A Complete Guide on Growing and Caring for Dahlias

Dahlias are one of the most popular flowers among gardeners, known for their vibrant colors and stunning beauty. These versatile flowers can be grown in a wide range of climates and soils, making them a popular choice for gardeners all over the world. In this article, we will explore the various types of dahlias, how to grow and care for them, and their fascinating botanical history.

To gain invaluable factual information on Dahlias, we sought help from none other than Dr. Keith Hammett. Dr. Hammett is a well-known plant breeder from New Zealand who has spent the last several decades developing new and improved varieties of plants, including dahlias. He is considered one of the world’s leading breeders of dahlia hybrids.

Born in 1942 in England, Dr. Hammett obtained a Ph.D. in Pathology from the University of Southampton in 1967. He came to New Zealand in 1967 to work in the horticultural industry and began his career as a plant breeder. Over the years, he has created a number of new plant varieties, including several award-winning dahlias.

Dr. Hammett’s dahlia hybrids are highly sought after by gardeners and horticulturists alike. His hybrids are known for their unique colors, shapes, and sizes, as well as their disease resistance and hardiness.

He was made Fellow of the Royal New Zealand (RNZIH) in 1986 and was awarded the Plant Breeder’s Award in 1988. In 1994 he was made Associate of Honour, the institute’s highest award. Dr. Hammett is currently the President of RNZIH.

Dr. Hammett continues to work on developing new plant varieties, including dahlias. He remains committed to the preservation of endangered plant species and the development of new plants that are more resistant to disease and pests. His work has had a significant impact on the horticultural industry, and his contributions to plant breeding and conservation will continue to be felt for many years to come.

Types of Dahlias

Dahlias come in many different types, each with its unique characteristics. There are over 42,000 registered dahlia cultivars, divided into different classifications based on their flower shape and size. Here are some of the most common types of dahlias:

  1. Ball Dahlias:

These dahlias have rounded, globe-shaped flowers that are usually smaller than other types, ranging from 2-4 inches in diameter.

  1. Pompon Dahlias:

These dahlias have small, spherical flowers that are less than 2 inches in diameter. They are often used as cut flowers and are popular for their long vase life.

  1. Anemone Dahlias:

These dahlias have a central disc surrounded by one or more rows of flat petals. They are similar to anemone flowers and have a unique and eye-catching appearance.

  1. Cactus Dahlias:

These dahlias have narrow, rolled petals that give them a spiky appearance. They are available in a range of colors and can grow up to 10 inches in diameter.

  1. Waterlily Dahlias:

These dahlias have fully double, bowl-shaped flowers that resemble waterlilies. They are popular for their delicate appearance and come in a variety of colors.

How to Grow Dahlias

Dahlias are relatively easy to grow, and with the right conditions, they can produce an abundance of blooms. Here are some steps to follow for growing dahlias:

  1. Planting:

Dahlias prefer well-draining soil with a pH between 6.0 and 7.5. They should be planted in the spring, after the threat of frost has passed. The hole for the plant should be around 6 inches deep and wide enough to accommodate the root ball. Once planted, dahlias should be watered deeply and kept moist but not waterlogged.

  1. Fertilizing:

Dahlias are heavy feeders and should be fertilized regularly throughout the growing season. A balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium can be applied every four to six weeks.

  1. Staking:

As dahlias grow, they can become top-heavy and require staking to prevent them from falling over. Stakes should be inserted into the soil around the plant, and the plant should be tied to the stake using soft twine or a plant clip.

  1. Deadheading:

To encourage continuous blooms, spent flowers should be removed regularly. This process, known as deadheading, directs the plant’s energy towards producing new blooms rather than seed production.

  1. Winterizing:

In areas with frost, dahlias should be lifted in the fall after the first frost and stored indoors for the winter. The tubers should be cleaned, dried, and stored in a cool, dry location until the following spring.

Caring for Dahlias

Dahlias require regular care to ensure they stay healthy and produce a bountiful harvest. Here are some tips for caring for dahlias:

  1. Watering:

Dahlias require regular watering to keep the soil moist. However, overwatering can cause the tubers to rot, so it’s important not to water them too much.

  1. Pest Control:

Dahlias are susceptible to pests like aphids, spider mites, and thrips. Regular inspection and treatment with insecticidal soap can help keep pests at bay.

  1. Disease Control:

Dahlias are susceptible to various diseases and pests, including powdery mildew, botrytis, spider mites, and aphids. Preventing and controlling these issues is important to ensure the health and vitality of your dahlias. One effective way to prevent disease is to provide proper spacing between your plants. Crowded plants can lead to increased humidity, which can promote the growth of fungal diseases. Good airflow is also essential, so avoid planting your dahlias in areas with low airflow.

Another crucial aspect of disease control is maintaining healthy soil. Dahlias prefer well-draining soil that is rich in organic matter. Adding compost and other organic amendments can help improve soil health and fertility. Regularly fertilizing your dahlias can also help keep them healthy and resistant to disease. If you do notice signs of disease, it’s essential to act quickly to prevent it from spreading. Remove any affected leaves or stems and dispose of them in the trash (not the compost pile). Treat the remaining plant with an appropriate fungicide or insecticide, following the instructions on the product label carefully.


Dahlias are a beautiful and rewarding addition to any garden. By following these guidelines for planting, care, and disease control, you can enjoy a stunning display of dahlias in your own backyard.

Remember to choose the right location, plant at the right time, and provide proper soil, water, and nutrients. Regular maintenance, including deadheading and staking, can help ensure the health and longevity of your dahlias.

By following these steps and staying vigilant for signs of disease or pests, you can cultivate healthy and vibrant dahlias that will bring joy and beauty to your garden for years to come.

Back to top button

AdBlock Detected

AdBlock Detected: Please Allow Us To Show Ads