How to Grow and Care for Rancho Dahlia
Learn to cultivate the Rancho dahlia through its entire seasonal cycle. Our guide offers clear, practical advice for healthy plants and successful tuber storage.
The Rancho dahlia is a distinctive flower known for its warm, shifting colors and elegant form. Classified as a waterlily-type dahlia, its blooms are fully double with an open appearance, often reaching four to six inches in diameter. The petals display a blend of orange and yellow hues that can soften to apricot or take on more golden tones as the flower matures.
This variety reaches a height of around 40 inches, making it a substantial presence in garden borders. Introduced in France, its strong stems also make it a lasting cut flower for arrangements. The bloom time extends from midsummer until the first frost of fall, offering a long season of color.
Planting Rancho Dahlia Tubers
Wait until the danger of frost has passed and the soil has warmed to approximately 60°F before planting. Planting in cooler soil can slow development and potentially lead to tuber rot. Choose a location that receives ample sunlight for abundant flowers.
These plants perform best in well-drained, humus-rich soil. Amending heavy clay or sandy soils with compost improves its structure and fertility. This preparation ensures that water does not sit around the tubers, preventing rot.
When planting, dig a hole four to six inches deep. Place the tuber horizontally inside the hole with the “eye,” or growth bud, facing upward. Space tubers 12 to 24 inches apart to give each plant enough room to develop.
After covering the tuber, do not water it until sprouts emerge. The tuber contains enough moisture to initiate growth, and adding water too early can encourage rot. A regular watering schedule can begin once green shoots appear.
Growing Season Care
Rancho dahlias require a location that receives at least six to eight hours of direct sunlight per day. In extremely hot climates, a position that offers some light afternoon shade can prevent wilting and stress.
Dahlias benefit from deep, infrequent watering rather than light, daily sprinklings. Provide a thorough soaking two to three times a week, allowing the soil to dry out slightly between sessions. This encourages the root system to grow deeper and stronger, but avoid overwatering, as soggy soil can lead to tuber rot.
To promote abundant flowers rather than excessive foliage, use a low-nitrogen fertilizer with higher percentages of phosphorus and potassium. Begin fertilizing after the plant is established and about a foot tall, reapplying every few weeks according to the product’s instructions.
As a taller dahlia, Rancho requires support to prevent its stems from snapping under the weight of its blooms, especially during windy or rainy weather. Place a sturdy stake next to the plant at planting time. As the main stalk grows, loosely tie it to the stake at regular intervals. For a bushier plant with more flowers, pinch off the central growing tip when the plant is 12 to 18 inches tall.
Overwintering and Storing Tubers
In climates with freezing winters, Rancho dahlia tubers must be dug up and stored. Wait until the first hard frost kills the top growth, which signals the plant has entered dormancy and the tubers have stored their energy for winter.
Start by cutting the blackened stalk down to about four to six inches. Use a garden fork to carefully lift the entire tuber clump from the soil, digging a wide circle to avoid damage. Gently brush off excess soil, but do not wash the tubers, as this can introduce moisture that leads to rot during storage.
After cleaning, the tubers need to cure for a few days. Place them in a dry, well-ventilated location protected from direct sun and frost, such as a garage. This drying period allows cuts on the tubers’ surface to heal, which prevents them from rotting in storage.
For storage, place the cured tubers in a cardboard box filled with a loose medium like peat moss or vermiculite, ensuring they do not touch. Store the container in a cool, dark, and dry location where the temperature remains consistently between 40 and 50 degrees Fahrenheit.
Common Pests and Diseases
Rancho dahlias can encounter several common pests and diseases. Vigilance can help manage these issues before they cause significant damage.
- Spider mites: Prevalent in hot, dry conditions, these pests cause yellow, stippled leaves and fine webbing on the undersides of foliage.
- Slugs: These pests chew irregular holes in foliage and flower petals, leaving behind characteristic slime trails.
- Earwigs: Often creating tattered-looking petals from their chewing, these nocturnal insects can be trapped in damp, rolled-up newspaper placed near the plants.
- Powdery mildew: This fungal disease appears as a white, dusty coating on leaves, especially in high humidity. Provide good air circulation between plants and remove affected leaves promptly to prevent its spread.