Tag Archives: Ecology


I know I know. Big-girl gardeners don’t say “ew.” But no matter how hard I try to appreciate and understand it in spite of its appearance, the earwig simply elicits an “ew” response from me.

Earwig. Photo courtesy Andrew Dennes.

Up until recently I considered these to be a mostly benign insect, not particularly liking them but not feeling any particular malevolence for them. I can recognize also that they’re part of the delicate food web, playing roles as decomposers, detritovores, fungivores, etc. Earwigs are also a food source for birds, insectivorous mammals, amphibians, spiders, yellow-jacket wasps and even bats (http://en.wikipedia.org/wiki/Earwig). That I find the insect particularly unattractive should not lead to its demise.

Until I planted some mustard greens and noticed holes accumulating in the leaves daily. Initially, I wasn’t able to determine the culprit- no caterpillars or other little bugs and the holes just didn’t jive with my experience with slugs and snails which tend to munch much more wholeheartedly from the outside in. A bit of research and a little garden digging et voila – earwigs! In retrospect, I’ve deduced that this past year of attempting to plant seeds and see them sprout and then perish may be at least in part due to the work of earwigs (and their nymphs) in the garden. Earwigs also have been known to feed on clover, lettuce, cauliflower, strawberry, seedling beans and beets, grass shoots and roots, as wells as a variety of tree fruits. Scavengers indeed!

The reason for their inconspicuousness is that they hide during the day, feeding on plants only in the wee hours of the evening. As with all things, earwigs are not all bad. I found through my research that they prey on aphids and other insect eggs and can provide a fair amount of biological control. So it seems the ideal approach is to seek a middle ground- to find a way to reduce populations enough so that tender little plants can grow enough to be able to not be completely demolished by the little bugs but not make excessive attempts to rid the garden of earwigs entirely (an impossible feat anyway, especially for a chemical-free garden).

The solution I found (through UC Davis IPM website) is to sink a can or low-sided container into the ground filled with vegetable oil. They also suggest adding a drop of fish oil, but I don’t have any and yes indeed, it seems to be working pretty well without!  Though now our concern is that the little vats of oil filled with juicy bugs may be a veritable buffet for other little critters that may visit our garden. We’ve often joked about setting up an infra-red camera to witness the nocturnal life of our garden – or perhaps it is best just not to know.

Recovering mustard greens by can of vegetable oil.

In the above image, notice the old, damaged mustard greens among the healthier new growth. Perhaps soon we’ll be able to harvest the lovely greens…and I suppose figure out a way to prepare them – Any suggestions?




the Zen of disorder.


Pile of rubbish you might say? Well yes, that is indeed one way of looking at it. And in my tiny urban backyard, allowing piles of such rubbish to exist seems a foolish waste of space- why leave such an unsightly pile when I could remove it and plant something lovely? It is my inclination to dispose of this pile (especially with San Francisco’s municipal composting, since it isn’t going into a landfill, why not just put it in the green bin?).

But recent readings remind me of the benefits such piles of rubbish, and other dead and decaying matter, can offer to my little garden, and I’m now thinking perhaps I should provide a space for the unsightly as well as for the overtly aesthetically pleasing.

One of the books I’ve mentioned previously, the Xerces Society’s Guide to “Attracting Native Pollinators,” discusses the importance of resources such as this brush pile for a variety of pollinating insect species. Perhaps beetles or mason bees will find these abandoned branches an alluring place to lay eggs. Other critters may find this brush pile appealing as well, such as spiders or any number of decomposing insects, which while slowly decomposing this organic matter will contribute to the soil and improve conditions for plants (well, perhaps, but more thoughts on this another time). The insects and spiders will provide many species of birds, even the seed-eaters, with much-needed protein.

Gene Lodgson (the “Contrary Farmer” found at http://thecontraryfarmer.wordpress.com/), wrote a book many years ago called, “Wildlife in the Garden,” and I have found it to be a refreshing and informative re-imagining of backyard gardens and landscapes.  He makes clear that the health and vitality of even the smallest garden is driven not by fertilizers, pesticides, weeding, and the kind of control (which to many a gardener, myself included, often feels like care) but by the connection to the cycle of life that can be cultivated by letting nature be. The Xerces Guide refers to this as “benign neglect.”

Other such examples from my garden are the stumps of trees and shrubs:

lilac stump

various seed heads on flowers and shrubs:

yarrow seed head

I also discovered recently that many species of hummingbirds use lichens to make their nests. I had previously viewed the lichens covering our old azaleas as a sign of their decline, thinking that perhaps if i removed the most affected branches that I could perhaps improve their health and vitality. But understanding this connection with hummingbirds helped me to become settled with (Zen-like, you might say) about such a decline, and see it as the continuation of the cycle of life. Perhaps the azaleas are dying, and these things happen. But in their process of dying, they will help support the life and growth of other parts of my garden.

lichens on old azalea

Perhaps of the most important tools in our gardening repertoire is the power of observation. Slowly looking and seeing, often before taking action I think can often alert us to some of these amazing connections happening right in our own back yard. Nature is indeed everywhere!


Hardly Strictly Native.

Though I do feel I should be. Strictly native that is. It is so very difficult though not to find myself swooning over a flower, a leaf, or even the twining tendril of some foreign plant to the point where I feel I must have this plant in my garden. My most recent enchanter was Helleborus ‘Penny’s Pink’ (aka Lenten Rose) which I came across at the San Francisco Botanic Garden plant stand.  

Helleborus 'Penny's Pink' flower on flickr

My guilt makes me curious- need I feel so guilty? To be sure, a yardful of natives would certainly provide more “natural” habitat and resources for local fauna. Though one must always use the word natural with consideration, as really, what is natural about my urban backyard in the first place? And what fauna will be provisioned by my backyard habitat? At the very least, I would hope that it could provide some sort of resource for some visitor or resident- be it pollen, nectar, or maybe at the very least a bit of shelter (it could end up just being an additional resource to the slugs in the garden- argh!)

So, a closer examination of my Lenten Rose. Largely of European origin Wikipedia tells me (http://en.wikipedia.org/wiki/Hellebore). The colorful parts of the flower are actually not petals, as is typical but modified sepals, while the petals have evolved to form nectaries (also referred to as honey leaves). 

Diagram of floral parts of Helleborus 'Penny's Pink'

My first question is, what pollinates it? A quick search of the web lead me to this site: http://www.helleborus.de/engl/botany.htm, which tells me that Helleborus species aren’t fussy about who pollinates them. Which makes sense considering that as early as these plants flower (early spring- March here in San Francisco, other parts of the U.S. later, the Missouri Botanic Garden states April) that fussiness would be a problem for pollination and seed set as there just aren’t that many pollinators around. Though an online journal article (http://aob.oxfordjournals.org/content/96/5/845.full.pdf) indicates that the genus is primarily pollinated by bees.

So maybe eventually one of our Yellow-Faced bumble bees will eventually find this plant and find the pollen and nectar a lovely additional resource at this early season when there isn’t a whole lot else blooming in the garden. And I’ve yet to hear of Helleborus being invasive, so seed set and distribution I shouldn’t think will be a problem. And perhaps a spider will set up shop under its leaves, and our friendly California Towhee who loves to scratch around looking for bugs will find it a good place to find lurking spiders and yummy insects.

Oh good! Perhaps a not-so-bad addition to our garden! And I get to swoon (with little guilt) over the flowers every spring too…and hopefully someday will witness a pollinator enjoying a drink of nectar from the honey leaves.