The Biscayne Times

Feb 22nd
Root Zone Ecosystem PDF Print E-mail
Written by Jeff Shimonski, BT Contributor   
December 2017

There’s a symbiotic universe beneath your toes

WPix_YourGarden_12-17hen I’m having a long day, one of my greatest pleasures is walking through my garden to see how everything’s growing. I’m always looking for plants coming into bloom or fruit, and what species of mushrooms are growing.

It’s a challenge to identify mushrooms, but it’s a worthwhile endeavor. Are they edible or poisonous? And are they mycorrhizal, meaning do they have a symbiotic relationship with the plants in my garden so that they and their “partners” are exchanging water and nutrients? When you see mycorrhizal mushrooms near trees and other plants, you have a good indication that the soil around the root systems is fairly healthy and that the trees and plants are doing just fine without the need for chemical fertilizers, fungicides, and in most cases supplemental irrigation.

The photo that accompanies this article is of a mushroom I often find growing underneath the large mature live oak tree in my garden. Its scientific name is Phylloporus rhodoxanthus, and it’s known more commonly as the gilled bolete. It is mycorrhizal and is commonly found growing near oak trees. The numerous species of mycorrhizal mushrooms in my garden make it a real sustainable landscape. I have no need for added chemicals -- no greenwashing here.

During many of my site inspections of properties with old mature landscapes, I often see mycorrhizal mushrooms. The irony is that when a new, much larger building goes up, the surrounding trees and vegetation will be demolished -- even though they are usually healthy and haven’t received commercial fertilizer in a long time, if ever. And trees that do remain onsite will be confined to very small spaces. This loss of root and soil volume will remove a healthy, symbiotic relationship that developed between the trees and the soil organisms, and became established in the root zone over many years.

I often wonder why people pay so much money to build a LEED building and then say it is all about sustainability. Leadership in Energy and Environmental Design is a great concept -- except that it seems to leave out the “environmental design” immediately beyond the building envelope.

The development and construction of the structure totally destroys any healthy root zones onsite. The soil and its beneficial organisms that evolved with the mature trees have been scrapped, removed, and never returned to the site for landscaping.

When the few trees and shrubs are finally installed at the end of the project, so the certificate of occupancy can be received, they are, of course, low-bid and usually low-quality plants. And any trees remaining on the project site were left without a functioning tree protection zone around them during construction. As a result, the soil around them is hopelessly compacted and now basically inert.

They’ll bring in different landscape soil that will be totally different from what’s currently onsite and probably “made to someone’s soil prescription.” The new plants will be drilled into the hard, nutrient-dead, and highly compacted structural fill. Then they’ll install an expensive irrigation system, and, hopefully, everyone will receive an award for the fancy, sustainable project.

When the new owners arrive, they’ll look for the lowest bidder to maintain this landscape. I’ve seen some of these contracts, with lots of upcharges that would be needless with the original sustainable landscape.

The workers will come by the property once a week with a huge trailer towed behind a huge truck. They’ll unload a bunch of gasoline-powered equipment and blast through the property as fast as possible. Maybe some fertilizer will be thrown down on the ground, and someone will walk around the property with a hand sprayer. Then the highest decibel blowers known to mankind will strip all loose vegetation, top soil, and cut grass, sending it into the street and neighboring properties.

This cut vegetation and topsoil that’s now going down the storm drain is exactly what needs to be left onsite to create or replenish that important topsoil and upper organic horizon that your plants and trees need.

When you think about it, this is what we criticize other countries for when they chop down their trees and let all the topsoil run down into the rivers.

All the vegetation that was removed from properties after Hurricane Irma should have been ground up or chipped, and used as mulch on the properties where the organic debris came from in the first place. Instead of driving it around for miles in gigantic trucks, that debris should have been prepped and then left in place for the property owners to distribute onto their properties.

I think it’s time for LEED building owners to address the huge carbon footprints they have outside their buildings.


Jeff Shimonski is an ISA-certified arborist, municipal specialist, retired director of horticulture at Parrot Jungle and Jungle Island, and principal of Tropical Designs of Florida. Contact him at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .


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