Dahlia ‘Penhill Watermelon’

Dahlia ‘Penhill Watermelon’ is a magnificent variety, embodying the grandeur and beauty that dinnerplate dahlias are celebrated for. Its enormous watermelon-pink blooms, combined with a sturdy growth habit and versatility in use, make it a prized choice for both amateur and professional gardeners. Whether illuminating a garden bed, gracing a large container, or starring in a floral display, ‘Penhill Watermelon’ is a true horticultural treasure, admired for its size, color, and presence. This dahlia is featured in our top 40 must-see dahlia flowers.

Dahlia ‘Penhill Watermelon’: An In-depth Look

Dahlia ‘Penhill Watermelon’ is a standout member of the dinnerplate dahlia category, famed for its exceptionally large and showy blooms. It is distinguished by its soft, watermelon-pink color, evoking the freshness and vibrancy of summer. Dinnerplate dahlias are celebrated for their substantial size and striking visual impact.

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. This variety is appreciated for its strength and vigor, making it a magnificent presence in any garden setting.

Size: It generally reaches about 40-48 inches in height (100-120 cm) and spreads around 18-24 inches (30-60 cm), depending on growing conditions.

Flowers: The flowers are the main attraction of ‘Penhill Watermelon’, with their lush, watermelon-pink hue. The blooms are colossal, often measuring 12 inches (30 cm) across. The petals are broad, slightly ruffled, and arranged in a full, rounded form, creating an opulent display of color and size.

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: ‘Penhill Watermelon’ is incredibly versatile in landscaping and floral design. Its grand size and captivating color make it a popular choice for creating dramatic focal points in gardens and as a standout centerpiece in large containers. In floral arrangements, its large, bright blooms add a touch of elegance and are often used as a statement piece.

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: The flowers attract pollinators such as bees and butterflies.

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.