PHOTO: Nikita/Creative Commons Attribution 2.0 Generic
Frank Hyman
October 11, 2019

I’m growing a high-dollar lemon tree in my backyard, yet I don’t live in Florida, Texas or California. My home is in zone 7 of the Piedmont region of North Carolina. It produced fruit and stayed evergreen through five winters with lows in the 20s. My lemon tree—a yuzu—even survived a week of 11-degree weather in January 2018. It lost all its leaves, which worried me, but I scraped back some bark and saw that the cambium was still green, so I waited. By the end of May, it had thoroughly leafed out with no loss of wood.

Unfortunately, it appears that no university program in the United States is studying the yuzu as a crop. However, farmers in Australia plant 20 acres at a time and make a lot of money from yuzu lemons. There, regular citrus sells for as little as $500 a ton, but yuzu lemons go for about $25,000 a ton wholesale.

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In California, small growers supply high-end restaurants with the fruit. They also sell yuzu saplings to growers and home gardeners. (See “Resources” sidebar below.) In San Francisco, chefs pay as much as $2.50 apiece for yuzu lemons. In England, yuzu lemons sell for 4 pounds apiece. A quart of the juice can cost $60 online.


What’s the Big Deal About Yuzu Lemons?

The yuzu (Citrus juno) tree has been known in China for centuries. From there, it found its way to Japan, where it’s revered for cooking as well as for bathing. On the winter solstice, in a ritual called yuzuyu, a few dozen ripe fruit are tossed into a hot bath to soak up the aroma of the rind while a person bathes. Yuzu is also said to repel colds, heal the skin and soothe the mind. Some describe the smell and flavor of the skin as evoking every citrus fruit known: grapefruit, lime, orange and, yes, lemon.

The fruit is the size and shape of a tangerine but has plentiful seeds and limited fruit. The juice is valuable, but the real appeal, pardon the pun, is from grating the skin. Chefs insert this unique and memorable flavor into dishes as plebian as coleslaw and as aristocratic as foie gras. It’s also a highly rated fruit for making marmalade, meringues and syrups for tea, not to mention use in cocktails such as a yuzu sour.

I bought my first yuzu lemon tree from the late, great Chuck Marsh, founder of Useful Plants Nursery in the mountains of North Carolina. There, on the border between zones 6 and 7, he was enthusiastic about yuzus.

“They have epic significance in Japan,” he told me.

The juice is mixed with soy sauce to make something similar to a vinaigrette that the Japanese call ponzu sauce. Marsh also said that yuzu have the most flavorful rind he’d ever used in cooking. Yuzu also bears many 2-inch thorns. I remember Marsh, wearing his beret and a big grin, telling me he simply snipped off the thorns with his pruner and saved them for toothpicks.

Marsh reported that the famous plant explorer Frank Meyer (of Meyer lemon fame) found a yuzu tree in 1914 near the Yangtze River while on an expedition for the U.S. Department of Agriculture. It was in a field, at an elevation of 4,000 feet and the same latitude as Atlanta, Georgia. So, Marsh long suspected that yuzu could be a cold-hardy and popular substitute for lemons and limes into zone 7. But as a smart experimenter, he protected his young trees with a couple of layers of heavy duty row cover to give them 5 to 10 degrees of extra warmth for their first couple of winters until they were established.

In warmer country, I bypassed the cold protection and didn’t regret it. Yuzu lemon trees can take cold weather that would kill almost any other citrus tree in zone 7.

Harvesting Yuzu Lemons

The fragrant flowers most often appear in spring, while the fruit ripens from late fall to midwinter. Most ripe citrus fruits remain in good condition for several weeks on the tree, but the best flavor for the yuzu lemon rind comes shortly after it first ripens.

That said, some chefs like the taste of the rind even when the fruit is green or yellow/green. If you grow your own trees, you can sample the taste of the rind at different stages and see for yourself. (You can also get a head start by contacting Pearson Ranch in California, online at www.pearsonranch.com. It will mail you ripe, half-ripe or green yuzu lemons for approximately $8 a pound.)

Popular as the fruits are, the tree itself has one unfriendly trait: those stiff, 2-inch thorns. In Australia, growers pick the lemons with hand pruners while wearing heavy-duty welding gloves with long gauntlets. The good news? The fruit ripens in cold weather and the gloves are so common they go for an affordable $10 to $20 a pair.

Some growers wear conventional leather gloves but snip the citrus stems with long-handled clipper/holders. These extend your reach by about 2 feet and hold the fruit after the stem is cut.

For market, snip off the stem and carry the fruit in wooden or plastic bins that allow it to breathe—then take a few deep breaths of the rind yourself.

Growing Yuzu Lemons

If you want to grow yuzu lemons or any other citrus trees north of zones 9 or 10, select sites that favor the trees on those unexpectedly cold winter nights.

That means plant them on:

  • a warm southern exposure;
  • a slope or top of a hill rather than a bottom where cold air collects;
  • well-drained soil, as they can tolerate drought but not sogginess;
  • ground with full sun or scant overhead cover of pine trees, which allow plenty of light but also hold warm air near the ground overnight;
  • ground near pavement or buildings that release warmth overnight;
  • soil amended with organic matter and a high nitrogen fertilizer; and
  • grafted on a rootstock of a very hardy ornamental citrus called Flying Dragon. This sturdy rootstock dwarfs the tree to 5 to 10 feet high, helps it mature early and adds a touch of cold hardiness.

Farther North

There are techniques for growing citrus trees in colder parts of the country such as using winter covers, miniature greenhouses and even swaddling the trees in Christmas lights. Those options are beyond the scope of this article, but if you feel brave, you can find great techniques for overwintering citrus in a book called Palms Won’t Grow Here and Other Myths by David Francko of Ohio in zone 6.

Francko describes in detail practices that let a gardener add as much as two hardiness zones to a garden. Using his techniques, some citrus trees normally restricted to zone 8 can be grown by farmers in zone 6, which covers Massachusetts to Kansas, the intermountain West and the Pacific Northwest.

Resources

This story originally appeared in the November/December 2018 issue of Hobby Farms magazine.

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