Dazzling Dahlias: A Complete Plant Care & Growing Guide

If you are looking for variety within a single plant family, look no farther than the dazzling beauty of the Dahlia. These dramatic and unique plants vary almost as much in size and texture as they do in color. You can find and plant Dahlias in just about every color under the sun (except blue!). Dahlias can be fairly hardy plants, but their needs vary slightly based on the zone that you live in. Check out this guide to learn all about how to plant, grow, and care for Dahlias.

How To Grow A Dahlia Plant

Dahlia’s are native to North America, originally hailing from the mountains of northern Mexico. At one time, their tubers were harvested as an edible food source, but they have since been popularly developed as a floral crop – and it’s not hard to tell why. They are wonderful ‘temperennials’ that bring an immense amount of variety to any garden. A ‘temperennial’ plant is perennial in certain climates (warmer, more tropical ones), but they are most often grown as annuals in colder climates. They are typically not hardy above zone 8.

The larger varieties require staking, but thanks to some significant research and determined breeders, there are now also much more compact pot size varieties available to those gardeners who can’t be bothered with staking. These compact varieties tend to grow a lot more flowers as well.

How To Plant Dahlias

Dahlias are grown from a tuber. Dahlia tubers are often referred to as bulbs, but they are actually a tuber, which is more like a potato. Each tuber has a tail, a body, a neck, and an eye. When you plant your tuber, you want to plant it with the eye facing up as that is what the sprout will grow out of.

You can plant Dahlia tubers in the ground in early to mid-spring, but if you live in a more northern zone, ensure that you wait until the risk of frost has passed before doing so. With that said, you can also start your Dahlia tubers indoors under lights and then plug them into your garden once the soil temperature reaches about 60˚F.

Dahlia Light Requirements

One important factor to remember when it comes to how to plant Dahlias is that they are sun-lovers! They will grow in partial shade, but try to select a location where they will get about six to eight hours of sunshine a day. 

Dahlia Soil Requirements

Dahlias can be a little bit particular with their soil preferences. Typically, we find that they come back quite readily as perennials in sandy, well-draining soil here in Virginia. They are quite susceptible to winter moisture, so if you plant your Dahlias in an area that has slightly heavier soil with more moisture, they may rot and not come back the following year. This is particularly important to note while they are in their dormancy. 

Dahlias appreciate good drainage, especially when dormant. We have noticed that under similar soil conditions if we plant our Dahlias in raised beds, they tend to become more perennial, likely because it provides more drainage than in some spots in the ground. 

Planting Your Dahlias

We do tend to plant our Dahlias indoors so that once the soil (and overall) temperature reaches about 60°F outside, we already have a plant established and don’t have to wait for it to start from dormancy. Plant your Dahlia so the crown of the tuber is just below the surface.

When planted in a compost medium, they should have all that they need to thrive. If you intend to plant multiple Dahlias, be sure to plant them far enough apart, so the plant has room to grow. Smaller, flowering Dahlias need about two feet of breathing room, while the larger ones should be planted approximately three feet apart.

How To Maintain Your Dahlia Plants

Dahlias respond well in the spring and summer when they get about a half-inch of moisture a week, so following the rule of watering deeply but less often will work well for them. They bloom best when the temperatures at night are in the late 50s to early 60s. Once the overnight temperatures start to reach 70˚ or 80˚, it will cause them to stop blooming, but don’t be too disappointed–they tend to make a comeback in the fall once things cool down a little again. Dahlias are the ultimate “cut and come again” plant. Aim to deadhead your Dahlia plant once a bloom has faded, and you will likely find that they will re-bloom quite nicely!

If you live in a cooler climate, you have two options once winter comes along. You can either treat your Dahlias as annuals or, you can dig them up and store them for the season. Once their leaves start browning, this is your signal to dig up your Dahlia tubers (very carefully!). Be sure to go way under the plant, loosen it up, gently lift them from the soil, shake them off, and leave them in a shady area to air dry.

Never wash or rinse your Dahlia tubers as it will cause them to bruise, particularly when they have come out of the ground as they are especially soft. By leaving them in a shady area to air dry, you allow the tubers to harden off. They can then be stored in a cool, dry area for the winter and re-planted in the spring. You might be surprised by how much the tubers themselves have grown over the season!

Some of Brent’s Favorite Dahlia Cultivars

Both Brent and our favorite pollinators (like bees and butterflies!) love single-flowered Dahlias, so if you are looking to attract wildlife to your garden—these varieties should be your go-to!

Dracula is a particularly lovely, single-flowered Dahlia variety. Its eye-catching leaves are quite a unique, almost black shade. Paired with its bright pink flowers, Dracula will bring a distinct drama to any garden.

Gallery Dahlias top the list in our books. This spectacular, compact, rich-flowering family of Dahlias are named after a variety of legendary artists. Gallery Monet, Gallery Leonardo, Gallery Pablo, and Gallery Rembrandt are all divine. This series will produce the largest number of flowers. While they are not ideal as cut flowers, they make for wonderful container plants due to their stems being relatively short.

If you are hoping to grow Dahlias to be cut flowers, a group called Karma is ideal for this purpose. They are quite tall with relatively strong stems and come in different scrumptious varieties like the chocolate-colored Karma Choc.

Buisson is another family of Dahlia we love, which are a little more bush-like. Bred primarily in France, these beauties will grow to about three-to-five feet in height. They are very strong and rich-flowering plants. Some of these family members include Dahlia Calin, Dahlia Jaipur, and Dahlia Tour De Monde.

Dahlias of all kinds can make for wonderful cut flowers, but they also lend themselves well to mixed border gardens, fitting in beautifully as companion plants. If this is your first time learning how to plant Dahlias, worry not; you’re well on your way with this guide! If you’re ready to take the plunge into the world of growing Dahlias, check out our online summer-blooming catalogue and order today.