Dahlia perennial or annual

No-Fail Tips for Planting Dahlias

Alison Miksch

When Kathy Whitfield took her mother to the mall in the fall of 1997, she had no idea that outing would change her life. The pair stumbled upon a sea of blooms in myriad shapes, sizes, and colors set up by the local dahlia society for its annual show. “I didn’t know what a dahlia was,” Kathy admits. “The flowers were so perfect—they didn’t look real.” People behind a nearby table invited visitors to join the dahlia society. She recalls, “My mother said, “You go join.” And in the South, you do what your mama says.”
A few months later, a letter arrived at the Whitfields’ mailbox in Hoover, Alabama. Kathy retrieved it and told her husband, “Ed, I think I’ve joined something.” Ed looked at the letter and announced, “I know what dahlias are! My grandmother grew them.” The die was cast. Today, the Whitfields grow 550 dahlias of more than 75 kinds in their backyard.
For the uninitiated, dahlias are tender perennials that grow from tuberous roots. You have to dig up and store them over winter in the Upper and Middle South (USDA Zones 6 and 7), but they can stay in the ground year-round south of there. Dahlia fanciers divide them into many classes based on flower form. Blooms come in all colors except true blue, range from 2 to 12 inches wide, and are great for cutting. Plants grow 1 to 7 feet tall.
Anyone who grows more than 500 dahlias every year has our respect. We asked Kathy for her best tricks to help you get started on your first 100.
Beat the Heat
Dahlias dislike long, hot summers, making them challenging to grow in the Lower South (Zone 8), where Kathy lives, and not recommended for the Coastal and Tropical South (Zones 9 and 10). They wilt in hot sun and often stop blooming when the mercury tops 90 degrees. Big-flowered kinds are the most heat sensitive. Kathy addresses this by shielding them in summer beneath 50% polyethylene shade cloth (available from gemplers.com), which blocks half of the sunlight. She also sets up beach umbrellas to shade some plants at midday. Don’t want to fool with adding shade cloth and umbrellas? Grow them in light afternoon shade.

Prepare the Soil
A dahlia plant prefers moist, well-drained soil that contains lots of organic matter. Every year, Ed and Kathy grind up and compost fallen leaves. In January and February, they dig these into the soil along with soil conditioner and mushroom compost. Plants growing in good soil don’t need very much fertilizer.
Plant in Spring
April and May are good months. Plant the roots about 1 foot deep, spacing tall selections (over 4 feet tall) 4 to 5 feet apart and shorter ones 1 to 2 feet apart. Kathy sprinkles a teaspoon of Epsom salts and a teaspoon of Osmocote fertilizer in each hole.

Water Wisely
Don’t water dormant roots after planting until sprouts show aboveground or the roots will probably rot. After that, water only when plants look wilted in early morning before the sun hits them.

Support Your Plants
All but very short plants need to be tied to a 6-foot rebar stake driven into the ground beside them.

Make the Cut
Dahlia varieties with full, tight blooms (such as formal decorative, ball, and pompon types) make excellent, long-lasting cut flowers. “For Sunday church displays, we’ll cut them on Saturday morning and make the arrangements, and they’ll still look good for Wednesday night,” says Kathy.
Order Early
Buy dormant roots in February and March for best selection. Two great mail-order sources are dahlias.com and hilltopdahlias.com.

When To Plant Dahlias

Dahlias are some of the lowest maintenance, highest production cut flowers and garden plants you can grow.

Here we share our tips on when to plant dahlias and other good to know information.

When to plant your dahlia tubers

Dahlias are tender tubers so they need to be started off under cover in early Spring, then planted out after the frosts. If you plant them out before the frosts are over, they may get frosted and die, so pot them up in March or early April.

To get them started half-fill a 3 litre pot with peat free multipurpose compost and place the tuber in the pot with the central stem upwards and cover with more compost. Don’t forget to label and water the pot, place is a nice warm spot, frost-free, so it can receive some warmth and light.

After 2-3 weeks shoots will start appearing – some varieties may take a little longer, but as these shoots grow pinch out the tips of the main shoot (you can use a sharp knife or a squeeze between your thumb and forefinger), down to the top pair of leaves.

Then, as the plant starts to grow remove all but five shoots sprouting from the tuber. It will feel harsh but by having only five stems, this will allow each stem to develop, grow strong and vigorous, resulting in lots of flowers!

Your dahlia tuber will then flower from June to early December (particularly in a sheltered spot).

They come in all different shapes and sizes, as well as some of the greatest colours, shop our collections today.

If you need further advice, simply watch Sarah’s video below on how to plant dahlia tubers , or visit our step-by-step guide here

To start your dahlia plants off right, consider where and how you plant them.

Soil for Dahlias: Dahlias like a rich, well-draining soil with plenty of organic matter and a fairly neutral soil pH around 6.5

If you are planting your tubers in containers, mix in 1/3 garden soil, for better moisture retention. Potting soil dries out quickly and the tubers need to stay moist until they have sufficient roots.

Planting Dahlias: You can get a head start on the growing season and pot up your tubers in late spring, to transplant outdoors after all danger of frost. The downside to this is that you’ll need large pots and lots of space. Or you can direct plant the tubers in the garden. Wait until the soil has warmed and dried a bit in the spring, before planting. They can be planted a couple of weeks before your last frost date, as long as the soil is not wet.

Dahlias can also be propagated by seed or cutting. Only the small flowers bedding dahlias do well from seed, and even they don’t grow true. If you’d like to try growing them from seed., sow it early, indoors in February or March. Cuttings are a better option if you can keep them warm and growing all winter.

Plant large tubers about 6 – 8 inches deep. The smaller varieties can be planted 3 – 4 inches deep. Only fill the holes a couple of inches deep so that the crowns are just buried. As the plant grows, fill in the rest of the hole.

All the large flowered varieties will need room to branch out as they grow. Spacing them about 20 – 24 inches apart should do it. Hans also advises that you stake them while you’re planting. With all those large flowers, most varieties will need some type of support.

Any type of tall stake is fine. There are special stakes that circle around individual stalks, but you can wrap twine around wooden stakes or use tall tomato cages. Three to four 5 ft. bamboo stakes surrounding the plant will hold it upright if you circle twine around them 1/3 and 2/3s of the way up.

Caring for Dahlias

Mulching will help keep the roots moist. They are shallow rooted and can dry out quickly. Once the plants bush out and cover the soil, it should be less of a problem.

The tubers need to store up energy during the summer, to get them through the winter. A mid-season application of an organic flower food will give them a boost. Whatever fertilizer you choose, look for one with a low nitrogen ratio. Don’t fertilize after August. You are going to be digging and storing the tubers soon and you want them ready to go dormant.

A lot of growing information says to pinch the growing tip, to encourage multiple stems. Hans says that is not necessary and will actually reduce the size of the mature plant. Instead, he recommends removing only the first flower bud. That will be enough for the plant to branch out.

If you are looking for the largest flowers possible, Remove the two side buds that form around the central bud. The central bud will produce the biggest flower and it will be larger still if the two side buds are not left there to compete for nutrients.

Finally, keep cutting your dahlias. Even if you don’t want them for arrangements, be sure to deadhead them or blooming will diminish.

Digging and Storing Dahlias: Wait until a frost hits your dahlias and the leaves blacken before you dig them up to store. You’ll find information on how to do that on in Dividing Dahlias and info on storing all types of non-hardy bulbs and tubers in storing tender bulbs

Dahlia Pests & Problems

  • Insects: The biggest pest is definitely slugs, especially while the dahlias are young and small. Earwigs, caterpillars, and thrips can also pose a problem.
  • Deer: Some people say deer love their dahlias and others claim they avoid them. Perhaps it depends on what else is available to munch on, but keep your plants protected, just in case.
  • Diseases: Dahlias can be prone to powdery mildew and other fungal diseases. Keep the foliage as dry as possible by allowing for good air circulation. More serious are leaf spot and dahlia wilt and viruses. Plants with viral infections often manifested by leaves that yellow in an irregular pattern, should be destroyed. There is no cure and the virus will spread.

Tender Dahlia Plants – Are Dahlia Flowers Annual Or Perennial

Are dahlia flowers annual or perennial? The flamboyant bloomers are classified as tender perennials, which means they may be annual or perennial, depending on your plant hardiness zone. Can dahlias be grown as perennials? The answer, again, depends on your climate. Read on to find out the real story.

Can Dahlias Be Grown as Perennials?

Perennials are plants that live for at least three years, while tender perennials won’t survive cold winters. Tender dahlia plants are actually tropical plants and they are perennial only if you live in USDA plant hardiness zone 8 or higher. If your hardiness zone is 7 or below, you have a choice: either grow dahlias as annuals or dig the tubers and store them until spring.

Growing Dahlias Year Round

In order to get the most of your dahlias, you’ll need to determine your hardiness zone. Once you know which zone you’re in, the following tips will help in growing or keeping these plants healthy and happy each year.

  • Zone 10 and above – If you live in zone 10 or above, you can grow dahlia plants as perennials. The plants require no winter protection.
  • Zone 8 and 9 – Watch for foliage to die back after the first killing frost in autumn. At this point, you can safely cut the dead foliage to 2 to 4 inches above the ground. Protect the tubers by covering the ground with at least 3 or 4 inches of bark chips, pine needles, straw or other mulch.
  • Zone 7 and below – Trim the dahlia plant to a height of 2 to 4 inches after frost has nipped and darkened the foliage. Dig clumps of tubers carefully with a spade or garden fork, then spread then in a single layer in a shady, frost-free location. Allow the tubers to dry for a few days, then brush off loose soil and trim the stems to about 2 inches. Store the tubers in a basket, paper bag or cardboard box filled with moist sand, sawdust, peat moss or vermiculite. (Never store the tubers in plastic, as they will rot.) Place the container in a cool, dry room where temperatures are consistently between 40 and 50 F. (4-10 C.).

Check the tubers occasionally throughout the winter months and mist them lightly if they begin to look shriveled. If any of the tubers develop soft spots or begin to rot, cut off the damaged area to prevent the rot from spreading to other tubers.

Note: Zone 7 tends to be a borderline zone when it comes to overwintering dahlias. If you live in zone 7b, dahlias may survive the winter with a very thick layer of mulch.

By Kathy McKay|March 23, 2010

If you are looking for a dahlia series with a great color range, excellent branching, big flowers and fast finishing, Fides has an answer: the Dahlinova Hypnotica series, which features radiant colors and elegant shapes.


Dahlinova Hypnotica was given its name because it hypnotizes and intrigues. It’s an appropriate name for a flower that has all the qualities to dominate its surroundings. Varieties in the series will capture eyes in any garden because of their attraction and brilliance. Fides introduced the series last year with great success, as Dahlinova Hypnotica Bronze Bicolor was named the best dahlia at Penn State University’s field trials.

New Radiant Colors

Five new colors in this series will be showcased at this month’s California Spring Trials: Red Bicolor, Rose Bicolor, Red Coral, Lavender and Dark Night. The new varieties, along with the others in the series, have vigorous plant habits and achieve good branching. Little to no use of plant growth regulators is needed in production and flowers are generally uniform, large and in abundance through summer. The crop time for the series is seven to nine weeks and all the dahlias are heat tolerant.

Rooting & Pinching

Fides recommends planting unrooted cuttings deep–at least up to the first set of leaves–and one liner per gallon container (see Table 1 for more details). Plants should be well misted until root initials appear. The rooting temperature should be 70°F. Average rooting time is two to three weeks.

It’s also recommended to pinch when plants are established, about two weeks after planting. Allow four leaves to remain after pinching for the best branching. It is, however, important to note that pinching delays flowering by five to seven days.

Watering & Feeding

Growers should thoroughly wet their growing media with each irrigation or fertigation. They should allow plants to dry slightly between irrigations. Do not over-water, and don’t allow plants to wilt. If plants do wilt, leaf margin burn can occur.

Good crop growth is obtained with 200 to 250 ppm nitrogen fertigation from a complete N-P-K water soluble fertilizer. The majority of nitrogen should be in the nitrate form. Growers should avoid high ammonia or urea fertilizers, which can reduce plant quality by encouraging soft, stretched growth. The growing media EC should range between 1.5 and 3.0 mS/cm (SME).

The Environment

The ideal day temperature for Dahlia Hypnotica is 65° to 70°F while the ideal night temperature is 63° to 65°F. High temperatures will delay flowering and reduce flower size. Low temperatures will limit growth and finished plant size.

Growers should use maximum light intensity with the series. They should also avoid shading from overhead crops and use supplemental lighting with 400 to 500 footcandles HID lighting for 14 hours daily in late winter and early spring.

Want more information on the series? Visit Dahlinova.com, where you can see more of the newest introductions and obtain additional production information.

Kathy McKay is the Western Sales Promotion Representative for Fides North America. For more, contact you Fides representative or visit FidesNorthAmerica.com. See all author stories here.

Are Dahlias Perennials or Annuals?

Dahlias deliver beautiful blooms in every possible color combination.

Been bitten by the dahlia bug? We’re there, too. These beauties are hard to beat for bold garden color, cutting flowers galore, diversity of bloom form and delicious color blends. With lots of gardeners growing dahlias for the first time, we’re often asked “are dahlias perennials or annuals?” Which is usually then followed by “can you leave dahlias in the ground over the winter?”

The answers depend on where you live.

Are Dahlias Perennials? Sort of . . .

Dahlias are considered “tender perennials”, plants that return year after year when the growing conditions are favorable.

Tender perennials re-sprout in the spring and deliver repeat performances in regions where winters aren’t too cold for their survival. So, what’s too cold for dahlias? If the soil in your area freezes, dahlia tubers left in the ground will freeze, too. And that’ll be the end of their story.

Ball dahlias are magically symmetrical

However, dahlias can overwinter outdoors where temperatures never get cold enough for the ground to freeze. It’s usually safe to leave dahlia clumps in garden beds in hardiness zones 8-10. Dahlias may also survive mild winters in zone 7b, sited in a sheltered location and/or with the help of protective mulch.

If your winters are mild and you want to leave your dahlias in the ground, here are a several tips.

• Cut the stems to about 4″ long. This helps clean up the bed.

• Because the stems are hollow, they can fill with water. This encourages rot at the stem junction. Avoid by covering the top of stems with little squares of plastic wrap, secured with rubber bands.

• If your region gets lots of winter rain, months of wet soil can rot tubers. Either dig the tubers or cover the bed with a plastic tarp to keep much of the water out. Remove any plastic coverings when sunny days arrive in spring to avoid heat build up underneath.

Do Pot-Grown Dahlias Come Back Every Year ?

Even dinner plate dahlias can be grown in large pots.

Dahlia can overwinter in containers if you keep in mind that pots typically freeze before the ground does. Cold air circulates on all sides of containers. So the soil, and tubers in the center of the pot, lose their retained heat and freeze more quickly. Soil temperature in the garden is buffered by, well, more soil. And because of this, garden beds take longer to heat up and cool down than does the soil in pots.

Typically, your container plants have hardiness ratings 1-2 zones colder than the rest of your landscape. If you garden in zone 7, your container residents experience winters more like plants in zone 6 or even zone 5.

(This same logic applies to early spring planting, too. Refrain from planting too early.)

Want to leave your dahlias in their containers? Where night temperatures dip to 35 degrees and colder, move those pots into an unheated garage or breezeway. Temperatures of 40 to 50°F are ideal for holding your dahlias over the winter. Keep the pots sheltered until spring’s warmth has arrived, then move them back outside.

What About Perennial Longevity?

Many dahlias have long, straight stems, great for cutting.

The other thing gardeners are thinking when they ask “are dahlias perennials?” relates to longevity, i.e. how many seasons will the plants grow when left in the same spot. Perennial plants can be counted on to sprout each spring and add beauty to the landscape for years.

Dahlias lose vigor and flower less robustly when left in the same site year after year. Even in warm regions, it’s advisable to dig the clumps every two to three years.

Dig To Revitalize

Many dahlias develop a sizable tuber clump each season. Some cultivars develop huge, soccer ball size clumps. After a few years, the clumps become overgrown and congested. They can be reinvigorated by removing dead tubers and broken pieces.

Dig your dahlia clumps at the end of the growing season. Snip off any tubers that aren’t firm and solidly attached. Then cut the clumps into two to four pieces, making sure each has a piece of the collar and a growing eye. Allow the cut surfaces to dry, dust the cuts with fungicide and store for the winter.

This video shows you how to dig and store dahlias.

Whether dahlias are treated as annuals or perennials in your part of the country, if you’re keeping them for several seasons, they’ll benefit from being dug.

So, Dahlias Are Annuals in Cold Regions?

Grow dinner plate dahlias to amaze your neighbors.

Technically, no. Annual plants complete a full life cycle in a single season. They sprout, grow, flower, set seed and die in the same year. Dahlias don’t fit that definition.

While dahlia top growth may die back each fall, the plant is still alive. Stored energy in the tubers allow dahlias to regrow the following spring.

However, many home gardeners treat dahlias as annuals, leaving the clumps in the ground in fall or adding them to the compost pile. This works well if you have no place to overwinter tubers, or no time (or desire) to dig them. Or if you simply love to experiment with all the options dahlias offer.

Starting fresh every spring means you can change up your dahlia varieties. You can add some of the newest cultivars and grow colors, forms and sizes that you love. And let’s face it, sometimes it’s just fun to grow something new!

Want some glorious new dahlias? Scout here: Buy Dahlias

Dahlias are brilliantly colorful flowers that put on a delightful, splashy display from mid-summer until the first frost.

Orange ‘Firecracker’ dahlia. Photo by Lorna Kring

Their pinwheel blossoms and eye-catching colors come at a time when many plants are lagging and past their best. And just as the garden needs a fresh burst of vibrant color, the dahlia presents her lovely blossoms on cue.

A tuberous, tender perennial native to the uplands and mountains of Mexico and Guatemala, they bloom annually, producing numerous flower heads on multiple stalks.

A member of the Asteraceae family, which is from the old Greek for “star,” the dahlia flower is typically star-shaped. Similar star-shaped flowers are also seen in other family members such as chrysanthemum, daisy, marigold, sunflower, and zinnia.

And, dahlias make some of the best cut flowers for floral arrangements! Bright, showy, and with a fascinating geometry, they put on a long-lasting display in a vase.

From the New World

From the New World, dahlias were first chronicled under the name acocotli, or “water pipe flower,” by Spaniard Francisco Hernandez in 1570.

However, they didn’t make their European debut (at the botanical gardens in Madrid) until the late 1700s, about the same time they were named for Swedish botanist and environmentalist Andreas Dahl.

Today, there are over 40 cultivars for the home garden, available in an amazing variety of colors, sizes, and shapes.

Flower sizes can be small, like the 2-inch patio varieties, while large, dinner-plate types can have flowers as big as 14 inches. Plant heights are equally diverse, ranging from dwarf varieties of 12 inches, to the towering D. imperialis, which can grow to 25 feet!

Many of the taller varieties also feature large flower heads, which may require staking if they become top heavy.

Dahlias have no scent and attract pollinators like bees with vibrant displays of bright colors – available today in almost every shade you could ask for, except for true blue.

Although they hail from Mesoamerica and like plenty of sunlight, they won’t do well in areas with excessive heat or humidity. They prefer cooler temperatures similar to those of their native highlands.

With a long season, they bloom from early summer until autumn, and will keep flowering until killed off by frost.

In areas with moderate to cold winters, the tubers will need to be dug up and stored before freezing temperatures arrive, as they’re only reliably hardy to Zone 8.

Made to Cut

Now here’s a fun feature about dahlias – the more flowers you cut, the more they’ll bloom!

For floral arrangements, cut a long stem of 12 inches, even if you need to include the two side buds. These side buds are usually smaller and weaker flowers, and removing them actually promotes more growth, while keeping the plant size healthy and manageable.

Care and Cultivation of a Late-Summer Bloomer

Dahlias can be planted in spring once the soil temperature has warmed to around 55 to 60°F – or around the same time that corn, tomatoes, and potatoes are planted in your area.

They need a location that receives 6 to 8 hours of sunlight each day, preferably with some afternoon shade, and good drainage.

Regular garden soil is sufficient, and should be amended with a spadeful of organic materials, like compost or well-rotted manure.

These tubers like to be planted in mounded soil about 4 to 6 inches deep, with eye buds pointing skyward. Mounding provides warmer soil and better drainage, and its loose texture makes it easier to create new tubers. It also makes lifting the tubers in fall faster and easier.

Avoid watering at the time of planting, unless you’re in a very dry area. Regular springtime precipitation should be adequate, as overly soggy conditions may cause newly planted tubers to rot.

Wait until the first leaves break the soil before watering. Then, give them a good, deep soak 2 to 3 times per week. Allow the top soil to dry out between watering, but for consistent growth, ensure the roots stay moist.

Pests and Problems

Dahlias are squirrel and deer resistant. But slugs and snails do enjoy munching on tender new growth, just as the leaves and stems emerge from the soil.

If these slimy gastropods are a problem for you, read our article on the best – and safest – methods to rid your garden of slugs and snails.

Powdery mildew can sometimes appear on dahlias, particularly in cool, damp conditions. Remove any damaged leaves and stems, and ensure your plants have adequate air circulation and drainage.

Avoid overhead watering and overwatering in general, and allow the surface soil to dry out between less frequent, but deeper watering.

To promote a compact shape with more flowers, pinch out the main stem early in the growing season.

Pinch the larger-flowered varieties just above the third set of full leaves. And for ones with smaller blossoms, allow the plants to grow until they’re 12 to 18 inches high, then pinch above the fourth or fifth full set of leaves.

A low nitrogen fertilizer of 5-10-10 can be applied one month after planting, and once again 30 days later. Avoid over-fertilizing, as too much will promote robust leaf growth with a low blossom count.

Small to medium-sized flowers take approximately 90 days to bloom, while the larger ones can take as long as 120 days.

Storage and Division

Digging and dividing tubers will keep your plants strong and healthy, produce more flowers, and create new tubers for yearly propagation.

Left in the ground, the tubers can form a massive clump, producing more and more stems with progressively smaller and fewer flowers – until the clump eventually stops growing.

And as they like to feel a touch of cold, don’t be too quick to dig them up in the fall.

Wait a couple of weeks after the first frost, when all the foliage has died back. Or, if you don’t receive freezing temperatures, dig up by mid-November.

Dividing dahlia tubers with a garden knife. Photo by Lorna Kring

Cut the stems back to 4 to 6 inches, then loosen and lift the tubers with a fork or spade. Shake or brush off excess soil, and allow to air dry for a few days in a spot with temperatures above freezing.

Place the clump in a bin or cardboard box and layer with a material such as sand, peat moss, or vermiculite, then store in a dark, dry spot with ideal temperatures of 40 to 50°F.

If you chose to leave the tubers in the ground over winter, cut the stalks down and provide a thick layer of dry mulch for protection. Dig and divide in the spring, dry for a few days, and plant when appropriate for your area.

For propagation, divide tubers in the spring using a sharp knife, ensuring each new piece has a bud or “eye” of new growth. Then, allow the fresh cuts to dry for a few days before planting.

Or, you can try growing them from seeds – although germination can be a bit spotty. Sow indoors in early spring, and germination will occur in 7 to 21 days, provided soil and seed are kept warm and damp, but not wet.

Plant outdoors once soil temperatures are warm enough, and stems have two true sets of leaves.

Dahlia Plant Facts

  • The family name Asteraceae refers to the flower’s appearance – like a star with surrounding rays.
  • Dahlias are available in all shades except blue.
  • In the mid-1800s, the Caledonia Horticultural Society of Edinburgh posed a reward of £2,000 for the first breeder to produce a blue dahlia – a reward that remains unclaimed to this day, although many have come close.
  • Reliably hardy in Zones 8-11.
  • Tubers in all zones should be dug and divided annually for propagation, and to maintain healthy growth with abundant flowers.
  • Once a food crop used by the Aztecs, the plant was called acocotli, or water pipe flower.
  • Dahlias have been the official national flower of Mexico since 1963.
  • To flourish, they require 6-8 hours of sunshine.
  • Plant in average soil, with good drainage.

Where to Buy?

‘Figaro’ seeds are available in a mix from True Leaf Market in red, violet, white, and shades of yellow and orange.

‘Figaro’ Mix

This variety reaches 10 to 12 inches with nearly 3-inch blossoms appearing in just 70 days. This mix includes both single and double blooms.

‘Harlequin’ Mix

‘Halequin’ seeds are also available from True Leaf Market. ‘Harlequin’ is a D. pinnata cultivar that grows to be 14 to 16 inches. This early flowering bicolor features contrasting colors in shades of pink, white, red, and yellow with semi-double blooms.

And tubers like these from Holland Bulb Farm are available via Amazon.

Park Princess Border Dahlia

Three tubers are sold per package, and this pink variety grows to 24 inches in height.

Plant and Enjoy!

Dahlias make a bright and bold addition to the late summer garden.

And although they require a little bit of extra care, they repay the attention in spades with a long, showy season and vases full of beautiful cut flowers.

For best results, divide tubers annually and plant in the spring once temperatures have warmed. Provide them with full sunlight, water deeply twice a week, and ensure they have a well-drained site. Once the frost arrives, dig them up and store for the winter.

And remember, that £2,000 reward for a true-blue dahlia still stands…

How about you folks, any questions or problems about dahlia care that we can help you with? Drop us a line in the comments below, or join us on our Facebook page!


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Photos by Lorna Kring, © Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Product photos via True Leaf Market and Holland Bulb Farm. Uncredited photos: .

About Lorna Kring

A writer, artist, and entrepreneur, Lorna is also a long-time gardener who got hooked on organic and natural gardening methods at an early age. These days, her vegetable garden is smaller to make room for decorative landscapes filled with color, fragrance, art, and hidden treasures. Cultivating and designing the ideal garden spot is one of her favorite activities – especially for gathering with family and friends for good times and good food (straight from the garden, of course)!

Dahlia, Dinner Plate Collection II

Dahlia may be grown from seed sown early indoors and transplanted outside after frost, or sown directly in the garden after frost, or grown from potted plants or tubers.

Sowing Seed Indoors:

  • Sow indoors 8 weeks before last frost using a seed starting kit.
  • Sow seeds ¼ inch deep in seed starting soil
  • Keep the soil moist at 70-75 degrees
  • Seedlings emerge in 14-20 days
  • As soon as seedlings emerge, provide plenty of light on a sunny windowsill or grow seedlings 3-4 inches beneath fluorescent plant lights turned on 16 hours per day, off for 8 hours at night. Raise the lights as the plants grow taller. Incandescent bulbs will not work for this process because they will get too hot. Most plants require a dark period to grow, do not leave lights on for 24 hours.
  • Thin to one seedling per cell when they have two sets of leaves.
  • Seedlings do not need much fertilizer, feed when they are 3-4 weeks old using a starter solution (half strength of a complete indoor houseplant food) according to manufacturer’s directions.
  • Transplant hardened-off seedlings to the garden after the frost.
  • Before planting in the garden, seedling plants need to be “hardened off”. Accustom young plants to outdoor conditions by moving them to a sheltered place outside for a week. Be sure to protect them from wind and hot sun at first. If frost threatens at night, cover or bring containers indoors, then take them out again in the morning. This hardening off process toughens the plant’s cell structure and reduces transplant shock and scalding.

Sowing Directly in the Garden:

  • Direct sow after danger of frost has passed.
  • Select a location in full sun with good rich moist organic soil. The more sun dahlias receive, the more flowers you will get. In hot climates, a bit of shade during the hottest part of the day will protect plants from heat, however.
  • Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones.
  • Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
  • Sow seed ¼ inch deep.
  • Firm soil lightly, water and keep evenly moist.
  • Seedlings emerge in 14-20 days.
  • Thin plants to 18-30 inches apart, depending on the variety, when seedlings are 1 inch high.

Planting Dahlia Tubers

  • Plant tubers when you receive them in spring.
  • Select a location in full sun with good rich moist organic soil. The more sun dahlias receive, the more flowers you will get. In hot climates, a bit of shade during the hottest part of the day will protect plants from heat, however.
  • Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones.
  • Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
  • Dig a hole six inches deep and wide enough to accommodate the tuber. Place the whole dahlia on its side (do not cut up dahlia tubers).
  • Cover with 2 inches of soil. As the plant grows fill in the hole until it is even with the rest of the garden.
  • For larger varieties inset the stake you will use to support them the same time you plant the tuber to avoid damaging the roots.

Planting Potted Plants:

  • Select a location in full sun with good rich moist organic soil. The more sun dahlias receive, the more flowers you will get. In hot climates, a bit of shade during the hottest part of the day will protect plants from heat, however.
  • Prepare the bed by turning the soil under to a depth of 8 inches. Level with a rake to remove clumps of grass and stones.
  • Most plants respond well to soils amended with organic matter. Compost is a wonderful form of organic matter with a good balance of nutrients and an ideal pH level, it can be added to your planting area at any time. If compost is not available, top dress the soil after planting with 1-2 inches of organic mulch, which will begin to breakdown into compost. After the growing season, a soil test will indicate what soil amendments are needed for the following season.
  • Dig a hole for each plant large enough to amply accommodate the root ball.
  • Set level with the surrounding soil. Fill with soil to the top of the root ball. Press soil down firmly with your hand leaving a slight depression around the plant to hold water.
  • Water thoroughly, so that a puddle forms in the saucer you have created. This settles the plants in, drives out air pockets and results in good root-to-soil contact.
  • Use the plant tag as a location marker.
  • For larger varieties inset the stake you will use to support them the same time you plant the tuber to avoid damaging the roots.

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