Posts for Tag : Gardening

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BEST TREES FOR MEMPHIS

THE BEST TREES FOR MEMPHIS

(AN ODE TO COLUMNAR DECIDUOUS TREES)

 

Though a good horticulturalist can be successful planting any time of the year, the best time to plant trees and other woody plants in the Memphis area is in the fall.  So, it’s time to start contemplating what you’re going to plant this fall! (This is the first of a series of blog posts I’ll be doing on fall gardening activities over the next few months.)

Columnar European Hornbeam in a bed designed by Jesse Howley and installed by the author at the home of Tom and Janet Wyatt on Angelus Street in midtown Memphis, Tennessee.

 

Trees are categorized in many ways. Aesthetically, trees are most often categorized by size, shape, and whether they are deciduous (meaning they lose their leaves in winter) or evergreen (meaning they keep leaves year round). The size categories are usually small, medium, or large, defined best here, https://www.arborday.org/trees/righttreeandplace/size.cfm, while canopy shape is defined best here: https://extension.tennessee.edu/publications/Documents/SP531.pdf.  The tree sizes and shape I advocate most for in urban environments, which usually have smaller yards, are small to medium sized trees with columnar shaped (also called fastigiated) canopies.

This row of arborvitae was planted at a private residence by Greg Touliatos & Associates, Inc. as part of a comprehensive landscape design and installation project.

 

Columnar trees have a strong vertical form and are often six feet or less in width.  The most well-known columnar tree forms are probably arborvitae and Italian cypress, both commonly associated with Mediterranean landscapes but widely used in Memphis.  For example, Presbyterian Day School has a row of small arborvitae, about 8 feet tall, on the south end of one of its playing fields bordering Central Avenue.  Then, there is a row of 3 very tall Italian cypresses, over 30 feet, in midtown on Evergreen, a couple of blocks north of India Palace Restaurant.  These two examples are both evergreen.

These 3 Italian Cypresses have been in midtown for years and have done well, though likely more were planted in the beginning.

 

But, lesser known, and I think under-utilized until the last few years in Memphis are columnar deciduous trees.  We often think only of deciduous trees as large shade trees, except perhaps for Japanese and other maples or the widely over-planted crepe myrtles.  Customers rarely specifically request a columnar deciduous tree at our nursery.  In fact, just as new wine drinkers often prefer sweet white wines before maturing into cabernets and merlots, inexperienced gardeners gravitate towards things that are covered in blooms part of the year or evergreen, preferably both, fearing the bareness of deciduous plants in winter and not appreciating the texture of mere leaves without flowers.

 

One big advantage of deciduous columnar trees over evergreens like arborvitae and Italian cypress is that they tend to have fewer problems.  The evergreens prefer the subtly different Mediterranean climate rather than ours, are sensitive to both under-watering and over-watering, and too often get bag worms and other pests, particularly in early summer.  In contrast, well-planted deciduous columnars are relatively maintenance and pest free, needing only the occasional pruning of dead branches.  Without leaves in winter, a sudden ice storm is less likely to damage them too.  Most importantly, as a gardener matures in her appreciation of the life cycle of plants, she comes to appreciate the changing shape and color of leaves over the course of spring, summer, and fall, and the architecture of bare branches in winter.

Group of Slender Silhouette Sweetgum and Emerald Arborvitae trees right after delivery to Urban Earth in Winter.

He who marvels at the beauty of the world in summer will find equal cause for wonder and admiration in winter…. In winter the stars seem to have rekindled their fires, the moon achieves a fuller triumph, and the heavens wear a look of a more exalted simplicity. ~John Burroughs

 

So, increasingly, the landscape industry and home owners are realizing that medium and small deciduous trees in general, including columnar cultivars, are better alternatives than columnar evergreens.  Moreover, they are realizing that smaller trees are better for the close confines of modern urban environments than the old standard unimproved shade trees like oaks, elms, gingkoes, and tulip poplars that were widely planted in Memphis during the twentieth century.  Indeed, if you have ever had to contend with a large old specimen of a deciduous shade tree too close to your home, you know how challenging they can be.  The roots can rip apart foundations and sewer pipes.  Leaf removal under the canopies of large old deciduous trees in the fall can be an enormous undertaking.  And, worst of all, falling limbs or entire falling trees, weighing tens of thousands of pounds, can destroy property and cause human injury or death.  To make matters worse, tree removal of a large deciduous tree that has been diagnosed as too unsafe to keep in place, can cost $15,000 or more.

Fallen tree in midtown after a recent wind storm in 2017.

 

Consider, for example, a mature oak tree, inexplicably planted 15 feet from the rear of an east-facing home.  The tree has been diagnosed with an incurable fungal problem, its roots have largely rotted, and its leaves are only green because of stored photosynthates.  It remains erect only because it weighs 70,000 pounds and is like a nail whose point has been tapped into the ground.  Eventually, because this is Memphis, a straight-line wind will come along from the west, push the tree over, and flatten the home, destroying it and everything in it.  A wise homeowner, faced with this information may feel they have no choice but to pay to remove it at a cost of as much as 10% or more of the home’s value, enough money to buy a new car or increase the size of the home.  Likely, this tree was not “planted” but rather was a volunteer, allowed, maybe even encouraged by a new homeowner decades before, a homeowner who likely felt very proud that he had not had to pay for it, regarding others who had designed intentional landscapes as spendthrifts.

 

But then, there are those who over-react to this problem, removing all trees from their property, leaving only foundation shrubbery and turf grass, with no shade, like the homes in new mid to low grade subdivisions.  This approach has its problems too.  There is no shade without trees so more energy is needed to cool the home in the summer and the benefit of deciduous trees that mitigate carbon emissions is entirely lost.  Further, for whatever reason, humans find the close proximity of trees comforting.  They have an inherent attraction for us and we do not find a landscape wholly devoid of them attractive or as appealing as a yard with one or more well-placed trees on it.

 

Hence, the arbor market is now producing more manageable small and medium-sized columnar cultivars of old standbys.  They tuck nicely into courtyards, make for beautiful allees, and form inspiring focal points in corner beds.  For greater impact they can even be clustered in trios! Here are some of my favorites from our growers:

 

Allés of European Hornbeams designed by Dale Skaggs at The Dixon Gallery and Garden in Memphis, Tennessee.

 

 

Columnar European Hornbeam (Carpinus betulus fastigiata) has been around for a while, the Frans Fontaine cultivar of columnar European hornbeam being my favorite of the various cultivars (a cultivar is a variety of tree discovered by a grower deliberately looking for variations within a population of trees and then propagating, usually by cuttings, that tree because of its atypical but desired qualities.)  The ‘Frans Fontaine’ cultivar tends to get about 25 feet tall and 6 feet wide, tucking into the corner of a foundation bed nicely or making a nice focal point in a larger bed.  They also look great in a formal row.  I first became aware of this tree when the Dixon Garden, under the direction of Dale Skaggs, planted an allee (a walkway or avenue lined on both sides with trees) of them a few years ago.  With alternate oblong-ovate leaves with rounded base and acute tip, pale green in spring, dark green in summer, and pale yellow in the fall, the canopy forms a dense oval of overlapping leaves that flutter in breezes and come across like an impressionist painting from even short distances.

 

Row of small columnar European hornbeams, likely ‘Frans Fontaine,’ planted at The Dixon Gallery and Gardens in Memphis, Tennessee by landscape architect, Dale Skaggs.

Though ‘Frans Fontaine’ gets larger in other climates, in our climate it tends to be more restrained, seldom getting much larger than 25 feet tall and 6 feet wide.  Unusually, the tree is tolerant of extreme pruning, some horticulturalists pruning the limbs all the way back to the trunk once each year to keep it even narrower than it already is.  It is not infrequently used as a screen or hedge, similar to how english hornbeams are used at one of Martha Stewart’s homes, as described here:

http://www.themarthablog.com/2013/09/sculpting-an-english-hornbeam-hedge.html

 

Goldspire Ginkgo (Ginkgo biloba ‘Blagon’) is a new cultivar of an old favorite.  Ginkgos have long been regarded as the oldest species in continuous existence on the planet, in either kingdom, with some fossils of ginkgo leaves as much as 270 million years old.  They have unique fan shaped leaves leafing out pale green in the spring, darkening, and then turning a striking fluorescent yellow in the fall just before leaf drop.  With a large genome of over 10 billion DNA nucleobase letters and over 41,000 predicted genes (the human genome has around 3 billion) the plant has excellent disease resistance and general all-around toughness, having lived through more existential threats than any other plant alive.  Though the species can get over 100 feet tall, the Goldspire cultivar (‘Blagon’) tends to be much smaller, 15-20 feet tall and 5-6 feet wide.

 

Because the cultivar was only introduced in 2010, coming from France, the tree is hard to find.  I have sold a handful to customers in Memphis but I don’t know where they are planted.  So, just like any new cultivar, it is a risk, since there is not much history to go on.  But, given the success of other ginkgo varieties and cultivars, and the benefits of an unusually small cultivar, perfectly sized for tight urban confines, it seems worth the risk.  If it proves itself over the next couple of years, it may replace ‘Frans Fontaine’ as my favorite columnar tree.  If you want this tree, be sure to email us right away to get on the waiting list for it, as we are only expecting to be able to get a few this fall.

 

Persian Spire Ironwood (Parrotia persica ‘JL Columnar’) is an even newer cultivar than Goldspire Ginkgo!  Discovered by John Lewis of JLPN Nursery in Salem, Oregon in 2013, it is an unusually slow growing ironwood, upright and columnar in shape, topping out at under 15 feet.  But, the most unique thing about this tree is its foliage, especially in fall, when it takes on purple, orange, and red hues, sometimes all on the same leaf, and holding onto the tree for quite awhile after the color changes, before fall abscission (leaf drop).  Read more about this great new cultivar on the the Pacific Northwest International Society of Arboriculture site: http://pnwisa.org/2017/06/persian-spire-upright-ironwood-parrotia-persica-jl-columnar-p-a-f/

Persian Spire Ironwood trees have an unusual colored edge when they first leaf out but become solid green as the summer progresses, finally evolving into beautiful multi-hued fall color.

As of this writing, Urban Earth has sold a total of 3 of this plant and has one in stock, all in 15 gallon containers, about 6 feet tall.  2 have been planted at an apartment complex across from Ardent Studios on Madison and one has been planted at a private residence.  We hope to get a few more this fall but don’t expect this cultivar to be easy to get for a few years.  There is no question that anyone who planted one of these trees this year would have one of the rarest trees planted in Memphis, for at least a few years.

Slender Silhouette Sweetgum (Liquidambar styraciflua ‘Slender Silhouette’) is the tallest of all of the trees referenced in this article.  Growing as tall as 60 feet and as wide as four feet, it more commonly tops out at 50 feet with a width of 3 feet.  It is also the quickest growing.  Though it is used in landscapes in Memphis in a variety of ways, one of the best ways I have seen it used is as a corner piece to soften the edge of a two story home in Germantown.  Read more about this tree here: http://www.hortmag.com/plants/plants-we-love/slender-silhouette-sweetgum

Lindsey’s Skyward Bald Cypress (Taxodium distichum ‘Lindsey’s Skyward’) has been around long enough, at least 16 years, to prove itself to be a great success in the Memphis area.  Though it is a conifer, it is, in fact, deciduous, but tolerating wet feet better than most.  A dwarf, it gets up to 20 feet tall and 6 feet wide.  A truly lovely tree, though this author does not have much experience with it, it is one of Greg Touliatos’s favorites.

Lindsey’s Skyward Bald Cypress Trees available for sale at Urban Earth Garden Center in Memphis, Tennessee August 9, 2017.

 

Mushashino Zelkova (Zelkova seratta ‘Musashino’) was named the “2016 Urban Tree of the Year” by the Society of Municipal Arborists.  Meant primarily to be a tough street tree, it can also be used, like all columnar trees, as focal points in the landscape, as allees, and as screens.  Though too new of a tree to know for sure, it is said that it “has the genetic potential to reach 45 feet in height and 15 feet in width at maturity,” with orange/red leaves in fall, with leaves in an oval shape and serrated at the edges, reminiscent of a hornbeam’s leaves.  Read more about this new tree of great promise here: https://www.amerinursery.com/plants/sma-announces-its-2016-urban-tree-of-the-year-zelkova-serrata-musashino/

 

Regal Prince Oak (Quercus x warei ‘Long’ REGAL PRINCE) is perhaps the fattest of the trees described in this article, though not the tallest, getting up to around 45 feet and 20 feet wide near maturity.  The older leaves turn a beautiful red in the fall after the tree has matured for a few years in the landscape.  Look here to find a good concise history of this tree, well proven in the Memphis area: https://www.uaex.edu/yard-garden/resource-library/plant-week/quercus-xwarei-oak-regal-prince-01-22-2016.aspx

Arnold Tulip Poplar (Liriodendron tulipefera ‘Arnold’) is an excellent cultivar of our state tree.  It is a compact solution for anyone who wants to show their loyalty to Tennessee but has too small of a yard for a full size tulip poplar.  Most commonly, you can expect this tree to mature at around 25 feet tall and 8-10 feet wide in the Memphis area, though it might get taller in other parts of the world.  Its blooms are yellow-green, tulip shaped, beginning in late spring through the summer.

 

The author, John Jennings has been manager of Urban Earth Garden Center since June 1, 2016.  Before that he was a self-employed landscaper for 8 years, having previously worked as both a real estate lawyer and a drug counselor in previous lives.  He grew up in the South Carolina low country, learning to garden in the fertile soil of Copes Island, a small barrier island near Beaufort, in Jasper County, the famed land of Pat Conroy.  He was taught the basics of planting by his step-father, Wade, his mother, Melissa, and his father, Karl.  Though both of his parents grew up in Memphis, and he spent vacations visiting his maternal grandparents, Richard and Diana Allen in Memphis, he did not become a resident of the city until he finished college in 1994.  He left South Carolina at the age of 14 to attend The McCallie School for Boys, in Chattanooga, Tennessee, graduating in 1990, before getting a degree in English from the University of Richmond, in Virgina,in 1994, finally graduating from the University of Memphis Law School in 1997.  He has a 10 year old son named Henry.

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Little bugs and black sticky stuff all over my crepe myrtles. Help!

Your crepe myrtles likely have a relatively new problem called crepe myrtle bark scale (CMBS). CMBS came over from Asia in a shipping container, possibly through Mexico, first arriving in Texas a few years ago. It has slowly moved East from there. The actual scale insects look like tiny pieces of puffed white rice. Though the male of the species is quite mobile, the female, which causes most of the problems, is relatively immobile, leaving us a little puzzled as to how the disease/pest spreads. Our thinking now is that it might spread by wind or birds but more likely spreads through mulch, bought in bulk from mulch yards, made of limbs and debris dumped at the mulch yard by landscapers, i.e. crepe myrtle bark pruning byproduct (think of the crepe murder that so many practice every year). Another possibility is that it gets on the clothing of landscapers themselves who travel from yard to yard. Regardless, it’s here!

The insect hurts the crepe myrtles in two ways. First, it feeds off of the tree, getting its nutrients from the outer cambium layer, depriving the tree of much needed nutrients, causing it to deteriorate. Second, it excretes a clear sticky substance, euphemistically called ‘honey dew,’ which becomes a perfect host for sooty mold, turning the tree black, coating the leaves and inhibiting photosynthesis, and often coating nearby plants too.

Currently, we are recommending a two-pronged approach, a systemic insecticide in the form of a soil drench, absorbed through the roots and moving throughout the tree, killing the insects when they feed on the tree. This is a slower but more thorough approach, slower because trees have a passive circulatory system and the substance is only pulled up through the tree as moisture transpires from the leaves during the night. The second prong is a contact pesticide or oil to provide a quicker knock-back, but a less complete kill. The important thing to remember is that a single pregnant female insect introduced on a crepe myrtle can have the entire tree covered in CMBS in just 2-3 weeks! So, act with a reasonable degree of haste.

We are currently recommending Fertilome Tree & Shrub Systemic Insect Drench (containing imidacloprid in a very high concentration) as the systemic, which may stay in the tree up to one year, combined with either horticultural oil or the liquid version of Sevin.

Environmental concerns: We prefer organic and natural approaches where possible, but there doesn’t seem to be an effective organic/natural control/kill for CMBS yet. Though this is debatable, with good arguments on both sides, we currently think the systemic, imidacloprid, despite being a neonic, has minimal impact on pollinators and other beneficial insects, because of the difficulty it has traveling into the flowers of the crepe myrtle. We do, however, caution that one should be cautious in using it near other plants that pollinators utilize, like perennial gardens. Additionally, we do know that any contact pesticide will kill any insect it comes in contact with. Therefore, out of respect for the benefits pollinators like butterflies, bees, etc., provide us, we urge you to only use the liquid Sevin, for example, closer to dark, when pollinators are less active. Finally, we urge that you consider cultural changes like switching to pine-straw mulch rather than wood mulch or at least getting the wood mulch in bag form, not planting crepe myrtles or removing and replacing the ones you already have with other trees, asking that your landscapers not come to your yard right after pruning infected crepe myrtles and making sure they are educated about the disease, making sure the trees are adequately watered and fertilized because we know that healthy trees are less attractive to harmful insects, etc.

Unfortunately, though we initially thought the CMBS species would limit itself to crepe myrtles, there is some evidence that it is attacking beauty berries, hawthornes, and maybe even other plants.

Each year, Greg Touliatos gives a seminar on this new disease and other pest problems. To learn more, check our facebook page or email us for a schedule of our free classes and attend them on Saturdays.

Caution! Don’t forget to read the label carefully and follow all procedures. The label is the law. Although we are told that imidacloprid is not easily absorbed transdermally, wear gloves and take other precautions necessary to keep it off of your skin and certainly keep it away from your face, i.e. not allowing it to splash as you are pouring. Further, remember that it is more harmful to pets than to humans. Therefore water it in heavily after applying it to the soil and keep your pets away until it has had a reasonable amount of time to sink below the surface.

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Mulch Ado About Nothing

When I first started as a landscape contractor, I loved hardwood mulch. The market rate for it, delivered and installed, was anywhere between $55 and $75 per cubic yard, with a 3-yard minimum. With landscaper discounts, I was able to get it for anywhere between $5 and $20 per cubic yard and the skill required to install it was not great, meaning that any properly motivated friend or recently unemployed person or teen, with 30 minutes training, could do it at a rate of about 3 cubic yards per hour. Properly shaken with a pitchfork, mulch provided a uniform appearance, covered up imperfections in the surface, blocked sunlight from penetrating to the dirt and promoting the germination of weed seed, and slowed the evaporation of moisture from the surface.

And, you should have heard my arguments for how beneficial it is for the environment! They were, of course, arguments I had heard elsewhere and believed. Mulch manufacturers take debris from cut-down trees, construction, and pruned limbs, etc., and grind it up until it has a uniform appearance. They sell it in bulk as a gardening product, rather than dumping it in a landfall, where it would degrade much more slowly.

Memphians love and like to pay for a fresh mulched yard. And, it creates jobs! How could one not love such a product?

I remembered growing up in my native South Carolina low country, where my stepfather and others would have me raking up “pine straw” (called pine needles by Memphians) to put in beds. After moving to Memphis, I found double-stamped “hardwood” mulch and could only pray that one day South Carolinians would discover it.

Pine straw mulch lays beautifully and is good for all plants!

Pine straw mulch lays beautifully and is good for all plants!

But, as they say, that was then and this is now. A decade later, after a few visits back to South Carolina and some careful reflection and listening to people like Caroline and Arthur Nave and Greg Touliatos, I now know why the azaleas, hydrangeas, camellias, and other plants are so much more beautiful along the Carolina and Georgia coast. It is likely, at least in part, because of pine straw.

But, what’s wrong with wood mulch? Well, a lot.

1. Wood mulch works best as a weed deterrent when it is in large chunks, but Memphians don’t like their wood mulch in big chunks any more than they like shredded pork sandwiches without slaw.They like their mulch at least double-stamped or even triple-stamped (referring to the number of times mulch is passed through a wood grinder). Though this mulch does prevent seeds below it from germinating, it is a perfect host for weed seeds dropped by birds. By having the wood more finely ground, they reduce its efficacy as a weed deterrent. (Memphians are right about barbecue, however. Theirs is much better than South Carolina’s.)

2. Wood mulch promotes termites. Every termite inspector I have met in Tennessee says that wood mulch should be kept at least 12 inches away from the foundation of a home, and some say it should be kept further away than that. Having recently taken a Tennessee chemical applicators licensing exam, I can tell you that official Tennessee guidelines for keeping termites at bay comport with this commonly held opinion. Listen to the experts. Termite damage is incredibly expensive and Memphis has the perfect climate for them.

But, I’ll just keep it 12 inches away from my house! Will you? With a tape measure? Won’t that look odd? Will you put down gravel in the 12 inch zone? Will the gravel mix with the dirt and the mulch? Do you expect the hourly summer employees of landscape companies to keep it exactly 12 inches from your house? Do you trust your spouse to get this right? Your teens? What happens if you pay to have your home treated for termites and your termite company points to a clause in their indemnity contract about wood mulch being too close to the home, and it turns out you missed a spot where a little was up against the foundation? Will they still honor the indemnity agreement.

But, I’ll just use cypress, or cedar, or redwood mulch and it will keep the termites away! Hardly. Mulches are rarely as pure as they are labeled. It is expensive and difficult to keep the types of wood used for mulch entirely separate. Most suppliers can, at best, warrant that it is mostly one type of wood. Second, opinions (the legitimate ones that count) vary about the degree to which these woods really repel termites. We know, for example, that only old-growth cypress heartwood has the resins in it that repel bugs, and there isn’t much old-growth cypress left in the United States. And, if we keep cutting down young-growth cypress, there won’t be any old-growth cypress, eventually. Remember the vague, pro-environmental, recycling argument I used above? If you use one of these kinds of mulches, you can pretty much forget that argument.

3. Wood mulch competes with your plants for nitrogen. This is because all organic matter, in its early stages of decomposition, is nitrogen robbing, only releasing the nitrogen back into the environment late in the process of decomposition. So, either you have to put down more fertilizer or you will see a slowing of new canopy growth, and a reduction in the plant’s ability to shake disease. One might rightly point out that pine straw is also organic matter and is also nitrogen-robbing in its early stages of decomposition, but, pine straw is far less dense. The nitrogen-robbing effect of hardwood mulch is exponentially greater than with pine straw.

4. The wood used in wood mulch didn’t end up in the mulch pile because someone made a great sacrifice. It ended up there because someone wanted it gone. And, very often, though not always, they wanted it gone because it was infected with a pathogen of some kind.

Hardwood mulch is a product of whatever landscapers unload into the mulch pile, all types of wood, all types of pathogens.

Hardwood mulch is a product of whatever landscapers unload into the mulch pile, all types of wood, all types of pathogens.

I used to tell my customers, “Oh, don’t worry. Because it’s in big piles and gets so hot, all the bad stuff gets cooked out.” Maybe, sort of, sometimes. (In my defense, I honestly believed that to be true for many years.) Consider, for example, the recent widespread spread of crepe/crape myrtle bark scale in the Mid-south. As Greg Touliatos has rightly pointed out, since the female of the species only moves a short distance in her entire life, a distance measured in inches, at most, we have to ask, how is it spreading? Could it be wind? Birds? Maybe, but it is still spreading awfully fast for that to be the only source of transport. The more likely explanation is landscapers and the wood mulch from mulch yards, bought in bulk. Can Greg prove that assertion? Not without a lot of time and money, but I regard it as probable, and you would be wise to do so, as well, until more data and a good competing explanation is presented.

I maintained this home for years as a landscape contractor, regularly using wood mulch.  It looked great but there were some problems.  The green mountain boxwood replaced two diseased American boxwood and the snow white Indian hawthorns in the background had frequent fungal infections.  In retrospect , these problems might have been prevented by using pinestraw mulch instead.

I maintained this home for years as a landscape contractor, regularly using wood mulch. It looked great but there were some problems. The green mountain boxwood replaced two diseased American boxwood and the snow white Indian hawthorns in the background had frequent fungal infections. In retrospect , these problems might have been prevented by using pinestraw mulch instead.

I suppose landscapers could change clothes and sanitize all of their equipment between yards, and pre-treat your wood mulch, but what consumer is willing to pay for that?

5. Wood mulch is heavy; unless you buy it in bags, you must transport it with a pickup or dump truck or pay someone else to deliver it. And, if you buy it in bags, you have to pay a lot more. In contrast, my source (read: the google) says the average bale of pine straw weighs less than 12 pounds. No wheel barrow or pitchfork required. Gloves are advised, but not strictly necessary.

6. If wood mulch is piled against the trunks of woody plants it promotes damage to the outer cambium layer, the thin outer ring of recent growth. It is the main, in some cases, the only highway for nutrients to move up and down the trunk of a plant. If this layer is damaged and/or rendered non-working, the plant dies, every time.

Wood mulch holds water, like a sponge, and, though the roots of plants absorb and utilize moisture very well, the trunk wood does not. Although good landscapers and gardeners know to keep the wood mulch off of trunks, this is not done as often as it should be. And, heavy rains can move mulch, leaving it in drifts piled up against trunks, even if the person who originally installed the mulch did so with great attention to this detail.

7. Bulk mulch can have a ph problem. Ph is the measure of alkalinity/acidity, the middle of the scale being 7 and most plants thriving at various points along the ph scale between 5.5 and 7.5. Anything below 7 is regarded as acidic and anything above that number is considered alkaline. Once, early in my career, I bought 20 cubic yards of wood mulch and had it delivered by dump truck from a mulch yard to a property owned by two scientists in Cordova. They were new clients, with willingness and ability to pay, so, I was not only pleased to be making the profit from the mulch install but also hoping for more business from them in years to come. The next day, all of the perennials they’d recently planted, several hundred dollars worth — perennials that were in perfectly good shape when I arrived on the scene — were all in a wilted and browned-out state. Saying they were annoyed was an understatement.
How could this be my fault? My assistant promised he had heavily watered it in to counter any moisture robbing effects. And, we had done a nice underlayment of composted leaf mulch to counter any nitrogen-robbing effect. I denied any wrong-doing on my part. But they, being scientists, tested the mulch’s ph and said that it was under 4 in nearly every spot — highly acidic — and, smelled like rotten eggs.

So, I began to research. Turns out that mulch not turned regularly at the mulch yard, though it cooks out many pathogens, promotes anaerobic organisms. Anaerobic organisms excrete compounds that are highly acidic and toxic to plants. Further, the excretions give off a rotten egg smell.

It cost hundreds of dollars to replace their perennials and I never again received any business or referrals from them.

Now, the supplier of mulch Urban Earth uses is very conscientious about this issue and, even if they weren’t, our mulch sits for some time in a smaller pile after transport to our garden center before being sold, allowing it to air out and get access to oxygen.

Even after I have explained all of this to my customers at Urban Earth, I still sometimes hear two arguments: 1) I’m sure pinestraw carries diseases too. 2) Your pine straw costs $9 per bale and I can get hardwood mulch for less than $5 per bag, and even cheaper by the truckload.

Let’s address these in reverse order. Depending on density of plant matter in your beds and how thick you put it on, the pine straw covers anywhere from 20 square feet to 50 square feet, with 30 square feet being about the median coverage factor, in my experience. Wood mulch covers about 10 square feet per bag. That means customers end up paying between 18 cents and 45 cents per square foot for pine straw and 25 cents to 50 cents for bagged wood mulch. So, if anything, pine straw is cheaper.

As for the disease argument, it is possible for anything to carry disease, but it is far less likely that pine straw will and, even if it does, it is less likely that the particular disease will effect your plants. Pine needles are shed by trees naturally and regularly. Even if the source pine tree is diseased, most diseases are pretty specific to a plant. So, unless you’re using it to mulch around other pines or closely related species, you’re in the clear.

So, there are a few things to learn from this. First, hardwood mulch is for chumps and you should stop using it. Second, the advice I give you may later turn out to be terrible and it does not offend me in the least if you double check it with other sources, including soliciting competing opinions from other staff at Urban Earth. Third, I am willing to admit I was wrong and I owe all of my old clients from my days as a landscape contractor an apology (but don’t try to get any money out of me). Fourth, Urban Earth carries bales of pine straw and you should buy from us when you need it. Fifth, Urban Earth also carries double-stamped wood mulch in bulk, sold by the cubic yard, but will likely discontinue carrying wood mulch in bags once our current supply runs out.

Unless our customers decide I don’t know what I’m talking about and continue to demand it.

— John Jennings, Manager