Weed World

When we first moved to the property, after an intense 16 months of securing the lot, designing the house and having it built, mustard (Brassica species) was threatening to smother the cut and fill areas where we had hydroseeded as well as dominating the 'weed patch' meadows that line the driveway down to Koenigstein. After destroying a couple of shovels with shallow thrusts at the mustard's tap roots - and hitting rock - Lorenz Schaller advised using a Pulaski.The switch to a fire-fighter's mattock increased the mustard mortality and had the added advantage of its being a tool that appealed to my then seventeen year old son. Together we got the weed under control, and this season there has been very little sign of it - so far. This has enabled me to transfer my weeding energies to erodium.

Walking up the drive recently, I saw some yellowish mustard-like plants growing in some profusion amongst the annual grasses in the disturbed areas to the east of the driveway. Checking with Uncle Miltie, (Wildflowers of the Santa Monica Mountains, Milt McCauly, Canyon Publishing, Canoga Park 1996) I was delighted to learn that they were common fiddle necks (Amsinckia menziesii) which is a native and common to burned or disturbed areas. The flower springs from a spiral raceme and its hairiness gives it the appearance of a coiled caterpillar - with small golden yellow flowers sticking out from its back. Like the larger and later flowering perezia (Acourtia microcephala) it is basically a fire follower but, at a pinch, will become a devotee of back hoe disturbances and has thus found much to like on our land.

Mustards, thistles and filaree (Erodium species) are the current focus of my weeding efforts. The last was likely deliberately introduced into Baja California as sheep forage and was perhaps the first of the exotics to become established in Alta California. These three genera, along with the exotic grasses like wild oats (Avena fatua), ripgut (Bromus diandrus) and foxtail chess (Bromus madritensis) were able to move into the chaparral in the 18th century because the land had been prepared to receive these colonizers by the native american practice of burning the brush. This activity had developed after deer became a primary focus of their hunting with the extinction of the megafauna, such as the mammoth, which occurred somewhere around 11,000 years ago.

Pure stands of chaparral did not support a large population of artiodactyls (deer, goats, antelope and bighorn sheep) until burning opened them up to areas of herbaceous browse. This native practice was clearly built on observation of naturally occurring fires and the complex mosaic of habitats that now exists is the result of this burn history together with more recent anthropogenic fires. This at least, is how Richard Halsey tells it in his pyrocentric natural history, Fire, Chaparral and Survival in Southern California, Sunbelt Publications, San Diego 2008. As dedicated followers of this blog will know (anyone?, anyone?...), others have mused that it was the introduction of Iberian cattle by the Spanish that broke up the ancient soil crust and thus allowed the exotics access. Rick concedes that widespread cattle ranching in the mid nineteenth century exacerbated the situation and he points out that the droughts of the 1860's created a perfect storm for the native flora: overgrazing, the presence of exotic weeds and highly disturbed soil crusts put much of the native habitat into a death spiral.

I am hampered in my efforts at focused weeding by my lack of knowledge. Now, is this a native clover included in the very expensive seed mix or some brutish Trifolium interloper? My rule of thumb is that anything I recognize from my childhood is a non-native. Walks with my parents constitute my early informal education in natural history. I knew, at the age of nine or ten, the common name for most of the west Surrey wild flowers and weeds. Later, an un-tutured appreciation for Australian bush was developed in a few courses at Sydney University to the point where I recognized the invasives such as gorse, lantana, blackberry and bracken amidst the gums (as the Australians call eucalypts), banksias, melaleucas, callistemons and acacias. And now there is my current bout of autodidacticism brought on by owning too many acres of chaparral in Upper Ojai and landing next door to a biologist who specializes in native habitat restoration. Backgrounds in the flora of Europe and Australia, however sketchy, turn out to be useful in California.

The water greedy eucalypt is a particularly vilified non-native and yet barely 100 years ago pioneers such as Abbot Kinney were lauded for their efforts at introducing examples of the vast eucalypt genus to southern California. Whatever home-sickness I suffered when I arrived on these shores in 1980 was usually assuaged by visiting the Huntington Gardens where I could again gaze on a ghost gum. Later, when we moved to Santa Monica Canyon, walks in the Rustic Canyon Park eucalypt grove established by Kinney were again salve to that little piece of antipodean soul that pined for the Australian bush. Gum leaf stencils continued as a motif of interest for me for a few years, and Hank Koning, the Australian born Los Angeles architect for whom I worked in the mid-80's, picked up on the idea and impressed gum leaves into the concrete fireplace hearth of his Santa Monica home.

Chaparral is more enigmatic then Sydney's bush which, while predominantly a shrubland, has glorious discontinuous stands of gum trees providing an open, lacy canopy. But they share the visual confusion they present to the casual observer and both require study to elicit their full charm. Both ecosystems are under threat from (mostly european) weeds and invasive species.

As I look out across the valley from our perch below the Topa Topas, I see meadows in the spaces ripped out of the oak canopy that otherwise covers the north facing damp slope. Here and there is a house or ag building; some horse properties with barns and fencing; at meadows edge some ragged gums (Eucalypt species); lining driveways, rows of cypress (Cupressus sempervirens).

Here, surrounded by chaparral, the emblematic plant community of California, the clearings in the echoing hills of Southern Oak Woodland across the valley - studded with exotic trees, the meadows comprised of exotic grasses -  confirm my attempt to restore our property to something approaching its native state.

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