Dahlia Primer: Part 1 - Growing
THE BELOVED DAHLIA
Because of the variety of shape, size, and color, dahlias remain one of the most sought after varieties of specialty cut flowers. Each plant is unique unto itself, and with every generation of seeds an entirely new variety of dahlia is born. Currently, the American Dahlia Society has over 10,000 cultivars, each producing their own very special flower. Among these cultivars are varieties shaped like peonies, anemones, lilies and even cacti in every color but blue. The urge to explore and develop these flowers has been exciting florists around the world for hundreds of years and that excitement only continues to grow! These flowers are among the most highly sought-after by florists for wedding and special events, however their short vase life and intolerance for refrigeration make them difficult to find in stores and shop coolers. An easy choice to source locally, say from your friendly neighborhood flower farmer!
The Basics
Dahlias are perennial from USDA zones 8 and up - they can be left to overwinter and will grow back as vigorously in the next year. Over several years, the plants may become less productive, but
at that stage they can be dug up and divided... more on that later. In zones 7 or higher, dahlia plants are grown as annuals. Each year, the plants will die off after the first hard frost. They can then be dug, divided and stored for replanting the following spring.
Plants will vary in height by cultivar, but can grow up to 5 feet or taller. Plants are multi-branching, and again while variable based on variety, will produce 10-20+ blooms! The blooming season begins in June or July, depending on zone, and continues through the first frost or ~October-November. It is because of this long blooming season that dahlias are a favorite among cut flower producers and gardeners alike.
At the end of growing season, each plant can produce hundreds of seeds, each of which will yield an entirely new flower in the next year. The tuber clumps? Yeah, they multiply too! Like peonies, after 1-2 growing seasons, the tubers can be divided to produce more plants in the following year.
So.. How do I grow them?
One of the most unique thing about dahlias is how they are grown. Dahlias are typically grown from a tuber, basically... a potato like root or clump of roots, though they can also be grown from seed. Similar to tulips or apples, however, when grown from a seed the resulting plant and flower will not be exactly the same as it's parent plant or plants. This is especially true if the plant is open-pollinated where it can be easily crossed with nearby plants and retain some of their characteristics, and how we end up with so many unique varieties. In either instance, dahlias require only a few key things to grow successfully in most any environment. The flowers shown below were harvested from plants grown from tuber and seed - both producing beautiful blooms in the first growing year.
When growing from tuber the steps are pretty straightforward. If you have purchased a tuber, ideally, it will already have what's called an eye - a node from which plant growth will start... again, similar to what you've seen sprouting from your overripe potato. This may be difficult to see, but check back for Part 2 where we'll share some tips on spotting them. For the sake of argument, we'll assume your tubers have eyes. For seeds - there is no mystery here, just getting the timing right and knowing that whatever flowers that little seed ultimately grows to be will be totally unpredictable and lovely. The flower shown below were grown from both tubers and seeds, with plants from both producing abundantly this year.
Growing from tuber
Step 1. Site selection: find a sunny spot (min. 8hrs full sun per day) with good drainage... dahlias don't like wet feet.
Step 2. Prepare the bed. Add 2-4" of compost and manure. Add a sprinkle of bone meal if you've got it on hand. Mix this well with the soil.
Step 3. Dig a hole about 4-6" deep and place the tuber, or tuber clump, in the hold with the eyes facing up. Cover with soil. Space plants AT LEAST 12" apart
Step 4. Resist the urge to water!! Overwatering can lead to rot early on so wait to water until you see sprouts.
Growing from seed
Step 1. Plan to plant your seeds about 6 weeks before last frost. Here in New York that is ~May 20, but check USDA for your zone.
Step 2. Fill your planting tray (we recommend no smaller than a 72-plug tray) with a potting soil mix that has vermiculite. Plant one seed per cell just below the surface. Lightly mist and place trays on a heated mat or in a room where the air temp is at least 70 degrees. Keep them damp, but not soaked and you should see sweet little sprouts in 1-2 weeks.
Step 3. As the dahlias get bigger, you may need to re-pot. Wait for the leaves of the seedlings to touch before doing so.
Step 4. Once you've had your last frost - be VERY sure it's the last.... follow the steps 1-4 for tuber planting above.
A Fun Experiment...
No matter the method, we're sure the results will be stunning. If you fancy yourself a mad scientist of growing, we invite you to take on the challenge of producing your own varieties and sharing the results. We harvested the seeds from both our known varieties and plants that we grew from seed this year. All were open pollinated, so no controlling for specific colors or varieties, essentially, every seed from the crop will produce a totally unpredictable combination of characteristics from stem length, to flower size, to color. Seeds can be purchased in our shop and shipped to your door. Send us your photos and maybe, just maybe we'll choose our favorites for a special surprise....
Parts 2 and 3.... Designing and Dividing, coming Soon. Sign Up for our Newsletter to subscribe!