The Dahlia Diaries: Caring for Your Blooming Beauties

Dahlias have always been one of my favorites. In my grandparent’s house, where I grew up, we used to have a mini dahlia garden that was so beautiful I pledged to have a bigger one when I was older.

Grown from tubers planted in spring, dahlias come in an array of colors and shapes that make them a beautiful addition to summer gardens.

These blooms know how to brighten up a space, and they also have symbolic value. They add personality to your garden even when other flowers may have finished blooming.

When do Dahlias Bloom?

Dahlia Flowers

Dahlias love warm temperatures, so they can start blooming in July; they will continue until September or October. 

They begin to bloom a couple of months after the soil gets warm, mostly in summer, and continue to bloom until fall. 

Environmental conditions and variety can impact when and how long they bloom, but as long as you plant them correctly and take care of them, they will bloom on time and for a long.

How Long do Dahlias Take to Bloom?

One big reason I love dahlias is how quickly they bloom. The year I planted my first one, it grew to bloom that same year, with only a few weeks between planting and blooming.

From planting the tubers to seeing the plant flowers takes about eight weeks in general. 

Because they cannot survive in cold temperatures, gardeners have to wait for the soil to be at the warmth of 60 degrees Fahrenheit in spring before planting.

After those eight weeks, they start to bloom in summer, which is why they start to bloom in July. 

How Long do Dahlia Blooms Last?

Most dahlias tend to bloom continuously until mid to late fall when they stop due to the drop in temperature. 

Dahlias have an impressive blooming season length of 120 days. In some locations, you might be able to get your dahlias to bloom for a couple of weeks more.

Dahlias will continue to bloom until the first frost kills them, so climate determines the length of the dahlia blooming season. 

How to Take Care of a Blooming Dahlia

Blooming Dahlia

Plantinag dahlias is pretty easy, but caring for them during the summer months when they bloom can be a bit challenging. 

In this section, I’d like to share a few tips for keeping your dahlia productive and healthy until they stop blooming in the fall.


Full-size dahlias with blooms as large as a dinner plate need some support to ensure the blooms stay out of the dirt.

The flowers get spoiled easily if the plant is left to flop on the ground. You can use a hardwood stake to support your plant.

You’ll need some twine to tie the branches to the stake. Make sure to check in often to see if they need to be tied higher, seeing as dahlias grow quickly.

For larger dahlia varieties, you should consider using a wire tomato cage. You’ll have to install this when the plant is a few inches tall. 


When you notice the flowers have faded, use a clean, sharp pair of pruners to cut the flower stem just where it grew from the main stem. 

Removing the spent flowers regularly encourages more flowering and stunts seed production, a process that takes up too much energy and reduces blooms. 


Fertilize your dahlia regularly with a liquid fertilizer that has high phosphorus content. The phosphorus will help to increase bloom production and keep the plant strong.

It is advisable to use liquid fertilizers because they are absorbed easily by the roots. Apply according to the instructions on the pack.


A lot of energy is put into bloom production and maintenance, so you’ll need to give your plant a drink often to replenish its stores.

Be sure to keep your plant hydrated, especially in times of drought. Water the plant deeply once a week.

This soaking will enable the deep roots to access the nutrients and water better.

Treat Infections

Fungal infections can strike quickly, stop bud production, and destroy the foliage, so try your hardest to keep them at bay.

Give your dahlias plenty of room to allow air circulation and trim nearby foliage for easy ventilation. 

If you notice any diseased foliage or bud, trim it off promptly and discard it properly.

How to Get a Dahlia to Bloom

Having a dahlia that is not blooming is indeed worrying because every dahlia owner wants to experience the vivid flowers of this plant.

Lack of sunlight, drought, planting at the wrong time, too much nitrogen, or an infection can be responsible for your dahlia not blooming, and here’s how to fix this situation.

Check where your dahlia is planted. The flowering will be affected if it is kept in a shaded area of your garden or home or doesn’t receive enough direct sunlight.

Move it somewhere it can receive at least six hours of direct sun daily. Morning sun is preferable, but it can have a bit of both.

Leaving your plant dry too often, especially when growing leaves and buds, will impede blooming, so ensure it gets the proper amount of water.

Soak the soil thoroughly to keep it moist, but do not overwater. Once blooming has started, increase the water from one to two inches per week.

Dahlias planted too early may have been killed by exposure to cold temperatures in winter and early spring. 

Planting too late will delay the blooms because the plant will need time to mature before flowering.

To fix this problem, plant your dahlia immediately after all danger of frost has passed. Check the soil temperature needed above.

Failure to deadhead your dahlia will slow down bloom production because the plant will focus its energy on seed production, abandoning the flowers.

Make sure you remove the spent flowers properly. You’ll begin to see new growth from the nodes below that region and, ultimately, new blooms.

Too much nitrogen, especially in the blooming season, will make the plant produce lots of healthy leaves, with flower production forgotten.

Powdery mildew is a fungal infection that might not be strong enough to kill your plant, but it stresses it enough to delay or suppress blooming.

It would be best for your plant to treat this infection immediately. 

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