Common concerns about newly planted trees

Perhaps it is simply human nature to want instant gratification. We plant a tree and, well, we want it to look beautiful and grow vigorously right away! We have this image of a mature, lovely specimen gracing our property, shading our patio, providing all those ecosystem benefits we keep reading about. Then reality sets in. It looks the same this week as it did last week. We have to be patient…Oh My Goodness!

If you purchased a ball and burlapped tree (BnB), it lost the majority of its roots in the process of preparing the tree for transplanting. These trees are initially grown in the field, then dug with a tree spade (less often by hand), the surviving root system is then wrapped in burlap. They can lose 85 to 90% of their roots during this process. If you purchased a tree in a container, its root system may be a twisted mess. See my previous blog Selecting A Quality Specimen to Plant.

No matter what method you purchased, freshly planted or transplanted trees will have an establishment period. The general guideline is it takes a year per diameter inch of trunk for the tree to establish. Example: If you plant a tree with a 2″ diameter trunk, it will take approximately 2 years for it to establish.

What does to establish mean? Primarily, the tree needs to develop a new root system as it likely lost a large portion of it during the transplanting process, as mentioned above. All of the water and nutrient uptake is through the root system; it has to redevelop. The more roots it lost, the longer it will take to establish. During that time, you are not going to see much going on above ground as a great deal of its resources need to go below ground. It should leaf out but those leaves may be a bit smaller, and you may not see much elongation in the twigs. Hang in there. Don’t panic yet. This is one of the major reasons we recommend planting bare root trees and/or going with smaller diameter trees. They will establish faster. The root-to-shoot ratio is much greater, enhancing its survival rate.

We hand dug this liner enabling us to save the vast majority of its root system. Transplanted to our property in 2011. Quercus robur x macrocarpa. English and bur oak cross.
© 2020 McNeill’s Tree Service
What that little liner oak tree looked like in 2019.
Quercus robur x macrocarpa
English and bur oak cross
© 2020 McNeill’s Tree Service

Why we recommend planting a smaller tree: Using 1″ and 4″ trees as examples assuming they were planted close to the same time and are of the same species, the one-inch tree will establish in one year and be off and running while the 4″ tree will spend the next 3 years still working on its root system. In that 3-year time span, the 1″ tree has likely caught up with and is surpassing the 4″ tree in size and development. This is illustrated in the photo below.

One inch trees were planted in spring of 2009 (row on right side of photo); four inch trees were planted in fall of 2008 (row on left side of photo) This photo was taken July of 2009. The one inch trees are going gangbusters.
Populus deltoids ‘Daly poplars’
© 2020 McNeill’s Tree Service

Not only is that smaller tree now a bigger, probably healthier, tree but it was a whole lot cheaper to buy and much easier to plant!

Planting a 4″ caliper ball and burlapped tree is heavy work.
© 2020 McNeill’s Tree Service

In addition to developing a new root system, the new plant may be coming out of a nursery where it was being grown in soil-less media (if in a container) or in soil of completely different physical and chemical composition. (Another good reason for planting a bare root tree: neither of those issues will be a factor.)

Both soil-less media from the container and the soil around a BnB tree can present interface issues interfering with water uptake. Osmotic pressure can create a drought situation in the root zone if the soil around the root ball is wicking the moisture away from the roots.

Purchasing a quality specimen of a tree hardy to your area, suitable for the soils you have with a site that is suitable for the mature tree, and planting it correctly are all important steps in helping your new tree get off to a good start.

Then there is the after care. It will need to be watered appropriately. Which means you will need to monitor the soil around the root ball and the root ball itself until that interface has been breached and equilibrium has been established. As the tree develops, you still need to water appropriately. This will have to be adjusted for its growth and species requirements as well as environmental conditions and soil characteristics that determine how much and how often you will water.

A chronic mistake. People do not think to adjust the initial irrigation set up as the tree grows.
© 2020 McNeill’s Tree Service

During the establishment period, and particularly that first season, your new tree may not look as good as it did in the nursery. This can be particularly shocking in the case of some conifers, especially pines. I tell clients to go ahead and get it planted then not to make eye contact for the first year. Well, you do want to keep an eye on it but it is definitely going to go through a stress period that will be a bit unnerving if you are unprepared. Pines may put out very little growth that first year after planting and look sparse compared to their appearance in the nursery. And deciduous trees and shrubs can desiccate, completely losing their leaves early. Check for new buds being set. If new buds are set, hang in there. All will probably be well. Give your new tree time; it will be worth the wait.

Quaking aspen

Populus tremuloides

Basic statistics: In the willow family, Salicacea. USDA Hardiness Zones 1 to 6 (you gotta love a tree that can go Zone 1!) General height from 20 to 50 ft; spread from 10 to 30 ft. Bloom is insignificant in early spring. Requires full sun and medium water. Typically has good fall color and attracts birds. Suggested use is for naturalizing as, otherwise, can be a high maintenance tree.

This wonderful tree gains its common name from the quivering attitude of its leaves in the slightest breeze. It also has the widest distribution of any North American native tree species. In fact, worldwide, there are only two other species of trees with wider natural ranges: the Populus tremula, European aspen, and the Pinus sylvestris, Scotch pine. (Silvics of North America, Populus tremuloides)

The quaking aspen is a pioneer species, which means it readily colonizes disturbed or bare soil. What that also means is full sun is pretty mandatory so it can be shaded out as other trees establish around it. This process is natural as they give way to successional species. It is considered a short-lived species; however, it is a colony tree establishing a clonal grove which can live a very long time indeed.

A natural aspen grove in the south valley of the Bitterroot Valley, Montana
© 2020 McNeill’s Tree Service

High in the mountains of Utah there is an aspen grove which has been determined to be in the range of 80,000 years old with some estimating the age to possibly one million years. The jury is still out as it is difficult to actually determine the age of the root system of this mammoth organism. It covers an area of approximately 106 acres. Individual stems within this clonal grove average 130 years, determined by tree rings. There is also documentation in the Rocky Mountain Tree Ring Research website of a 317-year-old individual located in rocky Mountain National Park, Colorado.

Now consider the urban or residential landscape. Many of our clients in this area, the Bitterroot Valley of Montana, have the impression this tree only lives 10 to 15 years. The extremely short life of an aspen planted in the landscape is determined by the care (or abuse) it receives. They have specific needs in addition to their growth characteristics. Establishing a grove, gorgeous in their natural setting, is less than endearing when the homeowner desires a highly managed and immaculate lawn. This is not the tree’s fault. In my opinion, nursery personnel and/or landscapers need to inform the client of the characteristics of this tree. This is a better option than selling a tree to a homeowner who doesn’t have a clue as to what may happen or simply telling people not to plant this species.

When asked about the desirability of planting aspens, we always let people know if they have the space to let an aspen grow naturally, establishing a colony, they will have better success and a longer-lived tree than if they plant one as a specimen in the middle of their lawn.

If they then try to control the ramets (the young stems produced from the main root system) that come up by using herbicides, they are poisoning the parent plant as well. My article on aspens goes into this conflict in more depth.

Outward visible signs of aspen borer activity.
© 2020 McNeill’s Tree Service
What the inside of an aspen stem can look like from larval feeding by the aspen borer.
© 2020 McNeill’s Tree Service

We also warn people this tree has the longest list of insect and diseases of any of our trees. That might be a slight exaggeration, but not by much. I believe this is one of the reasons it is listed as high maintenance. Again, if you let it be a grove, let it naturalize, you will have a self-perpetuating landscape where you only have to harvest the dead/dying trees that might be a hazard. If they can be left as habitat, so much the better. Plan your strategy for where this lovely tree would be best suited. Be honest with yourself as to whether you have the suitable environment for it.

Planted five, 4ft whips in 2012. Photo taken 2018. Just counted 56 stems in our mini-grove.
© 2020 McNeill’s Tree Service

What’s In a Name?

In a recently posted blog on Thuja occidentalis, I briefly mention confusion caused by common names.  As an example, common names for the Thuja occidentalis include Eastern white cedar and swamp cedar.  However, the Thuja occidentalis is not a cedar at all.  In fact, there are no true cedars native to North America.  The common names come from the fact that it smells similar to true cedars from the Mediterranean.  The North American trees most aromatically similar to true cedars belong to Cupressaceae or cypress family.  These include Juniperus, junipers, as well as the Thuja. However, not all members of the Cupressaceae are aromatic. 

Common names are colloquial and/or regional.  What someone calls a swamp maple back east may mean nothing to me in the west.  However, if they reference Acer rubrum, I know exactly what species of tree they are talking about.  These globally-accepted scientific names allow clear communication about specific species no matter where you are in the world, no matter what the native language is.   Which is exactly why scientific names were created; they cross all language barriers. 

The gentleman credited with formalizing binomial nomenclature (broadly meaning a name with two parts), was Carl/Carolus Linnaeus (1707-1778).  The first part is the “generic” name, which identifies the genus the plant belongs to.  The second part is the specific epithet, which generally is a descriptive identifier.  Originally the specific epithet may have been several words describing the plant in detail but was shortened to a single word.  Putting the genus and specific epithet together gives you the species: a formal (also called scientific or Latin) name of a specific plant.

Learning these formal or scientific names is really not hard and actually can be fun.  Go ahead and learn the ones of the species you encounter, it really does save confusion and misunderstanding. 

Thuja occidentalis Arborvitae

Please note:  There are many nuances to using plants for food, beverage or medicinal treatment.  I may mention some of these with appropriate citations and/or references.  However, I have no professional experience and am not an authority in this area.  In no manner should any comments in these profiles be construed as recommendations or endorsement. 

Basic stats

Hardiness zones:  3-7 (7 is probably stretching it – they are a northern species after all)

Size:  Smallish to large – Really depends on the cultivar of which there are numerous. 

Growth rate:  slow to medium

Diseases/pests:  Bagworms, leaf miner, spider mites, heart rot and deer browsing. 

Cultural needs:  atmospheric moisture as well as soil moisture.  Prefers well-drained loam (well, who wouldn’t?).  Slightly acidic soil.

Longevity:  Long-lived in natural settings.  Specimen have been found over 1000 years old.    In landscape settings, we have seen 50 to 75-year-old trees still going strong. 

Side bar:  If you want to research old trees, check out this website:  Rocky Mountain Tree Ring Research.  http://www.rmtrr.org/oldlist.htm

Pruning care:  This also depends on the cultivar, your personal preference and/or landscape design.  It is always best to select a cultivar that is going to max out in size for the space you want filled.  (This is actually a cross-the-board recommendation for many plants as it will minimize pruning needs, which will be beneficial for its health and welfare as well your pocketbook.) 

When allowed to grow “naturally”, Arborvitaes can become a majestic landscape statement as they mature, growing tall.
© 2020 McNeill’s Tree Service
Unfortunately, if planted too close to a structure, they are often shortened or sheared to contain them.
© 2020 McNeill’s Tree Service

Another reason people shear and/or shorten these trees is they simply think they should.  They see everyone else doing this and wrongly presume it is what the trees need. 

Availability:  I would rate availability as high.  If not already in stock, most nurseries should be able to order this species or the specific cultivar you need.   I have often seen them offered in balled in burlap and, generally speaking, they transplant well. 

The Arborvitae is an evergreen, meaning it retains green needles/leaves year-round.  (What that doesn’t mean is that those needles/leaves never drop.)   As a landscape plant, this species is very often planted in a tight row, creating a wonderful hedge which may act as a visual or physical barrier or as a delineation of space.  It may be incorporated in efforts at sound attenuation.

This Arborvitae hedge delineates an accessible parking area.
© 2020 McNeill’s Tree Service

Please note when I included deer browsing under the Diseases/Pests section above, this was not an incidental comment.  These trees are actually utilized in deer yards as browse during bad winters.  Here in our area, you can gauge just how bad the winter was on wildlife by how hard the arborvitaes were hit. 

Winter pruning courtesy of local deer population.
© 2020 McNeill’s Tree Service

If you don’t want them eaten, protect them with fences.  I have also seen success with chunks of Irish Spring soap and products such as Liquid Fence.  No endorsement is intended on specific brands; these are just products I have happened to use myself or have had clients who also have used them.  There are other products which might be just as effective.

Another alternative after the plant has matured, is to prune the lower branches off.  You will still leave the main upright stems for a multi-stemmed plant. The tree is fully capable of growing well past the height of browsing and the cleared trunk can take on a majestic look as seen in a couple of the previous photos posted this blog.

Common names include Eastern white cedar, Northern white cedar, swamp cedar, American or eastern arborvitae.  These common names give you a hint as to its native habitat which is northeastern US and southeastern Canada and it grows in moist environments.  In my neck of the woods, it is most often simply called an arborvitae. 

You may have noticed the other common names for this tree use “cedar”.  However, it is not a true cedar.  By the way, there are no true cedars, (genus Cedrus, family Pinaceae) native to North America.  The Thuja occidentalis is a member of the Cuppressacea which includes the junipers of which the Juniperus virginiana is typically the species used in aromatic wood projects such as cedar chests.  However, the arborivate is very aromatic as well, as any tree worker who has chipped one will attest to:  on-the-job aromatherapy. 

The name “Arborvitae”, meaning “Tree of Life”, is by far the most colorful and descriptive as it literally could be viewed as such.  Jacques Cartier, an explorer for France in the mid-1500s, is credited with bestowing this name.  The tale relates how his second voyage to North America was locked in ice for five months.  He and his men endured bitter cold and the swollen limbs, rotting gums, loose teeth and excruciating pain of scurvy.  They survived by drinking a decoction provided by Huron guides made from the bark and leaves of a tree the Indians called annedda.  The French called it l’arbre de vie; in English “the tree of life”, in New Latin “arborvitae”.  (This information is gleaned from a book by Sheila Connor, New England Natives, pg 51.  A really fun read!)

One of my trips this last year, presenting at Plant Health Care workshops, took me to Como Park Zoo and Conservatory in St. Paul, Minnesota.  I stayed with a friend (who happens to be a plant pathologist); she attended the workshop as well.  While scoping out the venue, we met with the horticulturist who graciously introduced us to an approximately 500 year old Thuja occidentalis bonsai.  We were thrilled.  Trust me, a highlight of the trip.

Approximately 500-year-old Thuja occidentalis.
© 2020 McNeill’s Tree Service

Diversity in Landscapes

In the arboricultural industry there is a great deal of talk about the necessity of planting a diversity of species of trees in the urban forest.   The theory, if you will, is to avoid catastrophic loss in case of disease or insect pressures that target a single species.  Common examples cited are a number of historic and devastating events that wiped out, literally, millions of trees.

Dutch Elm Disease, Ophiostoma ulmi and O. novo-ulmi  – Primarily targets native elm trees which were a preferred species in urban settings as a majestic street and landscape tree.  This introduced pathogen was first reported in 1928 and by 1989 75% of the estimated 77 million elm trees in North America were gone.

This devastating disease has slowly but surely made its way across the nation.  Yet, here and there, you will still see survivors such as this large specimen in downtown Hamilton, Montana.  There are still several in the area and are always a treat to see.

Ulmus Americana, American elm
Hamilton, Montana
© 2020 McNeill’s Tree Service

Trees killed by this disease are still capable of re-sprouting and sending up shoots, as seen in the photo below.  This tree was listed as “dead” on an inventory taken in 1992; however, when we re-inventoried the property in 2008 regrowth from the stump had put on significant growth.  “Never say never.” 

Ulmus Americana, American elm
Regrowth from a stump; original tree died of Dutch Elm Disease (unknown date)
© 2020 McNeill’s Tree Service

American Chestnut blight – First reported in New York in 1904, within 50 years this introduced pathogen, Cryphonectria parasitica, had decimated American Chestnut trees in the eastern North American forests, a number estimated to be some 4 billion trees.  This species was the dominant tree in many of the ecosystems in the Appalachians comprising approximately 25% of the forest. 

Emerald Ash Borer, Agrilus planipennis  – First reported in 2002, this invasive insect is thought to have been in this country since the late 1980s.  As the name implies, it targets ash trees both native and non-native.  In its native environment it is not considered a serious pest as there are natural controls; however, outside of its native range those controls are not present.  It has killed tens of millions of ash trees to date and is a serious threat to the 8.7 billion ash trees in North America.   Ash trees comprise large sections of natural forests but also have been prominent urban forest and landscape selections. 

Fraxinus Americana , White ash
© 2020 McNeill’s Tree Service

These disasters, affecting both natural forests and planted areas, resulted in various formulas being suggested for diversifying city tree inventories in an effort to reduce the potential for catastrophic loss when, not if, events such as these happen again.  These include the “10%-20%-30% rule” (no more than 10% of any species, 20% of any genus or 30% of any family) generally attributed to the late Dr. Frank Santamour.   However, Dr. Santamour stated in a paper he gave that he didn’t know who first came up with this proposal, but whatever.  

More recently another approach has been suggested by Dr. John Ball out of South Dakota State University:  “The 5% Solution”.   His proposal suggests genera with limited numbers of species and limited global distribution have less pest potential, and, therefore, should be less apt to be susceptible to this kind of devastating attack.  Hence, the suggestion to limit genus and species to 5% of the tree population. 

As with any solutions to a given problem, there are pros and cons.  The 10-20-30 rule can still end up with too many of one species in any of those groups and the 5% solution may be too restrictive in areas with limited species selection options due to climatic constraints.

Factors determining selection are often what is currently popular as well as what is readily available at the local nursery.  Nurseries stock what is going to sell and people tend to buy what they have seen and like.  Consumer demand drives stocking decisions by nurseries, which in turn, limits diverse options.  It is a classic “Catch-22”.  I have even read suggestions by professionals telling people to drive around their neighborhood and see what their neighbors have planted with the presumption that if it worked for them, it will work for you.  Not the way to encourage diversity.

In order to branch out and contribute to diversification, you need to do some homework.  Consider not only what is suitable in your hardiness zone but also with your water capabilities, site aspect, soil conditions and level of care you are willing to expend on its maintenance.  Consider also what function the tree is to provide:  shade, aesthetic appeal, flowering, and/or fruiting. You can then make a list of potential candidates.  At this point, you may want to contact a local nursery or professional arborist and get their feedback.    Don’t be shy about getting a second opinion; everyone has bias.

Quercus spp. Probably a Northern red oak; lovely fall color.
© 2020 McNeill’s Tree Service

If your nursery of choice doesn’t carry the species you are looking for, ask if they can order one.  If they can, how far in advance do you need to place the order.  Do you have the right of refusal if it is damaged or the wrong tree, assuming that was not your mistake. 

Remembering all plants in a developed area contribute to the urban forest, the individual homeowner can do a lot to help diversification.   And by selecting a non-target tree for primary pests, you are hedging your bets on longer term survival.  We need more trees to be planted but they also have to survive.  It does the environment no good if trees cannot survive for longer than 20 years.

Tree Species Profile

This category is being created to introduce or reacquaint people with various species; primarily trees, but you never know what else may creep in.  Since I am most familiar with the trees where I am located, the preponderance will be on species suited to this area.  However, as I have traveled, and will hopefully be able to continue to do so, I encounter trees I am less familiar with (I LOVE meeting new friends!) and will share some of those as well.

These profiles will contain the typical information as to environmental suitability, but hopefully, some lesser known facts, some fun, some maybe cautionary.  If there is a specific tree you would like to know more about, let me know.  I am a “stick chaser”.  If I don’t know something, I love to find out about it.

While studying dendrology, I quickly came to realize not all trees are in every tree identification book.  Which makes sense.  There are far too many.  Many books are specific to a region, which is all good and well if you are trying to find a native species from that particular area.  However, many non-native trees are planted around (and that is a good thing for diversity).  Determining what they are may involve other books.  I stopped counting the number I have after I reached a dozen.  And still look at every one I come across just in case it has some intriguing information hitherto unknown to me or even presented in a different manner.

With that said, my “go to” book (and author) remains Manual of Woody Landscape Plants by Michael A. Dirr.  He has numerous books, several which are still on my wish list.

Please note:  There are many nuances to using plants for food, beverage or medicinal treatment.  I may mention some of these with appropriate citations and/or references as possible.  However, I have no professional experience and am not an authority in this area.  In no manner should any comments in these profiles be construed as recommendations or endorsement. 

Benefits of Trees

Oh wow.  I can actually feel the rolling of eyes.  Who has NOT been inundated with a list of the benefits of trees?  I would like to expound a bit on some of those lists so, hopefully, you will hang in there with me.  Warning:  this is a bit of a rant.

Trees do give us many benefits such as those so often enumerated:  shade, wind breaks, sound attenuation, storm water mitigation, prevention of soil erosion, and of course, the all-important release of oxygen into the atmosphere.  As I say in my blog, Understanding Photosynthesis (which I STILL need to rename to Understanding the Importance of Photosynthesis), “we need trees, but they do NOT need us”.  

As a general rule, the bigger the tree the greater the ecosystem benefits.
Species pictured: Populus deltoides

The problem I have with some of the lists is it appears in trying to maximize the impact, the author(s) overstate some, understate others or simply reword a benefit to make it sound like an additional one.  In my humble opinion, this is unnecessary because the massive importance of trees is self-evident:  we wouldn’t be able to exist without them.

However, consider “beauty is in the eyes of the beholder.”  That gorgeous, flowering tree standing majestically in your yard may be a pollinator magnet, produce substantial shade with those lovely, large leaves and attractive seedpods adding aesthetic appeal in the summer.  But someone allergic to bees may not be so thrilled with the species.  If a person’s preference is for a manicured lawn, then fighting dense shade isn’t going to be popular, and when it comes to raking up those “lovely, large leaves and attractive seedpods”, which send up numerous seedlings, well, this is the “The Love/Hate Relationship with Trees”.

Tilia Americana alle

Then there is the first time someone hears trees emit volatile organic compounds (VOCs) which can include some products that may contribute to “pollution” (depending on your point of view) or they emit (hold on now) Carbon dioxide (CO2) (Yes, that’s the one getting all the press lately).   They are horrified.   How dare them!  (Meaning the trees.)  I read an article in which you could actually hear the author’s outrage:   trees were supposed to be cleaning our air not adding to the potential pollution of it with the added implication trees should be taking care of us and cleaning up our mess (presumably so we don’t have to).    I’m pretty sure the trees didn’t read the fine print in the contract as drafted.

The reality here is trees take care of themselves.  They have a wealth of products they synthesize for function and survival.  Many of these products are beneficial to us, medically, socially, aesthetically, economically, and/or environmentally.  But like many natural products, they can also have a flip side which is either not specifically beneficial to us or may be harmful in dosage.  

Trees are unable to control how we utilize their benefits, such as production methods we employ to harvest the raw material, refine it, sell it, ship it, use it and dispose of it.   The responsible application and/or utilization of the amazing array of benefits trees do give us falls squarely on our shoulders.

Dealing With Weeds

Many of us would prefer not to use pesticides.  BTW – the term “pesticides” is a general term indicating any product used to kill something.  Insecticides kill insects, rodenticides kill rodents, miticides kill mites and herbicides kill plants.  By itself, the term does not tell you what it is targeted to kill.  Ok, onward…

When it comes to controlling weeds, we often have other options besides chemicals.  There is always the ever-popular pulling-by-hand method.  This is a particularly useful method for keeping family members busy…and their friends.  It’s called “job security”.   It is recommended you call these “activities” rather than “chores”; puts the best spin on things.

I really don’t mind pulling weeds.  It is one of those tasks where you can go on automatic pilot and let your mind roam.  However, caution needs to be exercised if you are working in a newly emerging garden plot.  Do try to remember many baby plants look alike.  So maybe don’t let your mind wander too much. 

There are ways to minimize the task and benefit the soil as well.  And that is an important consideration….benefiting the soil.  I really do need to get a blog written on soil health, but every time I start, it turns into a book.   Will keep working on that; meanwhile, back to weeds.

Many recommend the use of landscape fabric to minimize weeds.  Unfortunately, if the area is to have plants, it has drawbacks.  Landscape fabric is typically top dressed with various products for aesthetic purposes.  Options include organic or inorganic products.  By inorganic, I am referring to the use of rock or stone appropriate for a pathway or drainage area.  If this is the application, then landscape fabric may be acceptable as your main purpose may not be improving the soil. 

However, if this is an area with plants your goal should be to improve the soil.  This is where you want an organic top dressing or mulch which will confer benefits to the soil as these products decompose.  These benefits include improvement in soil structure and aggregation, infiltration and percolation of water, aeration, and stimulation of soil microbial activity which will, in turn, make nutrients in the soil plant available.  If landscape fabric is used in these situations, it will block the interaction between the mineral soil below and the organic mulch above.  The soil won’t improve. 

Soil had landscape fabric with a top dressing of wood mulch for over 20 years. No improvement to the soil.

Therefore, in planted areas, add mulch but don’t use landscape fabric, which does mean you will be dealing with more weeds.  However, something to keep in mind is weeds growing in soil with good structure and aggregation, augmented with organic amendments over time, are much easier to pull than from straight mineral soil with little organic matter. 

Weeds in these heavily mulched pathways are very easy to pull. Jessie, one of our Jack Russell Terrier, is an able-bodied assistant.

There are numerous recommendations about how mulch suppresses weeds.  However, success with this strategy alone comes under the “it depends” category.  Combining mulch with the cardboard method as described in Creating a Tree Island is a viable option for weed management.   Just be aware, nothing is forever.  Weeds happen.  That’s life in a natural, healthy environment.  The best suppressive capability for maintaining weeds is to have something else growing there that you desire and let it/them outcompete the undesirable growth.

There is very little weed competition in the thick Basket-of-Gold (Aurinia saxatilis ‘Gold Dust’)

Perseverance is another factor.  A master gardener who writes a column for a local newspaper once said “weeds are not immortal”.  I know, they just seem to be.  But if you stay after them, you will notice the battle may be ongoing, but it gets easier.

What is an Urban Forest?

There are probably as many different definitions for an urban forest as there are people you ask. One definition on the internet stated simply it was a densely wooded area located in a city. Hmmmm, well. Do they mean a remnant of an original forest? Or are they talking about a planted park? Do these two features alone define an urban forest? What about those cities without remnant forests that claim to have an urban forest? I am picturing the cities that have grown out of the Great Plains which was prairie with barely a tree in sight.

Another definition I came across comes from Wikipedia: “An urban forest is a forest or a collection of trees that grow within a city, town or a suburb. In a wider sense it may include any kind of woody plant vegetation growing in and around human settlements.” (I like this a bit more.)

River Park, Hamilton, Montana, located along the Bitterroot River, providing natural habitat, walking paths, playgrounds and picnic areas in managed, yet still natural, setting.

Then a quote from the forest service website: “Over 130 million acres of America’s forests are located right in our cities and towns. Urban forests come in many different shapes and sizes. They include urban parks, street trees, landscaped boulevards, gardens, river and costal promenades, greenways, river corridors, wetlands, nature preserves, shelter belts of trees and working trees at former industrial sites.” Alright! Now, we’re talkin’!

I did find it interesting they specifically included “working trees at former industrial sites”. Actually, you could say all trees “work”. They are cleaning our air, replenishing oxygen into the atmosphere, taking in carbon dioxide, sequestering carbon, cooling our homes and streets, providing wildlife habitat, providing shade for those picnics and summer time festivals. They are mitigating storm runoff, reducing the heat island effect, and attenuating noise. They offer shelter and protection against wind. They provide recreational venues and the opportunity to find peace and tranquility in a hike.

Located on the campus of the Missouri State University in Springfield, Missouri, this beautifully landscaped bioswale is a great example of “working plants”; absorbing excess water and mitigating stormwater runoff, while containing erosion, photosynthesizing and looking beautiful while doing so.

If there are any of the above attributes you feel are undeserved, consider that not all trees perform the same functions in a like manner. Some trees have been misplaced (by us) which could minimize their abilities. Some are so mismanaged by us, they can offer only a mere shadow of their full potential. None of these circumstances are their fault but more often stem from our errors.

The Japanese Tea Garden, located in Golden Gate Park, San Francisco, California. While I have had the pleasure of visiting this beautiful garden, I don’t take credit for this photo. This was taken and generously shared by a friend, Nancy Togami.

An urban forest is not comprised merely of the street and park trees owned or controlled by a municipality. But, in my opinion, encompasses every plant in any built environment ranging from residential, semi-rural, exurban, suburban to the hardcore urban centers. And it doesn’t matter where they are planted. They might be located in a park, in boulevards, a private garden, downtown shopping malls, rooftop gardens, potted plants. They all count.

Notice I said “every plant”. If I were writing the definition, I would enlarge it to include every photosynthesizing organism. So we would include turf grass, annual and perennial flowers, herbaceous and woody shrubs as well as our long-lived, perennial trees. If managed properly, they all contribute to a healthier environment….because they ALL photosynthesize.

Photosynthesis is one of the two most important energy-related processes in the world, the other being cellular respiration. (See my blog Understanding Photosynthesis, which actually should be retitled to Understanding the Importance of Photosynthesis.)

If you live in a city that has an Urban Forest Management Plan, you may have seen or read the information on species inventory and the benefits these trees give back to the community. These inventories generally only tally the municipally-controlled trees and do not include those in the private sector which could easily double the number of trees and, therefore, the benefits provided.

Landscapes – A Work in Progress

A developing landscape

A landscape should be viewed as a work in progress. Its main components are living organisms which grow, spread and change as they mature at different rates and in different ways. What we start off with is not what we end up with, sometimes in ways we did not anticipate. And that is part of the fun and wonder.

Planting for diversity is a common theme in arboriculture and urban forestry. The premise is to preclude a major disease or insect infestation wiping out a majority of the urban (or natural) forest as has happened in the past and is ongoing in the present. Diseases such as Chestnut Blight, wiping out American chestnut trees, Dutch Elm Disease decimating American elms, Oak wilt killing trees in the oak species. Insect infestations are taking their toll as well. Emerald Ash Borer kills native and non-native ash trees and the Mountain and Western Pine Beetles have decimated pines across western North America. Most of this devastation is evident in the monoculture approach to planting and proves over and over the wisdom of having an urban forest comprised of a diversity of tree species.

When it comes to the individual landscape, diversity is equally as important, perhaps for more reasons than just surviving a cataclysmic event. It should include not just a diversity of trees, but a variety of plants from herbaceous and woody shrubs, annual and perennial flowers as well as grass species. Besides creating an aesthetically pleasing appearance, these all contribute to a healthy, living eco-system that becomes self-sustaining in a way many don’t appreciate.

Diversity in the landscape: trees, shrubs, annual and perennial flowers as well as grass species.

When considering diversity, you should consider not only species, but longevity, structure, size, characteristics such as blooming (or not), deciduous and evergreen. Why? Because not only does this give you a larger plant palette from which to choose, it also provides a more interesting design, will draw in an abundant variety of beneficial insects and will also contribute to diversity within the soil which means a healthier environment for the plants. This living eco-system you are developing does not stop at ground level but goes deeply beneath the surface.

Does your design matter? Only to the extent it meets your goals and desires. There are many designs and styles: Formal or informal; themes such as Italian, Oriental, English Country Garden, French. A design may meet your aesthetic goal but also serve a specific purpose: kitchen garden, xeriscape, encouraging pollinators and butterflies, or focusing on species from a specific area. It may be a combination of several. It doesn’t matter if it doesn’t fit into a specific designation or into many. What matters is that it suits you.

The wonderful thing, or I should say one of the many wonderful things about a landscape: it is never finished. It transforms itself daily if you pay attention, but even a casual observation will take note of the changing seasons with the perspective each gives. Then one day you realize you now have to look up to see the buds at the top of the little sapling you planted instead of bending down to note its growth. Perhaps that sapling is even now towering over your house.

The wonder of watching them grow.

Because you didn’t just plant trees, you planted understory shrubs and flowers, both perennial and annual as well, birds come in droves. Many of the annuals reseed themselves and so you have an ever-expanding flower garden that brings in pollinators and hummingbirds. Your landscape is now, literally, a-buzz.

Wildflowers amongst aspen and poplars. Forsythia and Bristlecone pine are banked by sunflowers.

Working in a garden becomes a time to share with a tremendous number of other living organisms as they go about their daily tasks. There is never a dull moment, many peaceful ones, but never dull. It is a time to let go of problems of the moment, let your mind wander. It gives you a task to focus on, gets you out-of-doors on your own terms, gives you physical exercise and mental stimulation. And at the end of the day, there is a self-satisfying feeling of accomplishment, the results of which you watch grow day-to-day.