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

Green mystery revealed

Another easy one, or else you guys are just too smart!  It is indeed a mistletoe.  Gold stars to KB, John, Kandi, and Deb, and an extra point to Jane for identifying the genus (Phoradendron).  I believe it’s Phoradendron bolleanum, an introduced species which parasitizes Cupressus arizonica (Arizona cypress).

In any case, I chose this puzzle plant in keeping with the holiday season!  Thanks for playing!

Fertilizers, crops and landscapes

Last week Jeff wrote about the dangers of using “balanced” fertilizers, especially in reference to phosphorus content.  Comments quickly followed about using fertilizers in many situations – on farms, in container plants, on trees – and so on.  One of the latest comments came from Nick and began “I don’t usually recommend fertilizer for perennials or woody plants to consumers. In most cases they aren’t needed.”  And this leads into today’s topic.

Many of the horticultural practices we use in our gardens and landscapes have, unfortunately, been derived from agricultural crop production.  Whether you’re growing a field of wheat, garden tomatoes, or containerized shrubs your goal is maximizing crop production.  By its nature, this is an unsustainable practice because it requires continual inputs of water and nutrients at higher levels than would naturally occur.

But this is not how you should care for landscape trees and shrubs, and why Nick’s comment was a good one.  You don’t need to routinely add fertilizer to these plants; they don’t need it to grow normally.  What we should be doing in landscapes is preventing nutrient deficiencies.  Once you have a soil test in hand, you’ll know what nutrients may be too low (or too high) and how soil pH will affect that.  For most of us, this may involve occasionally adding one of a few nutrients (most commonly nitrogen), or perhaps acidifying the soil to improve nutrient availability.

 How do you know when to add nitrogen to established landscape plants?  Let your foliage do the talking. If leaves are uniformly yellow, small and sparse, you might have a nitrogen deficiency.  This will be most common in the mid to late summer, when plants are growing most rapidly and competing with one another for resources.  Be sure this symptom is wide-spread, however.  If it’s just one plant showing deficiency symptoms, it’s probably not a landscape issue.

 

Friday puzzle unrolled

I knew this one was pretty easy, but I have my reasons (below).  Gold stars to KB, Jim, John, and Dave for correctly identifying rolls of sod (and they do seem thin, Peter):

Yes, sod.  I dislike instant lawns; they never look good for very long, at least in my part of the country.  And getting rid of sod (as we have in our landscape) is a nightmare with that *%&$^ plastic mesh in which the grass is embedded.  It breaks up into little bits that are constantly coming to the surface.

I don’t have an axe to grind about lawns; my philosophy is that if you want a lawn and can afford to maintain it well, more power to you.  But what’s wrong with the old fashioned way of seeding a lawn?  Sure, it takes a few more weeks to "grow your own", but seeded lawns look more natural and last much longer.

Snow falling on cedars…not always a good thing

Seattle had its first snowfall last week – a mere 3-6″ – and the city shut down.  (Yes, those of you in the snowier parts of the midwest and east can laugh…but we’ve got hills.  That’s the main problem.)  It was unusally cold, so the snow that fell was the light, fluffy kind that I remember from our Buffalo years.

Every year someone writes to ask whether they should remove the snow from their trees and shrubs.  Here’s what I suggest:

1)  If it’s very cold and the snow is dry and light, I advise leaving the snow on.  It serves to insulate tissues from freeze damage.

2)  If the snow is wet and heavy (i.e. temperatures are not that cold), you should remove as much as possible.  The insulation isn’t necessary, and the weight load can permanently damage trees and shrubs.

This damage can’t be easily repaired; the only alternatives are to cut bent trunks and branches out entirely (no stub cuts!), or to tie them up.  Not being into plant bondage, I generally cut bent branches away.

The decline of Extension and the increased need for science-based information

I hate to be the downer this week, given Bert and Holly’s inspired posts, but reality continues to hit – or bite.  The budget crises in Washington state continues to gut higher education, and one of the hardest hit areas at WSU is Extension.  Land-grant institutions have a federal mandate to provide Extension services, and this sets WSU and similar universities apart from other state schools.  Unfortunately, Extension generates relatively little in terms of outside grants and contracts.  Land-grant universities like WSU tend to put their dwindling faculty resources into hiring those who can bring in multi-million dollar grants.  And as we’ve bemoaned in past posts, that isn’t in gardening or urban horticulture or arboriculture or any of those great topics that you all love to hear more about.

Let’s look what’s happened with Extension specialists at WSU.  Before I came in 2004, the Extension plant pathology specialist had retired.  The position was refilled with someone else.  The Extension entomology specialist retired last year.  His position will be refilled with someone to work with the structural pest control industry (there is some money there).  The questions that come from the public are shuffled around among other faculty, who may or may not have some partial appointment in Extension.  In any case, the public outreach and education aspect of land grant universities everywhere is taking the back seat to bringing in grant dollars and teaching college students.  That means fewer Extension Bulletins published or updated and more reliance on well-funded companies to provide their versions – good or bad – of agricultural sciences.

I’m not going to rail about the idiocy of letting public higher education fail in this country through lack of state funding – I’m sure you can see that for yourselves wherever you live.  Instead, I want to point out an effort to gather the remnant state forces to have a national impact. 

This year I’ve become associated with eXtension (a national group of Extension personnel) in the Community Horticulture Community of Practice.  This is a fledgling effort to construct a national web presence containing relevant, current, science-based information on all things horticultural.  If you check out the link above, you can click on Garden Myths, where you’ll find information from…Jeff Gillman and myself.

It’s going to take a long time to get this web resource organized and populated with good information – but it’s a start.  If you, or someone you know, is interested in helping, be sure to post a comment or email Karen Jeannette, our intrepid coordinator in Minnesota.  (I can provide her email if you are interested.)

Trunk teaser untwisted

Good guesses over the weekend on what caused the twisty looking trunk structure in Friday’s puzzle.  Here’s a larger photo:

Nancy and Paul both got this one – it’s two trunks fused together.  I have no idea whether the production nursery grew two saplings together on purpose or accidentally, but here’s one reason that this tree might be a problem down the road:

This area is ripe for disease, as water will collect in the crotch.  In fact, the area is already discolored and could be diseased already.

One thing I hadn’t noticed when I took the top picture were the price tags on the nearby pots.  They say it all – W(hy) O(h) W(hy).

Needless to say, I hope, is that you wouldn’t want to buy this plant.