How To Grow And Care For Dahlia Flowers

Dahlias are a spectacular cutting flower that come in a rainbow of colors and bloom endlessly. They are a favorite to florists and home growers alike.

Dahlias are easy to grow and care for, though specific varieties may need a little extra love and support. This guide will walk you through everything you need to know to start growing your own dahlia flowers.

blush toned dahlia flowers with green foliage

Dahlias are literally available in hundreds of colors and shapes, with many varieties to choose from. There is a variety out there for every flower lover!

If you are just starting out on your dahlia growing journey we are here to help guide you. Dahlias are an incredibly quick and rewarding flower to grow. In just a few months you can have a beautiful home grown arrangement adorning your own table.

About Dahlias

Dahlias are native to the higher elevations of Central America and Mexico. The Spanish stumbled upon the beautiful flowers in the last 1700’s and introduced them to Europe. These vibrant flowers thrive in warm areas with lots of moisture and crave light. Dahlias are a bushy perennial ranging from 2.5 to 6 feet in height. They grow from a tuber and are commonly planted in the spring.

Dahlias have a long growing season, often up to three months long! They bloom well into fall, until the first frosts cause the plant to die back.

In the late 1700’s, dahlias were introduced to Great Britain from Spain. This is where many of the varieties we grow and love today were developed. Today, thousands of varieties are available to enjoy.

Inflammation dahlia flower.
Dahlia Flower “Inflammation”

Dahlias come in a wide array of varieties and are classified by their size and color. Huge dinner plate varieties can grow up to 15 inches, and their tiny cousins wave cheerily at just 2 inches.

Dahlias are planted in many areas of the United States, and have become a popular cutting flower. Large dinner plate dahlias are often used in wedding bouquets and decor.

This incredible cutting flower is reliably grown as a perennial in zones 8 to 11, and usually grown as an annual in zones 6 and 7. In these colder zones dahlia tubers can be dug up, overwintered and re planted in the spring.

Why You’ll Love Them

Dahlias are a fantastically popular flower that many seasoned gardeners adore. You’ll love them too. Here’s just a few reasons why:

  • Dahlias come in thousands of different colors and shapes, from romantic and muted to brazen and colorful
  • Dahlia tubers multiply and with a little elbow grease you’ll glean many more flowers from just one plant
  • These flowers bloom and bloom and bloom! Seriously, if you keep deadheading them, you will get so many beautiful flowers!
  • Dahlias are a gorgeous cut flower and provide many bouquets throughout the season
  • Bees love dahlias and they are an excellent flower for feeding our buzzing friends
  • From our experience, dahlias are forgiving. With a little care, they will recover from mistakes

Types Of Dahlias

Dahlias are beloved in part because of their magnificent diversity. There are over 50,000 registered cultivars worldwide! It is hard to keep track of the many vibrant and diverse dahlias.

Dahlias are classified by the American Dahlia Society into 6 sizes, 20 forms, and 17 colors. Here is a quick breakdown of different dahlia classifications:

Classified By Size

Sizing classifications start with pompon, which are just 2 inches wide in bloom. The largest classification is Giant, which are 10 inches in diameter. General sizing classifications fall in 8 categories: Pompon, Mini ball, Miniature, Ball, Small, Medium, Large and Giant.

Classified By Form

In addition to a variety of sizes, dahlias are also available in myriad of forms. Form refers to shape and symmetry of the petals and flower head, length of the flower petal, and whether or not the centers open.

Some dahlia flowers are round with symmetrical, cascading petals. In contrast, some have pointed cactus like petals. Some of the common form classifications are Peony, Orchid, Ball, Smi-Cactus, Waterlily, and Novelty.

Classified By Color

As vibrant and varied as a rainbow, dahlias can also be classified by color. Dahlias come in subdued, muted whites and creams as well as vibrant orange, red, and purples. A single bloom may embrace an ombre of pinks, a distinct colors of 2 different colors, or a single hue.

orange dahlia flowers at different stages of bloom
This dahlia would be classified as a formal decorative.

Popular Dahlia Varieties

Dahlia varieties are abundant, and there is a flower style for everyone among the generous varieties. Here are a few popular dahlia flowers of varied varieties and colors:

Purplicious

Purplicious is a bold and vibrant dahlia classified as a Stellar shape. The vibrant blooms are full of texture, and the flowers point back towards the stem, reminiscent of a firework.

Marshmallow

If you love white flowers, you’ll have to add Sweet Dreams to the flower beds. A Waterlily styled dahlia, the compact blooms mean that flower petals will have a bit of a longer vase life.

Sweet Dreams

Sweet Dreams is all about personality. The style of this dahlia is Semi-Cactus, and we love her spikey petals which off set a blushed toned ombre of pink.

Vixen

If you are looking for a vibrant, showstopping red, look no further than Vixen. Classified under the Waterlily subsection of dahlias, this compact peony makes an excellent cut flower.

Pooh Dahlia Flower

Pooh dahlia is an adorable smaller dahlia that is classified as a Collarette, or a single bloom with a collar of ruffled petals encircling the center. This style of dahlia flower makes lovely addition to bouquet with larger flowers, and Pooh is a great addition for a garden with kids!

Cafe Au Lait

The subdued, muted tones of the Cafe Au Lait dahlia offset it’s generous, oversized petals. Often used in wedding bouquets, Cafe Au Lait dahlia is a dinner plate sized dahlia that needs lots of support in staking but is well worth the extra love.

Growing Zones

Dahlias are considered a tender perennial because they can be grown as a perennial in warmer zones with gentler winters. In zones with harsh freezing they are grown as annuals.

Dahlias can be grown as a perennial in Zones 8 and above. They are grown as annuals in zones 7 or below, but their tubers can be dug up, stored and re planted in late spring when the weather warms.

Make sure to research your specific zone before planting dahlias so you can be prepared on how to care for them in your climate. You can read our guide on how to overwinter dahlias here.

Growing + Caring For Dahlia Flowers

Dahlias are easy to grow, but a few basic rules must be followed to keep them happy and allow them to thrive! You will need to consider soil, planting time, light, water and fertilizer when planting dahlias.

Soil

When it comes to giving dahlias soil they can thrive in you need two things: fertile soil and drainage.

While dahlias are not overly particular about soil, they do love a nutrient rich home that is well draining. Loose soil that is fertile and healthy will result in thriving plants. If your soil does not have these qualities, you can easily add soil amendments and improve drainage with just a few simple additions: compost and sand.

Adding sand will help break up heavy soil and increase water’s ability to drain. A good compost mixed into the soil will boost the nutrient quality and help your dahlias thrive. Lots of organic matter will also assist in drainage. The pH of your soil should be slightly acidic, between 6.5 and 7.

If needed, consider building raised beds for your dahlias and filling them with rich soil, compost mix and sand.

*Keep in mind that heavy clay soil can cause tubers to rot because it holds moisture in. Make sure to heavily amend clay soil before planting tubers.

Light

Dahlias crave full sun! They need to be planted in an area that gets 6 to 8 hours of full sunlight. They can tolerate some dappled shade.

While dahlias enjoy full sun, avoid planting them in a very hot environment, such as up against a southern facing white wall. Areas of hot, scorching heat are not ideal for dahlia flowers. Remember, they love light and moisture.

If you plant dahlias in a shady spot they will get leggy while reaching for sunlight, and their ability to bloom will be stifled.

Fertilizer

Dahlias can benefit from a low nitrogen, higher phosphorous fertilizer. This is often referred to as bloom food, because it encourages lush and full flower blooms. Fertilizers are labeled with numbers that represent Nitrogen-Phosophorous-Potassium, so a good rule of thumb is to look for a fertilizer that contains half the amount of Nitrogen as Potassium.

Fertilize once when planting and continue fertilizing once every 3 to 4 weeks.

Spacing

Giving your dahlia plant the right amount of space will prevent diseases like powdery mildew and allow each plant to grow to it’s potential. Commonly, dahlias are planted with 3 feet of room on each side.

When planting in rows, you can get away with tucking your dahlias in a little tighter, about 2 rows per 3 feet.

Watering

Consistent, even watering is essential to the health of a dahlia flower. Water dahlia plants deeply once a week. During the hottest days of the summer, increase watering to every 2 to 3 days. Drip irrigation is ideal because it directly waters the roots of the plants and keeps the foliage dry and moisture free.

When watering by hand, be sure to deeply water once to twice a week, and more frequently during intense, hot weather.

Here are a few key tips for watering dahlias:

  • To prevent over watering and rotting your dahlia tuber, wait until the green shoots from the tuber appear above the soil to start a watering routine.
  • Add a thick layer of mulch around dahlia plants when they are young. This mulch will help keep water in the soil during those hot summer days.
  • Consider drip irrigation to help stay on top of watering and directly water the roots
  • Dahlias in pots will dry out faster and will need to be watered more regularly
group of orange dahlia flowers

What Is A Dahlia Tuber?

The dahlia tuber is the root of the plant that contains the energy, water and nutrition for the plant to grow. Without a healthy dahlia tuber, you will have no dahlia flowers! Dahlia tubers are sometimes inaccurately referred to as dahlia bulbs.

Just like the flowers, dahlia tubers are incredibly diverse. Some are long and skinny, some are round and fat, and some produce a lot of additional tubers while others may only add a few small additional tubers.

Dahlia tubers produce additional tubers, giving you the ability to divide plants each year.

How To Plant Dahlia Tubers

Dahlias are most commonly planted from tubers in the spring. Planting is straight forward and easy. As mentioned above, you will want to wait until all danger of frost has passed before planting. Identify a full fun location and amend soil with nutrients and fertilizer as needed, then follow these tips for planting.

Choose Healthy Dahlia Tubers

A healthy dahlia tuber will have three in distinct parts: the eyes, neck, and body. Tubers come in all shapes and sizes, but in order to thrive it should have all three parts in tact and be healthy. Make sure the neck is not broken and there is no rot on the tuber before planting.

Dig Hole Or Trench

If you are planting many dahlia tubers, you may want to dig a trench to plant them. More commonly, they are planted in individual holes.

Dig deep enough to plant the tuber about 6 inches deep. Make sure the growing eye is pointed up, then cover with soil and mark the area with the type of dahlia planted and date (don’t forget this essential step). You want about 2 to 3 inches of soil to cover the top of the dahlia tuber.

Keep an eye on your dahlias, but wait to prevent watering until shoots come up through the ground. At this point, keep a sharp lookout for slugs and snails.

When To Plant

Plant dahlias outside only after all danger of frost has passed. They are very cold sensitive and will die in frosts. The best time to plant dahlias is in the spring. If planted in the fall you can risk tubers rotting over winter.

Check your zone to find the last frost date and be sure to plant your dahlia tubers several weeks after for best results.

pink dahlia flower with ruffled petals

Pinching Dahlias

Pinching dahlias may sound a little silly, but it’s key to having a bushy plant full of blooms! Removing buds encourages more branches to grow near the base of the dahlia plant, and this results in more stems with more flowers!

Pinching is one of those gardener’s secrets every gardener needs to know and practice! So, what does it mean to pinch dahlias? Simply put, pinching dahlias results in more branches, and more blooms.

To “pinch” a dahlia plant means to simply pinch or cut off the center stalk when the dahlia plant is 8-12 inches tall. You’ll find the top sprout and cut it off in the center, between the two leaves.

You can find a wonderful video tutorial for pinching dahlias here.

Orange dahlia flowers at dusk

Staking Dahlias

Healthy dahlias that are well fed and watered will grow into large, thriving plants. Although dahlias are not a fussy flower, when they become strong and healthy they will need significant support in the form of staking.

Growing many blooms on long stalks means that the dahlia plant is susceptible to breaking. This primarily happens with large flower heads, like dinner plate dahlias. Smaller dahlia varieties, less than 2 feet tall, typically do not need support. Wind and rain can be particularly brutal in knocking out lush dahlia plants.

There are a few ways to stake dahlia flowers. It is important to start staking early so that you have the support in place as the plant grows, and you are not trying to wrangle blossoms onto a new support system.

To support dahlias, you can pound stakes into the ground and use twine to tie them as you grow. Some growers like to plant their dahlias alongside a fence and secure the twine to the fence as the dahlias grow.

For stakes, use metal, wood stakes, or bamboo, You can get creative here- the most important thing is to support the dahlias as they grow and regularly tie the stalks off with strong twine.

Large purple dinner plate dahlia flower supported by fence

When Do Dahlias Bloom?

In most climates, dahlias begin blooming in mid summer and continue bloom well into fall. The bloom time months for dahlias are typically mid July through late October. Dahlias are a popular flower because you really get your bang for your buck- one dahlia plant can produce hundreds of blooms in a season.

Dahlias will continue to thrive and bloom all summer long with proper deadheading and the right amount of nutrients and sunlight. Regularly removing spent blooms every 3 to 4 days in summer is essential to continued blossoming. Read this article to learn how to deadhead dahlias for more blooms.

Removing Spent Dahlias For More Blooms

Deadheading dahlias has multiple benefits. Removing spent blooms will allow the plant to put it’s energy into new blooms, instead of creating seeds. Regularly deadheading your dahlia plant the right way will also encourage new flower buds to emerge.

Removing the spent blooms regularly will allow you to enjoy beautiful blooms all summer and fall. Read our tutorial about the right way to deadhead dahlias here.

Cut dahlia flowers and spent blossoms

Pests

Dahlias are susceptible to several different kinds of pests. Keeping plants healthy and vibrant will help them deter and survive insect damage. These predators vary based on the season and where you live, but slugs, aphids, snails, and earwigs all commonly feast on dahlias.

Slugs and Snails

Slugs and snails particularly enjoy munching on the tenders shoots of a young dahlia plant. The moist rains of springtime increase slug and snail activity, and make your young dahlias susceptible to being eaten.

To deter slugs and snails, we recommend using Sluggo, which is very effective and safe to use around kids and pets. Set out Sluggo around your dahlias several weeks after planting, and regularly sprinkle it around the perimeter of your plant to continue the battle.

*Lots of rain can deteriorate Sluggo more quickly, so be sure to check and replace bait regularly during wet seasons.

Insects

Earwigs are famous for their appetite for dahlia blooms. They love to chomp up and destroy otherwise impeccable flowers.

Food grade diatomaceous earth sprinkled throughout the garden can prevent slugs from dining on your dahlias (dry environments only). Once they have already infected a plant, Sluggo Plus is an effective way to kill earwigs. Spraying infected areas with a solution of dish soap and water can prevent earwigs from returning to the flower.

Aphids

There are two ways to deter aphids. As a preventative measure, regularly releasing ladybugs into the dahlia garden will keep the aphid population under control. If aphids appear to be overtaking the flowers, use organic insecticidal soap to control the population.

We recommend a natural and holistic approach in controlling dahlia pests. Whatever sprays and chemicals use on the plant will effect you, your children and pets– as well as the environment. While perfect blooms are a certainly a treasure, nothing is worth risking your health over.

Diseases

Like all flowers, dahlias are susceptible to their share of diseases. They can fall prey to bacterial, viral and fungal disease. The best way to prevent dahlia disease is to keep the plant healthy, with the right nutrients and appropriate amount of water. When you see a diseased part of plant, prune immediately to prevent it from spreading to other parts of the plant.

Viruses

Yellow streaking is a common sign of viruses. Remove any spots, streaking or discolored areas on the leaves of the plant. Be sure to destroy any part of the diseased plant and keep the removed parts away from other plants.

Fungus

Powdery mildew, leaf spot and smut are common fungal diseases that are caused by overcrowding and over watering. To prevent these problems, give your dahlias plenty of air flow and don’t overwater.

Bacterial Disease

Crown gall is a common bacterial disease that can affect the tubers. Bumpy white warts form all over the outside of the tuber and cause stunted growth and decay. Unfortunately, there is no treatment for gall. If you find it on your dahlia tubers, dispose of the tubers and avoid cross contamination with your other plants.

Weeds

Weeds can easily overwhelm a dahlia bed and leach essential nutrients from the soil. This can leave your dahlia undernourished and suffocate airflow that prevents disease. They are also unsightly and spread easily!

The best way to approach weeds is to start early! Clear all weeds and their from the flower site before planting. After planting dahlias, put down a layer of mulch and bark to prevent and suffocate weeds. Regularly check on your flower bed and use a hoe to remove any lurking weeds.

How To Harvest Cut Flowers

Dahlias are widely grown as cut flowers due to their huge variety and brilliant color.

One of the most exciting parts of growing dahlia flowers is harvesting those blooms for your own enjoyment and decoration! A single dahlia flower by itself can make quite a statement, but many flowers together make a sophisticated and stunning arrangement.

For best results, harvest dahlia flowers early in the morning before the heat of the day kicks in. Use a clean pair of flower clippers. Cut stems as far down as possible, and immediately place in cool water. Set your flower vase in a cool area out of sunlight.

The best dahlia flowers to pick have just opened, with firm strong petals. If you cut flowers that have already showed signed of wilting you will end up with petals all over the counter in short order!

How Long Do Cut Dahlia Flowers Last?

Harvested dahlia flowers last 3 to 5 days.

This is not a long lasting cut flower, sadly. (I guess they make up for that with how many blooms they produce!). They wilt more quickly than many flowers, but their life can be extended by cutting at the right time of day and keeping them out of heat.

Popular Dahlias For Cut Flowers

Dahlias make wonderful cut flowers for bouquets and arrangements. Keep in mind that dahlias have a very short vase life compared to many flowers, however they bloom so well that you can create bouquets all summer long.

Some of the most important considerations for cut flowers are the length and strength of the stem, petals that hold up for a longer period time, and the vase life.

While all dahlia flowers tend to last for about 3 to 5 days in a vase, ball varieties hold up the longest because the petals are more compact.

Some of our favoritie varieties for vases: Clearview Peachy, Ferncliff Copper, Peaches N Cream, Nijinksy, and Marshmallow are some of the best varieties for cut flower use.

Purple Ninjinsky dahlia flower with other dahlia flowers behind it.
Nijinksy dahlia makes an excellent dahlia for a vase.

Tips For Dahlia Bouquet Arrangements

There are a few easy tips that will allow you to get the most out of your cut dahlia flowers:

  • Harvest flowers early in the morning when it is still cool
  • Harvest when dahlias are 3/4 of the way open, dahlias do not continue to open once harvested so do not open in bud stage
  • Remove lower leaves from dahlia stem to prevent mold from forming and extend vase life
  • Use an appropriately sized vase. Dahlias with larger flower heads will need significant support
  • Use flower food and cold water in vase
  • Keep bouquet out of direct sunlight and in a cool dry place
  • Extend the life of your bouquet by putting it in the refrigerator at night
  • Compliment your cut dahlias with peonies, roses, wild sorrel, ferns, hydrangea, and more!

Growing Dahlias In Pots + Containers

Can dahlias grow well in pots? Yes!

Small, compact dahlia varieties often do very well in pots and containers. We would recommend you do not plant large dahlia varieties with heavy heads in containers (plant in raised beds or directly in soil).

There are a few benefits to growing dahlias in pots. They can be easily overwintered as you can pull your container in from the cold during the winter months. It is also easier to keep slugs and snails away from your plants.

Dahlias are often pre grown and purchased from nurseries and stores in containers. These dahlias will often need to be transplanted to a larger container that can sustain the growth of the dahlia.

Dahlias grown in pots need to be watered more regularly, especially in hot weather. They also need to be fertilized more frequently because they fertilizer drains through the bottom of the container quickly.

Beautiful purple pink dinner plate dahlia.

Do Dahlia Flowers Bloom The First Year They Are Planted?

Yes, dahlias planted from a tuber will bloom the first season they are planted. Be sure to plant in late spring, don’t over water your tuber, and keep an eye out for pests in order to give your dahlia the best chance at survival.

The quick turn around time for dahlia flowers to start blooming, and the generous rush of blooms given each summer is what makes dahlias so fabulous!

Are Dahlias Easy To Grow?

Yes, dahlia flowers are easy to grow- with a few exceptions.

Dwarf dahlias, and established dahlias grown in pots are very easy to grow. Dahlia varieties with larger flower heads are a bit more challenging. Dinner plate dahlias require extra staking to ensure that their heads don’t fall over and break the entire plant.

Buying dahlias that are already established in pots can be easier to grow than dahlias in the ground. You do not have to worry about slugs and snails feasting on the tender shoots of the baby plant. These dahlia plants can be purchased every spring at gardening centers.

Your growing zone also affects how easy or challenging dahlia flowers will be to grow. If you live in a zone that requires digging up dahlia tubers, more elbow grease will be involved in growing them as annuals.

Blush pink dahlia flower

What Month Do You Plant Dahlias?

Dahlia tubers are typically planted in late May to early June. This will be dependent on where you live and the current climate. A good rule of thumb many seasoned gardeners follow is to plant your dahlia tubers at the same time as planting tomato plants.

How Long Do Dahlia Plants Last?

With fertile soil, proper water and consistent deadheading, dahlia plants can flower for up to 4 months. This is dependent on the zone and current weather you are experiencing within your zone.

Dahlia flowers around the Portland, Oregon area, for example, typically bloom from mid July to the end of October, when first frosts hit. During a particularly rainy or cold year, however, this season can be cut short by several weeks on either end.

pink dahlia flowers with green leaves

Do Dahlia Flowers Multiply?

Yes, dahlias multiply each year. It is important to dig up and divide dahlia tubers semi annually, because the tubers multiply every year. This increases your number of plants, so be sure to dig, divide, and give away!

How Many Dahlia Flowers Do You Get From One Tuber?

One dahlia tuber produces one dahlia plant. A single plant, however, can bloom hundreds of times in one season. Continually deadhead to ensure you keep getting these beautiful blooms!

Each season the dahlia tuber will multiply. The quality and amount of additional dahlia tubers greatly depends on the variety grown.

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