Japanese mums, a popular group within the diverse chrysanthemum family, offer intricate beauty and a rich heritage. These distinct flowers are known for their varied forms and detailed petal structures. Their cultivation encompasses centuries of cultural appreciation and specialized growing techniques.
Distinctive Characteristics of Japanese Mums
Japanese mums encompass a wide array of bloom forms, each showcasing distinct aesthetic qualities. Varieties include:
Spider mums, with slender, elongated ray florets.
Quill mums, displaying straight, tubular florets.
Spoon mums, which have spoon-shaped florets with concave tips.
Brush and decorative types.
Chrysanthemums are categorized by bloom size. ‘Ogiku’ refers to large flowers, sometimes exceeding 18 centimeters in diameter, often grown for exhibitions. ‘Chugiku’ are medium-sized blooms, typically between 9 and 18 centimeters, used in floral arrangements. Smaller ‘Kogiku’ varieties are suitable for garden beds and bonsai displays.
Cultural Significance of Chrysanthemums in Japan
The chrysanthemum, “kiku” in Japan, holds significant historical and cultural importance. It symbolizes royalty, longevity, nobility, and purity within Japanese society. A 16-petal chrysanthemum design serves as the Imperial Seal of Japan, appearing on passports, coins, and representing the Imperial Throne.
Chrysanthemums arrived in Japan from China during the Nara or Heian period, initially as a medicinal plant. Over centuries, their cultivation evolved, and by the Edo period, new varieties and elaborate display techniques were developed. This appreciation is celebrated through events like the annual Chrysanthemum Festival, or Kiku Matsuri, held in autumn. These festivals showcase thousands of blooms, sometimes arranged into large “kiku ningyo” or chrysanthemum dolls, depicting historical figures.
Cultivating Japanese Mums: A Guide for Gardeners
Sunlight
Japanese mums thrive with ample sunlight, ideally at least six hours daily. Morning sun helps dry dew from foliage, reducing foliar disease risk. Plants near artificial night lighting may experience disrupted flowering due to day length sensitivity.
Soil
Well-drained soil prevents root rot. An ideal soil pH for chrysanthemums ranges from slightly acidic to neutral (6.0-7.0). Enriching soil with organic matter, such as compost or aged manure, improves drainage and provides nutrients.
Watering
Consistent moisture is needed, especially during establishment and blooming. Garden plants require about one inch of water per week, increasing to two or three times weekly as flower buds develop. Water at soil level, avoiding wetting foliage and blooms, as trapped moisture can create conditions for bacterial and fungal growth. Container-grown mums may need daily watering during warm weather.
Fertilization
Fertilization supports strong growth and many blooms. Begin feeding in early spring after the last frost, continuing monthly until mid-July, before flower buds form. A balanced liquid fertilizer (e.g., 15-15-15 or 20-20-20) works well. Alternatively, a slow-release granular fertilizer applied in early spring provides nutrients over several months.
Pinching
Pinching encourages bushier plants and more flowers. From late spring to mid-July, regularly pinch back growing stem tips. This delays flowering until later in the season, resulting in more compact plants with a greater profusion of blooms.
Planting and Overwintering
Plant Japanese mums in spring once soil warms, allowing root establishment before colder weather. For overwintering in colder climates (USDA Zones 5-9), after hard frosts, cut stems to 3-4 inches above ground. Apply a thick layer of mulch (e.g., straw or leaves) over the crown to protect roots from freezing and thawing. Potted mums can be moved to an unheated garage or basement, kept slightly moist throughout dormancy.
Addressing Common Issues with Japanese Mums
Pests
Japanese mums can encounter several common pests. Aphids are small, soft-bodied insects that feed on plant sap, leading to distorted new growth, yellowing leaves, and honeydew excretion. Spider mites are tiny arachnids that cause stippling on leaves and thrive in hot, dry conditions. Thrips can cause puckering of foliage and discolored, withered flowers. Regular inspection and insecticidal soaps or neem oil manage these pests.
Diseases
Powdery mildew appears as a white, powdery coating on leaves, often in humid conditions with poor air circulation. Rust manifests as pale spots on upper leaf surfaces with orange pustules underneath. Leaf spot diseases cause dark spots on foliage, typically starting on lower leaves. Good air circulation and avoiding overhead watering can help prevent fungal issues.
Environmental Factors
Environmental factors can lead to problems. Leggy growth, where stems become long and stretched, often results from insufficient sunlight or inadequate pinching. A lack of blooms can be attributed to insufficient light or artificial light interference at night. Proper site selection and consistent pruning maintain plant vigor and encourage many flowers.