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How Long Do Dahlias Bloom? (And How to Make Them Bloom for Longer)

How Long Do Dahlias Bloom? (And How to Make Them Bloom for Longer)

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You can get dahlias that produce all different colors of flowers, including some that have more than one color. They add personality to your garden all summer into the fall when many other flowers are finished blooming for the year.

Dahlias do best in zones 7 through 10, and they prefer milder temperatures. However, when you plant them properly and prune them strategically, they will produce healthy flowers that last a long time.

When Do Dahlias Bloom?

It normally takes dahlias around eight weeks to bloom once they have been planted. If you plant tubers in April, you should have flowers by June.

Most dahlias do bloom in July because they love the warmer temperatures, and they will last until September and October.

As long as you plant them correctly and take good care of them, they will bloom on time and continue blooming into the fall.

You should make sure that when you plant tubers, the bud points are facing the sky so that sprouts have access to the sunlight. If you look at them each day when you expect buds to start sprouting, you can pinch the first ones off so that larger buds will come.

Can You Make Dahlias Bloom Longer?

You can encourage dahlias to bloom longer. Their blossoming season lasts as long as four months, and if you deadhead them, they will bloom longer.

The way to do this is to cut off the dead blossoms as they appear, which encourages the plant to produce new flowers. Removing the flowers signals to the plant that it needs more for pollination and seeding.

Give Your Dahlias What They Need to Thrive

If you want your dahlias to bloom as long as possible, you need to make sure that they have everything they need. They are actually not difficult to grow.

First, they love the sun, and you need to make sure that they get at least six hours of sunlight each day. When they have the sunlight they need, they will bloom better, so make sure that you find a sunny location for them.

Even though dahlias do best in zones 7 through 11, you can actually grow them in zones 3 through 6 as well. In these zones, you can plant them in the spring as tubers and they should bloom by the middle of the summer.

You need to make sure that you plant them in soil they do well in. Make sure that it is loose and fertile with excellent drainage, and you can improve its quality by adding compost.

You should consider fertilizing your dahlias when you plant them, and make sure that you don’t grow them in soggy or compacted soil.

You should wait until any danger of a frost has passed before you plant your tubers. You can start them indoors or in a greenhouse between four and six weeks before that last frost.

You should use six- or eight-inch pots, and fill them with growing mix and plant one tuber in each pot. Then place the pot in a place that is warm and sunny.

Once the ground warms up and the weather is right, you can transplant them outside.

The Best Locations for Dahlias

You have a lot of different options when it comes to where you choose to plant your dahlias. No matter what location you choose, make sure that they have full access to sunlight for at least six hours each day.

One popular location is flower gardens. They are a great addition because they bloom for many months.

Your dahlias will start blooming in the middle of the summer, and they will continue into the fall. They look their best as most of your perennials are beginning to fade.

When you place them in your flower garden, be aware of how tall they will be and place the tallest ones in the back of the flower garden, with the border dahlias in the front.

People also place them in their entryways and on their patios and decks. There isn’t anything as inviting as a wide array of dahlias in containers around your home.

You can get compact bushy plants, and they will grow to be between 18 and 24 inches tall. They will cover themselves with flowers starting in the middle of the summer and lasting until the first frost.

It is also common for people to plant them next to their fences and use them as a screening. There are full-size dahlias that are great for privacy.

You can plant them in pots as well and use them for privacy when you want it. If you have a vegetable garden, you can plant them when you plant your tomatoes and peppers, and you can have fresh flowers on the table along with your vegetables.

Some people also have cutting gardens, and you can get cuttings from your dahlias to have flowers in your home.

How Should You Plant Dahlias?

You can plant your dahlias in April, as soon as the last frost passes. Start by choosing a location for them in your garden or in pots.

If you plan to plant them in pots, you can actually start them indoors before it is warm enough to move them outside. Once you take them outside, start by digging a hole that is between four and six inches deep.

You should make sure that you choose well-drained soil, and place the tubers in the hole with the stems facing up towards the sun.

The crown of the plant is where the tubers are connected to the stem, and this part should be between one and two inches deep.

If you find that the soil is dry, you might consider replacing it with moist soil. Water them to make sure that the soil stays moist, but do not drench them.

Your sprouts should start to appear in between two and four weeks.

Tips for Growing Dahlias Successfully

When you are planting your dahlias, you should make sure that they have access to full sun. They will grow up towards the sun, and they will bloom longer if they receive sunlight every day.

Another tip is to add compost to the soil, and feed them with an all-purpose granular fertilizer. This will give them the nutrients they need to grow and be healthy.

The tubes should be upright with the stem aiming towards the sun, as this will encourage growth. The sprouts will start to develop where the tubers and the stem meet. Make sure that this part of the plant is about one inch below the surface of the soil.

Wait for your dahlias to reach around eight inches tall and then fertilize them. You can give them an all-purpose fertilizer once every three or four weeks after that point.

You can also pinch them when they are ten inches tall, and you will end up with bigger bushes and more flowers. If you cut back some of the taller stems when the first flower buds appear, you will get a full plant with more flowers.

How to Help Taller Dahlias Stand up

When you grow taller dahlias with larger flowers, you might need to help them stand up. They can get top heavy, which leads to them bending and breaking.

One opinion for support is to use stakes. You can choose a six-foot stake for each one that needs it, and place the stake eight to ten inches into the ground.

You should know ahead of time if your dahlias are going to be tall, so you can place the stakes in the ground at that time. This will prevent you from damaging the plant by mistake later.

Some people use tomato cages to support the plants. This is uncomplicated, and you can place them there a little bit after you plant them.

You can also use the corral method, where you place stakes down a row of plants. As they grow, add twine between the stakes to support them.

You Can Grow Dahlias in Containers

You can also grow dahlias in containers, and they do best when you plant them on their own. Some dahlias need large pots, such as full-size dahlias.

If you have border dahlias, you can keep them in small pots that are 12 inches deep and 12 inches wide. You need to fertilize them every few weeks, or you can use a slow-release fertilizer.

Make sure that you water them so that the soil throughout the entire pot gets wet. You will also need to water them every day starting in the middle of the summer.

Final Thoughts

People love to add dahlias to their garden because they can bloom as many as four months out of the year. They often start blooming when the perennials are dying, so they keep color in your garden.

You can take good care of them to keep them blooming longer. They are versatile enough to grow in the garden or in pots and containers.

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Andrea Hill

Saturday 6th of May 2023

I have moved to Florida and it has thrown all of my plant knowledge out the window. lol. When I grew Dahlias up north they bloomed in the summer and I dug them up in winter. Now apparently I can grow them all year here. Will they bloom all year or have resting periods? Also, here in southern Florida it is very hot and very wet in the summer. Anything special I should do? THANK YOU!!

Lisa Bridenstine

Friday 19th of May 2023

Hi Andrea, Congrats on the move! You will want to make sure you have a heat tolerant variety of dahlia and plant it in well draining soil. Put it in a spot that gets a bit of shade in the afternoon and add a layer of mulch to your soil to protect the roots. With a good watering and fertilizing schedule, you should be able to enjoy their blooms from midsummer through fall.

Happy Planting! Lisa