Dahlia ‘Black Jack’

Dahlia ‘Black Jack’ is a standout variety in the dahlia family, prized for its deeply colored blooms and semi-cactus form. It’s a favorite among gardeners and floral designers for its ability to create an impactful visual statement in both garden settings and floral arrangements.

Dahlia ‘Black Jack’: An In-depth Look

Dahlia ‘Black Jack’ is an alluring and dramatic cultivar in the world of dahlias, known for its deep coloration and striking presence. It falls under the semi-cactus dahlia category, characterized by its long, pointed petals that curve inward. The blooms are noted for their deep, velvety burgundy color, almost black in certain light, lending the flower a luxurious and mysterious appearance.

Native: Dahlias are native to Mexico and Central America. This cultivar results from extensive breeding and does not occur naturally in the wild.

Plant Type and Habit: This dahlia is a tuberous-rooted perennial with a bushy, upright growth habit. It produces sturdy stems that support its dramatic blooms, making it a standout plant for garden beds and borders.

Size: It generally reaches about 36-48 inches in height (90-120 cm) and spreads around 18-24 inches (30-60 cm), depending on growing conditions.

Flowers: The blooms are large, often reaching 6-8 inches in diameter (15-20 cm). The petals are striking with their semi-cactus form. The deep burgundy, almost black hue of the petals is both enigmatic and elegant, making each bloom a focal point in itself.

Bloom Time: Blooming from mid-summer until the first frost it provides long-lasting color in the garden.

Foliage: The foliage is typical of dahlias, with dark green leaves that provide a lush backdrop for the bright flowers.

Uses: Ideal for borders, beds, and as a striking feature in floral arrangements. Its vibrant blooms are also popular in cut flower gardens.

Hardiness: Dahlias are hardy in USDA zones 8-11. In colder zones, tubers need to be lifted and stored over winter.

Toxicity: Dahlias are toxic to dogs, cats, and horses. Their ingestion can lead to gastrointestinal upset and other health issues in pets and livestock.

Wildlife: While visually stunning, the complex petal structure of this dahlia makes it more difficult for pollinators to access the nectar and pollen. It is less effective in attracting pollinators than single-flowered or open-centered dahlia types.

Deer and Rabbit: Dahlias are somewhat resistant to deer and rabbits but may still be vulnerable to browsing.

Invasiveness: Not invasive; dahlias grow from tubers and do not spread aggressively.

Dahlia Growing Tips

Light: Dahlias love the sun, so choose a location with at least six to eight hours of direct sunlight daily.

Soil: Dahlias prefer well-drained, loamy soil. They don’t tolerate water-logged conditions, so if your soil is heavy clay, consider amending it with compost or peat moss to improve drainage.

Planting Time: Dahlias are usually planted in the spring after the risk of frost has passed and the soil has warmed up.

Planting Depth: Dahlia tubers should be planted about 4 to 6 inches (10-15 cm) deep, with the “eye” (the small bump from where the stem will grow) facing upward.

Watering: Dahlias like consistent moisture. Water them deeply a couple of times a week, more often if your area is experiencing a drought. Avoid overhead watering to reduce the risk of fungal diseases.

Fertilizing: Dahlias respond well to low-nitrogen fertilizers, such as a 5-10-10 or 10-20-20. Too much nitrogen can lead to lush, leafy growth and fewer flowers.

Deadheading: Regularly removing the spent flowers (deadheading) will keep your dahlias producing more blooms.

Overwintering: In colder climates (zones 7 and below), you’ll need to dig up and store the tubers indoors over the winter.

Pests and Diseases: Dahlias are generally relatively disease and pest-resistant, but there are a few common issues to watch out such as aphids, botrytis blight, earwigs, powdery mildew, slugs and snails, spider mites, and thrips.