The dramatic, colorful foliage of New Zealand flax (Phormium tenax) makes a fabulous focal point whether planted in gardens or containers. In warmer climates its foliage is topped with orange-red flowers each summer, stretching to a towering 19 feet tall. In cooler climates, however, New Zealand flax is tamer, growing about 6 feet tall and flowering infrequently. Many cultivars are smaller, growing just 18 to 36 inches tall, and are handsome, durable container plants, as well as attractive garden plants. Placed in tough spots, such as patios around swimming pools, they will take intense sun and heat. In gardens, Phormiums survive in extreme locations—from the wet seaside to hot, dry climates.
Common name: New Zealand flax, phormium
Botanical name: Phormium tenax
Plant type: Perennial
Height: Varies with cultivar
Zones: 8 to 11, depending on cultivar
-Sun: Full sun
-Soil: Does best in well-drained soil with organic matter, but will tolerate a wide variety of soils.
-Moisture: Consistent moisture is important for container plants. In the ground, established plants need only occasional watering.
-Mulch: In Zones 7 and 8, plants may survive the winter in a protected site with a heavy layer of mulch around the roots.
-Fertilizing: None required on established plants.
-Pruning: On container plants, remove dying leaves as new leaves emerge.
-‘Atropurpureum Compactum’ (pictured) has burgundy-bronze, sword-like leaves. Attractive in a courtyard corner or next to a water garden as a single accent. Grows 5 feet tall. Zones 8 to 11.
-‘Dazzler’ has bronze leaves with burgundy, orange, and pink stripes. Grows 3 feet tall. Zones 9 to 11.
-‘Jack Spratt’ has bronze leaves. At just 18 inches tall, it’s perfect for smaller gardens. Zones 9 to 11.
-‘Thumbelina’ has slightly weeping, reddish bronze leaves and grows 12 inches tall. It’s ideal for firescaping. Zones 8 to 11.
-Pair Phormiums with Peruvian lily (Alstroemeria spp.), sea lavender (Limonium spp.), ornamental grasses, annuals with colorful foliage, or taller cultivars of marigolds, zinnias, and cosmos.
-Give consistent moisture to first-year plantings to encourage good root development.
-In cooler regions bring containers indoors before the first frost. Keep in a sunny, cool spot.
-Divide clumps every two to three years in early spring.
Pests and diseases
-Leaf spots occur occasionally.
-Slugs and mealybugs sometimes attack the plant.
-Divide in spring every three to four years.
All in the family
The Phormium genus includes mountain flax (P. cookianum) and some cultivars with golden-hued, variegated leaves such as P. ‘Sundowner’ and P. ‘Yellow Wave’.
Other popular plants in the Agavaceae family are Parry’s century plant (Agave parryi), mother-in-law’s tongue (Sansevieria trifasciata), and Joshua tree (Yucca brevifolia).
Text by Mary Pestel, photo courtesy of Monrovia Growers, www.monrovia.com.