Wednesday, February 19, 2014

Bringing Nature Home

One of my children's most watched films is 'The Lorax', based on the book of the same name by the famous author, Dr. Seuss.  It is a fable chronicling the plight of the environment as the 'Oncer-ler', a character representing corporate greed, strips the land of natural resources for production of a 'Thneed'.

It highlights the dangers of unsustainable growth as the last 'Truffula' tree (the Once-ler's major raw material), is cut down forcing the Once'lers factory to close. In the mean time, all the wildlife that coexisted with the Truffula trees becomes displaced as their environment is filled with toxic pollution.

This past weekend, I jumped at the chance of taking my daughter to meet a real life Lorax, who like Dr Seuss was 'giving voice to the trees for they have no tongue'.   Doug Tallamy, who I featured in a post entitled America's Top Gardeners is a Professor of  Entomology and Wildlife Ecology for the University of Delaware. He was in town to talk about award winning book, 'Bringing Nature Home', and to address the plight of our own environment. What I discovered during the presentation was a revelation, that my own gardening philosophy was causing more harm than good.

Bluebird with caterpiller
Flickr.com - kansasphoto
Tallamy discussed that 96% of bird life relied heavily on insects, mostly caterpillars, to feed their young. These protein rich morsels contains pound for pound more protein of beef that allows chicks to develop quickly. However, this food supply has been declining, adversely effecting everything within the food-web. So frightening is the rate of decline that since 1966 we've seen a drop of 1% per year of migratory birds who over winter in Central and South America. That is a 50% reduction in 50 years! Habitat loss is one area of concern but failing food-webs are the other.

As we all know, most insects feed on the foliage of plants. Plants are able to capture the energy of the sun, while insects are very good at converting this plant tissue into other types of energy, in the form of themselves. But, plants are smart. Many plants produce toxins to prevent being striped of foliage, which would lead to their demise. As a result, selected insects have co-evolved with selected plants to become exclusive consumers, resistant to the toxin that would otherwise kill them. The down side to this specialism is that when food plants become endangered, then the insect can't adapted to new sources and declines in numbers. This limiting factor then effects the next level up that relies on the insect for food, triggering a collapse of the  food-web.

Monarch Caterpiller
Flickr.com - mean and pinchy
One example Tallamy used was the demise of the Monarch butterfly. The Monarch caterpillar only feeds from the foliage of milkweeds, Asclepias sp. For a long time, both milkweeds and monarch could be found in mass numbers among crops grown for agriculture. However with hybridizing, many of our crops have been bred to resist damage from herbicide spraying, funneling more nutrients to the intended crops but eliminating the population of milkweeds that would have grown wild in our fields.  96.4% of migrating Monarchs have gone, leaving only 3.6% of what that number was. Apart from Monarchs, 11 other butterfly species are known to reproduce on Milkweeds.

The last stand of the Monarchs
Flickr.com - Henry McLin

New sanctuaries have to be found if change is going to occur and Tallamy's answer is our gardens. Plants are the lifeblood of earth but our gardens have always been designed as status symbols. In America, nearly 45 million square acres (3 times more than irrigated corn crops) of lawns are grown, fed and watered for purely aesthetic reasoning. However, lawns don't filter water, don't provide clean air and don't support wildlife. We also fill are gardens with exotic, non native plants that are impervious to insect damage or spray harmful chemicals to ward off attacks.  In theory are gardens have becoming food deserts, unable to support live. Tallamy's suggestion was to take some of this area and convert it back.



"If half of American lawns were replaced with native plants, we would create the equivalent of a 20 million acre national park – nine times bigger than Yellowstone, or 100 times bigger than Shenandoah National Park."


Doug Tallamy


One example Tallamy used was of a courtyard garden (15ft x 15ft) found growing at the Department of Agriculture in Delaware. The garden contained just four plants of milkweeds but were found to be supporting over 150 monarch caterpillars. With such a small area set aside for native plants, it had become an island where a threaten population could find a haven.

'Native plants support native insects' was Tallamy's clear message. If you want birds you have to have a food source for them. In turn, to provide a food source for birds you need plants that are hosts to insects. The dilemma for a gardener is to except that your prized plant will at some point be nibbled on but the payoff is greater than the worth. An oak can support up to 550 different species of butterflies and moths which in turn provides food for birds, while an invasive Norway Maple is food for none.

I've learnt that by filling my garden with exotic, non-native plants that insect don't feed on, I have produced an environment of little value with green statues everywhere. This coming year I will be changing some of my planting to include more wildlife friendly, native plants. It would be a sad day if a stroll in the garden didn't include the song of a bird or the fluttering colors of butterfly wings, Unless.....



“But now," says the Once-ler, "now that you're here, the word of the Lorax seems perfectly clear. UNLESS someone like you cares a whole awful lot, nothing is going to get better. It's not.” 


― Dr. Seuss, The Lorax

Check out Doug Tallamy website by clicking here




Wednesday, February 12, 2014

Becoming a Mulchologist!

Maybe just 2 more bags?
If ever such a professional title as a mulchologist existed, then last year I came pretty close to earning that accolade.  I hadn't given too much thought to the stuff until I was faced with some peculiar questions about are wood based mulches.  In fact, the more I dug into the world of shredded or chipped mulch the more I realized that it might be more foe than friend.

My training began early in 2013 as many landscapers and homeowners were breaking out of snow-mode and venturing back into the garden.  There's nothing better than cleaning up the remnants of last years fallen leaves or cutting back the odd ornamental grass to get us into the gardening mood again.  What better time to lay down that fresh carpet of mulch before all those perennials break through the ground.  Although not my favorite of mulch coverings, color dyed mulch has become very popular.  Black, brown or martian red, we sell enough scoops to probably pave the Washington DC Beltway (slight exaggeration).

The Lava flow
However, little did I know, you have to make sure that you have at least one dry day after applying the stuff or you run the risk of rain washing off the color.  So great is the demand for this colorful carpet, it is processed without time to properly cure.  Nothing is worse than waking up the following day after spreading it to discover your lava field of red mulch looks more like fresh milled chips spat out from an arborist's tree shredder.

For suppliers of mulch, one thing they have to watch out for is souring.  The large piles of wood mulch stored for long periods over the winter, or bagged mulch that remains too wet can undergo anaerobic fermentation.  This process converts organic matter into sulfides, acetic acid, ethanol and methanol, basically it becomes wood alcohol.  If not properly processed, this 'Moonshine mulch' releases gases that are toxic to plants, bleaching or scorching the foliage of surrounding plants and even running off into your lawn.  For some plants this can be detrimental, but woody plants will regrow any lost foliage once the hangover has pasted.  A quick sniff of the mulch, checking for an alcohol-like, vinegar or rotten eggs odor should alert to a potential problem before you spread it out.

We all know the virtues of mulching to control weeds and reduce moisture loss but it can be over done.  Excessive mulch will suffocate the soil and provide cover of rodents like my personal nemesis, the veracious vole, who likes nothing better than to chew off the roots of my plants undetected.  Long have we been told to not mound up mulch around trees, creating a volcano but it is still seen around our neighborhoods.

Lesser known but equally as damaging, is constantly re-applying mulch in annual layers.  Many of us don't realize the need to break up and aerate the crust that mulch can form throughout the year.  When shredded wood mulch is applied to thick and allowed to dry out, it becomes a breeding ground for certain kinds of water-repelling fungus.  This Fungus produces a mycelium mat, similar to roots of a plant, that becomes so dense it repels water.  The technical term is 'Hydrophobic', but this effect prevents moisture penetrating down to the soil, starving the roots of water.

The opposite of a Mulch Volcano - The 3ft deep, compact Crater

Now that's just not right!
Many microorganism live in and around mulch.  Some are beneficial to our gardens like mycorrhizal fungi. Others slowly break down and mineralize the mulch material, releasing nutrients that benefit the surrounding plants. However, some microorganisms can become a nuisance and become detrimental in our gardens. Who hasn't suffered from Tar spots on your siding or covering your car, fired from artillery fungus. And, what about those phallic toadstools from stink horns, aptly named for the stench they give off too. Nothing beats the slime molds. Commonly referred to as Dog Vomit Fungus as it looks just like its named! Wood based mulch is an ideal media for fungus establishment and if measures aren't taken to remove these annoying organisms, then the chances are great that they will re-inoculate fresh mulch after its applied.

These problems are just a glimpse into a bigger a debate about wood mulches dirty little secret.  I have been scarred by Artillery fungus's Tar Spot bombs and lost many plants from tunneling voles.  Gone is the desire to spread yet another 10+ yards of shredded wood mulch each and every year.  I confess, I'm cheap, but is there a better alternative?  Well according to Ohio State University Associate Professor of Agricultural Research and Development, Dr Dan Herms, the answer is compost!

In a study comparing ground or shredded wood mulch and composted yard waste it was found that the low Carbon to Nitrogen ratio of compost produced better plant growth and increased productivity.  The finding are too long to cover in this post, but isn't compost what we used to do before it became popular to buy shredded mulch?  It was only since the 70's that sawmills began removing the bark from logs in an effort to extend a saw blades lifespan.  Within a few years of that, nurserymen and landscapers were buying up all the waste from mills as an easy way to dress up our gardens.  Are we now beginning to discover some of the negative effects from this product.

So true Mr 'Most interesting man in the the World'
While I'd agree mulch is more aesthetically pleasing to look at, like icing on the cake, I would welcome something that improves the well being of my garden.  Gone for me are the days of bagging up grass clippings and fallen leaves for the trash truck.  For the past year I have been spreading my garden waste directly onto the beds and allowing those microbes to go to town on it.  Although the conventional wisdom tells me to process this material first, I've seen no negative effects on my plants.

One unexpected benefit I've recently seen is that neighborhood cats have been able to easily hunt down the voles.  It seems that these supreme hunters can seek out and attack subterranean voles better in compost than compacted mulch.  This is enough reason for me to continue using compost to mulch with but I suspect I will need to find more material to feed my gardens needs.  I'll have to keep an eye open for more curb side garden waste to use and recycle.  Someones trash will become my treasure!


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