100 WORDS FOR DROUGHT TOLERANT

by Hilary Gordon / Photos by Blair Randall

As a schoolgirl I learned that Eskimos have 100 different words for snow. That made sense, since snow could be what you build your house out of, or what blinds you in a life- threatening storm, or what the seal you are hunting is surfacing through, or 97 other meanings, each different, each very important.

As a college student in the (then) Ornamental Horticulture Department at SF City College, I only learned one word for drought-tolerant plants in 1984. In plant ID class we had to memorize the names, common and botanical, and the characteristics of plants. Each plant was either drought-tolerant or not drought-tolerant.

Twenty-five years later as water policies and practices have come under more and more pressure from increased demand and shrinking resources, we need one hundred words for drought-tolerance. Part of the task of the Garden for the Environment is to refine what this word can mean, and experiment with real world plants, soil, weather and exposure, to find out which plants can thrive with little or no reliance on summer irrigation. (PHOTO: Zauschneria at GFE, 2009)

Our first task was to create ‘hydrozones’ in the garden. This meant that instead of watering the entire garden every time we watered, some garden areas, where vegetables, fruit trees, roses, and other tender plants lived would be watered twice a week, while the drought-tolerant demonstration areas would be watered twice a month in dry weather. Some garden areas, where native plants were well established, actually needed no summer water.

The next step was to observe the success of plants in the drought tolerant areas of the garden. It turned out that many of the plants from the original plantings in the 1990’s were not actually capable of performing with really limited irrigation. One important plant in the original drought tolerant areas of the garden is Miscanthus sinensis. This is a large, arching, variegated grass which flowers beautifully at the end of summer with silky, bronze blooms shooting up over the clump of leaves. These blooming grasses were a big part of our loveliest cut flower bouquets the first Fall I worked in the garden. But it turns out that these grasses are not actually able to bloom without regular watering. They grow, but don’t bloom on the twice a month regimen. They may be more drought-tolerant than water-hogs like roses or Japanese maples, but they don’t actually belong in the drought-tolerant garden display. (PHOTO: Miscanthus at the GFE, 2009)

According to the Sunset Western Garden book they need “moderate to regular water.” They do make it into the East Bay MUD book Plants and Landscapes for Summer-dry Climates, which lists only plants appropriate for our Mediterranean climate. This authority says that they need “moderate” water. According to the Dry Gardening Handbook, by Olivier Filippi, “if they are to give generously of their foliage and flowers, they really do need water”, all except one cultivar, Miscanthus sinensis ‘Yaku-jima’.

So which is it? Are they appropriate for a summer-dry climate? Do they need moderate water? Or regular water? What about if they are planted in poor, sandy, soil? They would probably need more. How about right near the ocean? They would probably need less. If planted in a hot location, like the east side of Bernal Heights, would they bloom with only occasional water if given part shade during the middle of the day? (PHOTO: Yarrow at the GFE, 2009)

To completely muddy the waters, Plants and Landscapes for Summer-dry Climates gives the following six warnings to go with their water recommendations for plants in our dry climate. First, plants that prefer seacoast conditions must be planted near the coast. Drought-tolerance on 33rd Avenue in San Francisco or in Walnut Creek would be a completely different story. Second, that the previous winter and spring have provided “normal” amounts of rain. Third that plants are already well established. During their first and sometimes second years in the ground, even very drought-tolerant plants require extra irrigation. Fourth, when irrigation is used, plants are watered deeply. Superficial watering will cause even a drought-tolerant plant to develop a superficial root system which will never stand up to prolonged dry soils. Fifth, soil is well-mulched, and finally that drainage is adequate.

So is my newly-purchased plant drought-tolerant or not? The answer comes in many shades of grey. I can’t yet offer 100 words for drought-tolerant, but here is a beginning. (PHOTO: Sisyrinchium)

Summer-Dry Climate: Our normal climate in the Bay Area generally provides no rainfall from June until November. There are many regions of the world with similar climates, known as “Mediterranean” climates. Plants from these regions often do well in the Bay Area.

Drought: A year, or series of years, in which winter rainfall is below normal, resulting in dry soils, small snow packs, and low reservoirs. Little or no water is available for garden irrigation.

Drought-tolerant once established: A phrase traditionally used by gardeners to describe plants that can thrive in dry soils for some period of time. How long? Ask the gardener. Better yet, ask the plant.

Not drought-tolerant: A plant that needs continuously moist soil for good results.

Best with occasional watering: An irrigation regimen that calls for several deep irrigations during our dry summers, such as 3-4 times a year. These plants might become dormant and stop blooming if they do not receive any summer water.

Moderate watering: An irrigation regimen that calls for regular but infrequent deep irrigation during our dry summers, for example, every other week, or 10-12 times a year. These plants might actually wilt and die if they do not receive any summer water.

California native plants: Careful! Some California natives are streamside plants, like willows or big-leaf maples, that actually expect lots of summer water.

Xeriscape or Raingarden plants: Plants that require or prefer no summer water once established. Many, but not all, sun-loving California natives fit this profile.

In the San Francisco Bay Region we don’t really need more than one word for snow. But we could use much more specific language about drought-tolerance. Sometimes a slight shift in language can reflect a sea-change in awareness.

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present. Have a question for Hilary? Meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

November 2009

GO OUTSIDE AND PLAY!

by Hilary Gordon Photos by Blair Randall

My mother, who grew up in a small New England village, raised her kids with country culture, although we were in a quickly infilling suburb. When she had things to do, we were hustled out the back screen door to find our own way around the gardens, climb the trees, make forts under the shrubs, and pretend to be cowboys, superheroes, or pirates.

What makes a grown-up go outside and play? When my garden space is connected to my grown-up desires and values, it draws me outside. The garden may draw me outside because (yum) I want furry, pungent sage leaves to sauté in olive oil and drop into my white bean soup. It might draw me out to watch the drama of a hummingbird nectaring in the pineapple sage, dive-bombing and quarreling with any other hummer who might try to get a sip. Or I might want to watch my veggies, visibly bigger than yesterday, stretching out in the fertile, moist soil. (Photo: Flowering Maple, Abelia at GFE)

Food and flavor, wildlife, the sun and stars, all draw me outside. But what makes me wake up breathless with excitement is the eye-crossing beauty of the garden. It is more lovely to me than any artwork, because it is alive, fragile, and swiftly passing. The generous beauties of the garden may knock me out with a texture or color combination. But the next day, when I bring a friend to look, its perfection may be gone. The urgency, delight, and sorrow of time passing is more vivid to me in a garden than anywhere else.

This month in the Garden for the Environment we have seen many beauties come and go. In a mature garden where artists have been at work, the contrast and complement of one vista may peak, and make lovely sense, and then fade as something else wonderful happens. Here are a few visual moments that have arrived this month at the garden.

In the Southwest Gate of the garden, a shallow flight of wooden steps rises from the sidewalk between two enormous old Phormiums. Over a year ago, these elderly plants got a substantial division. We removed about half each clump, and then mulched them heavily. This summer they responded by producing their enormous, otherworldly flowers, which tower over passing pedestrians. The dramatic stems and bracts of these flowers are still standing, although the flowers have faded. (Bracts are modified leaves growing just below a flower. Sometimes they are more dramatic than the flowers themselves, i.e., Bougainvillea “flowers” are actually bracts.) (Photo: Salvia's at GFE)

The Phormium on the right (if you are standing on the sidewalk) is variegated, with cream and pink tones in its leaves. These leaf colors with the deep reddish-brown color of the flower stalks look beautiful against the dark burgundy bracts of the flowering Abelia behind them. The delicate pink of the Abelia flowers on their arching branches also matches the pink in the Phormium foliage. Add to these the red bells hanging from the Flowering Maple and you have a color colony of burgundy, red, pink, and mahogany which created a glowing, shady room of color all through the month of August.

Enter the garden up the wooden stairs and turn left. Ahead on the left side of the pathway, Salvia Mexicana “Limelight” is earning its name. The bracts on the deep blue flowers of this salvia are a brilliant chartreuse. Right now, this Salvia is in full bloom, next to the large yellow flowers of our native Evening Primrose Oenothera Hookeri. Another blue flowering Salvia is weaving between them (Salvia Cacaliifolia) backed up by a wall of peachy Alstromeria. The neon yellows and clear dark blues of this color colony glow like lovers meant for each other.

At the Northwest corner of the garden’s exterior border is another colorspot, this time of pale lavenders and brilliant oranges. The promiscuous bloom of Lavatera Maritima is unstoppable now, and on the fence behind it, the Cup and Saucer Vine (Cobaea Scandens) is full of flowers that have a similar size and color, but a completely different shape. Between and in front of them, Cannas are gleaming with their tropical reddish- orange blooms, just starting now and planning to blow our minds for months. Among these, matching so well that it seems like a disguise, a young Salvia Conferta has begun its first flowering. (Photo: Salvia Mexicana “Limelight” at GFE)

All these groups of related shapes, textures, and colors, peaking together like a symphonic moment, will soon be gone. They will be replaced with some other intrigue of stem and petal and leaf. As the garden matures, and as the gardeners mature, the pace and transition of these effects will be refined, but it will never be exactly the same again. The thrill of the detective, of the artist, and of the lover wake me up early in the morning, and draw me to “go outside and play”.

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present.

Have a question for Hilary? Meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

October 2009

HELICHRYSUM ERADICATION

Snuggled into the border of the Garden for the Environment, by the corner of 7th and Lawton, a glowing mound of lemon-yellow, wooly foliage covered the ground for many years. Summer and winter, its colorful foliage provided a contrast with the Lady Banks rose arching over it, the rich purple spikes of Penstemon in season, and the deeper gold of the Copper Canyon Daisy. Wonderful Helichrysum petiolare, or Licorice plant has been a reliable performer through the years in many tough spots in San Francisco gardens. Equally happy in sun or shade, not fussy about soil and water, Licorice plant brought light colors into shady, difficult nooks. It could thrive under shrubs or in north facing garden corners. It could draw the eye to the back of the garden with its light colored foliage, creating a sense of spaciousness. It could be cut back to a little stump and it would grow anew. The horizontal, naturally tiered habit of the plant when small created a visual structure around other softer or mounding plants. (Photo: Garden for the Environment)

So what happened to the Helichrysum?

Not only the patch by the 7th and Lawton corner, but also every other scrap of Helichrysum in the Garden for the Environment has vanished. The bad news is that Licorice plant has been listed officially as an invasive exotic, and no matter how useful it may be in the garden, it is no longer an appropriate plant for environmentally savvy gardeners to grow.

The website of Cal-IPC, or the California Invasive Plant Council, now shows Licorice plant in an alarming red box, with big red letters that say “Invasive, Do Not Plant!…Seeds are wind dispersed, and the spreading branches will root at any point of contact with the ground. Licorice plant has been found displacing native plants in the Golden Gate National Recreation Area and other sensitive coastal areas” (Cal-IPC.org) (Photo: Helichrysum, GFE)

Helichrysum joins many other plants listed as wildland weeds which were originally imported into our landscape from other bioregions, or even from other continents, often by landscapers and gardeners. Like many other tough, successful landscaping plants, Licorice plant comes from a region of South Africa with a climate very similar to ours. Fortunately, most imported species do not spread into wildlands. But while imported plants may be perfectly adapted to our climate, they are also miles away from any of their natural predators or competitors. That’s why some of them can take over in our wildlands, choking out our native plants.

Some of the most familiar and problematic invasive exotics are ice plant, broom, eucalyptus, and pampas grass. Hikers and backpackers now can see bull thistle spreading prolifically all the way up to Sierra mountain passes, displacing the fragile alpine plants in the mountain meadows and forest floors. Volunteer crews meet on weekends to weed broom and thistle out of the slopes of Mt. Tamalpais. But if you’ve ever been frustrated trying to weed a little garden, just imagine trying to weed a mountain! (Photo: Shasta Daisy, GFE)

Many of the late l9th and early 20th century gardeners and farmers who brought plants from other parts of the world to California were trying to do a good thing at the time. There was a time when people thought eucalyptus could be an economically important timber crop. Gardeners who loved the broom of European hillsides and moors weren’t thinking that it would be destroying fragile and unique California vegetation in the 21st century. Those people lived at a time when nature was seen as an inexhaustible reserve, which we were entitled to shape to our own desires. Draining wetlands and building dams were considered heroic feats. Now we have to work just as hard to reverse many of these experiments and protect the diversity of the natural world which we now know to be fragile and finite.

Home gardeners can play a part in the protection of wildlands by avoiding the use of landscaping plants which are listed by the Invasive Plants Council. Many responsible nurseries will not sell listed plants, but there is always a lag between the time the native plant society becomes concerned about an exotic and the time when nurseries stop selling it. In the meantime, it’s a good idea for home gardeners to check the lists themselves, and remove any garden plants which have been listed. There are always wonderful alternatives that can fill the gap in the landscape. (Photo: Plectranthus argentea, GFE)

Back at the corner of 7th and Lawton, a variegated geranium (Pelargonium to enthusiasts) with glowing yellow foliage and striking orange flowers has replaced the Helichrysum. Nearby, dwarf Shasta daisies provide another alternative groundcover and bank stabilizer, while bringing light, bright colors into the border. Inside the garden, Heuchera maxima, our native coral bells, will replace the Licorice plant in one shady spot. Another choice plant to bring light silvery foliage into a dry shady location is Plectranthus argentea ‘Silver Shield’. And for the toughest dry shade locations, don’t forget Rubus pentalobus, Taiwan Bramble, (not at all like our weedy blackberry, thank goodness) with its charming white strawberry-looking flowers and an edible fruit to follow!

While it is always sad to say goodbye to a familiar garden plant, sometimes the gardener has to play the role of grim reaper. And when that happens, it’s also an opportunity to renew the border and surprise the eye with some fun new choices. A Helichrysum eradication may just turn out to be a Shasta Daisy and Coral Bells houseparty! (Photo: Variegated Geranium, GFE)

Hilary Gordon is Perennial Plants Collection Manager at the GFE.  A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present.  

Have a question for Hilary? Meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

September 2009

NOSTALGIA AND THE TRANSPLANTED GARDNENER

by Hilary Gordon Photos by Blair Randall

Many of my most precious memories are tied up with plants. When my mother moved to a new house, she took slips from her mother’s (my grandmother’s) lilacs to plant by the kitchen window. Now when I smell the heavy, dreamy fragrance of lilacs, the sweetness brings three generations of gardeners together. When I was born, my mother and father planted a Japanese maple sapling in their front lawn. “They are slow-growing,” my mother explained, “so we thought you could grow up together.”

(Lilac at GFE)

Like many Californians, I am a transplant from another climate zone. The plants in my personal stories, the lilacs, maples and lawns of New England, were ones I wanted in my California story. I’ve planted and cared for them here in the Bay Area. But unfortunately, people travel to different climates more easily than plants. Most Japanese maples in San Francisco are showing burned leaves by mid-summer. They object to wind, dry soils, and salty air. Many lilac varieties bloom erratically or not at all without a cold winter. Lawns are not a sustainable choice in a state constantly troubled by water shortages.

A Deeper Look

To connect with the gardening stories from my family’s past, I have to look deeper than the specific plants. My grandmother’s garden echoed the seasons in the wildwood. Her ferns and Jack-in-the-Pulpits were the same ones blooming in the local forests. The soft, natural shapes in her garden followed Nature’s lead with generous and curving beds of plants that looked as though they had grown there on their own. The succession of bloom and fruit and fall color were modeled on the successive wonders of the unfolding year.

I can have all these qualities in my California garden, if I follow the inspiration of my grandmother’s garden without trying to copy the specific plantings. The California native landscapes offer the variety of shapes and colors I need. I can bring the beauty of a seasonal creek bed, wet in winter and dry in summer into my garden. Or perhaps I’ll mimic the deep reverence of a redwood forest understory, or the bright generosity of a seaside cliff in spring sunshine, buzzing with pollinators.

By translating the spirit of my grandmother’s garden into the language and palette of California climate appropriate plants, I can have my memories and still do what she did; grow a healthy and sustainable garden with love and respect for nature.

The Garden Echoes Nature

This month at the Garden for the Environment, the drought-tolerant demonstration beds by the south gate of the garden echo the colors and textures of a California seaside meadow. In early summer, as California seaside soils dry out from winter rain and the salty sea air rolls in with marine fog and wind, tough summer meadow plants are blooming amid golden flowering grasses. At the GFE, their garden hybrid relatives are putting on the same glamorous look. The gorgeous orange of self-seeded California poppy contrasts with the yellow button flowers and silvery foliage of Lavender Cotton. Behind them rise the soft, flat butterfly platforms of yarrow “Moonshine” blooming next to the bright orange tubular flowers of Lobelia laxiflora, a southwest desert native. Golden, windswept Mexican feather grass completes the picture.

On the other side of the pathway, look for self-seeded sweet alyssum and poppies backed by pink flowering variegated thymes. Above them Asteriscus maritimus “Gold Coin” opens its yellow daisy eyes, surprised by the brilliant brick-red of yarrow “Papricka”. Graceful and tall, fernleaf lavender stands at attention to anchor the view.

New Memories

The Mediterranean climate garden has its own magic and mystery. My children’s memories will be full. True, they won’t have my memories of mown grass, thunderstorms and lightening bugs. But they will have the vivid summertime jumble of Bougainvillea, plum blossoms in January rain, springtime Ceanothus (California Lilac) singing with tiny wasps and bumbling bees. These are the fragrances, colors, and sounds that will nourish their sweetest rememberance.

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, she has worked as a professional landscape gardener from 1984 until the present. If you have questions for Hilary, meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

July/August 2009

SPRING BLOOMING BULBS FOR BAY AREA CLIMATE ZONES

by Hilary Gordon | Photos by Blair Randall

Fairy wand, Harlequin flower, Bugle lily, who wouldn’t want to see flowers with such magical names? They are all blooming right now at the Garden For the Environment, a public, educational garden located at 7th Avenue and Lawton. (photo right: Bugle Lily at GFE)

For many traditional gardeners, the springtime bloom of tulips and crocuses is an annual ritual of garden culture. These garden favorites do not bloom without a winter chill which the Bay Area climate cannot offer. So gardeners like myself, entranced with these nostalgia-laden flowers, buy new bulbs each year. We refrigerate them for four to six weeks and plant them out when our soils have cooled in late November and December. Next Spring, we are rewarded with fabulous bursts of color in dramatic flowerbeds. Then we dig the bulbs up, discard them in the green bin in April and May, and wait for August when the next year’s bulb catalog arrives, tempting us to make lists and designs for our next outrageous bulb order.

It’s too much to expect us to give up our tulips and crocuses “cold turkey.” Yet, this annual planting spree followed by throwing out the bulbs can’t last in a world were sustainability is the new byword. That’s why we need a substitute: beautiful, graceful spring flowering bulbs which are suited to our climate so that they can naturalize, returning year after year. There are many choices. Some, like Cala Lilies and Agapanthus are relatively well known, even over-used or weedy. Some, like daffodils and bearded irises, are fairly well-known to thrive in Bay Area gardens. But some of the climate-appropriate, drought-tolerant bulbs from around the world are relatively unknown.

A favorite performer here at the Garden for the Environment is Sparaxis, or Harlequin Flower, originally from South Africa out of a climate zone similar to the Bay Area. These brilliantly colored and beautifully streaked flowers open in March, and are still making a splash in the drought tolerance demonstration bed at the South end of the garden. Enter the garden by the South gate and walk straight ahead. On your right Sparaxis is performing in a drift of orange, red, pink, and ivory, while on your left the orange daisies of Arctotis “Pumpkin Pie” and the lavender daisies of the California native Erigeron glaucus echo their tones. At crocus time, late winter/very early Spring, this same bed sports the pale blue flowers from bulbs of Ipheion uniflorum, or Spring Star Flower, which bloom over a long period to promise the coming end of winter. Ixia maculata (African Corn Lily), the star of the bulb show in late Spring, hasn’t started blooming yet, but its generous buds promise May flowers. (Photo: Sparaxis at GFE)

Outside the South gate, on either side of the border, you can see the tall sentinels of Watsonia borbonica (Bugle Lily) standing at attention with graceful spikes of white flowers. Last summer we divided an old, overgrown clump of Watsonia and planted ten new clumps from one old one. Like many other bulbing plants which are evolved for a climate like ours, these lovely blossoms return in greater force every year, so before you know it, instead of buying bulbs, you are giving them away to your friends and neighbors.

One of my favorite spring bulbs at the GFE is Dierama pulcherrimum, blooming now in the Southern section of the 7th Avenue border. These delicate flowers look like grasses when the buds first emerge. Then each bud expands into a pendant white flower so graceful that it earns its common name, Fairy wands. (Dierama actually comes from what botanists call a corm, not a bulb, as do Watsonia and Sparaxis.) (photo: Dierama pulcherrimum at GFE)

All the bulbs (and corms) mentioned here will die back after blooming, and can be left undisturbed in unwatered areas of the garden to bloom even more gloriously the following year. When designing a border, it is a good idea to interplant clumps of these bulbs with other drought-tolerant perennials or shrubs which will be growing and budding up just as the spring bloomers are finishing. Yarrows, Sages, Coreopsis and other Daisy family relatives, and Hollyhock relatives such as Anisodontea or Lavatera which bloom in summer, are some of the many good choices to fill in after the bulbs have finished their spring fling.

Please come see the beautiful, climate appropriate and drought tolerant spring bulbs blooming at the GFE. We hope you fall in love with them too, and can find a spot in your garden beds to try these alternatives to yearly replanting of crocuses and tulips. (Photo: Arctotis at GFE).

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present.

Have a question for Hilary? Meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

Check out: Garden for the Enviroment Website

June 2009

What’s In A Name?

by Hilary Gordon • Photos by Blair Randall

“What’s in a name? That which we call a rose

By any other name would smell as sweet;

So Romeo would, were he not Romeo called,

Retain that dear perfection which he owes…”

In the well-known play by Shakespeare, young Juliet gives her opinion that a name doesn’t matter. Her opinion matches that of many people who are beginning to learn about gardening. Why do we need to learn all those stupid Latin names for plants?

But thirteen-year-old Juliet turns out to be a little naïve, and as the play develops, the names of Montague and Capulet turn out to be a matter of life and death for Romeo, Juliet, and their young friends. (photo: Rose at GFE)

While not nearly so dramatic, the names of plants turn out to be important also. So you want a sage in your garden. Do you want one that is eight-feet tall and drought-tolerant with bright red winter flowers? Or do you want a plant that stays four inches tall, likes shade and moist soil, rewarding you with blue summer flowers. Or do you mean the culinary herb that is used in Tuscan bean soup, Salvia officinalis? Or do you mean the silvery-leaved foliage plants whose common names include the word “sage” like Sandhill sage or Big Sagebrush, which are not salvias at all but rather artemesias with tiny daisy-type flowers?

One of the foundation plants of the border at the GFE is copper canyon daisy, Tagetes lemmonii. For years, I called this plant Mexican marigold, having learned that (wrong) common name from another gardener. When I went to buy some more of these plants at the nursery, and asked for Mexican marigold, I was shown to a bench with a completely different type of plant, the annual marigolds that are familiar old-fashioned garden plants. These plants would last less than a week in our borders at the GFE. They are a favorite appetizer for snails and slugs, need constantly moist soil, hotter days than we can offer, rich garden soil, and lots of TLC to reach their ultimate 12 inch size. They bloom beautifully and then die, like any good annual. (photo: Tagetes at GFE)

The plant I was looking for, by contrast, is tough as nails, grows six feet tall or taller, thrives on poor dry soil, isn’t picky about heat and fog, and will probably be going gangbusters in our border after we are long gone, blooming prolifically year after year without the least fuss.

The two plants have similar looking foliage, and in a four-inch pot, it wouldn’t be hard to mistake one for the other. Since I had the name wrong, it was a good thing I knew the plant I wanted very well (it has a distinctive smell) and I knew right away that I wouldn’t buy the plants labeled “ Marigold”. Instead I went to the reference desk, looked up my plant, and then armed with the right name, went back out in the nursery and found what I wanted.

The scientific names of plants, like those of other living things, are Latin words. The first word indicates the genus of the plant, and the second word indicates the species. Most of the Latin words turn out to be simple descriptions of the plant. These descriptions are often very commonplace when translated such as pittosporum (sticky seed) or coprosma (manure smell). Sometimes the Latin name includes the name of a person, such as the person who first classified the plant, or the name of someone they wished to honor, such as the rose “Lady Banks” which is named for a person. These names always make me imagine stories, adventuresome or romantic, and wonder who that person was and why, when their contemporaries are long forgotten, we still discuss them every year in the garden. (photo: Shasta Daisy at GFE)

The last part of the plant name, if it appears in apostrophes, means something quite different. Ceonothus ‘Diamond Heights’ for example, is not a species, but rather a specific plant that was either discovered or hybridized intentionally. This plant is propagated not by seeds, in which case each individual plant would have its own unique genetic make-up, but by cuttings or some other type of asexual propagation. As a result, each plant you buy with that apostrophized name is genetically identical to the original, and will perform exactly the same under the same conditions. Ceonothus ‘Diamond Heights’ for example is a cultivar of California lilac which has variegated green and yellow leaves unlike the pure green leaves of most Ceonothus, and which is happy to grow in some shade, unlike most Ceonothus which prefer full sun.

Here at the GFE we are in the middle of an enormous project of creating a data base which will allow visitors to the garden to look up the name of most plants in the garden. This huge project would not have been possible without the determined efforts and expenditure of time of one of our committed volunteers, Christophe Kreis. Each garden bed will be assigned a number, and soon an up-to-date list of plants currently growing in that bed will be available on our website. Many of the plants will also have photographs available, so if you want to plant a Copper Canyon Daisy after reading about it in this article, you will be able to go to the garden and find one growing. That way you can find out what the plant actually looks like, and what you’re going to have when the plant is mature. (photo: Gaillardia at GFE)

Romeo and Juliet learned that a name may make a tremendous difference in the outcome. The same is true for gardeners, and it is worth the effort the learn the right names for the plants you buy, or grow from seeds or cuttings from friends and neighbors.

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present.

Have a question for Hilary? Meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

Check out: Garden for the Enviroment Website

May 2009

A New Gardening Year

by Hilary Gordon • Photos by Blair Randall

In the final days of January, the buds were swelling on the purple plum trees that grace San Francisco streets. The tiny new moon heralded the Chinese New Year, marking the beginning of another growing season. By the time this newsletter reaches its readers, the plum trees will be in full bloom, as clouds of pink blossoms assert Mother Nature’s confidence, despite a dry winter in the watershed and in the economy. (Photo :Flowering Plum at Golden Gate Park: Doug Comstock)

Winter Rain Brings Weed Problems

For gardeners, the plum blossoms also signal the growing season for weeds. The bright yellow flowers of cape oxalis (Oxalis pes-caprae) are as much a mark of spring as the plum blossoms, and much less welcome. This weedy oxalis, which has naturalized in San Francisco gardens, is originally from South Africa. Perfectly adapted to our mild climate and dry summers, oxalis is dormant throughout the dry season, and grows again as soon as the soil is moist in the fall. By spring, many gardens are so awash with oxalis that nothing else can be seen but its clover-like leaves and its yellow flowers.

Oxalis When oxalis has grown successfully the season before, it stores its extra energy in little brown bulbs deep in the soil, but not strongly attached to its roots. For a gardener digging up oxalis, it is almost impossible to get all the bulbs out with the plant. Unfortunately, this weed will be glad to regrow from any bulb left behind. Last winter at the GFE, we started the season trying to dig our oxalis with the bulbs, but unfortunately it was growing faster than we could dig. A little research (in Pam Pierce’s columns in the Chronicle) suggested a different strategy, which we are now following successfully.

Wherever we see oxalis growing, we are trying to pull off the top of the weed, being careful to pull it below the stem joint where the leaves begin to separate from the main stem. This deals the plant a blow, and it takes a bit of time and energy for the bulbs to generate another growing tip. We try always to mulch heavily on top of the newly weeded soil, which also makes it harder for the oxalis bulbs to push a new growing tip up into the sunlight. In some areas of the garden, where we have done this several times in the course of two years, the oxalis bulbs have exhausted themselves and are no longer regrowing.(Photo: Oxalis pes-caprae at the GFE: Blair Randall)

Sheet Mulching Another strategy we use against oxalis is sheet mulching. After weeding out an area, we spread cardboard or layers of newspaper over the soil with the edges overlapping so that no sunlight can penetrate to the soil surface. Then we cover the layered area with mulch or manure, and water. The oxalis bulbs will exhaust themselves trying to grow out to the sunlight while never reaching it.

What is a weed?

This is a question new gardeners always ask in the Basic Organic Gardening class. A plant may be called weedy if it competes aggressively and successfully with other plants, and if it multiplies freely. But in the last analysis, a weed is simply a plant growing where the gardener doesn’t want it to grow. A good example in our borders are the calla lilies (Zantadeschia aethiopica). Vigorous, lovely, and a good cut flower, calla lilies are a useful and appropriate plant for San Francisco gardens. However, they multiply freely in a watered garden, and pretty soon they are everywhere. When they cross the invisible line and become a weed is a question only the gardener can answer. Last year, we let them stand in the border, while we tried to stabilize the sandy slope and begin new plantings. Now that the border is more stable and full of new plants, we are selectively weeding them out. (Photo:Zantadeschia aethiopica: Blair Randall)

Invasive exotics One of the prices nature lovers pay for globalization is that plants from around the world are brought here, either intentionally as nursery stock, or unintentionally as weeds in other plants or products. Some of these never take off in our climate, but others love it here in California, and actually compete very successfully with our native plants.

The eucalyptus trees which many people think of as a signature California plant are all from Australia originally, planted in the 1900s with hopes that they could become useful for timber. That never worked out, but the eucalyptus naturalized and took over some areas from the native plants that lived there before. When exotic plants take over our wild natural areas, this is a problem because most exotics don’t support our native wildlife. If eucalyptus, broom, ivy, fennel, pampas grass and bull thistle were allowed to grow freely on Mt. Tamalpais and other wild lands, eventually our native insects, like the Mission Blue butterfly, would not have an opportunity to reproduce. Their host plants would no longer have any habitat. Luckily, dedicated volunteers and hard-working GGNRA staff do their best to limit the spread of wildland weeds. Can you imagine trying to weed Mt. Tamalpais?

One thing home gardeners can do to help with these efforts is to check the status of plants before buying them at the nursery. Invasive exotics are listed at the California Department of Food and Agriculture website. To find out more about efforts to limit wildland weeds, contact the California Native Plant Society, or read more on this topic in Pam Peirce’s book Wildly Successful Plants.

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present. Have a question for Hilary? Meet her in the garden Wed. 10-2 and Sat. 10-4.

Visit gardenfortheenvironment.org

March 2009

The Blessings of Rain

By Hilary Gordon Photos: Blair Randall

December brought the blessing of rain, and a few cold nights; just enough to let the plants know that it is wintertime. In our microclimate, the year is like the proverbial snake eating its tail. Fall’s colorful leaves still persist as the first spring blossoms make a tentative trial. In just a few short weeks, we’ll see our first plum blossoms, and then the year will unfurl again, as it has so many times before.

But this year brings change, and not just on Inauguration Day. During the end of the twentieth century, drought in California was news. Water rationing came, but mostly went. Gardeners let their lawns go brown, and carried water from the shower in buckets to their favorite roses and rhododendrons. Then, we mostly just waited for water rationing to go away again after a year or so. (Photo: Matilija Poppy: Blair Randall)

Now, because of population growth, urban sprawl, and climate change, water rationing is beginning to look like a semi-permanent situation. Housing developers, agriculture, and wildlife protection all compete for the scarce drops of water, and home gardeners must stand in line with everyone else. Many of us will need to “retool” our gardens for a new reality.

One of the most important tools in our toolbox is called ‘hydrozoning.” Just as the garden is divided into sunny and shady areas, with appropriate plants in appropriate places, it can also be divided into irrigation zones, such as completely non-irrigated areas, areas with occasional deep summer watering, and areas with regular water. For this to work, plants with similar water needs must be grouped together, just as sun-loving plants are grouped together in a south facing border while ferns and fuchsias gather in the shade.

If part of the garden is designated a “no irrigation zone,” perhaps a sloping area, or the back or side of the garden, this area can be planted with California natives, or non-thirsty plants from other similar climates zones where a half-year drought is nothing unusual. This garden area will reward you with bursts of color in the winter and spring, as our annual rains stimulate the growth cycle of these plants. During the summer, they will stay neat while dormant and discourage weeds which would otherwise grow there. It makes sense that native plants from the S.F. Bay Area or nearby parts of California, will thrive in our unamended soils and with the weather conditions provided by nature. But some of these plants can also give fabulous blooms and garden effects that make them classy performers anywhere. Some examples are California Lilac (Ceonothus), Flannel Bush (Fremontodendron), California Sagebrush (Artemesia californica), and Matilija Poppy (Romneya coulteri).

Equally good in unwatered plantings are tough customers from similar climate zones all around the world where they have evolved to thrive with mild wet winters and cool, dry summers. Some of the top performers are Leptospermums and Grevilleas from Australia, and Leucadendrons and Phormiums from South Africa. Consider also plants from the Mediterranean such as Rosemary, Lavenders, and Rockroses.

The next part of the garden can feature plants that benefit from a occasional deep watering during our annual drought, but that don’t mind going dry in between. Think about creating a transition zone between the completely unwatered background areas, and those that receive regular water and attention, which are probably closer to the house. Because these plants are sustained by occasional deep watering, they can extend your garden’s beauty into the summer and fall months. They can be useful as well as beautiful.

This would be the perfect water zone for a planting of culinary herbs such as Sage, Thyme, and Oregano. (Annual herbs like parsley and basil belong with the vegetables in the regular watering area.) Many other fragrant and lovely plants will perform their best under these water conditions. They actually don’t want their soil constantly moist and will benefit from drying out between waterings. Some of these plants are the cornerstones of the perimeter border here at the Garden for the Environment, and some of them bloom without stopping all year around. They include Copper Canyon Daisy (Tagetes lemonii), Tree Mallow (Lavatera bicolor), and many dramatic Sages, including Salvia mexicana.

The final section of the garden will receive regular watering; here are the vegetable and annual flower beds, and the fruit trees along with a few prized ornamentals such as the rose from grandma’s garden or the white azalea which reminds you of home. By concentrating irrigation water where it will do the most good, and grouping plants together that need a moist soil during the summer months, we can save water and money while still getting great results from our plantings.

For those of us with established gardens, this is a great time of year to look over the garden as a whole, and make some decisions that will save water next summer and for the future. The rainy season is the best time to transplant old favorites into new garden spots, or to plant out new purchases. Many ornamental trees, fruit trees, and roses are available bare-root now, and it is an excellent time for planting. Many natives and other drought tolerant plants are best planted in the fall as the rains first begin, but that chance is gone for this year, and now is the second-best time, with days beginning to get longer and many months of moist soils still ahead. Those of us who are just getting started with a garden, have the advantage of planning hydrozones from the beginning, and can put each plant in the watering zone it prefers.

Any plants transplanted to new locations in the garden, or newly planted out, will need irrigation in the summer months ahead, even if they will eventually be drought tolerant when established. The first few years in the ground, even drought tolerant plants need regular, deep watering, in order to get a strong deep root system established. If you reorganize your garden this winter to hydrozone, keep a close eye on transplanted and newly planted friends. Don’t let them wilt. Keep them growing this summer and next, and they will reward you with many years of beauty for years to come, without running up your water bill.

Pick a sunny day and stop by the Garden for the Environment at 7th and Kirkland to see these and many other wonderful plants doing their best to woo you. We are there Wednesdays 10-2 and Saturdays 10-4, and we would be glad to show you some of these plants, and share some hydrozoning tips. Visit gardenfortheenvironment.org

Hilary Gordon is Perennial Plants Collection Manager at the GFE. A life-long gardener, trained at the City College Horticulture program, she has worked as a professional landscape gardener from 1984 until the present. Question for Hilary? Meet her in the garden Wednesdays 10-2 and Saturdays 10-4.

Feb. 2009