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

Friday fun!

It’s the holidays, but this pine tree is feeling anything but merry.  It was installed about a year ago.  While the upper foliage looks lush and green, the lower branches have no new needles and in fact the current needles are dropping:

This is a two part question:

1)  What might be directly responsible for the needle decline on the lower branches?  (Hint:  this is caused by the plant itself.)

2)  What might be the underlying stress causing the needle decline? … Continue reading this article “Friday fun!”

Inspecting nursery plants, part IV

(Note:  this is a really LONG post.  Not in text – but in photos!  Sorry for all the scrolling.)

I don’t know about you, but after spending three weeks on my hands and knees looking for trunk rots, surface roots, and suckers, I’m ready to become bipedal again.  So today let’s look at trunks – and what shouldn’t be missing on them.

Many young trees have numerous short branches along their trunk, as shown in the photo below:

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Unfortunately, many nurseries and gardeners think this looks scruffy, and respond by pruning these branches off, leaving a tree such as the one in this picture:

Personally, I think these trees look like lollipops, but aesthetics aside, this type of pruning can inadvertently damage young trees. … Continue reading this article “Inspecting nursery plants, part IV”

Friday puzzle answers!

Good speculation on the rhododendron leaf damage!  Jim in Wisconsin zoomed right in on the causes:  the first photo was taken on a year where we had an unseasonable freeze right as leaves were expanding, and the second was taken on a year where we had unseasonably hot weather as leaves were expanding.

In both cases, the ultimate cause of damage is lack of water in rapidly expanding tissues.  Once dormancy is broken, leaf and flower buds are highly sensitive to environmental extremes – they are expanding and are most sensitive to anything that interferes with water content.… Continue reading this article “Friday puzzle answers!”

Justice finally

This just in from our Saturday paper:  US man wanted for ecoterror sentenced in China.

For those of you who don’t know my history, I was an associate professor at the Center for Urban Horticulture at UW when it was firebombed in May 2001 by ecoterrorists.  It’s a long and sad story, but if there’s an upside, it’s that this event was the ultimate reason I’m doing what I’m doing now.  Otherwise I would probably still be doing lab-based research – which is good and necessary, but not nearly as personally satisfying as working directly with people who want to understand and apply plant sciences as they relate to garden and landscape sustainability.… Continue reading this article “Justice finally”

Post-turkey puzzler

I hope everyone had a great holiday yesterday!  Since I am NOT a shopper, I’m avoiding “Black Friday” and posting another puzzle instead.

Consider this photo:

This is a rhododendron in my own landscape.  The photo was taken in July, though the damage on these new leaves occurred earlier than that.  In Seattle, rhododendron leaf bud break generally occurs in April.

Now consider this problem.  Same plant, different year – and actually a different problem!

So what caused this damage?… Continue reading this article “Post-turkey puzzler”

Inspecting nursery plants, part lll

By now you’re probably ready to stand up, brush off your pants, and stretch your back after crawling around looking for surface roots and root crowns.  Not so fast!  There’s one more thing to look for – and to avoid.

Take a look at these two photos:

 

You can easily see the suckers at the base of these trees.  Whether or not they are actually suckers (coming from the roots) or watersprouts (coming from the base of the trunk) doesn’t matter. … Continue reading this article “Inspecting nursery plants, part lll”

Friday Can O’ Worms

I was pleased to see that at least two of you dug into the literature over the weekend to read these papers!  (I can still remember the first time as a Master’s student when I was assigned a journal paper to review.  I had NO idea what, exactly, I was supposed to be doing.  It took a long time to figure it out.)

In any case, kudos to Jimbo and Diana for their thoughtful comments – and for zooming in on the problems. … Continue reading this article “Friday Can O’ Worms”

Friday puzzler revealed!

Lots of discussion about the mysterious white streaking on the hedge.  The pictures below show a little more detail than those on Friday:

As you can see, Jimbo was on the right track when he suggested the hedge might be near a parking lot.  But it’s the heat escaping from the engine compartments that’s been causing the damage. 

(I am now committed to find some good photos of urine damage by dogs, donkeys, or drunken frat boys!)

Friday puzzler addendum

OK, I know we gave you a tough assignment for the weekend, so I want to post something fun as well.  (Think of this as dessert after your healthy meal!)  Take a look at the photos below:

This hedge is regularly sheared and no one part of it has been maintained any differently than another part.  Both sections of the hedge face east, and the damage is anywhere from 2 to 4 feet from the ground. … Continue reading this article “Friday puzzler addendum”

Friday puzzler: Opening a can of worms

Part of being a Garden Professor is evaluating, interpreting, and passing on good science to the rest of the gardening world.  I was recently made aware of two articles soon to be published in Crop Protection and Pedobiologia, both peer-reviewed, scientific journals.  (You can download these articles just by clicking on the highlighted journal names.)

Briefly, what one expects from a scientific article is (1) a statement of the research question (the hypothesis) to be investigated, (2) a clear description of the materials used and procedures followed, (3) a listing of the results, along with their statistical significance, and (4) a discussion of the results, including whether they supported the hypothesis.… Continue reading this article “Friday puzzler: Opening a can of worms”