It’s midsummer and your garden is an unabashed and climactic display of fragrant colors to marvel the senses. Nothing uplifts the heart of a gardener more than bearing witness to months of effort culminating at this very moment.
But just when you thought your summer garden has peaked and most spring plantings are in final blossom, dahlias begin their gloriously colorful and long blooming cycle.
Dahlias are considered an “old-fashioned” garden treasure but there is nothing antiquated about them. This genus of bushy, tuberous, herbaceous perennials offer an outrageous diversity of shape and appearance from formal decorative, pom-pom, water lily, cactus and dinner plate that raise them to ‘deva status’ in and garden bed. Whichever variety of these easy-to-grow delights you choose to plant, they will never fail to enchant.
The final journey of the dahlia into the home garden is a centuries long story rich in history. Spanish explorers reported discovering the dahlia in Mexico in 1525, but the dahlia had long been propagated and utilized by the Aztecs as both a food and medicine prior to the Spanish invasion. Cultivated and gathered in the wild by indigenous people, the dahlia was a purported treatment for epilepsy, and utilized as a water pipe due to its large hollow stem.
Their leader Moctezuma as a young prince followed in his father’s footsteps, as an avid horticulturist. Dahlia specimens from the high plateau and highlands of the then Aztec empire were gathered, and transported for final planting in the gardens of Aztec nobility amidst great ceremony and ritual.
It comes as a surprise to many that all of the 27 known dahlia species originate from Mexico, and not Europe. During the months of August and September, you can still observe a massive profusion of blooming dahlias along the roads, cliff sides, cultivated fields and volcanic mountains of Mexico.
The dahlia found its way to Spain in 1791, where European cultivation began. By 1934, Dahlia cultivars numbered over 14,000.
The love affair with the dahlia, whether home or professionally grown, is ongoing today on a global scale. This stunning flower is cherished on both sides of the Atlantic prompting the formation of dahlia societies, while generating an industry with revenue in the millions from plant and seed exchanges, horticultural shows, and publications on everything dahlia.
Planting and care
The dahlia family is cold hardy in USDA Zone 8a and warmer. In Zones 7 and colder they are treated like tropicals or annuals requiring the gardener to dig up the tubers each Fall. Fortunately here in Del Norte County we can leave our tubers in the ground but a good thick layer of mulch will ensure protection and flowering success for the following season.
Closer proximity to the coast will require a full sun location, and ample protection from the cold ocean winds. If you live in the warmer climes of Del Norte County your dahlias will still enjoy the full sun but some afternoon shade is appreciated.
Dahlia tubers — often referred to as bulbs — are a springtime planting endeavor. Wait to put in the ground until after the last frost.
Dahlias thrive in rich, humus soil with low nitrogen amendments. I prefer to use the organic Dr. Earth brand bulb food that has an N-P-K of 3-14-2, which provides the tubers with an abundance of nutrients for excellent green growth, and fabulous blossoms.
Dig a hole approximately 1 foot deep, with 16-24 inches spacing between plants. If planting a cutting dahlia or a dinner plate dahlia, I recommend placing a large 3-6 foot stake toward the middle of the hole for securing your dahlias during late season growth. Dahlia blossoms can be quite heavy, particularly the dinner plate variety, so the smart gardener will place the stake early to avoid any risk of harming the bulb at a later time.
Place your bulb 4-6 inches deep and cover it with 2 inches of soil along with a generous handful of your organic bulb food. Do not water until the tuber sprouts. As the tubers grow keep adding soil to promote a strong base, which in turn keeps the roots cool. Do not overwater.
If a more compact plant is desirable, pinch the new shoots early to promote bushy rather than tall and leggy growth. Just say no to chemical herbicides and weed by hand throughout the growing season. You’ll be rewarded with a multitude of flowers if you keep cutting as they continue blooming.
Dahlias multiply underground with very little effort, making them readily available for gifting within your gardening network. If you’re new to the dahlia world, it’s time to get on board for next season. With minimal expense and effort you’ll understand why the world has had a love affair with the dahlia for more than five centuries.