The Berner Oberland Dahlia is a captivating garden plant, known for its striking blooms and lush foliage. Its visual appeal makes it a favored choice for adding rich color and texture to outdoor spaces.
Characteristics of Berner Oberland Dahlia
The Berner Oberland Dahlia showcases impressive blooms, 4 to 6 inches in diameter, in shades of purple, magenta, or plum, often with a vibrant, true magenta hue. Petals have a decorative, waterlily-like form, with fully double flowerheads featuring flat or slightly incurved florets. This dahlia grows to 3 to 4 feet tall, creating a substantial vertical element in garden designs.
Planting Berner Oberland Dahlias
Tubers should be planted after the last spring frost has passed and the soil temperature has warmed sufficiently, ideally to at least 60°F (15°C). Selecting a site that receives full sun for at least six to eight hours daily ensures robust growth and abundant flowering. The soil needs to be well-draining, fertile, and enriched with organic matter.
Before planting, loosen the soil to a depth of at least 12 inches (30 cm) and incorporate compost along with a balanced granular fertilizer. Dig a hole and position the dahlia tuber so that the top, where sprouts emerge, is about 3 to 6 inches below the soil surface once the hole is filled. After placing the tuber, backfill carefully, ensuring no air pockets. Water thoroughly, then refrain from further watering until the first green shoots appear, as overwatering at this initial stage can lead to rot.
Ongoing Care for Berner Oberland Dahlias
Once sprouts emerge, deep water once or twice a week, allowing the top inch of soil to dry between waterings. Avoid overhead watering to prevent fungal diseases.
Fertilize every three to four weeks until September with a water-soluble fertilizer. Ceasing fertilization in September encourages tubers to prepare for overwintering.
Staking is recommended to support their strong stems and large blooms, preventing flopping, especially in windy conditions. Pinching the main stem when the plant reaches about 12 inches (30 cm) tall encourages branching, leading to a bushier plant with more flowers. Deadheading spent blooms promotes continuous flowering. Removing faded flowers redirects the plant’s energy into producing new buds.
Troubleshooting Common Dahlia Issues
Pests like aphids, slugs, and leaf miners can affect plants. Dislodge aphids with a strong water spray; manage slugs with bait or handpicking.
Powdery mildew can occur, especially in dry conditions. Ensure good air circulation and avoid overhead watering to prevent this. Rot, often caused by excessive moisture, can be a problem, especially if tubers are overwatered after planting.
Lack of blooms or wilting leaves indicate underlying problems. Poor flowering can stem from insufficient sunlight, inadequate water, or nutrient deficiencies. Wilting may signal underwatering or root rot. Observe symptoms and adjust care, such as watering schedules or drainage, to resolve issues.
Overwintering Berner Oberland Dahlias
In colder climates, overwintering Berner Oberland Dahlia tubers is necessary. After the first hard frost blackens foliage, prepare tubers for storage. Cut top growth, leaving 2 to 4 inches of stem above the soil line.
Carefully dig up tubers, avoiding damage. Dry them for a few days in a frost-free location away from direct sunlight. Once dried, gently remove excess soil, keeping 1 to 2 inches of stem attached.
Store clumps in a cool, dry, dark location (40-50°F / 4.4-10°C). Place them in a ventilated box or basket with peat moss, wood shavings, or vermiculite to maintain humidity and prevent drying. This ensures viability for replanting next spring.