Mulch Volcanoes

After Linda’s post yesterday I just had to add my own 2 cents about gator bags.  I use ’em and I like ’em.  But, that said, I never allow gator bags to sit against trees for an extended period of time  (Maybe 6 weeks when the tree first goes in).  That’s just asking for trouble!  But looking at those bags got me thinking about a project which we’re finishing up this year.  Volcano mulching. Believe me, it sounds a lot cooler than it is.  Volcano mulching is when you make a big pile of mulch along a tree’s trunk, as in the picture below.

The reason we’re looking at volcano mulching is that everyone says it’s bad, but no-one has really proven that it’s bad.  The reasons that volcano mulching are supposed to be bad are twofold:  First, the mulch could cause rot on the tree’s stem (as with those gator bags) and second, because it might be possible for a tree’s roots to grow up into the mulch, potentially surrounding the stem, which might lead to the roots choking the stem as the
tree grows larger.  Not a good situation.  Anyway, early in 2007 we took a field of maples and cut squares in their trunks, as seen below, and then either did or didn’t mound up mulch around these tree’s stems.

What we expected to see was that, over time, the wounding and presence of a mulch volcano would lead to diseases in the stem.  Instead what we found
is that, for many of the trees, deeper mulch actually led to the wounds closing more rapidly.  The image below is of a wound that was covered with mulch.

While this next image is of a wound that wasn’t covered with mulch.

Of course some of the wounds without mulch closed fine as well, as you can see in the next image.  (Why isn’t anything ever cut and dried?)

So what does all this mean?  Well, nothing yet.  Research is a funny thing: it rarely gives you quick and easy answers.  I won’t recommend mulch volcanoes because we still haven’t examined those roots that may enter the mulch and surround the stem.  And before I say that the volcanoes didn’t affect stem rot in this study I want to take a closer look at those wounds by cross sectioning the tree which we’ll probably do this fall. Plus we’ve got to run statistics on all the different trees….. and then it would be great if someone else would take a stab at this study to confirm what we see…. I tell you what, nothing’s easy.

What I Learned This Summer (Part 1)

Just flew in from St. Louis and boy are my arms tired! [Baadum – ch!]

I have very diverse responsibilities and interests, but all in one way or another relate to this thing called Gardening. I recently attended two very different conferences, both in St. Louis but thankfully scheduled back-to-back. The first was the Perennial Plant
Association (PPA): a colorful, enthusiastic, slightly eccentric group of growers, breeders, designers, and geeks of the highest order. Bus tours and talks centered on plants, glorious plants….of which we simply cannot get enough.

  Paul Westervelt is so excited...PPA visits Missouri Botanical Garden

Hot plants!!! Paul Westervelt expresses his enthusiasm during the PPA tour of the fabulous Missouri Botanic Garden.

The second was the American Society for Horticultural Science (ASHS) annual conference. Not so colorful. Lots of data…even presented some myself. But very necessary – especially in our realm (publish or perish). “Horticulture” is a ridiculously broad umbrella, under which falls food crops, ornamentals, biotechnology, econom cs, and some social sciences.  There were speakers and posters on a mind-boggling array of topics – from horticulture curricula to stress physiology; tropical fruits to public horticulture. Some of this research and information is ready for “technology transfer”, that is, with a bit of tweaking,
the results are directly applicable, whether to a nursery grower or a consumer.  Much of it is not; and will exist only in that “researcher to researcher” ether.

My point: there are many outlets for the information shared at PPA, i.e. hot new plants on the Terra Nova website, design articles by the various garden writers in attendance, the newest book from Timber Press, etc. For ASHS, not so much, unless you subscribe to HortScience and receive the 1000+ pages of abstracts from the meeting.

This is where we can help. Jeff Gillman has done a yeoman’s job at translating science to gardeners, and now all of us involved in this blog are going to chip in.  Call it “insider
information” or the less-glamorous “stuff that’s technical/boring to read but with
hidden nuggets of usefulness”.  The one thing we hope makes this useful to you is that we all consider ourselves gardeners, and though our day jobs certainly inform how we manage our own little piece of heaven, you’ll get a good dose of adventure, frustration, triumph, plant lust, and humor.

My next few blog contributions will be “things I learned in St. Louis”.  Not least of which is the hoppy goodness of locally-brewed Schlafly Pale Ale.