Dahlias, a Fall Favorite

Very few plants offer as many colors, sizes and forms as dahlias do. Dahlias can be grown successfully in the garden or in containers and will bloom from mid-summer to first frost. 

Dahlias originated in Central America where they were called Acocotli and Cocoxochitl by the ancient Aztecs. Spanish explorers brought the plants back to Europe and it was a staff member at the Royal Gardens in Madrid, Spain who named the plant after Swedish botanist Andreas Dahl.  Dahl considered the flower a vegetable. The first varieties with large, double flowers were bred in Belgium in the early 1800’s.

Now there are hundreds of varieties to choose from, ranging in size from less than 2" in diameter to over 8" and flower types from ball to semi-cactus. Dahlias are grown from tubers and are planted in late May through early June, when the soil temperature is warm enough and late spring frosts are rare. Dahlias love the sun, so pick a place in the garden that gets the most sun during the day. 

Dahlias will grow in an area where there is some shade, but the plants will be taller and you’ll typically get fewer flowers. Amend the planting site with compost and peat moss. Mark each tuber as you plant it and water thoroughly. Planting time is also the right time to add staking. Dahlias will need to be staked in order to keep the stalk upright and the blooms from falling over. Stakes should be at least six feet tall and driven into the ground until firm. Once vegetation has emerged, feed your dahlia tubers with a fertilizer that is high in Phosphate and Potassium and low in Nitrogen.

About August, you’ll see buds forming at the top of the stalks. Blooms follow shortly and will continue until frost, providing color to your garden and forage for the pollinators. 

Dahlias are tender bulbs and must be dug and stored through the winter if you want to save them. You’ll be amazed at how much the tubers have grown through the season. Wash the tubers off and let them dry for a day. Once dry, pack the tubers in a loose, fluffy material such as peat moss or vermiculite and store in a cool, dry place. Tubers may be divided before you put them in storage or in the spring, as you are getting them ready to plant.

Dahlias are one of the most spectacular of the garden flowers and there’s always something to learn about them. On Saturday, August 25 and Sunday, August 26 The Flower Bin will host The Colorado Dahlia Society 2018 show. The theme of this year’s show is Let’s go to the Movies. This is a great opportunity for you to enrich your dahlia knowledge. For more details, visit the Colorado Dahlia Society website: http://www.coloradodahlias.net/events/category/upcoming_cds_events/