Kōwhai (Sophora microphylla)

Also known as: Weeping kōwhai

Kōwhai, an evergreen flowering shrub or small tree native to New Zealand, is renowned for its striking long yellow flowers, which are often regarded as the country's unofficial national flower. Interestingly, the nectar of kōwhai flowers is toxic to honeybees.

In This Article

Care Tips Water Sunlight Temperature Soil Fertilize Prune Propagation Repotting Toxicity

Attributes of Kōwhai

Lifespan

Perennial

Plant Type

Tree, Shrub

Plant Height

3 m

Spread

3 m

Leaf Color

Green

Flower Size

2.5 cm

Flower Color

Yellow

Images of Kōwhai

Quickly Identify Kōwhai

Small tree up to 25 feet (7.62 meters) tall

Vivid yellow blooms in late winter to spring

Divaricating, bushy juvenile phase transitioning to upright mature form

Resilient to low temperatures, surviving down to at least 20°F (-6.67°C)

Compound leaves with fine texture

Scientific Classification of Kōwhai

Phylum

Vascular plants

Class

Dicotyledons

Order

Fabales

Family

Legume

Genus

Necklacepods

Species

Kōwhai

Planting and Growing of Kōwhai

Care Difficulty

Easy

Watering Schedule

Every 2 days

Sunlight Requirements

Full sun

Sunshine Duration

6-10 hours

Ideal Temperature

65-75℉

Soil Type

Potting Mix, Peat Mix

Soil pH

5.5-8

Fertilizer Type

Balanced

Pruning Season

Spring, Summer

Pruning Area

Branches, Leaves

Pruning Frequency

2 times a year

Repotting Season

Spring

Pot Type

Plastic, Ceramic

How to Water Kōwhai?

For Sophora microphylla, you should aim to thoroughly drench the soil with about 500 ml of water each time you water. The goal is to hydrate the entire root zone without leaving the soil soggy. Ensure the water penetrates deeply to encourage root growth.

What are the symptoms of an underwatered Kōwhai? ›

What should I do if my Kōwhai is not getting enough water? ›

What are the symptoms of an overwatered Kōwhai? ›

How to save an overwatered Kōwhai? ›

What Are the Sunlight Requirements for Kōwhai?

Sunlight Requirements: Full sun, Partial sun

Duration of light: 6-8 hours daily

Ideally, Sophora microphylla should receive full sun to partial sun with 6-8 hours of sunlight a day. This balance ensures vigorous growth, vibrant foliage, and prolific blooming, optimizing its ornamental appeal.

What type of light does Sophora microphylla prefer? ›

How to achieve ideal lighting for Sophora microphylla? ›

What benefits are gained from ideal lighting? ›

More About Sunlight Requirements Techniques→

What Is the Ideal Temperature Range for Kōwhai?

Ideal Temperature: 65 ~ 75℉

For optimal growth, Sophora microphylla thrives best in temperatures ranging between 65°F and 75°F. These temperatures ensure the plant's metabolic processes function efficiently, promoting robust growth and vibrant foliage.

What Soil is Best for Kōwhai?

Soil type: Loam, Sandy loam

Soil PH: 5.5 ~ 8

Sophora microphylla thrives in well-drained soil, which prevents waterlogging and root rot. This type of soil improves aeration and provides room for roots to grow, ensuring healthy plant development. This plant benefits from soil with moderate fertility. A balanced nutrient profile supports healthy foliage and vibrant blooms. Regularly testing soil fertility can help you fine-tune your fertilization routine. The addition of organic matter like compost boosts soil structure and nutrient content. Enhanced soil fertility encourages lush growth and enhances the soil’s moisture retention properties.

How to Fertilize Kōwhai?

Fertilizer type: Balanced

For Sophora microphylla, apply liquid fertilizer monthly at half the recommended strength on the fertilizer label. For solid, slow-release fertilizers, use approximately 50 grams once per application. This amount maintains optimal nutrient levels for healthy growth.

How to Prune Kōwhai?

Pruning Time: Spring, Summer

Begin by observing the overall structure of your Sophora microphylla. Identify dead, diseased, or crossing branches that may hinder growth or airflow. Start the pruning process by carefully cutting off any dead or diseased branches. This not only improves the appearance but prevents the spread of disease. Trim back longer branches to maintain a balanced and appealing shape. Follow the natural contour of the plant, ensuring even distribution of foliage. Pruning helps to stimulate new shoots by cutting back older growth. Clip back to just above a bud facing the direction you want the branch to grow. More About Pruning Techniques→

How to Propagate Kōwhai plant?

Propagate Time: Spring,Early spring,Late spring

Begin by collecting mature seeds from the plant. Clean the seeds to remove any pulp, and dry them thoroughly. This step ensures that they are ready for sowing, reducing mold or rot risks.

Fill seedling trays with a well-draining potting mix and sow the seeds approximately one inch apart. Cover lightly with soil and water gently. Ideal germination occurs in a warm and humid atmosphere.

Select healthy, non-flowering shoots and cut them about 4-6 inches long. Remove the lower leaves. Apply rooting hormone to the cut end to encourage root development before planting it in moist compost.

More About Propagating Techniques→

How to Repot Kōwhai plant?

Repotting frequency: Every 2-3 years

Sophora microphylla should be repotted when you notice roots emerging from the drainage holes or the soil drying out too quickly after watering. These are clear signs that the plant has outgrown its current pot and requires more space to thrive.

Choose a pot that is one size larger than the current one. Ensure it has adequate drainage holes to prevent water accumulation, which can lead to root rot. A slightly larger pot provides more space for root expansion and promotes healthier growth.

Opt for a well-draining soil mix; a combination of potting soil, sand, and perlite works well. This mix provides excellent drainage, preventing waterlogged conditions, and ensures that roots receive enough oxygen to promote healthy growth.

Toxicity

ingestion

WARNING

The judgment on toxicity and danger is for reference only. We DO NOT GUARANTEE any accuracy of such judgment. Therefore, you SHALL NOT rely on such judgment. It is IMPORTANT TO SEEK PROFESSIONAL ADVICE in advance when necessary.