Noted for its showy, remarkably fragrant purple flowers, american wisteria ‘Amethyst Falls’ is a vine smaller than the parent plant, and less vigorous than the Chinese wisteria (Wisteria sinensis) and the Japanese wisteria (Wisteria floribunda). Due to its less aggressive nature and small size, it’s perfect for small gardens with limited space.
I. Appearance and Characteristics
‘Amethyst Falls’ wisteria is a deciduous, climbing vine in the Fabaceae (bean) family. It is a wisteria cultivar from Head Ornamentals, Inc. Unlike the more common Asian wisteria, you will be pleasantly surprised by the less aggressive nature of this American vine. Considered by some to be a dwarf wisteria, ‘Amethyst Falls’ has smaller leaves and smaller flowers than its exotic Asian relatives. Once this plant is established, it can climb 18 to 20 feet high and has a spread of 10 to 15 feet wide.
‘Amethyst Falls’ should be planted in full sun and in moist soil with good drainage. Space the plants 6 to 12 feet apart. This plant blooms on new wood, providing a gorgeous, heavy bloom in the late spring and a lighter, repeat bloom in summer. The flowers are lightly fragrant, lavender-purple, and borne in cascading 4- to 6-inch racemes in May. Due to the fact that our native wisterias bloom on new growth, vines can be moderately pruned back each winter. This characteristic helps gardeners train ‘Amethyst Falls’ onto arbors or to almost any trellis form. This plant has a low toxicity to cats, dogs, and horses.
II. How to Grow and Care
Sunlight
American wisteria ‘Amethyst Falls’ likes ample sunlight and need to be exposed to over 6 hours of light every day. The plant can thrive in open fields and gardens, as well as on the sun-facing sides of buildings. If it doesn’t receive enough light in the flowering season, the number of blossoms may reduce and the flowers might be smaller than normal.
Temperature
American wisteria ‘Amethyst Falls’ originates from East Asia and likes warm, moist climates. It is suitable for growing in environments with a temperature range of 18 to 28 ℃. It can tolerate temperatures as low as -30 ℃ but may grow poorly when the temperature rises above 35 ℃. It requires abundant water. Soil should be kept moist in spring and summer or its growth and blooming will be affected.
Watering
Thriving in its native moist habitats, american wisteria ‘Amethyst Falls’ has adapted to require consistent moisture, reflecting its origins. It exhibits a preference for regular hydration without being waterlogged, maintaining a balance that supports its lush growth. For optimal health, american wisteria ‘Amethyst Falls’ should be watered twice a week, ensuring the soil remains evenly damp. Typically cultivated outdoors due to its climbing nature, american wisteria ‘Amethyst Falls’ benefits from mulching to retain soil moisture during dry spells, enhancing its flowering potential.
Soil
American wisteria ‘Amethyst Falls’ has deep roots and best grows in deep, neutral soil (pH value at 6-7) with good drainage. Soil with poor drainage affects the growth of the roots, causing difficulty with water absorption that can lead to the plant losing water, and even disease. If the soil is poor in air permeability and water drainage, you can improve it by adding a reasonable amount of peat soil, organic manures, or river sands. Additionally, grow the plant at an elevated site to help water drain appropriately.
Fertilizing
In spring and summer, fertilize plants once every two weeks, or every month depending on how the american wisteria ‘Amethyst Falls’ is growing. When a plant buds in spring, apply some balanced fertilizers (with a 20-20-20 NPK ratio), and switch to phosphate and potash fertilizer to promote blooming. This helps flowers flourish gorgeously and in greater numbers. When american wisteria ‘Amethyst Falls’ shed leaves in the fall, apply organic fertilizers to the plants and water adequately. This will aid in growth the following spring.
Planting Instructions
Transplanting is best performed in spring or summer. Because american wisteria ‘Amethyst Falls’ has long roots that easily wind, extra caution is needed for transplanting. It’s best to transplant it with the roots wrapped in the surrounding soil to prevent root damage. Before transplanting, apply a little organic fertilizer to the planting pit. Water adequately after transplanting and shade in partial sunlight to prevent water loss.
After american wisteria ‘Amethyst Falls’ is planted, draw each plant’s branches to the trellis. Because it has a long life span and can grow very lush and exuberant foliage later, a wooden trellis might not be sufficient. Therefore, it’s best to use a metal trellis. Prevent the branches from overlapping each other and make sure the foliage is equally exposed to sufficient sunlight, then secure the branches with ropes.
Pruning
American wisteria ‘Amethyst Falls’ likes ample sunlight, so it’s a good idea to prune off overly dense foliage to improve light conditions in the lower parts of it. This will also improve ventilation and help prevent pests and diseases. After blooming, properly prune off the withered flowers to reduce its nutrient consumption. If slender, weak, old, dried, pest-infested, or disease-infected branches are found, prune them off promptly.
Propagation
For the propagation of american wisteria ‘Amethyst Falls’, dividing the root system is an effective method. Care should be taken to ensure each division has several strong roots and at least one set of leaves or shoot node to facilitate growth. The divided sections should be planted in well-draining soil, given ample water, and placed in a location with sufficient sunlight. Consistent monitoring and proper care will enhance root establishment and support vigorous growth.
Transplanting
For american wisteria ‘Amethyst Falls’, the prime relocation period is from the warmth of late spring to the early summer caress, fostering root establishment with minimal stress. Select a sun-bathed spot, ensuring soil is well-drained. A welcoming, nurturing demeanor aids in successful transplantation.
Repotting
Repot american wisteria ‘Amethyst Falls’ during early spring every 2-3 years to support its vigorous climbing habit and lush foliage. Opt for a large, sturdy container to accommodate its growth. Post-repotting, place american wisteria ‘Amethyst Falls’ in a sunny spot with well-draining soil and maintain consistent moisture. Prune lightly to encourage branching, ensuring american wisteria ‘Amethyst Falls’ thrives after its transition.
III. Uses and Benefits
Wisteria frutescens ‘Amethyst Falls’ is an exception to the species, producing richly scented flowers in May and June. You can also grow this variety in a large container, where it will grow to become a marvellous potted specimen for the patio.
