Home & Garden Columns

Garden Variety: Gardener, Spare That Tree! Especially Its Roots

By Ron Sullivan
Friday July 20, 2007

I ran into an old friend from hospital nursing days and we got together to go on about old times and friends—it’s amazing how many of them are still working where we’d met; they’re definitely made of tougher stuff than I am—and, surprise, about gardens. She’s got a rental house with a yard and a co-operative landlady and a pleasant garden already, and was looking for ways to make the place bloom more. 

She also has a neighbor with a rototiller, and he’s worked over some of the back yard already. The landlady had some sod installed, just a little playspace for the fox terrier and the cat, both of whom are engagingly rompity. The cat has been known to ride the dog, just for example, and I think that’s worth a patch of sod. Giddyup, pup. 

There’s a shady patch in front, a northern exposure further shaded by a Chinese elm by the sidewalk. Mister Rototiller has offered to give that little spot, now home to a comb-over of grass, a thorough treatment too, and the landlady wanted to get rid of the tree because “the roots got into her sewer pipes a few years ago.” 

So what am I telling my friend? 

First, vis-à-vis the direst prospect: Please don’t let anyone mess with that tree. It’s one of a row of Chinese elms gracing the whole block. Its shade is light and open—most of the shade on that patch is from the house—and to judge by that block, El Cerrito has a tree crew who do good work at lacing out street trees.  

There’s no reason to believe that that individual’s roots were the ones in the sewer pipe, or that if it were gone that the rest of the street trees’ roots wouldn’t take over. The old rule of thumb is that a tree’s roots extend in a rough circle whose radius is one and a half times the height of the tree, and there are at least four other trees that close to the lot. 

Now, that rototiller. I’m suggesting that she give the neighbor a beer and tell him “No, Thanks this time,” because the tree’s support roots are just under that patch. Instead, put down some organic mulch and plant, oh, native coralbells (Heuchera spp.) or their colorful cultivars, or some nice small bunchgrass and forest flowers.  

The virtues of sweat with regard to garden soil are overrated, in my experience. If you have to get the rutabaga crop in quick because you’ll be living on it all winter, OK. But with a little time, you can lay down some nice organic material and let your earthworms do the work and the neighboring plants, trees, even the soil will be the better for it. Worms are skilled workers.  

American Soil has old reliable Walt Whitman compost for this, but my current crush is their pomace mulch. Pomace is the dry stuff left of grapes after winemaking. As mulch it’s elegant, finely granular, very dark (almost black) and I swear has boosted the red colors in my shady foliage garden.  

Smells better than Walt too.  


Ron Sullivan is a former professional gardener and arborist. Her “Garden Variety” column appears every Friday in the Daily Planet’s East Bay Home & Real Estate section. Her column on East Bay trees appears every other Tuesday in the Daily Planet.