Penhill Watermelon, Dahlia Tubers

Penhill Watermelon Dahlia Tubers

Watermelon, peach, and blush blend across enormous flowers
Ruffled twisting petals give every bloom romantic movement
Informal dinnerplate form makes a luxurious focal point
Perfect for statement bouquets and late-summer borders

See product details

Key Attributes

Botanical Name

Dahlia

Days to maturity

90 Days

Sun

Full Sun

Zones 8–10 Check your growing zone

About Penhill Watermelon, Dahlia Tubers, Dahlia Tubers

Penhill Watermelon 'Dinnerplate' dahlias produce huge, informal decorative blooms in soft shades of watermelon pink, peach, and blush with beautifully ruffled, slightly twisted petals that give each flower a loose, romantic look. The large blooms, often reaching 8–10 inches across, sit atop tall, sturdy plants that typically grow 4–5 feet high, making them perfect for cutting gardens and dramatic landscape displays. Flowering from midsummer until frost, this variety is prized for its unique coloring and airy texture, adding warmth, movement, and a touch of vintage charm to bouquets and garden beds alike.

Growing details

Planting

Germination Type

A - No Pretreatment

Plant profile

Life Cycle

Tender Perennial

Hardiness Zone

Zones 8-10

Plant Height

60 inches

Growth Habits

Clumping, Upright

Seed & variety

Color

Pink

Seed Type

Bulb

Before Planting

Firm tubers with sound necks and visible eyes are worth planting; discard pieces that are soft, moldy, or badly shriveled. Prepare a sunny, wind-sheltered bed with crumbly drainage and moderate fertility. Put supports in place now so stakes will not pierce expanding clumps later.

Planting

Wait for warm soil and the end of frost danger. Position each tuber horizontally with the eye upward, then cover it at the variety’s recommended depth without snapping the neck. Unless the bed is exceptionally dry, withhold substantial irrigation until green shoots break the surface.

Watering

Dahlias shift from needing little moisture before emergence to requiring thorough watering in active growth. Once shoots are established, soak the bed deeply once or twice a week, adjusting for heat and rainfall. Let the soil drain between applications to discourage rot.

Fertilizer

Choose a formulation lower in nitrogen once active growth begins. Additional light feedings during heavy bloom can help plants in lean soil, but lush leaves paired with few flowers usually signal too much nitrogen.

Harvesting

Select newly opened flowers with firm petals, cutting long stems early in the day. Place them promptly into clean water and leave enough foliage to keep the tuber clump productive. Frequent cutting also prevents aging blooms from slowing new bud development.

Tips

Pinching above several leaf pairs produces a fuller plant, while early tying prevents tall stems from breaking. Where winters freeze the ground, lift the clumps after frost blackens the tops, dry off surface moisture, and overwinter them in cool, airy, frost-free storage.

Pests & Diseases

Inspect dahlia tubers for crown gall, bacterial soft rot, Fusarium decay, and virus symptoms before planting. Discard galled, mushy, or badly shriveled stock—cutting away visible damage is unreliable. Divide with disinfected tools, cure storage wounds, and keep labeled clumps separate so suspect stock is not propagated.

Young shoots attract slugs and caterpillars; later growth may host aphids, thrips, mites, or Japanese beetles. Check buds and leaf undersides rather than spraying on a schedule. Remove isolated pests and damaged tissue first, especially while pollinators are visiting the flowers.