I didn’t always love dahlias. As the offspring of an intense, knowledgeable and slightly obsessive gardener, I knew what a dahlia was by the time I was in preschool. But out of all the plants my mother grew furiously in her hillside garden in Normandy, dahlias were my least favorite. I remember finding them fussy, complicated and dramatic.
Then one spring day about 10 years ago, I found a paper bag on my porch. Inside was a funny looking clump of roots covered with dirt, and at the center a sprout pointing upward with intent. It was a gift of flowers asking to be born, and I knew just what to do.
As it turns out, this is how most dahlia addicts are made, with an innocent gift from a dear friend. As I watched my present grow and bloom in the most lovely shades of white and purple, I realized I too had grown since my last experience with dahlias and was now equipped to appreciate their intricate and ever-changing complexity.
Holy Octoploids!
The discovery of dahlias is quite an epic story of missed opportunity. Spanish conquistadors pushing through new land in Central America looking for spices and precious metals barely noticed a plain-looking flower with bland-tasting tubers. They drew it, catalogued it and then walked away from it – completely unaware that they had just passed over a genetic treasure with a DNA structure so unique it had the potential of becoming the most diverse genus of the plant world. It took another 200 years for someone to put a few tubers in a crate and ship them back to the old world where they exploded in popularity.
Dahlias are octoploids. Where most plants (and animals) possess two sets of chromosomes, dahlias have eight. They also possess transposons, or jumping genes, which allow their DNA to rearrange randomly. Imagine now the infinite number of combinations at the fingertips of plant breeders holding the knowledge and patience to exploit these mutating beauties. Endless possibilities. Which is why from the original 36 species there are now 50,000 varieties.
In Every Size and Shape
Dahlias come in many shapes and sizes, and even more colors. Their flower classification is fairly complex and ever-changing, so it helps to think of them in somewhat simpler terms. Shapes range from small and simple to very large and extremely complex. On the simple end of the spectrum, you will find the singles, stars and collarettes as well as peony- and anemone-shaped dahlias.
On the other end reside the multiples: balls, decoratives, cactus shapes, stellars, laciniated (fringed) and my personal favorite, the waterlilies. Color ranges from pure white to almost black, hitting many shades of yellow, purple, orange, pink and red along the way. There are no green or blue dahlias.
Smart Dahlia Shopping
When it comes to sourcing tubers, buy domestically from a reputable farm. You can peruse online catalogues of dahlia farms until you find the one variety that makes your skin tingle and hope that it is available. (You will most likely fall in love with more than one variety!) Sales usually go live in late December or early January. The rare or popular varieties sell out very quickly, sometimes within hours. Many servers have been crashed by crazed dahlia lovers trying to get a piece of a hot new variety.
The website dahliaaddict.com is a great resource when looking for a specific variety: you can click on the variety you are looking for and it will show you who sells it. You can then compare prices and look at customer reviews for each farm. Once your order is placed, your tubers are then shipped to you in the spring.
To Start Indoors or Out?
There are two ways to start dahlias in the spring: You can direct plant when the ground has reached 50 to 60 degrees F (or when the lilacs are in full bloom), or you can get a jump start by potting them indoors four to six weeks before the last frost. Starting dahlias indoors can give you blooms as early as late June, whereas direct-planted dahlias will not bloom until late summer. Potted dahlias should be hardened off slowly before planting by bringing them outside during sunny days and back in at night for a week or so.
When all danger of frost has passed, you can plant your dahlias. To the soil in your planting hole, add a little bonemeal and a low-nitrogen fertilizer, which will promote blooms over foliage.
Location, Location
When picking a location for your dahlias, a fenced garden is ideal for deer protection, but dahlias can make nice additions to perennial gardens too. A full-sun spot is best. Plan to put your tallest varieties towards the back of the bed and go ahead and put a stake (or two) in the ground with each. They will need the support. Short varieties can get away with less support. Mulch around the plants to keep the roots cool and the soil healthy. Dahlias like to be watered deeply two or three times a week. (Water needs to reach the roots, not just wet the top of the soil.) Happy dahlias should bloom well into the fall, until the first hard frost.
The Winter Storage Challenge
On the Vineyard, dahlia tubers cannot survive the harsh winters in the ground; they must be dug up at the end of the season. Wait until the tops have turned almost completely brown in late fall. Then gently dig or fork the tubers out. You will find that while the plant was producing flowers above ground, it was also producing tubers underground. One single tuber can yield five to ten new tubers. Each one of these tubers can become a new plant, expanding your collection or creating opportunities to share with others. You just have to overwinter them successfully.
Perfecting storage protocol is one of the hardest parts of growing dahlias and often the reason gardeners give up. If the environment is too moist, they will rot. If it is too dry, they will shrivel and die. I’ve found that a cardboard box with sphagnum moss or wood shavings works well. If possible, store the dahlias in a room that is dry and around 50 degrees F. The good news is that you can easily determine if there is an issue by simply checking on your tubers regularly and adjusting the conditions.
You might be thinking right about now that growing dahlias is way too labor intensive, an opinion shared by my husband and children while they watch me lovingly dig, brush, inspect, divide and pack my precious tubers on Thanksgiving day. While it’s true that dahlias require quite the commitment, there is a real bond that forms when caring for something so much. Maybe it’s the Florence Nightingale effect, but the idea of simply overwintering them in the ground saddens me. I would miss not seeing them in the fall, holding the new tubers in my hands, and introducing myself. For dahlias are to me about more than pretty flowers; they are about connection – to the plant and also to others who love them.
Dahlia People
In the spring/early summer of 2018, as my collection was growing along with my obsession, I often found myself in late-night text conversations with the very friend who had gifted me my first dahlia. We talked about varieties we were growing or ones that we lusted after, when to plant or how to prep soil. We helped each other troubleshoot our hurdles. We also texted each other pictures of blooms we were particularly proud of. It felt wonderfully supportive and was a welcome escape from our daily stressors. I started wondering if there were more of us out there looking for connection, kinship and yes, free tubers, so I went on Facebook and created the Vineyard Dahlia Collective group, invited a few people and waited to see who would come out of the woodwork. The group grew, and I found a tribe.
This spring I hoped to organize a tuber swap to physically bring our micro- community together to learn from each other and exchange tubers. We had found a venue and I was working on a poster concept. Then the world shut down and our lives were stripped of the connections we need so badly. But dahlias remained. When Islanders poured their souls into their gardens, raiding nurseries for seeds and building new beds and borders, our little dahlia community also grew stronger. 2021 will be a great year for a swap; we might even add a speaker or a flower arranging workshop. I hope we see you there.
Amandine Hall lives in Vineyard Haven with her husband and three children and teaches chemistry at the Martha's Vineyard Regional High School.
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