Friday, May 16, 2014

Every Year Is Different: The "Succession Theory of Plant Migrations"


This is why I love the month of May. It gets warm suddenly. It's eighty one day this week, just simply mellow, and I can squat in the weeds in my shirt sleeves luxuriating in the tiniest growing things imaginable. Then it goes to fifty the next day with a damp breeze off the ocean and I don't even want to set foot out of doors (except to stock up on ice cream for when the warm returns). And then the warm does return the day after that,


 
but it's sort of cloudy and muggy all day and -- feels like a humid summer day in July (evidence: Anne complains) -- but for me it's a day when I can stoop over expanding and contracting waves of groundcover species and contemplate my newly developed "Succession Theory of Plant Migrations"...
            It's an illusion to think that plants don't move. They move, when viewed as colonies, or tribes, rather than individuals -- I also think of them as "nations" -- just much more slowly than animals.
            And sometimes they follow each other across the landscape according to laws of their own nature and the conditions they encounter. That red and violet foliage of a very low to the ground, delicate groundcover plant called purple Acaena? I'm missing it this year; it's moved away. It's a New Zealand native and year by year has fled from the lands I awarded to it and policed with some vigilance, removing invaders every spring.This plant nation expanded greatly the year after I planted it, but in subsequent years retreated. It's as if it gave the place its best shot, saw that it wouldn't do, and began an irreversible retreat for greener pastures.
            I'm guessing it's heading back to New Zealand.
            For a couple of years I watched the Acaena battle off a challenge from a neighboring colony of thyme groundcover, called "woolly thyme" (Thymus praecox). (See second photo; with violets.) I had assigned them to neighboring pieces of earth, though with no hard barriers between them, so naturally they infiltrated one another. As I said, plants don't want to stay in one place --their apparent immobility is an illusion we get from fixing our glance on very tall and heavy trees. Oaks don't appear to move; but forests creep.
            For a while the two nations blended into one another, and then both seemed to retreat. The woolly thyme is still around, but has moved to the edges of things. It likes to shelter just off the red bricks in various curvilinear paths, sometimes filling tiny gaps between them. The ground the two nations surrendered has big spare spots this year (see top photo). Is some new invader on the horizon? Maybe the plants know something I don't.
            Meanwhile in other sections of the back garden, I've noticed that when plant colonies flourish and overgrow their space, overextend themselves, perhaps, that weeds (i.e., in their classic definition of "plants that are in the wrong place") force themselves up between individual roots and sprouts, one plant species appearing at times to emerge right from the center, or flesh, of another.
            These invaders are often common native violets or a range of familiar wild plants (weeds, again) I discover flourishing as opportunists wherever bare ground is available.
            In some cases it appears to me that one plant nation has expanded to the limit of its strength and the instant that strength begins to fade, another one appears to push it along. Some rule of natural succession is taking place, at its own pace and in its own way. Again this law is most clearly in operation among the low groundcovers.
            In another patch of earth a flat plain of densely grown thyme, a different variety -- "thymus albiflora," I believe -- after achieving a dense mat-like surface, curiously uniform and mono-cropped (a state I am now beginning to think of as "unnatural") has been increasingly vulnerable to incursions from other plants right in its very center. For a few years I've been pulling out, obsessively, all the tiny violet leaves that indicated the weakening of the thyme's roots and the determination of the violets.
            Last year I loosened my grip. A large-leaved echinacea had forced its way into the vulnerable spot, the very spot where violets have been forcing their way. I like echinacea (or cone flowers), they make large colorful blossoms, so I thought I'll leave it there and let the thyme grow around it. This year the retreat of the thyme from this spot is ten times more visible.
            Not only is the echinacea back, but a handful of hardy colonists of the sweet woodruff nation are solidly entrenched around it. A groundcover itself, the woodruff is much taller and thicker-leaved than the thyme. This looks to be a case of a bigger plant pushing a smaller one around.
            Other plants are pushing their way into this spot as well. Probably I stick my hand in and try to establish a new order.
            But while the woodruff is making gains in this place, it has been almost wholly driven off from an original homeland it occupied just a few years ago, which I term "the country of the cat" because we have installed (planted?) a brown cat sculpture we inherited from Anne's parents, in whose more woodsy terrain it could not find a home. A plant I never intended to grow there, the bugleweed ajuga (see fifth photo, simply forced its way in and took over.
            The ajuga smiles at me with a perfect purple gleam this week, showing an array of beautifully spiky teeth. (Close-up view in last photo.)
            In other areas, campaigns of succession are being waged where I planted an array of groundcovers without any solid divisions between them: no stone or wood barriers or impasable stretches of pavement. I like to see them brush up against each other and rub shoulders. I like to see their shapes and colors reflect upon one another. It "looks more natural" to me (see sixth photo). But, in truth, the nations of plants have no more respect for my esthetic than they ought to have.
            In one particularly busy landscape, nations of mazus (a very low, thinly rooted, fast-moving groundcover; see fourth photo) has completely overrun a neighboring dianthus, while a low sedum tries to hold off a thick-leaved greeny vine whose name I don't know, and a patch of stolid clover-like groundcover by the pretentious name of double trefoil birdsfoot are all mushed together. While of course the ubiquitous "common violet" sticks its nose in everywhere. (Third photo.)
            I'll continue to play the dishonest broker, favoring particular species (or "nations") in one spot or another. But in the end ancient laws of rise and fall, expansion and contraction, succession and migration will decide what grows where.
            I just fiddle around the edges.