Piper methysticum
Kava
Overview
Piper methysticum is an evergreen shrub 6-13 feet (2-4 m) tall and 4-8 feet (1.2-2.4 m) wide, built from succulent jointed stems swollen at each node. Stem colour separates the named cultivars and runs from pale green through mottled green to near-black purple. Leaves are alternate, heart-shaped, 4-10 inches (10-25 cm) wide, hairless, untoothed, and marked by 9-13 veins radiating from the leaf base. The plant is a sterile cultigen selected from Piper wichmannii: it sets no viable seed and every plant in cultivation traces back to stem cuttings, so a growing region often carries only a handful of clones. Below ground the rootstock forms a knobbly mass reaching 22-130 pounds (10-60 kg) after 4-5 years, and kavalactones concentrate in that rootstock and the basal stem rather than in the leaves. Growth requires steady warmth, shade, and 80 inches (2,000 mm) or more of annual rainfall, and plants collapse under drought or frost. Aerial parts contain pipermethystine and are separated from the root at harvest. Preparations made from the rootstock are restricted or regulated in several European countries following reports of liver injury.
Native Range
Piper methysticum was domesticated in northern Vanuatu from the wild species Piper wichmannii, which occurs in New Guinea, the Solomon Islands, and Vanuatu. Because the crop is sterile, its range reflects human transport: Pacific voyagers carried cuttings east and north to Fiji, Samoa, Tonga, and Hawaii. It is grown commercially in Vanuatu, Fiji, Tonga, Samoa, Papua New Guinea, and Hawaii between sea level and 3,300 feet (1,000 m).Suggested Uses
Grown as a root crop in shaded plots and agroforestry systems at spacings of 5-8 feet (1.5-2.4 m), commonly under coconut, banana, or breadfruit. The dried rootstock is ground and steeped in water to make the beverage central to ceremonial and social life across Vanuatu, Fiji, Tonga, Samoa, and Hawaii. Plants are also grown as a foliage shrub in shaded tropical gardens and in large containers under glass.How to Identify
Appearance
Size & Dimensions
Height6' - 13'
Width/Spread4' - 8'
Reaches mature size in approximately 4 years
Bloom Information
Piper methysticum is a sterile cultigen and seldom flowers. Where spikes do form they are slender green-white structures 1-3 inches (2.5-7.5 cm) long borne opposite a leaf, and they set no viable seed. Propagation is therefore entirely from stem cuttings of 2-3 nodes taken from stems two years old or older. Plants reach harvest size 3-5 years after planting.
Detailed Descriptions
Foliage Description
Medium to dark greenGrowing Conditions
Sun Requirements
Requires 2-6 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Piper methysticum grows under 30-70 percent shade with 2-6 hours of filtered sun, in deep, free-draining volcanic loam at pH 5.5-6.5. Annual rainfall of 80-120 inches (2,000-3,000 mm) or equivalent irrigation is required, and soil moisture must stay steady, since drying beyond 2-3 weeks kills the fleshy roots. Temperatures of 68-84F (20-29C) support growth, below 50F (10C) growth stops, and frost kills the plant outright, holding it to USDA zones 10-12. Stems are brittle, so plantings are staked or set among taller shade crops for wind shelter. Cucumber mosaic virus, Fusarium spp. and Phytophthora spp. root rots, and kava dieback are the principal disease pressures, and infected stock is not used for cuttings. Balanced fertilizer at 3-4 ounces (85-115 g) per plant twice a year supports rootstock bulking.Pruning
Lower lateral shoots are thinned in early spring to leave 4-8 main stems per stool, which directs growth into the rootstock. Stems are cut at 6-12 inches (15-30 cm) above ground when material is taken for cuttings, and the stool resprouts within 4-6 weeks. Broken and wind-damaged canes are taken out at the base at any time of year. Whole-plant harvest at 3-5 years lifts the rootstock and ends the plant.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
early spring
Container Growing
✓ Suitable for container growing
Minimum container size: 20 gallons