Take Redwoods Off the OK List — and Ask Costco to Stop Selling Them

Coast redwood is the tallest species on the planet. It is also, in most Bay Area suburban lots, a slow-motion mistake. Every consulting arborist in this county has walked a homeowner through the same conversation: the tree they planted twenty years ago from a five-gallon pot at Costco is now heaving the driveway, drying out the foundation soil, and dropping duff into a gutter that cannot be cleaned safely from a ladder.

Sequoia sempervirens evolved in a narrow fog belt with deep, moist alluvial soils, cool summer nights, and a hydrology built around lateral fog drip. Almost none of the residential lots on the Santa Clara Valley floor look anything like that. Planted here, redwoods survive — they do not thrive. They cone-stress, they shed prematurely, they compete aggressively for the small volume of irrigated soil available to them, and they grow tall enough to become a liability the homeowner cannot afford to prune correctly.

The policy fix is straightforward. Municipalities in the Bay Area should remove coast redwood from their approved species lists for street trees, front-yard plantings, and any parcel under roughly a quarter acre outside of the historic fog belt. The species belongs in parks, in riparian corridors, and in the western hills — not on a 5,000-square-foot lot in Sunnyvale next to a sewer lateral.

The retail side matters just as much. Costco, Home Depot, Lowe's, and OSH-successor nurseries move enormous volumes of five-gallon redwoods every spring, marketed as fast-growing privacy screens. A homeowner is not going to read the CalFlora range map at the checkout aisle. If the tree is on the pallet, it goes in the yard. The single most effective canopy-quality intervention available to Bay Area cities right now would be a coordinated request — county-wide, with the local chapter of the Western Chapter ISA behind it — asking major retailers to stop selling Sequoia sempervirens south of the fog line.

This is not anti-redwood. It is pro-redwood. Every redwood planted on a Sunnyvale lawn is a redwood that will be removed at forty years old, at a cost of $8,000 to $15,000, generating a stump the homeowner then pays to grind. The species deserves better than to be a landscape-industry loss leader that ends its life in a chipper.

The alternative species conversation is not hard. Valley oak, coast live oak, western sycamore, big-leaf maple, California buckeye, and — for smaller lots — western redbud and toyon do the job the homeowner was actually trying to do: shade, structure, screen, wildlife. They belong here. They were here before us. Get them onto the OK list and get the redwoods off it, and in one planting cycle the working canopy of this county gets meaningfully better.