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

Packing Pearls

Yes, not my day to post, but I just received an email with a link to a new product called Packing Pearls.  These are polystyrene balls that fill the bottom of large containers so they aren’t so heavy.  They are promoted as “improving water drainage and oxygen flow.”  You can find a link here

The “pearls” are separated from the soil and plant roots with a pot liner (composition unknown).  We’re told that the roots can’t grow through the pot liner.  So now my question:  can a material that “improves water drainage and oxygen flow” be impervious to root growth?  Doesn’t it sound as though you’d be waterlogging the soil by installing this liner?

I honestly don’t know the answers to these questions, and the web site is not detailed (nor does it contain any links to research).  The emailed advertisement states “Tests show that flowering plants bloom two to three months longer when grown in containers with a base of Packing Pearls. Plants are also visibly healthier and hardier.”

Anyone used this system before?

Friday turf troubles

To no one’s great surprise by now, the white substance in Friday’s photo is mesh:

Like so many “instant” lawns that never really establish, the original grasses in this sod have died, leaving only weeds, debris, and the netting used as a matrix to support bunchgrass production.

(I have a personal grudge against sod netting, having removed the tenacious remains of black plastic netting when we replaced our lawn with alternative groundcoverings.  Like Velvetta and Twinkies, this stuff never dies.)

International Ag Labs – who are they and what do they do?

Last week I posted a short message about this company, asking you to do a little homework.  Bryn, CP, and Karen all have teased out some details that agree with my skepticism on how reliable this company is for soil testing and analysis.  (See last Wednesday’s post and comments if you haven’t read them already.)

To back up a little bit, I received an email from LB last week, along with the attached soil test, analysis and recommendations. LB intends to do some “market gardening” and here are his questions:

1. Is there anything to this perspective? Understanding your soil and rl37 (a “Jack of all trades” product).

2. I “get” that I should not willy nilly spread compost over everything, but what in the attached recommendation (based on the soil analysis) should I follow (Note: Crescendo and Stimulate are no longer offered, but there are lots of other interesting products here.)

3. Have you read any peer reviewed research that supports their “High Brix” market garden approach that uses sugar content and refractive index to supposedly correlate to improved flavor and higher nutrient content in selected vegetables?  I have heard of chefs using this to evaluate certain produce (carrots and tomatoes) in the market but nothing in a peer reviewed journal.”

Take a look at the linked report from IAL (from the second paragraph).  This is a confusing analysis, as it combines traditional ppm measures with pounds/acre.  (My understanding is that you can divide this latter number by 2 to get ppm.)  However, pounds/acre only represents a portion of what’s actually available in the soil.  It’s not an indication of how much, if any, of these nutrients to add.  (If you’ve never seen U. Mass Amherst’s soil testing lab, take a look at their webpage, especially their fact sheets related to soil testing.)

What irks me is the recommendations (which are in the first table in the attached document).  I’m not even sure of the rate – I assume it’s per acre, but who knows? And what is the purpose of all this stuff?

This company is heavily used by many people, including researchers (if you Google the name of the company along with site:.edu, you’ll find reference to articles and university reports that use their services.

Let’s have some discussion on this.  I’m certainly not an expert on performing soil tests, but I’ve had enough of them done that I have a pretty good idea how to interpret them and their recommendations.

Friday puzzle solved…finally

We’re back to civilization, so I can finally post the answer to the puzzle.  I’ve been without cell service and our only computer access was dial-up at a glacial 37.2 kbps.  Yes, kbps.

Back to our puzzle.  Here’s a larger version of Friday’s photo:

It is bark, as many astute readers pointed out.  As far as I know, it’s a London plane tree (Platanus), but given the promiscuity of the genus, who knows exactly what species or hybrid it is?

Other tree species were suggested by others and I immediately Googled them to see what their bark looked like.  Check out Pinus bungeana (thanks to @Garden Hoe), Parrotia (from Deirdre), Smilax bona-nox (Bryn), Stewartia (one of Deb’s hedged bets), and Corymbia maculata (from Jimbo).

And now, thanks to Ed, I will forever look for pictures hidden in bark.  Someone should make a “Gardener’s Rorshach test” from variegated bark!

Native vs. introduced species – the discussion continues

I was asked earlier today to comment on the Garden Rant blog regarding the issue of nonnative plants and insect survival, specifically in reference to Dr. Tallamy’s research.  Though I haven’t read his popular book (Bringing Nature Home), I did read one of his most recent papers (DW Tallamy and KJ Shropshire, 2009.  Ranking lepidopteran use of native versus introduced plants, Conservation Biology 23(4): 941-947).  The authors argue that lepidopterans prefer native to alien species for egg laying.  A serious problem I see in this paper is that the authors are literally comparing apples to oranges.  They do not compare effects among species in the same genus (the reasoning is there aren’t enough publications to look at), but among genera.  Thus, they lump at least 179 “alien” woody species into “native” woody genera and compare those to woody genera that are completely alien.  There are only 112 species in the latter.

I would bet that if he separated out these 179 woody species and added them to the alien genera list his findings would be quite different.

Comments?

Friday quiz time – and happy Valentine’s Day

I thought it would be fun again to do a “what is it” photo:

Answer and a larger photo on Monday…if I can. I’ll be on a dial-up modem and who knows if I can actually get anything posted.  If I can’t, it’ll be up Tuesday.

And from all of us Garden Professors, have a happy Valentine’s Day!

My summer vacation

I’m following Holly’s lead and slipping into fantasyland today.  Though this part of the country has no snow, it is a typical cool, misty and gray winter morning in Seattle.  So I’m going to a happy place and reminiscing about my summer vacation to Sechelt, British Columbia.

Sechelt (pronounced like “seashell” with a “t” at the end) is a lovely place full of wonderful people (and great gardeners!), but I’m going to focus on the coastal rock gardens at Smuggler’s Cove Marine Provincial Park.  We visited on a day much like the one I’m experiencing now, so there weren’t many visitors.  All the better for us.

Since my interests trend towards plant adaptations to harsh environments, this rocky, salt-sprayed landscape naturally drew my eye.  Trees colonize the bare rock, rooting along cracks and fractures.

Even though we were past the flowering season, these natural gardens were still striking with their miniature plants.  Many of these are cushion formers, and together they formed living patchworks.

And there were still a few wildflowers left as well.

 

Hot and dry in the summer, constantly sprayed with salt, and living on the thinnest of soils, these rock gardens nevertheless have a rich diversity of plant and insect life.  And all without vitamin B-1, compost tea, Epsom salts, or any of the other products aggressively marketed to the gardening world…truly amazing.

So much for my happy summer vacation

It figures.  After I write a happy post I get an email question that brings me back to reality.  I plan on sharing a little more about the question – and my answer – with you later, but I’m going to give you some homework.  Let’s see what you can find out about these topics:

International Ag Labs

High Brix Gardens

Reams’ Biological Theory of Ionization

Hint: they are all interrelated.  Post your comments on the blog and let’s see where we go with the discussion.

Friday puzzle untangled

Well, either the puzzle was too easy or you guys are too smart!  Deb, Christopher, Lori, Foy, Jim, and Hap go to the head of the class – it was, indeed, staking material left on way too long.  Here’s a photo from over 10 years ago.  I’m not sure this is the very same tree, but it’s from the same parking lot/torture chamber:

I “liberated” these trees with my handy wire-cutters (never leave home without them) shortly after taking the pictures.  Several take-home lessons from this example:

1)  Plastic tubing does not protect bark from girdling wire injury

2)  Parking lot trees, even in very upscale shopping malls, are abysmally managed

3)  Trees are amazingly resilient

Have a good week!