Friday, May 3, 2013

Reed Versus The Volcano (tree volcano that is)

A neighbor's tree that I transplanted 7 years ago.  The
root flare is at lawn grade, and in 2 years the contractor
has added 18 inches of mulch. ©2013 BDG
I am angry, as I just drove by an elderly neighbor's house where the landscape contractor is piling mounds of artificially-dyed mulch on top of last year's mulch.  This annual process is building up soil levels around the base of relatively new plants, and it is starting to kill them.  The result of this reckless heaving of mulch around trees is the ubiquitous "Tree Volcano".

For those of us who live in suburbia, the annual rite of spring is the arrival of numerous 'mow and blow' contractors who come to clean up the gardens and lawns and get them ready for the coming season.  For many it means multiple gas blowers, both backpack and ground, de-thatchers, mowers and a small army of workers edging, pruning, raking and the grand finale of laying mulch.

Azaleas drowned in a foot of black-dyed
wood mulch. ©2013 BDG
As someone who spends time trying to educate clients and friends about their gardens and proper maintenance practices, it is infuriating to see so-called professionals killing their client's gardens.  That said, there are plenty of reputable contractors who perform excellent work, but often in search of saving a few dollars, people go with contractors who promise the same work for less.  Over time, it costs so much more.

This tree has been 'volcanized' for
years.  Last year they removed more
than 50% of branches that were dead.
Some from Winter Moth and some
from poor cultural practice.
©2013 BDG
Last year I wrote a piece called, Mulch?  This Is Not Mulch!, and I want to focus on three critical elements in this follow-up piece regarding mulching in the garden:  preparation, material and quantity.

The worst practice is to pile new mulch on top of old mulch.  When prepping beds, often you will find that raking out the existing mulch may provide partial or even substantial coverage for the coming season, and it is important to rake out the mulch, turn it over and let air in to help in the decomposition process.  If you want to add new mulch on top of the old mulch, that is great, provided you are not building up the level around your plants.  Adding mulch or soil around the base of plants will contribute to their demise by burying the root crown and keeping air out of the root zone which is critical along with water and nutrients.  It doesn't happen immediately, which is why bad contractors often don't get the blame.
The biggest 'Tree Volcano' I have seen on such a small
tree.  This mound is over 2 feet high and look at
the mounds in the beds.  ©2013 BDG

The soil level around plants should remain the same year after year.  A contractor I spoke with said that clients like the mounding of beds and he uses mulch to get the profile raised.  If you want to raise a bed then you need to remove the plants and add back after the grade has been adjusted with soil but you have to be careful changing grade around large established trees.  Away from the trunk, some trees are OK with grade adjustments, while others can be very sensitive to having their surface roots buried.

Many contractors will remove old mulch and add a whole new layer of new mulch because they want the fresh look of new mulch.  By doing this they are removing a layer of mulch that has been decomposing for a year and is that much closer to providing available nutrients and organic matter for the soil.

A Double Volcano, there are five in this front yard.  These
are big trees and the mounds are 18-24" high. ©2013 BDG
In fact the whole process of removing material from beds is part of the problem.  Gardens need every bit of organic material to help them regenerate each spring.  Like everyone else I can appreciate a neat and clean suburban garden bed, and in the fall I remove leaves only to return them in the spring as leaf mold(more on this later).

As a final word on preparation, make sure you are providing the best opportunity for your garden to receive good organic material to improve the soil quality help supply nutrients for your growing plants.  While mulching can be seen as a decorative element, it should primarily be seen as an opportunity to improve the quality of your soil and provide protection from weeds and heat during the season.

My 6 month old leaf mold composted over winter
with Dried Blood as a nitrogen source to
help break down.  ©2013 BDG

Many people love the look when the landscaper leaves and their gardens are clean and have been mulched with red, brown or black mulch.  Often, contractors have used a good bark mulch product that has been well processed and often times aged and composted.  The purpose of using a natural  mulch is to decrease weeds and weed germination, keep soil moist and at constant temperature and most importantly to add organic material to beds that are asked to produce flowers, shrubs and trees year after year.  Organic material that is utilized by plants, needs to be replaced and mulch and compost are critical elements in this cycle.

Close-up of my remaining leaf mold to be
put in the garden.  ©2013 BDG
In recent years, the demand for mulch has outgrown the supply of quality mulch and suppliers have created mulch that is made from recycled wood products that need to be dyed (badly I might add) to replicate the natural color of brown Pine and Spruce bark mulch, reddish brown Hemlock mulch or the aged and composted black mulch.  These 'created' mulches have no value to existing soils and often steal nitrogen from the soil so that they can decompose and they do so at a very slow rate.  The really bad mulches bleach out during the summer as their dye wears off to reveal chunks of recycled wood.  These mulches take years to break down and can cause more harm than good by removing nutrients from the soil that your plants need.

Azaleas after a year in 12 inches of dyed, chipped wood.
These were new and healthy last year before they
go buried alive.  ©2013 BDG
The best product to use as mulch for flower and shrub beds are composted or aged mulches, compost or leaf mold.  If you want to save a lot of money in mulch, you can recycle your leaves in a very simple process.  In the fall when the leaves are dry, I spread out a days worth of raking on my driveway and go over it several times with my lawnmower.  This helps to break up the leaves into smaller pieces and helps in the decomposition process.  If you want, you can get a small garden shredder/chipper and run them through to get a more even consistency.  I put the leaves in a corner behind my house and add a few pounds of Dried Blood, an organic amendment available at most any garden center.  Dried Blood is pure nitrogen that will help the leaves to compost  until spring.  Come spring when my beds are prepped and it has started to warm, I add the leaves, liberally back to my garden beds.

If you don't want to go through this process, find a local supplier of leaf mold.  It is one of the best amendments for perennial gardens.  As for woody mulch, talk to your supplier or landscaper and make sure that you understand the type of mulch that you are purchasing.

So how much mulch is necessary to suppress weeds but also allow water to penetrate to the plant roots. For most garden beds, 2-3" is plenty, and around perennials I would suggest slightly less.  If you add fertilizer for perennials or other plants during the season, too much mulch will limit the amount of nutrients to actually get to the plants.

With the proper amount of quality mulch, much of it will break down during the course of the season and be available for the soil and plants.  Compost and leaf mold will break down and work into the soil during the season.

All of the images in this post were taken within a five minute drive of my house and all were done by professional companies.   Our plants are under enough stress from environmental conditions, new disease and insects, and the last thing we need to do is add poor management practices.  Shame on the contractors who jeopardize their client's garden's out of ignorance and economic influences.

One last Volcano on the way to my son's school.  ©2013 BDG


  1. Love this post Reed! I've ordered compost last 5 years and this year was going to succumb and go for mulch but I may have to rethink my 'suburban yard' plan!!!

  2. Mulch volcanoes drive me crazy and my neighborhood is erupting with them! How amazing that a 'wild tree' doesn't a mulch volcano but a domesticated suburban tree can't live without one. So profoundly stupid!

    I don't rake off my old mulch but I do break it up every fall and then only add as much new mulch as is needed. As for my leaves, I let them stay where they fall so they can break down over winter. Those that fall on the grass are hit with the mower. Throwing away leaves is as dumb as overmulching with freakish red mulch. I know my opinions are strong, but ya hit a hot spot with me on this one! :o)

    1. With you as the first member we will start the UBOPLACTV. United Brotherhood(or Sisterhood) of Plant Lovers Against the Creation of Tree Volcanos.

    2. Awesome!! Can I wear the boots I wore in my Portrait of a Gardener Post? They might make me look tough! :o) I'll just try not to laugh or fall over so I don't blow my cover.

  3. Its hysterical to see the photos of the big trees with huge trunks having small mounds of mulch. Why? Just let the grass grow up to it. I love the red dyed mulch, if I was an alien from Mars. Who came up with the idea of red mulch to start with. Next we'll have green dyed mulch to spread in areas where grass won't grow. Hey, there's an idea!

  4. Rob, your are too late to the colored mulches. Someone is already doing brightly colored is one of the worst I have ever seen.

  5. Great informative post. I could not believe some of those crazy volcano photos!

  6. Great post, very comprehensive and well written. I love the photos you got. I thought I had seen volcano's, I was wrong THOSE are volcano's.

    My mulch preference is for using a nice layer of compost with a layer of leaf mulch on top to dress it up a bit.