QUESTION: Are dahlias annuals or perennials? I keep looking around and can’t get a clear answer. Patricia F
ANSWER: Dahlias are considered tender perennials. This means that they can return each year as long as they aren’t exposed to frost.
In many cases, these flowers are grown as annuals. How you choose to grow your dahlias will depend upon your planting zone.
If you live in planting zones seven or lower, you’ll need to either plant dahlias as annuals or dig up the plants’ tubers at the end of the growing season.
You do this by digging up the plant after the foliage has died back. Allow the tubers to air dry in the shade for 48-72 hours.
From there, dust the tubers with sulfur to deter diseases from forming. This is especially necessary if the tubers have been damaged or nicked during the digging or drying out process.
Once the tubers are dry and have been dusted, store them in a cool, dark location until next spring.
When spring arrives, you can plant the tubers again to have another generation of dahlias.
If you live in planting zones eight and nine, your dahlias will experience some hard frost. However, with the right protection, they may come back in future years.
Once the foliage dies back from frost, cut the plant back to where it’s only two inches above the ground.
Then cover the plant with a few inches of mulch. This will provide insulation from the winter temperatures and should help the plant survive winter.
Finally, if you’re in planting zones ten and higher your dahlias won’t need any winter protection.
No matter where you grow these plants, they must all be planted in adequate growing conditions.
Dahlias like to grow in nutrient-dense, well-draining soil. It’s vital that the soil drains adequately to keep the tubers from rotting.
You should also grow dahlias where they’ll receive a minimum of six hours of direct sunlight each day. If you choose a larger variety of dahlia, be sure to provide some form of support to discourage the stems from breaking.
Now that you know what to expect when growing dahlias in each planting zone, take the time to figure out which zone you’re in.
Then take the tips given here and apply them to your gardening experience. As long as dahlias are given what they need in growing conditions and protection from the cold, they should produce immense beauty around your home.