Dahlia Planting & Care: A Complete Guide

No flower will give a gardener a more spectacular reward than the Dahlia!

This flower and all of its many varied forms, is an absolutely show-stopping variety that brings a stunning rainbow of color to any garden!

Learn more about these unique blooms and their care today!

All About Darling Dahlias
Planting Dahlia Tubers
Dahlia Care Needs
How to Dig and Store Dahlias In The Fall
Start Your Dahlia Obsession Here!

All About Darling Dahlias

Native to Mexico, Dahlias are tuberous, herbaceous perennial plants that range from miniatures that are a few inches tall, to huge flowers that are the size of dinner plates!

Dahlia has leafy stems that range in height from 12 inches to more than 8 feet! Featuring a single flower per stem, but Dahlia has multiple stems on each plant and keeps pumping out the blooms until frost!

There are over 40 species of Dahlias, and these plants come in a multitude of heights, sizes, colors, and number of rows of petals. These include spiky Cactus flower forms, Waterlily, Single and Decorative, round Pompoms, Orchid-Forms and Ball Dahlia, Peony and Anemone-Flowered, Collarette, and the grand Dinnerplate flower forms of Dahlia! We’re sure you’ll find the right one for you!

Adding Dahlias to a garden bed or large planter creates a brilliant focal point in your garden and vivid landing pads for pollinators and Hummingbirds!

Dahlia blooms almost continually all growing season, and the more you cut for bouquets or deadhead as they fade, the more they will produce! Dahlias make long-lasting cut flowers and their multi-layered petals can add body and beauty to any arrangement. Dahlias are often used to express personal sentiments.

No Pollinator garden, Perennial bed, cut flower border, or proper English Cottage garden should be without these magnificent extended-bloom flowers!

Planting Dahlia Tubers

Even though they are often referred to as “bulbs” the roots of this plant are tubers (like potatoes) and sprout from their “eyes” and have shallow roots.

The key to successfully growing Dahlias is good soil preparation, and once the plants are established, it is suggested to add mulch to conserve moisture and protect the roots.

Plant Dahlia about the time you plant Tomatoes in the late spring after the threat of frost
Or - Start indoors 4-6 weeks before your area's last frost date
Plant Dahlia tubers between 10-12 inches deep in loosened, enriched soil
Space tubers apart based on their mature spread so they have plenty of room to grow
Cover with soil and water in well - just enough to remove air pockets and prime the soil
Water again once you see new growth (the tubers need little until they are growing)
Transplant indoor starts once the threat of frost has passed and water in well

Additional Dahlia Tips:

Tubers planted directly in the ground will start to sprout in about 3 weeks depending on your climate and weather. Once they do get growing - they take off!

Deadhead blooms as they fade to encourage new blooms to quickly follow.

Water your plants only at the root level to avoid getting excess water on the foliage.

Using a layer of mulch around the plant (not pushed up against the stem) will prevent water from splashing onto the leaves - carrying with it potential fungal and disease issues. This also helps keep the vegetative leaves looking cleaner!

In addition to working compost into your Dahlia bed, apply a good organic high-in-potassium (K) fertilizer before planting. Choose a flowering plant or bulb fertilizer that’s low in nitrogen to encourage blooms and not leafy growth.

Dahlia Care Needs

It is best to plant Dahlias in an area that gets at least eight hours of direct sunlight a day. If you live in a hot summer climate, choose a location that provides morning sun and afternoon shade.

The morning sun is best due to its drying power to clear the leaves of dew. Dahlia foliage also appreciates very good air circulation!

Choose a location that is well-drained and enriched with plenty of organic matter and water regularly. Preferring consistently moist but not soggy conditions. A 3-4 inch deep layer of arborist mulch and/or compost helps hold in moisture, reducing watering frequency, and insulating the roots.

For larger Dahlia or gardeners that grow them in windy/storm-prone areas, a bamboo stake, trellis, or other structure will help keep your flowering stems standing tall.

How to Dig and Store Dahlias In The Fall

Dahlias can be grown as perennial bulbs in the ground year-round in USDA planting zones 8 and up, but Dahlias grown in colder than Zones 2 to 7, need to be lifted in the autumn after the foliage begins to die back after a light chill. Do not let them be exposed to a hard frost where the ground freezes, as this will damage the tubers.

In very cold climates, to save your tubers for the next year, dig up the plants, remove the wilted leaves, and snip back the stems.

Using a spade or garden shovel, dig a ways away from the stem to not damage any roots, dig straight down all around the plant and locate the tubers.
Gently lift them from the ground and shake loose/hose off the soil.
Let the dug tubers dry out some (not completely) and remove any further excess soil. Don’t leave them laying in direct sunlight.
Place in paper bags or boxes in a cool, dry, and dark location with good air circulation.
Throughout the winter, mist them with a little water if the tubers are drying up.

If you live in a warmer climate, simply trim back the stems to keep your plants looking their best and fresh growth will appear in the spring.

Start Your Dahlia Obsession Here!

Nature Hills has a wide selection of Dahlia plants, and dormant Dahlia bulbs for you to choose from!

From the star-shaped Verrone's Obsidian Dahlia and Destiny's Teacher Dahlia to the pompom-like Sassafras Dahlia, the coneflower-like Pulp Fiction Dahlia, and the many bi-color forms like Rebecca's World - Dahlias never cease to amaze you with their vivid, saturated colors, multitude of petal-forms, and range of heights from small to large!

Once you've grown one of these beauties, you will want to add more! Growing Dahlias can easily become an obsession once you see the staggering array of choices available to you!

Happy Planting!

Frequently Asked Questions

How do I care for dahlias throughout the growing season?

Dahlias thrive with consistent moisture, so water deeply and regularly once plants are established, and apply a layer of mulch to conserve moisture and protect the shallow tuber roots. The more you deadhead fading blooms or cut stems for bouquets, the more flowers the plant will produce, so keep harvesting throughout the growing season right up until frost. In fall, once frost kills the foliage, dig and store your tubers in a cool, dry location to replant the following spring.

Can you grow dahlias in pots or containers?

Yes, dahlias grow beautifully in large containers and planters, making them a versatile choice for patios, decks, and smaller garden spaces. Choose a pot large enough to accommodate the tuber and mature root system, with excellent drainage to prevent rot. Plant tubers in late spring after your last frost date, just as you would in the ground, in enriched, well-draining potting mix. Water consistently, fertilize regularly throughout the season, and deadhead spent blooms to keep your container dahlias flowering at their best all the way until frost.

How much sun do dahlias need to bloom their best?

Dahlias perform best in full sun, requiring a minimum of 6 to 8 hours of direct sunlight per day to produce their most abundant and vibrant blooms. In hotter climates, a little afternoon shade can help protect the flowers from scorching, but too much shade will result in leggy plants and fewer flowers. Choose your sunniest garden bed or large planter for these plants, and orient them away from the shadow of taller structures or trees to maximize their exposure throughout the growing season.

Are dahlias perennials or annuals?

Dahlias are tuberous herbaceous perennials native to Mexico, though in colder climates they are often grown as annuals since their tubers cannot survive hard freezes in the ground. In USDA zones 8 and warmer, dahlias can remain in the ground year-round with a layer of mulch for protection. In colder zones, gardeners should dig up the tubers each fall after the first frost blackens the foliage, store them in a cool dry location over winter, and replant them in late spring around the same time they would plant tomatoes.

How do I water dahlias properly without overwatering?

Dahlias prefer consistent moisture but are prone to rot if overwatered, especially before they have sprouted and established roots. Water deeply once or twice a week rather than frequent shallow watering, and always allow the top inch of soil to dry out between waterings. Applying a 2-3 inch layer of mulch around plants helps retain moisture and reduces the need for frequent watering. Check soil moisture at the root level before watering, and cut back during cool or rainy periods to avoid soggy conditions that invite tuber rot.

When should I dig up and store dahlia tubers for winter?

Dig up your dahlia tubers after the first frost blackens the foliage, typically in fall before the ground freezes hard. Cut the stems back to about 2 to 4 inches, carefully lift the clumps with a garden fork, and allow them to dry for several days before storing. In colder climates (Zones 3 through 7), storing tubers indoors over winter is essential for protecting them from freezing temperatures. Pack them in a breathable medium like peat moss, vermiculite, or dry sand and store in a cool, dark, frost-free location between 40 and 50 degrees Fahrenheit until replanting time in spring.

How do I get dahlias to produce more blooms?

The more you cut dahlias, the more they bloom. Regularly harvesting stems for bouquets or deadheading spent flowers as they fade signals the plant to keep producing new buds throughout the entire growing season, right up until frost. For the best results, cut stems early in the morning and deadhead consistently every few days to keep your plants performing at their peak.

What kind of soil do dahlias grow best in?

Dahlias thrive in loosened, enriched soil that has been well prepared before planting. Good soil preparation is the single most important key to successfully growing these plants. Amend your garden bed with compost or other organic matter before planting tubers 10 to 12 inches deep, and once plants are established, apply a layer of mulch to conserve moisture and protect the shallow roots.

How do I fertilize dahlias for healthy growth and big flowers?

Dahlias are heavy feeders that benefit from a low-nitrogen fertilizer, such as a 5-10-10 or 0-20-20 formula, applied every three to four weeks once plants are established. Avoid high-nitrogen fertilizers, which encourage lush foliage at the expense of blooms. Begin fertilizing when plants are about 12 inches tall and continue through the growing season until frost approaches. For the biggest flowers, side-dress with a phosphorus-rich fertilizer in midsummer to support strong root development and abundant blooming.

What pests and diseases should I watch for when growing dahlias?

While the provided article does not specifically address pests and diseases for dahlias, common threats to watch for include aphids, spider mites, slugs, and earwigs, as well as fungal issues like powdery mildew and botrytis, which thrive in humid conditions. Inspect your plants regularly throughout the growing season, paying close attention to the undersides of leaves where pests tend to hide. Keep good air circulation around plants by spacing them according to their mature spread, avoid overhead watering, and treat any infestations early with insecticidal soap or neem oil to prevent larger problems.

Planting and Taking Care of Dahlias!