All About Dahlia

It’s hard not to love Dahlia. They are bold and cheerful and come in a wide range of colours, forms, and sizes. Some cultivars have flowers that are just 2 inches wide while others offer flowers that are 8, 10 or even 12 inches across!

The Variety of Dahlia Flowers

Dahlia flowers come in almost every colour of the rainbow except for true blue and many flowers are bicoloured or even tricoloured. Their forms can be single or double and their petals offer all manner of shapes and sizes. They bloom over a long period through the summer and fall, when spring and early summer perennials have finished, and they love the heat. While the large-flowered cultivars need more time to come into flower blooming at the peak of summer, many of the smaller-flowered cultivars can begin to bloom in June. Some plants grow only one foot high while others tower at six feet. Most Dahlia have green leaves but some have rich, burgundy foliage adding an extra layer of beauty before and during bloom.

Cultivation and Care

Dahlia are easy to grow in full sun in containers or the garden and, though not hardy for most Canadian gardeners, they are easy to store over winter. For those on the West Coast, Dahlia can be hardy in protected locations in zone 8 where soils are not too wet in the winter months.

Origins and Cultural Significance

The wild species of Dahlia, of which there are 42, are native to Mexico and Central America. In fact, the Dahlia is the national flower of Mexico. They are members of the Aster family and are thus related to black-eyed Susans, Echinacea, Zinnia, and sunflowers. The local indigenous people, including the Aztecs, used Dahlia tubers as a food source and a source of medicine. The hollow stems were used as pipes and for various other purposes.

Popular Cultivars

Such is the diversity of Dahlia in the wild that breeding work has led to the creation of a diverse range of flower types. Here are the most common:

Dinner Plate
Huge flowers 8-12 inches wide on tall stems 4-6 feet high.

Burgundy Leaf
Rich burgundy, chocolate, and near black foliage. Flower types can vary but they are often single, mignon or peony type blooms. The smaller flowered cultivars usually start blooming in early summer.

Decorative
Double blooms with broad, flattened or slightly curved petals, usually medium to large in size.

Cactus
Large, double blooms with narrow, pointed ray florets.

Fimbriata
Large, double blooms with split or notched tips to the ray florets.

Mignon & Collarette
Small single or semi-double (collarette) blooms. Flowers can often start blooming in early summer.

Ball and Pompon
Round or spherical double blooms, ray florets usually with blunt or rounded tips. Pompons have miniature flowers while Ball types are larger.

Anemone
Smaller to medium sized flowers with a ring of ray florets topped with a central ruff of smaller florets often in a different colour.


Dahlia prefer full sun in rich, well-drained average to sandy soils though they are tolerant of clay soils that have been amended with organic matter. To get the most flower power out of your tubers, make sure to give lots of rich compost and provide an organic or conventional fertilizer with a higher middle number for an extra dose of phosphorus.

Dahlia should be lifted in fall, usually around or just after the first hard frost. Knock off the soil from the tubers and store in dry peat, perlite or vermiculite in a frost-free location. Check periodically through the winter for rot.

If you are growing in containers, you can also just leave the tubers in the pots over the winter as long as you can get the soil to dry out before storage. Move your pots closer to the house and out of the rain in September so you can control the amount of moisture in the potting mix as your plants get closer and closer to dormancy.

In coastal British Columbia, you can often overwinter Dahlia outside in the ground but you’ll need to find a good location with free-draining soils, preferably in a raised bed or on a slope or in an area with overhead protection from conifer branches, the overhang of the house, or other garden structures. Mulch heavily with fallen leaves to protect the tubers from winter freezes and to help shed the rain away from the tubers.

 

At Phoenix Perennials we offer potted Dahlia for sale through the spring, summer, and fall season. We also include a huge selection of tubers in our Summer Bulb Pre-Order that launches in the winter for spring pick-up or shipping.


Give Your Garden the Phoenix Perennials Touch:

At Phoenix Perennials we offer over 5000 different plants every year for in-person shopping at our garden centre and plant nursery in Richmond, British Columbia, part of Greater Vancouver. Additionally, we offer more than 3000 different plants each year for mail-order shipping across Canada. Stay connected with our diverse offerings and all things Phoenix Perennials by signing up for our E-Newsletter and Alerts and engaging with us on social media. Happy gardening!