• Dark red black jack dahlia up close showing all the cactus like petals
  • Dark red black jack dahlia up close showing all the cactus like petals
  • A cluster of dahlia tubers with dirt on the ready for planting.
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Ships Spring 2027

Dahlia Tubers (Semi-Cactus) - Black Jack

Semi-cactus form brings unique texture to this dramatic beauty

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About the Variety

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Key Features

Heat Tolerant
Prefers Moist Soil
Container Friendly
Attracts Bees
Attracts Butterflies
Fast Growing
Easy to Grow
Perfect for Cut Flowers
Perfect for Borders
Edible

Plant Details

BOTANICAL NAME

Dahlia 'Black Jack'

LIFE CYCLE

  • Perennial

SEED TYPE

  • Tuber

LIGHT REQUIREMENT

  • Full Sun

BLOOM SEASON

  • Summer through Fall

GROWTH HABIT

  • Upright

PLANT HEIGHT

  • 48 to 54 inches

PLANT TYPE

  • Semi-Cactus

COLOR

  • Red
  • Black

Bring dramatic contrast to the garden with Dahlia Black Jack, one of the darkest dahlias you can grow. Its deep burgundy blooms appear nearly black in low light, while flashes of rich red emerge in the sunshine. Narrow, pointed petals create a striking semi-cactus form, and long, sturdy stems display the dramatic flowers beautifully in the garden and in bold, sophisticated arrangements.

  • • Blooms measure approximately up to eight inches across
  • • Striking dark blooms make an impact planted against lighter, contrasting colors
  • • One of the latest blooming dahlias

Planting Information

PLANTING SEASON

  • Spring

SOWING METHOD

  • Direct Sow

PLANTING DEPTH

  • Deep Enough to Cover with 2 inches of Soil

WATER NEEDS

  • Average

PLANT SPACING

  • 24 to 36 inches

HARDINESS ZONES

  • 7
  • 8
  • 9
  • 10
  • 11

COVERAGE

Amount Recommended Coverage
2 Bulbs / Ships in Spring Up to 0.75 Sq. Ft
4 Bulbs / Ships in Spring Up to 1.5 Sq. Ft
8 Bulbs / Ships in Spring Up to 2.75 Sq. Ft

Planting Guide

View our Dahlia Planting Guide to learn more.

Ready to Grow

We guarantee that our seeds & bulbs will be true to type and ready to thrive. If something doesn't grow as expected, we will make it right. Questions? Call us at 855-440-2929

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    Dahlia Tubers (Semi-Cactus) - Black Jack FAQs

    When do I plant dahlia tubers?

    Think of planting your dahlias when you plant your tomatoes. Plant in spring after the danger of frost has passed and the soil has warmed to at least 60°F. In warmer climates, planting can begin earlier than in regions with colder springs.

    Are Black Jack Dahlia flowers actually black?

    Not quite. Black Jack produces exceptionally dark burgundy-red flowers that can appear almost black, particularly in certain lighting. The rich coloring creates beautiful contrast against lighter flowers and green foliage.

    Do dahlias need staking?

    Staking is recommended, particularly in windy locations or when plants become heavily loaded with flowers. Providing support early helps protect stems as the plant grows.

    What is the difference between semi-cactus and cactus dahlias?

    Both types feature pointed petals, but cactus dahlias have narrow petals that roll backward along more than half their length, creating a spiky appearance. Semi-cactus dahlias have broader petals that are rolled for less than half their length, giving the blooms a fuller, slightly softer appearance.

    Will dahlias come back every year?

    Dahlias are tender perennials that can overwinter in the ground in sufficiently warm climates with good drainage. In colder regions, tubers should be lifted after frost and stored in a cool, frost-free location until spring.

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