Dahlias are popular for their diverse forms and vibrant colors. ‘Karma Maarten Zwaan’ is an elegant and sought-after variety. This guide covers planting, care, and overwintering for successful blooms.
Understanding ‘Karma Maarten Zwaan’ Dahlia
The ‘Karma Maarten Zwaan’ dahlia is a distinctive waterlily type, known for its refined appearance. Its blooms measure between 5 to 6 inches across and feature a soft, blended coloration. While often described as pure white, it can present subtle hues of salmon pink, apricot, or cream, creating a sophisticated display.
This variety grows to a height of about 28 to 48 inches (approximately 70 to 120 cm), making it a mid-sized dahlia that fits well in various garden settings. Its strong stems contribute to its suitability as a cut flower, providing a long vase life for indoor arrangements. The plant’s overall form, combined with its elegant blooms, makes it an attractive focal point in garden beds or borders.
Planting ‘Karma Maarten Zwaan’ Dahlias
Proper planting is key for ‘Karma Maarten Zwaan’ dahlias. They require full sun, ideally 6 to 8 hours daily, for robust growth and abundant flowering. Well-draining soil is crucial, as tubers are prone to rot in soggy conditions. Amending heavy clay soils with organic matter like compost, peat moss, or sand can improve drainage and aeration.
Planting should occur in spring after all danger of frost has passed and the soil temperature has warmed to at least 60 degrees Fahrenheit. Place tubers about 4 to 6 inches deep, with the “eye” or growing point facing upwards. Space tubers 12 to 18 inches apart to ensure good air circulation. After planting, avoid heavy watering until sprouts emerge, as too much moisture can lead to tuber rot.
Ongoing Care for ‘Karma Maarten Zwaan’ Dahlias
Consistent care supports vibrant blooming once ‘Karma Maarten Zwaan’ dahlias sprout. Deep water 2 to 3 times a week, especially during dry spells, ensuring moisture penetrates 8 to 10 inches. Avoid frequent, shallow watering, which does not encourage deep root development. Dahlias benefit from a balanced fertilizer, low in nitrogen and higher in phosphorus and potassium, to promote flower production. Fertilize every three to four weeks until September.
As plants grow, pinch the central stem when 8 to 12 inches tall to encourage bushier growth and more blooms. Taller varieties like ‘Karma Maarten Zwaan’ require staking to support stems and heavy blooms, preventing flopping in wind or rain. Regular deadheading of spent blooms signals the plant to produce more flowers throughout the season rather than going to seed. Monitor for common garden pests or signs of disease to address issues early.
Overwintering ‘Karma Maarten Zwaan’ Dahlias
In colder climates (USDA Hardiness Zones 3-8), ‘Karma Maarten Zwaan’ dahlia tubers are not winter hardy and must be dug up and stored indoors to survive. The ideal time to dig them up is after the first hard frost has caused the foliage to blacken and die back, which signals the plant to store energy in its tubers. Allowing the tubers to remain in the ground for one to two weeks after this initial frost can help them cure for storage.
Carefully dig around the tubers to avoid damage, then gently remove excess soil. After digging, allow tubers to dry and cure for a few days in a cool, dry location out of direct sunlight. Once dry, store them in a cool (40-50 degrees Fahrenheit), dark, and well-ventilated area. Common storage mediums include peat moss, vermiculite, or wood shavings, which help maintain appropriate moisture levels. In very warm climates (USDA Zones 8 and above), tubers can be left in the ground, provided the soil is well-draining and does not become waterlogged during winter.