Growing Dahlias in Minnesota
Mary Gadek, Dakota County Master Gardener
As Minnesota settles into summer, blooms are starting to burst out everywhere in our gardens. One all-star beauty for the garden is the magnificent dahlia. Not only are dahlias beautiful in the garden or inside in a vase, but they are economical. Dahlias are a bulb plant and, although they can’t survive a Minnesota winter, the bult can be dug up in the fall, overwintered and planted again next spring. Read this article to learn more about how to choose the right dahlia for you and how to care for and overwinter the plant you have chosen.
As Minnesota settles into summer, blooms are starting to burst out everywhere in our gardens. One all-star beauty for the garden is the magnificent dahlia. Enjoy a few dahlias in your outside garden. Or, better still, include them in a cutting garden which allows you to bring vibrant color and fragrance indoors to further celebrate the fruits of your labor. The dahlia bestows a beautiful and unique specimen to your dining table bouquet at the end of summer.
Read along here to find out how to choose, plant, nourish and store dahlias in Minnesota gardens.
Where to start
Minnesota garden centers offer many choices for dahlia bulbs. Dahlias originate from Mexico and Guatemala, which makes them “tender” bulbs, (meaning they cannot survive freezing winter weather). But dahlias are still an economical buy. As “bulbs,” they can be overwintered and grown again in subsequent years.
There are so many different sizes and colors of dahlias that it can be hard to choose which ones are best for your garden. If you are undecided about which dahlia bulbs to choose, visit the University of Minnesota Landscape Arboretum Dahlia Trial Garden to experience the many colors and varieties of dahlias.
Planting
Late May to early June meets the ideal conditions for planting dahlia bulbs; that is - when the soil has reached 60’F and the threat of frost has passed. Find a spot in your garden that has at least 6 hours of sunlight, with morning sun and afternoon shade, in well-drained soil.
After you have chosen and planted your dahlia bulbs, you need to know how to care for them. The Minnesota Dahlia Society provides an excellent resource for planting and care of dahlia bulbs:
Four care steps to highlight are:
Watering: Dahlias need one inch of water every week.
Topping: To achieve a bushier plant, remove the tip of the plant after three sets of leaves have grown.
Disbudding: The maximum potential of dahlia buds is obtained by removing the side buds to direct growth energy to the top bud of the plant.
Staking: For taller dahlia varieties that grow up to 3 feet, add a plant support, such as a garden stake or chicken wire fencing, at the time of planting. Secure the plant to the stake once it is about 1 foot tall, and then again as the plant gets taller, to help prevent wind and storm damage.
Winter Storage
Dahlias cannot survive our Minnesota winter, unfortunately. But the good news is that you can dig up dahlia bulbs, store them over the winter and plant them again the next spring. After 7-14 days of a fall killing frost, dig up the frost sensitive bulbs. Store in a 40-50-degree part of your house in a medium, like peat moss or an unsealed plastic bag, to prevent drying out the bulbs.
Next May, take out your stored bulbs an enjoy your magnificent Minnesota dahlias all over again!
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