Summer’s Dazzling Dahlias

As summer moves into full swing, with temperatures over 100 for many sweltering days at a time, the gardener is profoundly grateful for those plants and flowers that (with a little water) can stand up to heat and refresh us just by virtue of their cheerful faces. Dahlia’s rank high for me this time of year, so it seemed a good time to re-visit this piece on growing dahlias with Chico gardeners Joan Eisenberg and Brian Rea.

Dahlias are a wonderful story of fortitude and transformation – a sort of visual rags to riches, and proof that beauty comes from within – deep within. A dahlia begins life as a wrinkled, misshapen tuber – a bit like an old sweet potato you forgot in the back of the bottom drawer of the fridge – but which, given the right conditions and care, grows up to be a stunning, long legged and confident Beauty Queen. Some dahlias could even be classified as Drama Queens. They are one of the stars of the late summer garden – beginning to bloom for real in July, coming into their own in August and blooming happily through first frost. Photo above: a dahlia tuber with one season’s growth.

Long-time members of the Chico community, Joan Eisenberg and Brian Rea grow a great many things in their garden, a great many Dahlia’s among them. And when I say “a great many”, in the case of the dahlias, I mean 91 individual Dahlia plants. Many gardens have secret nooks to discover or chance upon, Joan and Brian’s garden is in a league of its own in this way, taking the unsuspecting by total surprise. The further you move toward the back of their sweet, historic bungalow dating to 1910 in old-town Chico, the more you see the garden open before you – stretching the width and depth of not one but three historic bungalows, which Joan and Brian have purchased and renovated over the past 35 years. Photo above: a shining example of a Peony Form dahlia.

The history of the houses are stories in and of themselves, but “there had never been a fence between these three back-yards,” Joan tells me, and so it seemed natural to continue that way as she began to garden there. As she and Brian bought the houses on either side of theirs to fix up and eventually rent out, it soon became apparent that various long-term renters were happy to have Joan and Brian garden their back yards as well. And who wouldn’t be? Fruit and flowers, walking paths and peaceful seating areas, are open to all three houses. Photo above: The very uplifting site of the Gardenparty Flower cart open for business.

While the garden is a complex unit of many elements, it is the dahlias that stand out. Each plant is fortified with a thick (3- 4” round, 6 -7 foot tall) wooden post of a stake and an embracing, protective cage of wire fencing to keep the foliage and flowers supported on their yearly journey from small sprouts to massive, 4 – 6 foot tall shrubs each season. Joan started planting dahlias fairly early in the garden’s evolution. Living on the loamy Valley floor as they do in downtown Chico, the tubers are very happy – thriving on the good drainage and fertile soil. Brian and Joan (did you notice how Brian came first in this sentence?) amend the soil around the dahlias every year with a few inches of well-rotted manure -based compost to keep up the soil biology and fertility, as dahlias are pretty heavy feeders. Individual plants start as that one withered tuber in spring and can grow by fall into a clump of as many as five large tubers in that one season. Given the fact that dahlias are winter-hardy in Chico, and some of Joan and Brian’s tubers have been in place for 25 years, imagine the underground clumps they have. Photo above: A Peony Form dahlia.

Dahlias are native to high (5000 feet above sea level) sandy meadows of Central and South America. The first recorded western description of the plants is said to have been by a Spanish physician in the mid- 16th century. Roots and seeds of dahlias were first grown on in Europe in the mid 1700s, most notably by Swedish Botanist Andres Dahl, a student to of Linnaeus, and after whom the genus was named. The Aztecs are said to have eaten the sweet starchy tubers and used them for medicinal purposes. Grieve’s Modern Herbal (originally published in 1931) lists dahlia tubers as a source of natural inulin, once used to help people with diabetes, and still prized for its health benefits. Photo above: Joan Eisenberg at work among the dahlias.

The sweetness factor may be what leads to the snail, slug and earwig appeal in early spring: “Before the growth is tall and sturdy, snails, slugs and earwigs can decimate the young shoots,” warns Joan. She has had success with the organic version of Sluggo, spread in a liberal ring in the early evening “right before the perpetrators will be really active” around each plant. “Eventually the plants outgrow the snails and slugs and earwigs and you’re ok.” Photo above: A typical selection of dahlias for sale at the Gardenparty cart. The tight one at center-left is a Pom-Pom Form dahlia.

Another thing that will bother those big, blooming heads is a heavy rain or impending frost. The stakes or cages you set up around them can help to hold them up, but unfortunately dahlias are not great at blooming indoors if cut as a bud. They hold the best indoors when cut in full bloom. Dahlias like regular water and in the heat of summer, Joan and Brian will run their drip irrigation and misters twice a day for 12 minutes on the dahlias. Because of off-and-on gopher and mole issues, as well as to insure excellent drainage, Joan and Brian plant most of their dahlias in mounded soil. They cut the plants back to the ground each year after the first killing frost, “but we sometimes still have great flowers at Thanksgiving!,” they tell me. Photo above: Another selection of Joan and Brian’s dahlias. The large orange one at left is a Cactus Form dahlia.

In areas where the ground freezes in winter you can treat dahlias as annuals or your can lift the tubers, let them dry out, and then store them in sand, sawdust or wrapped in newspaper in a cool dry place (cellar or dry garage) until safely past the first frost in spring.

Dahlias were loved by Victorian plant collectors, so it seems appropriate that this garden embellishes these houses today. At the height of the dahlia’s favor some sources say that up to 50,000 named varieties were for sale. More than 30 species of dahlia grow wild in their native regions but most garden dahlias are hybrids of just two or three species. While the plants lost favor as “old-fashioned” for a long stretch of the late 1900s, they seem to be coming back in force. Dahlias can be propagated from seed, from basal shoot cuttings or from division of the tuber clumps. They hybridize readily and garden varieties vary widely in plant and flower size and form. In milder climates, however, you can plant early-, mid- and late-blooming varieties for the longest bloom time even through extreme late summer heat or early cool stretches.

Dahlias the likes of Joan’s are prized by serious collectors and for exhibiting competitively. She now sells the exuberant blooms as available at a cheerful little flower cart on Laburnum Avenue between 2nd and 3rd Avenues in Chico. A sandwich board sign on the corner of 1st and Laburnum tells passers-by if the cart is open or not from May through October/November (weather allowing) and payment is on the honor system. Joan is also busy supplying and preparing the blooms for weddings and other special summer events – if you would like to inquire about ordering flowers, contact her at: The cart and flower supply endeavor are fittingly called: Gardenparty. All I have to say is: “Party On!”

All I have to say is: “Party On!”

    Joan’s favorite resources and sources for dahlias include:

Swan Island Dahlia in Canby, Oregon (, who host a Dahlia Festival at the end of August annually.

Corralitos Gardens in Corralitos, California

Old House Gardens in Ann Arbor, Michigan (, specializing in heirloom varieties of bulbs. Their oldest dahlia dates back to 1882.

American Dahlia

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In a North State Garden is a weekly Northstate Public Radio and web-based program celebrating the art, craft and science of home gardening in Northern California. It is made possible in part by the Gateway Science Museum – Exploring the Natural History of the North State and on the campus of CSU, Chico. In a North State Garden is conceived, written, photographed and hosted by Jennifer Jewell – all rights reserved In a North State Garden airs on Northstate Public Radio Saturday mornings at 7:34 AM Pacific time and Sunday morning at 8:34 AM Pacific time.

Jennifer Jewell
In a North State Garden is a bi-weekly North State Public Radio and web-based program celebrating the art, craft and science of home gardening in Northern California and made possible in part by the Gateway Science Museum - Exploring the Natural History of the North State and on the campus of CSU, Chico. In a North State Garden is conceived, written, photographed and hosted by Jennifer Jewell - all rights reserved In a North State Garden airs on Northstate Public Radio Saturday morning at 7:34 AM Pacific time and Sunday morning at 8:34 AM Pacific time, two times a month.
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6 Responses

  1. Another delightfully informative and wonderful jewel of an article. Thank you, Jennifer Jewell. 🙂

  2. Avatar `AJacoby says:

    My mother was a dahlia cultivator. She loved everything from the dinner-plate dahlias to the tiny pom-poms. As she was an inveterate amateur floral arranger, she found them particularly useful in her arrangements.

    If you are a dahlia lover and ever get the chance, visit the Sawn island Dahlia Show and Sale in Canby (just south of portland), Oregon in the fall.

    Thank you for another informative article, Jennifer.

  3. Avatar Carrie Dokter says:

    I fondly remember the rows of dahlias my father-in-law used to have years ago here in Happy Valley and how he nurtured them so lovingly. Thanks for the memory and the beautiful pictures. 🙂

  4. Avatar Pamela says:

    Gorgeous photos! Simply stunning.