The Merlot Dahlia is a captivating variety, highly prized for its deep, rich coloration and sophisticated appearance in garden settings. Its unique appeal stems from the velvety red hues, often with a subtle hint of purple, that resemble a fine merlot wine. This dahlia has become a popular choice for gardeners seeking to add dramatic color and elegance to their landscapes.
Understanding Merlot Dahlia Characteristics
The Merlot Dahlia features deep red to burgundy blooms, sometimes with a yellow tint as they mature. These large, full flowers typically measure 6 to 8 inches in diameter, with wide, smooth, and slightly rounded petals. The plants grow 3 to 4 feet tall, exhibiting a strong, upright habit. Their dark green foliage provides a striking contrast to the deep-colored flowers. Merlot Dahlias are known for abundant, long-lasting blooms from mid-summer through the first frost.
Planting Merlot Dahlias
Plant Merlot Dahlias after the last spring frost, once soil temperatures have warmed sufficiently. These dahlias thrive in full sunlight, ideally at least six hours daily, as ample sun exposure promotes better flowering. Well-draining, fertile soil is crucial for healthy growth, as soggy conditions can lead to tuber rot. Amending the soil with compost and a balanced organic fertilizer before planting provides a nutrient-rich environment.
Dig a hole 4 to 6 inches deep for each tuber, placing it horizontally with the “eye” or sprout facing upwards. Space tubers 12 to 18 inches apart, or up to 3 feet for larger varieties, to ensure proper air circulation. Gently backfill the hole with soil, covering the tuber completely. Avoid immediate watering unless the soil is exceptionally dry, as this can cause rot. Regular watering can begin once green growth appears, typically within 2 to 4 weeks.
Ongoing Care for Thriving Merlot Dahlias
Water Merlot Dahlias consistently, especially during dry periods, keeping soil moist but not waterlogged. Deep watering, reaching 8 to 10 inches below the surface, two to three times weekly promotes strong root development. Once plants are 24 inches tall, use a low-nitrogen fertilizer with a balanced NPK ratio (e.g., 5-10-5 or 5-10-10) to encourage blooms over leafy growth. Apply fertilizer every three to four weeks during the growing season.
Deadheading, the removal of spent blooms, is an important practice that encourages the plant to produce more flowers throughout the season. Snip off faded flowers just above a set of healthy leaves or buds. For taller Merlot Dahlia varieties, staking or providing support is necessary to prevent stems from breaking under the weight of large blooms or due to wind. Install stakes at planting time to avoid damaging the tubers later, and tie the growing stems to the supports every 12 to 18 inches. Pinch the plant when it reaches about 12-16 inches tall, by removing the central stem above four sets of leaves, to encourage bushier growth and more blooms.
Winterizing Merlot Dahlia Tubers
In colder climates (USDA hardiness zones below 8), Merlot Dahlia tubers are not hardy and require digging up and storing indoors for the winter. The ideal time to dig tubers is a week or two after the first hard frost, which signals the plant to enter dormancy and toughens the tuber skin for storage. Carefully cut the stalks down to about 4 inches above the ground. Using a pitchfork, gently loosen the soil around the tuber clump, then lift the entire clump from the ground.
After digging, gently remove excess soil from the tubers. Allow them to air dry and cure for a few days to several weeks in a cool, dark place with good air circulation, ensuring they are not exposed to freezing temperatures. Once cured, store tubers in a cool, dark, and dry location where temperatures remain consistently between 40-50°F (4-10°C) with around 80-90% humidity. Tubers can be stored in cardboard boxes, plastic bins, or paper bags, often nestled in a medium like peat moss, vermiculite, or wood shavings to help regulate moisture. Regularly check stored tubers for any signs of rot or shriveling throughout the winter.
Troubleshooting Common Merlot Dahlia Problems
Merlot Dahlias can occasionally experience issues such as a lack of blooms, which often stems from insufficient sunlight, cold soil temperatures, or inconsistent watering. Over-fertilization with too much nitrogen can also promote leafy growth at the expense of flowers, so using a balanced fertilizer is important. Leggy growth may indicate inadequate light, prompting the plant to stretch towards a light source. Ensuring full sun exposure and proper pinching techniques can help prevent this.
Common pests that may affect Merlot Dahlias include aphids, slugs, and spider mites. Aphids cause yellowed, curled leaves and leave a sticky residue, while slugs create irregular holes in foliage, especially on young plants. Spider mites cause mottled yellow leaves and fine webbing, thriving in hot, dry conditions. Organic solutions include spraying aphids with a strong stream of water or insecticidal soap, using slug bait or traps, and applying horticultural oil for spider mites. Fungal diseases like powdery mildew may appear as white, powdery spots on leaves, especially in humid conditions. Improving air circulation, avoiding overhead watering, and removing affected leaves can help manage powdery mildew.