Green Wednesday: Lemon Lineage and Autumn Intricacies
By David Shubin, U.C. Master Gardeners of Napa County / Kathleen Scavone, Environmental Contributor
Green Wednesday: Gardening and Ecological Insights
Every Wednesday Napa Valley Features brings you Green Wednesday, featuring articles from environmental voices and the UC Master Gardeners of Napa County. These contributors share research-based horticultural advice, insights on sustainability and climate topics relevant to our region.
Summary of Today’s Stories
In "Be Grateful When Life Gives Us Lemons," David Shubin explores the complex origins, genetics and nearly year-round productivity of lemons, highlighting their unique place in citrus history and home gardening.
“So, no, life doesn’t just give us lemons.” — David Shubin
In "Intricacies," Kathleen Scavone highlights the detailed natural phenomena of autumn in Napa Valley, weaving together astronomy, spider webs, seasonal fruit and leaf pigments to underscore the science behind fall's beauty.
“Today on the trail I’m stalking intricacies.” — Kathleen Scavone
The Magical Intricacies of Napa Valley in Fall
By Kathleen Scavone
NAPA VALLEY, Calif. – Morning is still velvety dark when I awake to take in the new day. The air is sweet and skies are devoid of the Pickett Fire's smoke, thanks to the many dedicated fire personnel who battle the blaze. Starshine sparkles like crystal rather than the stained-glass orange it did during the worst of the blaze. Refreshing cloud cover influenced by coastal conditions cools us. After the night unravels its net of darkness, I rinse ash off my car.
As I'm sipping my coffee on this, the third planet from the sun, Earth is rotating approximately 1,000 miles per hour. As they say, it's all relative, and the exact speed of a given place depends upon where you sit in the world. Those who sit farther from the equator move more slowly. All of this unending action gives us our nights, days and the time frame that we adhere to in our busy lives. What a wild ride!
The blessed, bright stars I witness prior to dawn appear fixed as luminous points before they disappear for the day. They are giant balls of hot gas. The pinpricks sparkling above are, in actuality, giants in the sky that are comprised of hydrogen, helium and other elements. These incandescent bodies each have their own life cycle, aging out from millions to trillions of years.
As our star, the sun, begins to illuminate the trail, I lace up my walking shoes and spy a skunk as it disappears into the blackberry brambles by the creek. Since skunks are nocturnal, it appears to be heading home. More than likely it ate its fill of crickets, grubs and other tasty fare. I detect a whiff of eau de skunk, whose odor can travel up to 2 miles on a windy day!
Today on the trail I'm stalking intricacies. Rather, intricacies are popping up around me. I marvel at how the slanted sunlight renders apples on my trees as glowing LED lights at this hour of the day. Apple-picking time is right around the corner. Then, I'll be up to my elbows in crunchy snacks, apple juice, apple sauce, apple pies and whatever new apple recipes I find to experiment with. Apples, according to Wikipedia, originally came from Central Asia and have been around for thousands of years. North America has European colonists to thank for some of the 7,500 cultivars of apples that have been bred for specific uses such as cooking or eating raw.
Sunlight shines its ever-changing angle just right on a spider web attached to the apple trees. Its tell-tale “fishing line” anchor web catches my eye. A closer look reveals a foot-wide orb web with an insect of some sort wrapped up and stored near the center of the woven masterpiece like a mummy, as well as a moth that has been captured and is stuck fluttering in the web. Nature can be cruel.
The spider's ideal trap, its web, is a paradox of design being both delicate and strong. Webs, like spiders, come in all shapes and sizes, from the large aforementioned orb web to tangled webs, wooly webs, funnel webs and more. A spider's silk is a complex and miraculous multistep web-weaving material. Bay Nature magazine explains that spiders have silk glands inside their abdomens. While tarantulas contain one silk gland, some spiders contain eight of the protein-rich silk glands. Talented spiders' silk glands are joined to tiny spigots located at their spinnerets, or silk-spinning organs, when they craftily construct powerful snares to allow them to make a living.
Speaking of weaving, wild grapevines that have woven themselves between blackberry brambles are beginning to transition from verdant green to eye-popping reds and oranges. Similarly, California bay laurel leaves are falling into the creek to mirror themselves while creating impressionistic still-life renderings reminiscent of a van Gogh painting.
The science behind autumn's color palette is an annual show of complicated choreography of chlorophyll, carotenoids and weather. Warm autumn days partner with cool nights to create a wondrous series of events within the leaves. Sugars are produced in daylight, becoming trapped in leaf veins that are not permitted to move out, then cause the color schemes we love. These are called anthocyanin pigments. Additionally, carotenoids contained in the leaves cause the showy yellow hues that we also enjoy each season.
Which of nature's intricate color schemes will light up your wonder and whimsy genes? The gentle hum of beauty in all of its nuances is ready to provide us with every day epiphanies in the wild autumnal season. Include some vineyard viewing (and wine tasting!) as an added dimension to your day, since each varietal is imbued with its own self-timed leaf color.
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Kathleen Scavone, M.A., retired educator, is a potter, freelance writer and author of “Anderson Marsh State Historic Park: A Walking History, Prehistory, Flora and Fauna Tour of a California State Park,” "People of the Water" and “Native Americans of Lake County.” She loves hiking, travel, photography and creating her single panel cartoon, “Rupert.”
Be Grateful When Life Gives Us Lemons
By David Shubin, UC Master Gardener of Napa County
NAPA VALLEY, Calif. — Let’s talk about citrus. It’s a wonderful genus — a prolific producer of fruits we know and love: oranges, limes, grapefruits and mandarins as well as citrons, kumquats, finger limes, pomelos, yuzu and calamondins. And, of course, lemons.
You’ve heard the phrase, “When life gives you lemons, make lemonade.” As if lemons are just a default bad thing life throws at you. But honestly? Lemons are all kinds of amazing.
Their history stretches deep into time. There is archaeological and genetic evidence suggesting that lemons have been cultivated for more than 4,000 years.
Lemons likely originated in northeastern India as a natural cross between a citron and a sour orange. Given that research suggests that citrus lineage could go back 8 million years, lemons are shockingly new on the scene. Data suggest that lemons were being cultivated in Persia (modern-day Iran, Iraq and Egypt) by the 10th century. They arrived in the Mediterranean around the year 200 and eventually made it to the Americas in 1493, a legacy of colonialism.
The citrus family tree is messy. The lemon seeds that arrived in North America came by boat via the Canary Islands from lemon trees introduced to the Canaries by the Arabs. The fact that we have so many types of citrus and so many reliable varieties is impressive when you consider that citrus does not grow true from seed. If you plant seeds from your neighbor’s wonderful lemons, you will not get a tree with the same fruit. Without human intervention and care, lemons would have certainly faded into obscurity.
Almost all of the citrus we know today came from just three ancestral species: citrons, which are large and thick-rinded with little flesh; mandarins, which are sweet and easy to peel; and pomelos, which are huge, sweet-to-bitter and very seedy.
From there:
Sour orange = mandarin + pomelo
Grapefruit = pomelo + sweet orange (itself a hybrid of mandarin and pomelo)
Lemons = citron + sour orange
Tangelos, tangors, clementines and yuzu are all second-, third- or fourth-generation crosses. And limes are a mess. They aren’t even true citrus but instead close relatives that got pulled into the family drama.
The Meyer lemon, everyone’s favorite, is known for its sweet, floral notes. As you might now suspect, it is a hybrid. Many people are surprised to learn that the Meyer lemon is botanically closer to a sour mandarin than a true lemon. While its exact parentage can’t be confirmed with existing technology, genetic analysis suggests that the Meyer may be a cross between a citron and a mandarin/pomelo hybrid.
Frank Meyer, a plant explorer for the U.S. Department of Agriculture, discovered the fruit in China in 1908. The Meyer lemon was improved and deemed a virus-free tree in the early 1950s. These days all Meyer lemons are “improved” whether the plant tag includes the word or not. So they are delicious, yes. But let’s be real: Meyers are barely lemons.
Most citrus varieties follow a seasonal rhythm, bursting into fragrant bloom in spring, then ripening their fruit in one big harvest. But lemons play by their own rules. Varieties such as Eureka, Lisbon and Meyer will flower and fruit almost year-round in Napa Valley, producing blossoms, green fruit and ripe lemons all at once.
This everbearing habit comes from their origins in warm, frost-free regions without a defined dry season, so they never developed the need for a dormant period, which other citrus require. While some limes, calamondins and a few mandarins may occasionally bloom out of season, lemons are the most reliable for continuous harvests.
In the right climate, you can pluck a fresh lemon for your tea in January, zest lemons for a marinade in summer and still see new flowers opening in autumn. It’s one of the reasons the lemon is such a beloved tree or shrub. Its beauty, fragrance and fruit are on display all year long.
So, no, life doesn’t just give us lemons. In fact, life probably only gave us lemons once. The rest is the result of human curiosity, breeding, grafting, trade, migration and intention. The saying should be, “When life gives you lemons, count your lucky stars and thank the humans who came before you who made them happen.”
Events
Tree Walk: Join UC Master Gardeners of Napa County for a docent-led tree walk of Fuller Park in Napa on Friday, Sept. 12, from 10 to 11:30 a.m. Historic Fuller Park is an arboretum with many exotic and native trees planted over the past 120 years. Meet at the corner of Oak and Jefferson streets in Napa. Registration is required for each participant.
Fall Faire: Join UC Master Gardeners of Napa County for the annual Fall Faire — “Where science fair meets carnival”—on Saturday, Sept. 20, from 1 to 4 p.m. at the UC Cooperative Extension, 1710 Soscol Ave., Napa. Enjoy kid-friendly demonstrations and talks that range from dehydrating produce to designing a pollinator-friendly garden, along with plenty of gardening advice. A plant sale will feature ornamental plants and seven varieties of winter vegetables, with all proceeds supporting Master Gardener programs. Event entry is free.
Become a Master Gardener Volunteer: UC Master Gardeners of Napa County is now accepting applications for the Class of 2026. Visit napamg.ucanr.edu for more information and register to attend a mandatory information session for applicants. Applications are due by 5 p.m. on Sept. 25.
Help Desk: The Master Gardener Help Desk is available to answer your garden questions on Mondays and Fridays from 10 a.m. until 1 p.m. at the University of California Cooperative Extension Office, 1710 Soscol Ave., Suite 4, Napa. Or send your questions to mastergardeners@countyofnapa.org. Include your name, address, phone number and a brief description of the problem. For best results attach a photo.
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David Shubin is an ISA Certified Arborist and UC Master Gardener of Napa County.
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