Dahlias are the favorite flowers of gardeners and flower enthusiasts alike for their stunning and diverse blooms. Knowing when dahlias start blooming is important to plan for a successful garden or cut flower arrangement. The bloom time of dahlias varies depending on several factors, including the variety, location, and climate. In general, dahlia blooms begin to appear in mid-summer and can last through the first frost of late fall.
However, many gardeners prefer to plant their dahlia tubers earlier in the dahlia season, starting in early spring after the last frost date has passed. This allows for a longer growing season and more time for the dahlias to produce flowers. It’s important to note that different varieties of dahlias bloom at other times in your flower garden. Additionally, dahlia blooms can be encouraged by dead-heading spent flowers and pinching back the plant to encourage bushier growth.
They need adequate water, nutrients, and morning sunlight to promote more blooms when growing dahlias. In our guide, you can learn more about how to plant Dahlia tubers, and after you plant the dahlia tuber first, when you can expect your Dahlia bloom. By the end, you’ll better understand when you can expect your garden to be full of flowers and what you must care for your blooming plant. (Read When Are Sunflowers In Season)
When Do Dahlias Bloom
Dahlias are a popular flowering plant that produces blooms in various colors and sizes. Knowing when dahlias bloom is essential to ensure you can enjoy their beauty in your garden.
Factors that Affect Dahlia Blooming Time
Several factors can affect when dahlias bloom. Here are some of the most important ones:
- Planting Time: Dahlias are planted in the spring, and their blooming time depends on when they are planted. If you plant them early in the season, they will bloom earlier. If you plant them later, they will bloom later.
- Temperature: Dahlias require warm temperatures to bloom. If the temperature is too cold, they will not bloom. Once the temperature reaches around 60°F, you can plant your dahlias, and they will begin to bloom in about ten to sixteen weeks.
- Light: Dahlias require full sun to bloom. If they do not receive enough light, they may not bloom or will produce fewer blooms.
- Watering: Dahlias require regular watering to bloom. If they do not receive enough water, they may not bloom or will produce fewer blooms.
- Fertilization: Dahlias require regular fertilization to bloom. If they do not receive enough nutrients, they may not bloom or will produce fewer blooms.
- Variety: Different varieties of dahlias bloom at different times. Some bloom early in the season, while others bloom later. Ensure to choose a type that blooms when you want them to.
Factors that Affect Dahlia Blooming Time
Dahlias are beautiful flowers that bloom in various colors, shapes, and sizes. While the blooming time of dahlias can vary depending on several factors, it is generally between mid-summer and late fall.
Climate and Temperature
The climate and temperature of your location can have a significant impact on the blooming time of dahlias. Dahlias are native to Mexico and prefer warm climates. They thrive in temperatures between 60°F and 70°F. If the temperature drops below 50°F, the growth of dahlias can be stunted, and their blooming time can be delayed.
Varieties of Dahlias
Once you plant dahlias, the type you choose affects the blooming time. Some varieties, like the ‘Café au Lait’ and ‘Labyrinth,’ typically bloom mid-season, while others, like ‘Rebecca’s World,’ bloom later in the season.
Planting Time and Location
The time and location of planting dahlias can also impact their blooming time. Dahlias should be planted after the last frost date in your area. Morning sunlight is essential for the growth of dahlias, so choose a location that receives at least six hours of direct sunlight. The planting hole should be 12 inches deep and filled with soil and peat moss.
Dahlias are a tender perennial and require winter storage in colder climates. The Dahlias tubers or Dahlia seeds can be used with tubers the more common. (Read When Do Irises Bloom)
Planting Dahlia Tubers
When planting dahlia tubers, timing is vital. Wait until the soil has warmed up to at least 60 degrees Fahrenheit.
Here are the steps to planting your dahlias:
Preparing the Soil
Before planting your dahlias, ensure the soil feels dry and crumbly in your hand. You can amend the soil with compost or well-rotted manure. It’s also vital to ensure the soil pH is between 6.0 and 7.0.
Planting the Tubers
Dig a hole about 6 inches deep and wide enough to accommodate the tuber. Place the tuber in the hole with the “eyes” facing up, and cover it with soil. Space the tubers about 18-24 inches apart, depending on the variety. Water the tubers well after planting.
Caring for Dahlia Plants
Dahlias thrive in full sun and require regular watering. Avoid getting water on the leaves, which can lead to powdery mildew.
Dead-heading and Disbudding
As plants grow, you can encourage dahlias to produce more flowers, so it’s vital to dead-head spent flowers regularly.
Pinching is another technique of Dahlia care to help dahlias produce bushier plants. When the plants are about 12-18 inches tall, pinch off the top inch or two of growth.
How to Fertilize Dahlias
Dahlias really must be fertilized. These plants need a lot of good food. They should be grown in rich soil. But even in the rich dirt with good drainage, most dahlias need some extra food. You should pick a fertilizer recipe that has a moderate amount of nitrogen. Even though it’s important to fertilize your dahlias, you don’t have to do it all that often.
If the leaves on your dahlia flowers are going yellow and the flowers are drooping, cut back on the fertilizer. (Read When Does Bird Of Paradise Bloom)
How to Mulch Dahlia Cultivars
If you live in a dry place where water evaporates quickly? Consider putting mulch around your dahlias to keep the dirt moist. But mulching can make the soil cooler, and dahlias do best in hot weather. So, please don’t do it unless you must mulch to keep the dirt from drying out.
How to Stake Dahlias
Dahlias can get quite large and heavy; if they are too heavy, they can fall. So, stake some of your own dahlias to bloom with metal or wooden stakes, string, or twine.
How to Pinch Dahlias
In the spring, you have to “pinch” your dahlias. It can be a pain, but you only have to do it once per season, which is good. As the stem grows, it splits into two. When there are three pairs on the stalk, pinch out the middle. This makes the plant grow more at the bottom, making it bigger and giving you more blooms.
How to Disbud Dahlias
You might be excited if you see many buds on one stem. You might think your dahlia plant will make a lot of big, beautiful flowers.
But all those flowers will be smaller and less impressive than you think. Dahlias make more flower buds than the plant’s tuberous roots can feed. Disbudding is needed so a certain number of flowers can get enough food.
How to Dead-head Dahlias
Dead-heading the dahlias early is a topic that is worth discussing. The time to dead-head them is worth it because it makes the growing season last longer.
In addition, dahlias are harder to dead-head than other plants. The trouble is it’s hard to distinguish between a dahlia flower that has lost its petals and a fresh flower bud just by looking at them.
Why Grow Dahlias?
Here are a few reasons to consider adding gorgeous dahlias to your garden:
- It would be almost impossible for one grower to grow all kinds of dahlias.
- They can live just about anywhere.
- Dahlias can come back year after year in most temperature zones if handled well during the winter.
- Long-lasting flowers.
- If you trim dahlias right, they can bloom for four months.
- Most of the time, deer don’t bother them.
- They can be grown in pots.
- Butterflies and hummingbirds might like them.
- Butterflies and hummingbirds love growing Dahlias flowers.
Recommended Dahlia Flower Varieties
You’ll find an endless choice of dahlias to choose from. So, you can pick during the Dahlia season or buy Dahlia tubers ready to plant for the following Dahlia season.
Dahlia growers start Dahlia tubers around March or April, well before the blooming season arrives. Before learning the individual cultivars of dahlias, it’s helpful to know that the American Dahlia Society groups dahlias into 14 different groups:
- Group 1 – Single-flowered dahlias (Sin)
- Group 2 – Anemone-flowered dahlias (Anem)
- Group 3 – Collerette dahlias (Col)
- Group 4 – Waterlily dahlias (WL)
- Group 5 – Decorative dahlias (D)
- Group 6 – Ball dahlias (Ba)
- Group 7 – Pompon dahlias (Pom)
- Group 8 – Cactus-flowered dahlias (C)
- Group 9 – Semi cactus dahlias (S–c)
- Group 10 – Miscellaneous dahlias (Misc)
- Group 11 – Fimbriated dahlias (Fim)
- Group 12 – Single Orchid (Star) dahlias (SinO)
- Group 13 – Double Orchid dahlias (DblO)
- Group 14 – Peony-flowered dahlias (P)
Dahlias are tuberous plants in the Asteraceae family, which also include sunflowers, daisies, chrysanthemums, zinnias, and, of course, asters. You’ll find them flexible and grow in flower beds, or you can plant Dahlia tubers indoors or outside once the frost has passed. Either way, you can snip them for cut flowers in the home during the Dahlia season.
How Much Sun Do Dahlias Need?
Beautiful Dahlia blooms love the sun. So, if you can, give them full sunshine for 6–8 hours daily. The more sun they get, the more flowers you will see.
What Type of Soil is Right for Dahlias?
Dahlias grow best in soil with a pH between 6.5 and 7. Dahlias don’t do well in soil that isn’t good, so plant Dahlias in good soil. Clay is not a good place to plant dahlia tubers outdoors, it’s too thick, and when it rains, it turns clean dahlia tubers into a muddy, soggy mess. Plant the tubers in well-drained soil, and ensure they are undercover even if they are winter-hardy plants when grown. (Read When Do Morning Glories Bloom)
How Much Water Do Dahlias Need?
Most Dahlia varieties must be watered often and grow best in moist conditions. But you don’t want the dirt to get too wet, so ensure it drains well and don’t water too much or too often.