April 5, 2009

To mulch, or not to mulch, that is the question when it comes to naturalizing.

Even in a field, Narcissus look best when planted naturally. No bark mulch here in this field, but rather, thick, deep grass. This meadow near us at the Tower Hill Botanic Garden is a fine example of a more natural planting, sometimes referred to and naturalizing, but these rarely self seed in the dense grass, although they may divide a bit to form clumps, to achieve real naturalization, narcissus seed needs to be collected and sown in pots. Although, in my rock garden, some varieties and species are seeding, which is nice to see. If you mulch with wood bark, forget about seedlings from anything, but if you use gravel, many bulbs will self seed easily, as long as you look carefully - since many of the small one or two year old plants look like grass for the first few years. So if you are looking for tidyness, forget about naturalized drifts.

Narcissus rupicula, perhaps my tiniest daffodil, is barely the size of a dime. Look at it compared to the Muscari nexst to it. Doll house sized daffodils like this are always hard to come by, this one came after some heavy bidding at an auction a few years ago. I just love it, too bad it spreads so slowly. In the rock garden, it too gets just an annual mulch with native gravel, which is basically what it is growing in, too. More like an alpine scree, rather than soil.

The miniature naricissus, 'Snipe' blooming in the rock garden, where a gravel mulch adds to the high alpine aesthetic one wants to achieve in high elevation themed gardens. This is a garden one would never use wood bark mulch on.

Like so many things in our modern lives today, convenience has become the driving force in much of what we consumer. Maybe because my 96 year old father lives with me, which means that since I just turned from 49 to 50 years old, I am a little unique in my generation, being raised by depression era parents. This has given me a different perspective on the use of everyday luxuries such as paper towels, disposable diapers, bottled water, the use of leaf-blowers and packaged dinners, since I was brought up in a world of home made (or bakery) bread, canning ones own vegetables en-mass (freezing ones own, was still considered rather modern, even in the 70’s), and in a home where glass and cast iron was preferred over plastic. None of these decisions we’re made because of the environment or in an effort to be green, it was just an everyday norm, to bring scraps out to the massive compost pile (even Newspapers and egg shells from our chickens were recycled), it was more about a mindset of not wasting, rather than one of convenience. Which brings us to mulch.

I was raised in a world where wood mulch was not only seen as the lazy mans way to avoid weeds, but that any garden that did result to using mulch simply was seen as unsightly, for mulch was never used by ‘real serious gardeners’, (except for using hay in the vegetable garden, which was OK). This fact was reinforced when I got my first job as a gardener at an private estate, where certainly, any mulch would have been seen as unacceptable, although rock gravel was used in certain beds beyond the rock garden for design purposes ( a Fletcher Steele thing), and fresh manure was used a more purposeful mulch, but only on the borders of Grus en Achen roses, which was another directive by the landscape architect himself.

Today, in our modern, fast, lives, few of us have the time to weed and hoe every bed and border to achieve that perfectly manicured edge and weedless soil, which was the goal of every gardener (and estate owner). I still associate wood and bark mulch as unsightly, opting for freshly cultivated weedless soil rather than the red or brown mulch, but only recently, I have had a change of heart (or knees), and find myself ordering ten or so yards, every year, if only to keep the weeds down.

There are many pros and cons in using any mulch, but with wood bark mulch, the controversy continues. But much of what you may read is not true, for urban legends continue about insects, disease and plagues of one sort or another, few, if any of these problems are true. Fundamentally, most wood mulches are good for plants (as are any mulches). They keep the soil cool, help retain moisture, and decompose like a compost pile does, thus improving one soil composition.

These two year old seedlings of the wild primrose, Primula acaulis from western Europe, blooms very early here in New England. I hated to mulch it with this Hemlock mulch, for surely I am suffocating numerous Corydalis seedlings, but by June, I might be happy once the Impatiens seedlings become suffocated too.

Here is the same planting of Primula acaulis from last year. Notice how nicer the bed looks with a natural mulch of native leaves rather than the bark mulch. Now I wish I never mulched this garden. But I never set aside leaves last year, or shredded any to mulch with this year. Shredded leaves partially composted would be best.

Some people feel that mulches look good. I like the smell of many of the wood mulches available in the North Eastern part of North America, where I live, mostly Canadian Hemlock (Tsuga canadensis) and White Pine (Pinus strobes), but I still find sadness in the fact that many people associate a nicely mulched bed as the epitome of a perfectly groomed garden. Make no mistake about it – the perfectly green and trimmed lawn and red dyed wood mulched beds and tree trunks are far from ‘perfect’. All this says about your garden is that not only are you lazy, you are an irresponsible and uninformed steward of the land. Which I am, sometimes, for I have finally started using wood mulch for some of our beds, and I am not proud of it.
Now, I feel like one of those executives who golf’s on Saturday mornings rather than a plantsman who gets his knees dirty carefully weeding and cultivating his garden. I do cultivate parts, but I use the excuses of money and time as the primary reasons why I need to result to mulch on other parts of the garden. Remember… Martha doesn’t use mulch in her garden beds at Bedford or Bar Harbor, nor does one see wood mulch at Kew, proper English gardens, and certainly, no real English border would ever use wood mulch. Gardeners do a much better job weeding and cultivating the soil (we couldn’t even leave a foot print or a hand print), but these ‘gardeners are rare are expensive today. I mean, only the very rich can afford a gardener, and only the wealthiest can afford one who is a real plantsman.

So we resort to Mulches. Sadly, we must either spread it our selves, or hire “landscapers’ to spread it (often poorly, and ineffectively, mounding it around tree trunks – don’t get me started about ‘landscapers, please. They are nothing more than ‘guys who cut the lawn. (and don’t get me started about the purpose of lawns!

Some Pulsatilla from seed, growing in the alpine garden. This is a white form, of this vernal high alpine seen in the alps and in the mountains of the west. Poorly sited, ( this is growing now under a dwarf mugo pine, and in a few years, I will lose it), I should try to move some of these plants, but I fear that their root systems have become too deep.
These are same folks who fertilize their lawns each spring, and wear golf shoes on Saturday, and who are obsessed in controlling nature to such a point where they treat their yards more like living rooms rather than as natural, gardens. A modern backlash is occurring in gardening products, which may seem like a trend, but believe me, if you think that the use of systemic insecticides is bad (perhaps the reason for the decline in the honey bee populations world wide) and the recent horrors expressed about the use of any salt based or water soluble fertilizers (such as Miracle Gro), which are being boycotted by many, the fact is gardening has a terrible history of environmental abuse, (just look at any vintage garden magazine, and you will see ads for Blue Whale Fertilizer and DDT), wood mulches too, are being seen as dangerous for the environment by some.

Still, the cons, I believe are less bothersome. The greatest may be the cost; I have to dish out about $500 a year for mulch, at $42 a yard, plus delivery charges. Then, of course, there is the labor, which I don’t pay for except in water soluble Epsom salts (is that bad for the environment, too?). The best reason I could find for not using mulch, is that an unmulched garden allows many plants and bulbs to reseed, which one rarely sees today in American gardens. If you are a serious gardener, consider not mulching parts of your garden to observe the benefits of allowing your plants to seed.

The very tiny Narcissus, 'Midget', only 4 inches tall, but a clear miniature of it's giant brethren, bloom in the raised rock wall where it too is allowed to seed naturally in the gravel mulch. The blue Chinodoxa has spread everywhere in drifts, where it's seed has dropped.

My ephemeral bed, which is a bed which is mostly planted with Hellebores and native woodland wildflowers like Bloodroot ( Sanguinaria), Primula species (like Primula veris, P. denticulata, P. aucaulis) small spring blooming bulbs, like Corydalis solida, Erythronium ( dogs tooth violets), and a bunch of wildflowers like Virginia Blue Bells, White Trillium (Trillium grandifloru, and T. erectum) and Phlox divaricata. This bed was not mulched for the past three years, and now, seedling are emerging that I have never seen happen before, when I was mulching. Next to my Hellebores, young seedlings are emerging, many of these requiring one or two years of stratification, but most exciting, is the number or Corydalis solida seedlings emerging, something which most gardeners rarely see if they mulch or weed too much.

Eranthis seedlings sprouting after a year or two of outdoor, natural undisturbed stratification. SInce a gravel mulch was used, the seedlings are able to emerge naturally.

In the rock garden, I use granite gravel as mulch, and many small bulbs are reseeding in amazing quantities. Along the greenhouse, in the raised rock wall, the small blue flowering bulbs of Chinondoxa are self seeding in drifts, in the undisturbed gravel, along with various tulip species and narcissis seedlings. The trick is to not resurface with new mulch each year, which is the reason why the woodland or ephemeral garden reseeds so nicely. In spring, the leaves are not removed from the maples and birches over head, which drop a natural mulch each autumn ( think – what happens in the woodland), this is natures natural mulch which breaks down naturally during the winter here, and by spring, is decomposed enough for spring bulbs and woodland plants to poke right through it.
The natural microrhyza can grow, allowing for a perfect balance necessary for many seedlings to sprout and grow.

So the best mulch? Perhaps it is leaves. The most informed and successful gardeners know the tricks, save ones leaves in the fall, shred or chop them in a shredder and either resurface each bed in the fall, or save them in a compost pile and use the compost as a mulch in the spring. OF course, it all makes perfect sense, for it is the most natural. Leaves fall in the autumn, in the woods, and decompose all winter, and by spring natures natural garden emerges without the need for shredded bark mulch. So take a hint from Mom Nature, and save your leaves next autumn, and look for those tiny seedlings of Eranthis and Crocus next spring.

A Mariposa Lily blooms in New England.
In the greenhouse, the western USA native bulb of the Mariposa Lily, Calochortus lutea, is blooming in a few pots of fast draining soil, in the cold greehouse bulb plunge bed. It opens when the sun hits it in the late morning, and by evening, it has closed.

Lastly, one of my favorite asian Primroses, especially for wet areas, Primula denticulata. Here, a blue variety begins to bloom. THis early emerging Primula will be twice as large next week. It is often referred to as the drumstick Primrose. This is the first blooming after starting from seed last year, and planted out in the summer. These plants are growing in the rich loam in front of the greenhouse, but I should have tried some in the vernal pools in the woodland garden, since the moisture in the spring, would make these plants gigantic compared to these. Still, they are quite nice, and at least we can enjoy them on the stone path that leads to the greenhouse.


  1. Interesting article. I've actually felt guilty for not mulching my flower beds, but I haven't had to replant snapdragons or Cleoma for years because they keep reseeding. I decided to splurge on some cocoa mulch (from the cocoa shells), partly because it smells like chocolate when the sun warms it up. Hopefully it won't completely stop my reseeding plants.

  2. Matt, I couldn't agree more about mulch...100% My father Jack would be 93 if he were still with us (9/11), and we grew up with the same set of frugal,logical values as your family.
    The volunteer seedlings are the best reward for a more natural mulch of gravel or shredded native leaves!

  3. I'm new to gardening, but very interested in the topic. Why do you have to shred the leaves? Is it primarily for looks, or because they don't really decompose in one season?

  4. Monique2:04 PM

    Here I was just searching the term microrhyza because of a watershed nutrient management plan I am working on and I became fascinated by your blog. I almost want to quit my planner job and come and hoe for you. Thanks for the little history on mulch. My world of reducing runoff is so focused on practices to retain water that this thought of no mulch never even crossed my mind. I love hoeing my soil rather than covering it up and now I feel I am doing the right thing. Lovely. I'll be back.


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