Invasive plants, politics and science

I’ve had a hectic week (taxes! financial aid!) and haven’t had a chance to think about posting.  Fortunately, yet another colleague just sent me an interesting link that’s worth sharing and discussing.

For those of you who aren’t familiar with how Master Gardener programs work, they are built on volunteers who receive training in garden-related sciences and then contribute a significant number of hours to outreach education.  Many MGs work in plant clinics, and others volunteer in public gardens.  Regardless of where they spend their volunteer hours, they are always representing their sponsoring university and therefore dispense advice and follow practices based on the best available science.

This will help explain why the Master Gardeners who volunteered at the Racine Zoo felt they had to resign their volunteer positions.

(Note that the zoo is losing out on 1300+ hours/year of donated garden upkeep, but the zoo president and CEO is confident that the zoo staff can pick that up.  Wonder if he’ll be out there weeding and watering?)

Why did the worm cross the road?

…To get to the other side. Of course.

All the rain we’re having is causing the earthworms to crowd the sidewalks and driveways. They fling themselves out of the ground and onto the pavement because they’re drowning, right?  Nope. Urban myth (by the way, why are there no Rural Myths?).  The punchline is not too far off: they can only move about above ground while it’s raining. They use rain events to safely relocate, and can allegedly live for a while in a puddle.  But we all know what happens when the sun comes out…crispy Ramen time.

I had just come in from flinging a bunch of worms off the pavement in front of our building – they were going to get mashed or eaten by robins otherwise. I probably put them right back from whence they came, against their earthwormy wishes.

Portrait of Two Worms
– by H.L. Scoggins

Then I read Bert’s post…it’s like reporting that the Easter Bunny has rabies or something. I’ve always been delighted to see earthworms, under any conditions. To the point of saving their squirmy little lives whenever possible.
Not sure what to think about this new bit of information.

Invasion of the killer earthworms

It sounds like a B-grade horror movie.  Millions of earthworms, moving silently beneath soil, wreaking havoc until the entire planet is uninhabitable.  Sound a little far-fetched?  Not to ecologists that study northern hardwood forests.  While most of us grew up thinking earthworms were ubiquitous, turns out they are not native in parts of North America that were covered with ice during the last glacial period.  Most of us also grew up thinking that earthworms where the good guys/girls (they’re hermaphroditic), churning up compacted soil and leaving nutrient-rich castings behind.  In many northern hardwood forests, however, exotic earthworms, have become invasive and ecologists believe they are having profound effect on ecosystems.

I have to admit I hadn’t paid that much attention to the invasive earthworm issue but I attended a seminar last week by Dr. Lee Frelich, Director of the Center for Forest Ecology at the University of Minnesota.  Dr. Frelich’s seminar touched on several areas of research, almost all of it extremely depressing, related to climate change and invasive species.  He and his colleagues have documented significant changes in soil ecosystem processes and plant succession associated with increasing populations of earthworms.  Nightcrawlers, in particular, cause a lot of problems because they consume fresh leaf litter causing it to decompose at a much faster rate compared to un-invaded ecosystems.  The net result of these soil changes is that few trees or shrubs can reproduce in the understory.  Over time this may lead to a very different looking forest than exists there today.

Of course, we may end up with a very different forest in any event, given some of the climate change scenarios Dr. Frelich presented.  One worst-case model predicted the climate of the Boundary Waters area of Minnesota would resemble that of present-day Oklahoma City by the end of the century.  But I try not to worry; I figure by that point I’ll be food for the earthworms anyway.



For more info on the earthworms that ate Minnesota, check out these links, if you dare…

Genetic Engineering, Veal, and Rennin

Today I thought I’d go just a little off topic. Lots of people out there are really upset about the idea of putting genes into plants, like putting genes for Round-Up resistance into soybeans, or genes for caterpillar resistance into corn. And, I do agree, this is a pretty powerful technology that needs to be used carefully – probably more carefully than it’s being used right now with plants.

But the funny thing is, one of the places where transgenic creatures really dominate the market is in a place that is almost never considered. Today 80-90% of cheese made in the United States is produced using bacteria genetically engineered to produce rennin. What is rennin you ask? Renin is the stuff normally found in a cow’s stomach which causes milk to curdle – and cheese to be created. For those of you interested in looking into this further look up rennet which is the substance in a cow’s stomach which naturally contains rennin.

After looking around a bit I really can’t find that many people upset about the use of genetically engineered microbes to produce rennin.  Actually, some people who are quite sensitive to environmental concerns may prefer it.  Historically rennin comes from dead young cows – it’s a byproduct of veal production (kind of a nasty industry if you ask me).  Rennin that comes from genetically altered bacteria has nothing to do with dead cows and so vegetarians often find cheese produced with genetically engineered rennin to be more appropriate.

California Flower, Food and Garden Show

I’m giving two talks at the California Flower, Food and Garden Show in Sacramento today and tomorrow: details are linked here. It would be great to meet some of our California readers in person if you plan on being there.

I’ll try to take some photos and share my thoughts about the show on upcoming posts. Maybe I’ll even find my Friday quiz topic lurking there!

Rain barrels

A few weeks ago one of our readers, landscape architect Owen Dell, sent me a link to his blog where he takes on rain barrels. It’s a great analysis of the (im)practicalities of rain barrels and it got me to wondering how many of our readers (and my GP colleagues) use these as supplemental sources of irrigation water?

I have two in our back yard that were made from old olive oil containers retrofitted for collecting and dispensing water. They’re hooked together so that when one fills, the rain is diverted to the second.

We use this water pretty much for watering container plants, especially those on our south-facing front porch that require watering every other day during the summer. The barrels each hold 55 gallons and are always full during the winter and spring. We drain them almost dry over the summer, but even a brief rain results in several gallons collected.

So I think they’re a pretty good deal, since we use relatively little water from the hose to keep our container plants happy. But Owen brings up some valid points in his analysis, as do commenters on his blog.

What do you all think?

Mulch much?

[Try to say post title three times fast. Heh.]

Here on the GP blogski, we’ve discussed both the merits and shortcomings of many non-traditional forms of mulch; rather, stuff that covers the ground that is referred to as mulch. Shredded rubber, marble chips, lava stone, dyed lava stone (ick), etc.

But this is a new one on me:

Naturally, I immediately shoved my hand in the biggest tub of glass (part of the Scientific Method). It was not…super smooth. A couple of pieces stuck, and there was a bit of sparkly-dust residue. I tried to remember not to rub my eyes for the rest of the day. Not sure I’m buying the recommendation to “use in pathways.”

"Aaargh! My Eyes!"

Pretty colors…soooo shiny. And recycled!

What’s this? A warning label on the aqua mulch: “Parents, please watch your children’s hands around the glass mulch.”Whoops.

Aargh! My eyes!

April foolery revisited

You certainly had fun with this!  Yes, it’s “lucky bamboo,” a name which is completely inappropriate given that it’s not bamboo (but Dracaena sanderiana) and it’s certainly not lucky:

Now “spiral lucky bamboo” is usually dracaena (or as I like to call it “not-bamboo”) that’s been exposed to a unidirectional light source and turned at intervals to create a contorted spiral shape:

These plants, on the other hand, have been cut into straight sections and bound with shiny gold wire in ever increasing lengths so that we have a leaning tower of not-bamboo surrounded by adulating ceramic frogs (good eyes Anne and Jam!).  Given enough time – a few weeks, maybe – whatever architectural appeal this arrangement had will be covered with leafy growth from all those sprouting nodes.

There’s a homework assignment for someone:  buy one of these, then film it under time lapse photography.  If our tech guys ever get our video capability up on this blog, I’ll post them!

Looking for the lowdown on tree rings

Often we use our blog space as a soapbox from which to pontificate, but today I’m looking for some input from our loyal readers.  Last week I received a note from an editor looking for some words about tree rings.  We’re talking about landscape tree rings for planting annuals or perennials, not dendrochronology.


The editor was interested in specifics on tree rings for large existing trees such as what type of materials to use, what types of flowers or plants worked best, which trees can or can’t have tree rings, etc.  My reply was short, maybe even a little curt, “I don’t have any experience with tree rings but our general recommendation is to avoid grade changes around trees whenever possible. After I sent the reply I started thinking, is there any real harm to tree rings?  I’ve seen some that looked pretty nice (seen many that look like crap, too).  For most trees the amount of surface area covered is small compared to total surface root area.  If care is taken not to bury the root collar and trunk, would the tree notice covering a little bit of mostly structural roots?   Would appreciate thoughts (pro and con) from those with direct experience.