Kowhai Sophora tetraptera
ABOUT
Sophora tetraptera, commonly known as the kowhai, is a distinct and attractive plant renowned for its beautiful display of golden yellow flowers. These pendulous, bell-shaped blooms are a standout feature and come together in clusters along the plant's branches. Each individual flower is significant in size and has a tubular shape. The flowers are an important source of nectar for many local bird species, adding to the ecological value of the kowhai. The foliage of the kowhai is made up of bright green, pinnate leaves, which are divided into numerous leaflets with a somewhat oval shape. The texture of these leaves tends to be smooth, and they come together to create a dense, lush canopy. This adds an element of grace and texture to the plant's overall appearance. When the sunlight filters through the leaves, they can create a play of light and shadow that enhances the visual interest of this species. Additionally, the bark of the kowhai is rough and deeply furrowed, providing a striking contrast to the delicate flowers and soft foliage. Over time, the bark typically darkens, which can give the plant an air of ruggedness and maturity. This combination of striking flowers, attractive foliage, and textured bark makes the kowhai a cherished plant in many gardens where it serves both an aesthetic and functional purpose within the landscape.
About this plant
NamesFamily
Fabaceae.
Synonyms
Kowhai, New Zealand Laburnum.
Common names
Edwardsia grandiflora, Edwardsia tetraptera, Sophora grandiflora.
ToxicityTo humans
The plant known as kowhai, with the scientific name Sophora tetraptera, contains alkaloids that can be toxic to humans if ingested. The whole plant, especially its seeds, is considered to be poisonous. Ingesting parts of the kowhai plant can lead to symptoms including nausea, vomiting, and diarrhea. In severe cases, poisoning could potentially lead to neurological symptoms such as dizziness or convulsions. It is therefore advised to avoid ingesting any part of the kowhai plant to prevent the risk of toxicity.
To pets
Kowhai, scientifically named Sophora tetraptera, is also toxic to pets if they consume parts of the plant. It contains alkaloids that can cause similar symptoms in pets as they do in humans. If a pet ingests kowhai, especially the seeds, they may experience vomiting, diarrhea, and lethargy. In severe cases, neurological symptoms such as tremors or seizures could occur. It is essential to keep pets away from this plant to avoid the possibility of poisoning.
CharacteristicsLife cycle
Perennials
Foliage type
Deciduous
Color of leaves
Green
Flower color
Yellow
Height
20 feet (6 meters)
Spread
20 feet (6 meters)
Plant type
Tree
Hardiness zones
8
Native area
New Zealand
Benefits
General Benefits- Ornamental value: Sophora tetraptera, commonly known as Kowhai, is highly appreciated for its vibrant yellow flowers which add aesthetic value to gardens and landscapes.
- Nectar source for wildlife: The flowers are a significant source of nectar for bees and native birds, particularly the New Zealand bellbird and the tui.
- Shade provider: As a medium-sized tree, Kowhai can offer a moderate amount of shade, making it suitable for planting in parks and gardens.
- Erosion control: The root system of Kowhai helps stabilize soil, particularly in sloped areas, and is useful for controlling erosion.
- Nitrogen fixation: Like many legumes, Kowhai has the ability to fix nitrogen in the soil, enhancing soil fertility and reducing the need for fertilizers.
- Cultural significance: Kowhai holds cultural importance especially in New Zealand, where it is considered a national flower and used in various cultural practices.
- Wood uses: The hard wood of Kowhai is sometimes used in woodworking for crafting small objects and inlays, although it is not a primary timber tree.
- Education and research: As a native species of New Zealand, it is often used in ecological and botanical studies, providing educational value regarding native flora.
Medical PropertiesThis plant is not used for medical purposes.
Air-purifying QualitiesThis plant is not specifically known for air purifying qualities.
Other Uses- The wood of Kōwhai is dense and can be used in fine woodworking projects, such as creating intricate carvings or small objects.
- Kōwhai bark has been traditionally used for dyeing, providing a yellow color that can be applied to fabrics and textiles.
- The flowers of the Kōwhai, rich in nectar, can be a source of food for domesticated bees, aiding in the production of unique local honey.
- In landscape gardening, Kōwhai is used for its aesthetic appeal, with its bright yellow flowers adding a splash of color to gardens and parks.
- The plant's hardy nature makes it suitable for erosion control on banks and slopes, helping to stabilize the soil.
- Kōwhai trees can be used for shelter belts or windbreaks on farms, protecting crops and livestock from strong winds.
- The natural resilience of Kōwhai makes it a suitable candidate for revegetation projects in degraded areas or for establishing green urban spaces.
- Kōwhai pods can be used in arts and crafts for children and adults, becoming a part of educational nature-based activities.
- The fibrous parts of the plant have been used in traditional weaving practices by indigenous Māori to create baskets, mats, and other artifacts.
- Kōwhai plants are sometimes used in perfumery; the scent of the flowers may be captured to produce fragrances or essential oils.
Interesting Facts
Feng ShuiThe Kowhai is not used in Feng Shui practice.
Zodiac Sign CompitabilityThe Kowhai is not used in astrology practice.
Plant Symbolism- Resilience: The robust nature of Sophora tetraptera, commonly known as Kowhai, suggests resilience. Native to New Zealand, the Kowhai grows well in varied environments, symbolizing the ability to endure and thrive through difficulties.
- Beauty: The bright, golden-yellow flowers of the Kowhai are a symbol of beauty. Their stunning appearance when in bloom makes them a natural representation of aesthetic appeal.
- Renewal: As a deciduous plant, the Kowhai loses its leaves in winter and blooms with vibrant flowers in spring, symbolizing rebirth and new beginnings.
- National pride: While not an official symbol, the Kowhai is often considered an unofficial national flower of New Zealand, representing pride and connection to the land.
WaterThe Kowhai, commonly known as Sophora tetraptera, requires regular watering, especially during dry periods. In the growing season, water the plant once or twice a week with about 1 to 2 gallons, depending on the size of the plant and soil moisture levels. Ensure the soil is well-draining to prevent waterlogging. During winter or cooler months, reduce watering to once every 2-3 weeks. Overwatering can be detrimental, so it is essential to check the soil moisture before watering; the top inch of the soil should be dry to the touch.
LightKowhai thrives best in full sunlight, so it should be placed in a location where it can receive at least six hours of direct sunlight a day. Partial shade is also acceptable, but the flowering might not be as prolific. The ideal spot for Kowhai would be in an unobstructed southern or western exposure where it can bask in the day's sun.
TemperatureKowhai prefers a temperate climate and can tolerate temperatures as low as 20°F, but for optimal growth, it is best kept in conditions above 32°F. The ideal temperature range for Kowhai is between 50°F and 75°F. It is adaptable to various conditions but should be protected from harsh frost and extreme temperatures exceeding 85°F.
PruningPrune Kowhai to maintain shape and encourage strong growth. The best time to prune is after the flowering season ends in late spring or early summer. Remove any dead or crossing branches and trim back to a healthy bud to promote new growth. Pruning every 2-3 years is typically adequate for Kowhai, ensuring that the plant retains its natural form and vigor.
CleaningAs needed
SoilKowhai prefers a well-draining soil mix with a pH of 6.5 to 7.5. A blend of loam, sand, and peat moss or compost will provide the necessary structure and nutrients. Ensure adequate organic matter for fertility.
RepottingRepot Kowhai every 2 to 3 years during the spring season, before the onset of new growth. Younger plants may require more frequent repotting.
Humidity & MistingKowhai thrives in moderate humidity levels. It does not require high humidity but should not be exposed to very dry air for prolonged periods.
Suitable locationsIndoor
Place Kowhai near a sunny window; avoid drafts.
Outdoor
Plant Kowhai in a sunny spot; protect from strong winds.
Hardiness zone
8-10 USDA
Life cycleThe Kōwhai (Sophora tetraptera), native to New Zealand, starts its life as a seed, often dispersed by native birds that eat the bright yellow seeds after they split from their pods. Upon finding suitable soil, the seed will undergo a period of stratification before germination, breaking its dormancy with the fluctuating temperatures of the environment. The germinated seed develops into a seedling with a characteristic pair of cotyledons, after which true leaves develop as it enters the vegetative growth stage. Once mature, the Kōwhai enters the reproductive stage, producing distinctive pendulous yellow flowers that are rich in nectar, attracting birds such as the native Tui and bellbird which aid in pollination. Following pollination, the plant sets seed pods that mature, dry, and open, releasing seeds to complete the life cycle. The Kōwhai is long-lived and can continue this cycle for many years, with some trees known to reach over a century in age.
PropogationPropogation time
Spring to Summer
The most common method of propagation for the Kowhai, which is known botanically as Sophora tetraptera, is through its seeds. Typically, the best time to sow Kowhai seeds is in spring. For successful germination, it’s advisable to first soften the seed's hard coat. This can be achieved by nicking the seed coat with a knife or rubbing it with sandpaper, then soaking the seeds in warm water for 24 hours. The seeds should then be sown in a well-draining seed-raising mix, at a depth approximately twice the size of the seed. Placed in a warm, sunny location, the seeds usually germinate within two to four weeks. Once the seedlings have developed a few sets of true leaves, they can be transplanted into individual pots for further growth before eventual planting out in the garden.
