Dahlia ‘Kelvin Floodlight’

Dahlia ‘Kelvin Floodlight’ is a magnificent variety, embodying the grandeur and beauty that dinnerplate dahlias are celebrated for. Its enormous, sunlit yellow blooms, combined with a sturdy growth habit and versatile use in gardens and arrangements, make it a prized choice for both amateur and professional gardeners. Whether it’s lighting up a garden bed, gracing a large container, or starring in a floral display, ‘Kelvin Floodlight’ 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 ‘Kelvin Floodlight’: An In-depth Look

Dahlia ‘Kelvin Floodlight’ is an illustrious member of the dinnerplate dahlia category, renowned for its exceptionally large, vibrant yellow blooms. Dinnerplate dahlias are characterized by their substantial flower size, often exceeding 10 inches in diameter (25 cm), and ‘Kelvin Floodlight’ is a prime example of this spectacular group.

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 vigorous grower is known for its reliability and impressive stature in the garden.

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 flowers are the star feature of ‘Kelvin Floodlight’, with their radiant, sunny yellow color. The blooms are colossal, often measuring 10-12 inches (25-30 cm) across. The petals are broad and slightly curved, arranged in a full, almost circular form, creating a mesmerizing 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: ‘Kelvin Floodlight’ is incredibly versatile in landscaping and floral design. Its grand size and striking color make it a popular choice for garden focal points, mixed borders, and as a stunning centerpiece in large containers. In floral arrangements, its large, bright blooms add a touch of sunshine and are often used as a statement piece.

Award: Recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society.

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.