB 1271 & SB 5194 banning the sale of fertilizer containing phosphorous:

1) The intent section contains scientifically inaccurate statements, creating a false precedent that turf fertilizer is a significant surface water pollutant and is not necessary for a healthy lawn.… Continue reading this article “Proposed phosphate fertilizer ban”

When trees attack!

I’ve been suffering through my post-holiday, post-annual-reporting cold and/or flu, so I don’t feel as witty (or snarky) as I might otherwise be.  Instead, I feel like my body’s been invaded by a slowly spreading mass that reminds me…oh, I don’t know…of what trees can do when they encounter an immovable object.

Not much of a segue, I know, but I just had the urge to post some interesting photos after Holly’s photo-fest yesterday.  (Memo to self: not fun being Holly’s follow-up act.) … Continue reading this article “When trees attack!”

Fast food is unhealthy for plants, too

In early December, I posted my thoughts about fertilizing crops vs. landscapes.  An anonymous reader asked if we could follow up by discussing the relationship between excessive fertilizers and plant susceptibility to pests and disease.  It’s taken a month to get the scientific literature (and my act) together, but here it is.

There are decades’ worth of articles about the direct relationship between increased nutrient availability and increased susceptibility to pests, disease, and disorders.  One of the earliest articles linked the incidence of celery blackheart to over-fertilization. … Continue reading this article “Fast food is unhealthy for plants, too”

A comment about home remedies from Catherine Daniels

In case you didn’t see yesterday’s comment that was added to Jeff Gillman’s January 6 post on home remedies, I’ve posted it here.  Dr. Catherine Daniels is WSU’s pesticide coordinator:

I’ve enjoyed reading the science-based information on your site. Keep up the good work. As regards home remedies, that is slippery slope, both legally and morally. Having a written definition of what you will or will not accept is helpful, especially if done in advance. Then you can be sure of being consistent and deliberate at least.… Continue reading this article “A comment about home remedies from Catherine Daniels”

Pampas unpuzzled

Great discussion and answers on this one, gang!  Yes indeed, this is a plant out of place – as several of you noted.  But not only has it escaped from an ornamental landscape, it’s decided to grow, quite happily, in the median strip of I-5:

Another odd thing is that the species has not been officially recognized as invasive in Washington State.  It’s been languishing on the “Monitor” weed list for at least two years.  Our climate is a bit chilly for it, which may be part of the reason it looks so bad right now. … Continue reading this article “Pampas unpuzzled”

Pampas puzzler

Here’s a photo of some pampas grass (Cortaderia selloana), much beloved by many homeowners in their landscapes:

But what’s unusual – and undesirable – about this particular specimen?  Hint:  the landscape has been modified a little.

Answer on Monday!

Will cabling a tree’s crown make it stronger?

In a previous column (December 1, 2010) I discussed the problems that wet, heavy snow can cause for trees and shrubs – particularly evergreens.  In response my colleague Terry Ettinger mentioned a cabling technique discussed in the 2nd edition of Arboriculture (1991).  I think it’s worth looking at the science behind this practice and some of the unintended consequences.

Harris’s Arboriculture text is considered the bible for landscape professionals, including certified arborists.  In the late 1990’s, Dick Harris was joined by Jim Clark and Nelda Matheny, two other gifted academics who have crossed over into practical writing. … Continue reading this article “Will cabling a tree’s crown make it stronger?”

Friday puzzle uprooted!

Wow, we had some very creative answers on this one – and all of them made sense!  Peter, however, was spot on with his identification of roots (of a Thanksgiving cactus) growing in water (in an antique graduated cylinder).  I made it tricker by turning the photo upside down on Friday.  Here it is right side up:

What I love about this photo is that the various parts of actively growing roots are clear (more or less):  starting from the bottom you can begin to see the root tip and the hairless zone of elongation, followed by the zone of maturation with fuzzy root hairs, followed at the top by the area where lateral roots develop.</d

Last puzzle of 2010

I had a few weeks’ hiatus while scrambling around for the holidays – but have one last teaser for you before the close of 2010.  This photo is reminiscent of what Christmas trees will start looking like in the next few weeks. Can you figure out what it is? 

Ignore the parallel horizontal lines – they will be explained on Monday.  And yes, the photo quality’s not great, but the reason for that will be clear on Monday as well.… Continue reading this article “Last puzzle of 2010”