Dahlias have incredible blooms with bright colors and are showstoppers in many backyards around the country. After the blooming season, many people wonder if Dahlias will grow back and bloom the following season. Happily, we can say if you live in warmer areas, then yes, Dahlias are considered a perennial.
Dahlias are a perennial and re-sprouts in its warmer climate from the same root system year after year. The dahlias’ root systems send up shoots every year and blossom great big flowers in the spring.
The dahlia is an incredibly beautiful and robust flowering perennial. Read on for more information about perennial dahlias and how to care for them in your backyard.
Where Do Dahlias Grow Best?
Dahlias sprout new shoots and blossom fresh flowers every year from the same set of roots and root system that gets left in the soil from the previous year, but they only do this in warmer climates. Dahlias are winter hardy for USDA climate zone 8 through zone 11.
The USDA recommendations for perennial plants in zones 8 through 11 can withstand outdoor winter temperature lows of 10 to 15 degrees. The temperature range is the frost resistance range for Dahlias meaning zone 8 through zone 11 are partially frost-resistant. Zone 8 through zone 11 make up a good part of the west coast and much of the southern United States.
Just because you may live in a colder climate than zone 8-11 doesn’t mean you can’t grow dahlias. Starting dahlia cuts and roots in a greenhouse or indoors is possible for colder climates, allowing you to bring the flowers out into the summer sun. However, perennial dahlias need warmer temperatures for their roots to live through the cold of winter.
How to Grow Dahlias
Growing dahlias is not tricky, but can be time consuming. You must get a solid root system established before you can sit back and enjoy the dahlia flowers year after year.
Propagating dahlias requires a cutting with decent root rhizome exposure. Make sure the roots or bulbs get planted in a well-drained and sunny location. Poorly drained soil needs some fine gravel or substrate mixed into the ground. Peat moss is also suitable for amending the soil around dahlias. Just be sure that the substrate or amendments don’t have nitrate as a fertilizer.
Some pointers about planting and growing cuts or roots of dahlias are listed below:
- Bury root structure two to four inches deep in the soil.
- Amend about 6 to 12 inches in diameter of soil with fertilizer and compost and some small gravel substrate if it is poorly draining soil.
- Make sure giant dahlias get planted 3 feet apart.
- Plant giant dahlias with spiral or straight wood stakes of bamboo for support.
- Backfill the hole with native dirt
- Fertilize monthly, especially in the months leading up to the blooming of dahlias.
- Avoid nitrogen-rich fertilizer; otherwise, you will get a lot of foliage and not much flower growth.
Overall, dahlias are a little more particular about soil, watering, and sun than other hardy perennials. But, the dahlia will last for a long 120 day growing season, meaning that there is a lot of work needed for the full potential of all dahlias types and sizes to be seen in your backyard. But, for those willing to put in the work, dahlias make an excellent addition to any yard and keep coming back year after year once the root system gets established.
Sizes of Perennial Dahlias
Dahlias grow in three different distinct sizes. The larger flowering perennial is about three feet tall. It needs some sort of structure to hold them upright for them to make it to flowering maturity. These large blossoms are sometimes the diameter of a large dinner plate. They are showstoppers that need lots of nutrients and water for their full potential of growth.
The medium-sized dahlias are some of the most recognizable in flower stores. Medium-sized Dahlias are much more common and don’t usually need structural support for their blossoms. However, they are also tall and need lots of sunshine. Make sure that the dahlias are about three feet apart, even for medium-sized flowers, so that they don’t cast shade on the foliage of other plants.
Finally, the small or petite dahlias put out tiny little flowers in the size and shape of lollipops. These smaller dahlias have the same soil, water, and growing length of time and all other requirements for developing that the more enormous dahlias have.
These petite flowers are much more plentiful on the plant and are better for keeping on the stem. In contrast, the large blossoms are best for cut flowers in centerpiece designs. However, petite flowers are also great for mixing with other summer flowers. Summer annuals may benefit from the root base and soil amendments already in place for your small dahlias.
Dahlias are perennials that shoot out big, brilliant flowers that can be up to the diameter of a dinner plate. These perennials grow best in warmer conditions in zones 8 through 11. They are some of the best flowers for cutting and using as decoration. The petite type of dahlias are perfect for mixing with other flowers, and all dahlias are quite a lot of work for their 120 days growing season.
If you are a fan of cut flowers or looking for a robust, hardy perennial in your zone 8 through 11 climates. In that case, dahlias are an excellent investment in time and work that will keep giving you blossoms each year in the same position in your garden.
We also discuss whether mums are perennials.