Are Dahlias Perennials or Annuals? We Share Everything You Need to Know
These flowers can be seasonal or year-round depending on your climate
Jacky Parker Photography / Getty Images
Dahlias offer beautiful, bold flowers that bloom from summer through late fall and can be grown in your garden or even in pots. They are easy to grow and come in an assortment of colors, but depending on where you live, they can be perennials or annuals, requiring different types of care. If your area freezes, for example, you won’t be able to leave your dahlias in the ground during winter.
To better understand when and where to grow dahlias as perennials or annuals, we talked to dahlia experts who know all about their care. Read on for their advice and tips for growing dahlias.
Are Dahlias Perennials or Annuals?
Dahlias are technically perennials, however, leaving them in the ground over the winter is not recommended if you live anywhere where the ground freezes below 32 °F.
“In their native environments, such as in Mexico, dahlias are perennials and can survive outdoors year-round,” Deborah Stone, co-owner and operator of Stone Hollow Farmstead, says.
Stone explains how it's important to think of dahlias as annuals if you live in regions where the ground freezes unless you take steps to protect their tubers from freezing temperatures.
Zones 8 - 11 are warm enough to leave dahlias in the ground, however, it's risky because it could lead to potential rot or possible freeze, Stone says. In colder zones (7 and lower), dahlias are not likely to return a second year so think of them as an annual that needs to be removed from the ground and stored indoors.
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Can Dahlias Be Grown as Perennials?
Dahlias can be grown as perennials in cold zones if their tubers or bulbs are dug up and stored indoors during the winter months. If your zone is on the border of another that freezes, pull your dahlia tubers from the ground to be on the safe side.
“Our farm, Stone Hollow Farmstead, is located in Zone 8,” Alexandra Stone Flowers, co-owner and operator of Stone Hollow Farmstead, says. Although the farm is on the cusp where ground freezing could be a concern, they consistently dig up their tubers every winter.
“It’s crucial to adapt gardening practices to your specific climate conditions—using local insights and instincts can make all the difference," Flowers says.
How to Properly Overwinter Dahlias
Dig Up the Tubers
After the first frost has killed the above-ground foliage, dig up your dahlias to overwinter the tubers.
Cut back the dahlia’s foliage back to the stems to about 2-3 inches.
Take a hand trowel and dig around the dahlia tuber. Be careful not to break the roots coming from the tuber (or bulb).
Once the tuber is out, gently shake the dirt off.
Repeat these steps until you’ve dug up all the tubers.
Clean the Tubers
Clean the tubers by gently washing the dirt off with a garden hose.
Remove any excess soil.
Gently dry the tubers.
Divide the Tubers
If the tubers have several eyes, or sets of cells where the dahlia plants grow from, you can divide them to create more dahlia plants.
Use a sharp knife to divide tubers.
Store the Tubers
Tubers need to be stored in a cool, dark area with some humidity. Stone explains that the ideal temperature for storage is between 40-50°F, in a medium like peat moss or vermiculite that keeps them dry yet prevents them from drying out completely.
You can store the tubers in a range of containers, from plastic bins to paper bags. Just be sure there is enough space left between each tuber and good air circulation in the room.
Check Them Over Winter
Periodically check your stored tubers over the winter for any signs of rot or excessive drying out.
If your chosen storage space for your tubers is too moist and humid, your tubers will rot and turn to mush. If this happens, remove those tubers and decrease the room’s moisture. If your storage space is too warm, however, and your tubers shrivel, mist them with some water to help them slowly rehydrate.
Frequently Asked Questions
Do dahlias come back every year?
Yes, these flowers grow back every year, but depending on
what USDA zone you live in, you will have to take them out of the ground and
overwinter them. Replant these tubers again in summer.
How do you tell if a dahlia is a perennial?
The variety of dahlia does not matter. Rather, it is the growing conditions and environment that do. USDA Zones 8 - 11 are warm enough for dahlias to stay in the ground, so there they can act like a perennial flower.
Can you leave dahlias in the ground over winter?
Only if your growing zone does not freeze. Remember to always check your growing zone before determining whether or not to remove your dahlias from the ground.
Read Next: 20 Plants With Large, Beautiful Flowers You Should Grow
Read the original article on The Spruce.
