Gardening the the Land of Earthquakes

Castles built on shifting sand, sink into the sea, eventually.
- Jimi Hendrix

In California, we rarely have basements, preferring to build on land scraped flat and paved with a four inch slab, or built up on stilts if the ground is too hard or steep to grade. Sometimes, instead of explaining that builders are too lazy to excavate basements, we say it's a practice to live with stability in the land of earthquakes. We used to have a big magnolia tree planted so close to the house it cracked the slab. When we had the tree removed, we planned to pave the area with flagstones. Our task was complicated somewhat because we couldn’t level the ground after the tree was gone. The roots had managed to work their way down into the decomposing granite ground. The roots you see here aren’t round. They are 6-8 inches wide, but they stretch beneath the ground for more than 10 inches - which was as deep as I excavated before giving up.

The flagstone path is thus lovely in pictures, but treacherous to walk on because the grade dips over 4 inches from pond to cement patio. An earlier owner built the crooked uneven narrow concrete path at left in first picture. It too, spoils the grade and is almost as hard as the tree roots to remove. Someday before I’m confined to a wheelchair, I’ve got to do something about that. But I have another problem that’s more immediate.

When we built the arbor, we couldn’t seat it on concrete piers buried in the ground because we didn’t want to resort to dynamite (I’m not kidding) to level the ground. When our pond was built, the builder broke TWO rented jackhammers trying to make it below ground level, and thus he had to build up with cinderblocks to get the minimum depth of 2 feet. That’s why we have to have the pond in the background of the first picture covered with a net – the fish can’t dive deep enough to escape the giant herons that see their pond as a buffet.

We have to live with the shallow pond, but now the arbor is leaning because the left-hand leg sits just about on the original trunk - you can see the roots radiating out from where the crooked post now stands. The guys who removed the tree chopped the trunk into sawdust down almost a foot, but the sawdust/remaining root has subsided while the other legs of the arbor seem to be content pretty much where we originally placed them. In the process, the drip irrigation which fed all the plants on/beneath the arbor has stopped working – most probably because of the subsidence of the rock planter which pinched the tiny line. I now have to hand water daily to keep these guys alive. Which leaves me with two choices:

I could prop the arbor up, perhaps on an extended ladder, excavate beneath the crooked leg, find something solid to replace beneath it, and replace it in a more vertical position. That means removing all the plants, and disassembling the planter at the base. That might enable me to fix the drip line while I’m at it.

Or, I could call this my earthquake arbor, tell people the ground is shifting beneath us every day, and the lopsided arbor stands as a metaphor for the impermanence of man amid the giant boulders representing the relative immortality of Nature. My orchids and other delicate plants in this spot would have to be moved, or hand-watered daily, or die, or they might be able to evolve drought tolerance in one season. My limited horticultural knowledge tells me the last option is unlikely, but you never know.