The Dry Garden: A sunflower or two. Or 200,000

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There’s overdoing it, and there’s what I did. After sowing a pound of sunflower seeds last winter, eight months later, the phrase “height of summer” can now be taken literally. In lieu of a front hedge, I have sunflowers. One astounded woman even came to my door asking when and how to plant them. Neighbors call my home “the sunflower house.” Out back, my yard is a vertical meadow.

I’d known that our native sunflowers easily reached 12 feet tall, but I’d never appreciated what happened when you planted roughly 200,000 seeds. The upshot out back from the fraction that germinated feels less like a garden and more like a field. From a distance, a sea of yellow ripples in summer breezes. Following a long path into the back garden, the person strolling becomes engulfed. There have been games of hide and seek. Then there’s the scent, less floral than edible. When the sun hits the sunflowers, the garden smells like a pan of freshly baked cookies.

This tease should come with a caveat – the sunflowers in question are not the massive-headed domesticated sort that can be crushed for oil or provide seeds for trail mix. They are wild, the type that sunflower growers and most seed companies call “weeds.” The first thing that strikes you on crushing a dried flower head is how small the seeds are compared with their commercial and culinary cousins –- smaller than a grain of rice. Only after ordering wholesale from S&S Seeds in Carpinteria, a company that specializes in wild land restoration, did I check what I was doing by sowing a pound. Their formula is ¼ pound per thousand square feet. It was dumb luck that I wanted to cover about 4,000 square feet, though it took some culling to free up the vegetable plots.

The reasons for planting so many were five-fold: First, second and third, I love them. A mere glimpse out the window at their waving heads can pierce the darkest of moods. Unlike many commercial single-headed sunflowers with names that connote their enormity (Mammoth, Titan, Giant), the heads of wild sunflowers are small and each plant produces many blooms on a steady progression of arterial branches. One plant is quite capable of turning into a towering bush. The flowers just keep coming. So do the finches, which now commute from flower to water fountain as if my backyard were an endless loop produced by Disney.

The fourth reason for what one visiting garden designer, after gasping, called “exuberant” use of the seeds was water. Wild sunflowers need little or no irrigation. While many similarly broad-leafed plants have such high evapostranspiration rates that they will wilt on any hot 24-hour cycle, wild sunflowers have a built-in cooling system in the form of markedly tough and hairy leaves. The botanists behind the Helianthus annuus treatment in the Jepson Manual treatment go one word better, describing these leaves as “rough-hairy.” If you do water native sunflowers in summer, the presiding authorities O’Brien, Fross and Bornstein are absolutely right when they caution in “California Plants for the Native Garden” that overhead water can encourage rust on the foliage. Use drip or simply aim low with the hose.

My fifth intention for strewing so many seeds last year was shade. I was seeding around newly planted fruit trees, native lilacs, sages and fuchsias on land that had recently been, for lack of a better word, lawn. After razor-cutting the mix of weeds and grasses, then smothering it with mulch, I had a lot of open ground between the saplings and seedlings that will in years come to dominate the garden. Though I knew I would have to irrigate the nursery starts, I was worried about how they would fare on an exposed south-facing slope. I sowed sunflowers on the gamble that these crazy tall annuals would afford the nursery starts some shade while also bringing in pollinators.

With constant culling to free up the trees and shrubs, that strategy has worked. As the sunflowers grew, there were also two welcome and wholly unexpected fillips. The emerging army of wildflowers protected the young plants from the crashing play of carousing dogs. Even more usefully, and more remarkably, the sunflowers seemed to be suppressing the grasses and mallows and various weeds of the former lawn.

At a guess, the massive root systems needed to hold up such towering plants and draw water from a receding groundwater table were simply out-competing the lawn plants. But there may be another reason. It’s been in the ether among gardeners for ages that sunflowers may have alleopathic virtues –- that is to say, they may emit chemicals that suppress growth of plants near them. Agronomists are even exploring their potential to stand in for herbicides. So they may actually be serving as a natural alternative to weed killers, a tool that I personally balk at using when murdering lawn. Whatever the reason, the vertical meadow as transition from lawn to native, fruit and vegetable garden is proving more successful than I’d ever dared hope.

I should add that the sunflowers did not have to contend with the ultimate noxious lawn plant, Bermuda grass. For those of you wondering if I haven’t switched out one problem for another, you may have a point. However, I’m not worried about feral sunflowers next year. They’re easy to weed when young, though I doubt I will be culling too heavily.

Sunflowers are famed for youthful heliotropism before thickening stems leave the flower heads fixed facing due east. This year I found that wild ones will face any direction that is not already filled up by another flower. If they germinate in the shade, the stem will crawl right along the ground until it hits sunlight from any direction, then it will begin growing upward.

I have gone deep and long in this section in the past on the history of our wild sunflowers, about how a sunflower is not one flower, but many little disk florets crowded on a head called a “composite” and about how the seeds are not technically seeds but little fruits called “achenes,” so there is little point in reprising that. The only thing that returned me to the subject here was this recent, blowout experiment and to add some planting tips. For those interested in a raucous meadow next year, the best time to pick some ripe seed heads is now through October. The ideal time to sow them is between Halloween and New Year.

If you collect your own seeds, and only want to cover a couple hundred square feet or less, a pocketful of flower heads, each of which will be stuffed with dozens of tiny achenes, should do it. Allow for attrition by birds. Pick them when brown, after the yellow “petals” (actually ray florets), have dropped. The folks at S&S Seeds estimate that the achenes can last up to three years if kept in a cool, dry, dark place. When you’re ready to plant, crumble them up over the soil, rake them in and mulch. With luck, rain will do the rest. If you water in the fall, which ideally shouldn’t be necessary, keep watering so seedlings can send down the all important tap roots. As they germinate and fill out, thin them.

Or not.

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-- Emily Green

Photos, including of her neighbor Jasmine, by Emily Green.