Dahlias are known for their large colorful flowers with some varieties having flowers that grow 12 inches in diameter.  They are one of the most beautiful flowers you can grow.  It is a member of the Asteraceae family, which is related to daisies as well as chrysanthemums and sunflowers.  There are 42 species and 20,000 varieties of dahlias.  The plant can be grown from seeds, but they are mainly grown from tuberous roots.  

Planting Dahlias

Dahlia tubers are planted in the spring when the soil has warmed, and the chance of frost has passed.  This is usually in June in most parts of the US.  A good rule of thumb is to plant your dahlias at the same time you plant your tomatoes. Look for a location with full or partial sun.  You need to have at least 6 hours of direct sunlight each day.

They need a location where they have plenty of room to grow and spread out.  Dahlias need good soil and drainage.  You can fortify your soil with compost and then sprinkle general-purpose fertilizer on top.  After that use, a shovel to work the soil. 

Put your tubers directly in the ground once you have dug a hole about 4 to 6 inches deep.  While every tuber looks different put the eye in the ground face up.  The eye is the point on the shoulder, or crown, of the tuber from which the plant grows.  If you are planting several dahlias in the same location, plant them about 2 feet apart.  It is also a good idea at this time to put stakes in the ground as these plants grow tall and will need to be tied up, so they do not topple over.  Putting the stakes in the ground makes sure you do not disturb the plant roots after they have grown.

After you plant your tubers do not water them. If you water them before there is growth you can cause the tuber to rot. It is best to wait until there is some green growth, approximately one month after planting to water them.  If it rains, you do not have to worry. Once your dahlias take off, water them once a week.  If you live in a location where it gets hot you will need to water them more often.

Dahlias can also be planted in containers and there are specific varieties designed for that purpose. Containers are a good idea, if you do not have space or your soil is poor.  Since pots dry out faster, they will need more care.  They will also need to be fertilized once a month.  It is best to get a variety meant to be grown in containers.  This type of dahlia is more compact and will not topple over.

Care Of Your Dahlia

As your dahlias are growing you might want to consider pinching them.  Pinching encourages the plant to grow more branches, which will give you more flowers.  It also encourages a stronger, bushier, and sturdier plant.  Pinching can be done when the plants are about 10-12 inches.  It is done at this stage because the plant is growing rapidly and can recover quickly.  Use sharp pruners or scissors to trim off the top of the plant, just above the center set of leaves. Make sure you do not tear the stem or damage the other leaves.

Removing the plant’s terminal bud will stimulate the buds on the lower part of the stem to develop new stems.  When the sprout is removed, the plant will generate two shoots rather than one.

Your plant will bloom profusely until frost.  A heavy frost will kill the plant.  Once your plant has died and you live in a zone 8 or higher, you can leave your tubers in-ground for the winter. In a colder climate, wait a couple of weeks after the freeze, then cut the dead plant to the ground and loosen the soil to get the tuber out of the ground to store them.  Store them in a cool, dark place until next spring.  For more information on storing your tender bulbs, review this article.  The American Dahlia Society is also a great resource for growing dahlias.  Learn more about Dahlia University.

One of the delights of growing dahlias is being able to use them for bouquets.  Dahlias are not a flower that will continue to open after cutting, so select flowers for your bouquet when they are open, but they have not started to decline.  Cut them at the coolest part of the day because the flowers are hydrated.  Put them in a bucket or vase of water after cutting and remove lower leaves and then enjoy them, especially since you grew them.

If you are a dahlia lover, let us know your favorite one.