The ease and versatility of growing potted dahlias

Dahlias. One would never describe the flowers of this late-summer beauty as subdued or understated. Just the name dahlia is enough to evoke an enviable sigh.

At one time or another, many gardeners, including myself, have purchased dahlia tubers, potted them up in spring, fussed over them in summer, picked their showy blooms for cut flower arrangements, and at the end of the season, dug up the tubers and stored them over winter. It can be very rewarding to grow dahlias from tubers. And yet, dahlias, even with their dazzling flowers, have not been as prevalent in gardens as petunias, impatiens, begonias, or zinnias.

Potted dahlias are rewarding, too, and very easy to grow. In recent years, there has been a surge of new varieties of compact, container-friendly dahlias introduced to the market. These are still tuberous plants, but they are marketed in the same way as annual bedding plants. Selected for their bushier habits and shorter stems (no staking required), these new varieties offer earlier flowering and a long, reliable flowering period. Breeders are also focused on criteria such as better heat tolerance and excellent mildew resistance, essential attributes when summer days turn hot and muggy.

Admittedly, ready-to-grow potted dahlias do not produce dinner-plate-size flowers. But they do bloom prolifically, come in a wide range of colours and unique patterns and perform very well in mixed container arrangements.

The Venti series from SelectaOne is a vigorous, anemone-type dahlia suitable for large containers or planting directly in the garden. The series includes 12 distinct varieties featuring double flowers and bicolours. Dahlia Venti FireBurst is an award-winning dahlia with fire-engine red outer petals and a bright yellow centre. Venti Tequila Sunrise and Venti Pink are standouts as well but any of the varieties in the series make wonderful thrillers in the container garden. Mature height and spread is 41 to 46 cm.

The City Lights series, also from SelectaOne, is especially notable for its dramatically dark, greenish-purple foliage which at times almost looks black. Incredibly, the natural anthocyanin pigments in the foliage look even darker with sun exposure and cool temperatures. Imagine the contrast when the brightly coloured flowers start to bloom!

The City Lights series is extremely well-branched. While tall dahlia varieties, like dinnerplate dahlias, benefit from having their top growth pinched to create a bushier plant, the City Lights series is naturally bushy. it’s almost like a small shrub, frankly.

I am growing City Lights dahlias in my garden this year and although the flowers are not as big and splashy as the Venti series, I am really impressed by this series. Varieties include Apricot Glow, Golden Yellow, Lavender Pink, Neon, Purple, and Red. But the names don’t do justice to the actual colour. City Lights Golden Yellow, for example, is a bicolour combination of almost burnt yellow with peach tips. The rich ruby red flowers of City Lights Red have vivid colour saturation. City Lights Purple dahlia could almost have been called Magenta, the tone is so jewel-like. I would like to see City Lights Neon dahlia which is described as having bright pink flowers. My guess is that the description is inadequate.

Somewhat shorter than the Venti series, City Lights has a height and spread of 30 to 36 cm.

Dahlia Coffee Shop Lavender Latte from Syngenta Flowers takes the prize, though, for most imaginative name. But what’s the meaning behind the name? Was it conceived at a coffee shop over a cup of creamy espresso and scribbled on a napkin? I have no answer to that question but can tell you that this unique hybrid dahlia is billed as having double-shot blooms on dark-roast foliage. Let’s translate that.

The dark foliage of this new cafe-inspired dahlia deepens in shade and intensity under bright conditions and the cream to lavender shade blooms are fully double. This hybrid dahlia grows to a commanding height of 46 to 61 cm but has a narrower width of 25 to 41 cm. What’s especially notable is that Coffee Shop Lavender Latte Dahlia has been bred for excellent powdery mildew resistance.

When the telltale signs of mildew — a white, flour-like powder — make an appearance on a beautiful dahlia loaded with buds and blooms, panic can start to set in. Because without quick action to remove the affected leaves, mildew can quickly spread to the rest of the plant. Sometimes the whole plant needs to be removed. That’s very inconvenient if the plant happens to play a central role in a mixed container.

Strong garden performance and excellent powdery mildew resistance is essential if dahlias are to look fresh and healthy throughout the summer right up to the first frost in fall. It’s reassuring to know that recent potted dahlia introductions are thoroughly trialled for powdery mildew. But that said, it is very important to avoid overhead watering. Water directly at the root zone. And water regularly, especially during hot, dry periods. Good air circulation is beneficial.

Dahlia XXL Star Fire from Dummen Orange holds some surprises. The fully double blooms are substantial in size. A bicolour dahlia, initially the flower opens to solid brilliant red with just a hint of bright yellow at the centre. But as the flower matures, the band of yellow widens. The foliage on this exotic beauty is green. Dahlia XXL Star Fire reaches 45 to 66 cm in height and 45 to 50 inches in width. This new variety is well-suited as a thriller in a mixed container, but it would be tempting to grow multiples in a monoculture container for a truly eye-catching floral impact.

Dahlia Summer Bees from Dummen Orange is a delightful novelty dahlia with cheerful flowers that bloom abundantly. The single flowers with their bright petals are especially appealing to bees, butterflies, and other beneficial insects who are looking for easy access to nectar and pollen. This new potted series features three varieties — Salmon Bicolour, Red Bicolour, and Red Star. The small, manageable size of Dahlia Summer Bees makes it an attractive choice for groupings of containers on a sunny balcony, porch, or patio.

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