The Story
Plant Bio
Sophora microphylla, known as kōwhai, is a small semi-evergreen tree native to New Zealand that features a distinct, tangled juvenile growth phase before maturing into an upright, weeping form. In late winter and early spring, it produces pendulous clusters of tubular, golden-yellow flowers that attract nectar-feeding birds and insects.
This species is distinguished by its fine-textured, fern-like foliage consisting of up to forty pairs of tiny, dark green leaflets on each pinnate leaf. All parts of the plant, especially the hard orange-yellow seeds, contain toxic quinolizidine alkaloids and must be handled with caution around pets and children.
Uses & Benefits:
Essentials
At a Glance
Plant Type
Tree
Height
300"
Width
150"
Light
Full Sun, Partial Sun
Zones
8, 9, 10
Water
Moderate
Humidity
Moderate
Lifespan
Long-lived
Native To
New Zealand
Toxicity
Toxic if ingested
Bloom period
Late winter – Mid spring
In flower about 3 months of the year
Planting
How to Grow
- Select a planting site in full sun to light shade with highly permeable, well-drained soil.
- Dig a hole twice as wide as the root ball but no deeper, ensuring the plant sits at its original soil level.
- Backfill with native soil, firm gently, and water in thoroughly to settle the roots.
- Apply a light layer of organic mulch, keeping it clear of the main stem to prevent rot.
Pro Tip
Avoid pruning back into old, leafless wood, as the plant lacks the ability to regenerate from bare branches and will fail to shoot back.
Keep It Thriving
Care Guide
Do
- Ensure the soil drains rapidly to prevent root rot.
- Protect young plants from deer and rabbit browsing.
- Allow the plant to go through its natural tangled juvenile phase without heavy pruning.
Don't
- Do not plant in heavy clay or waterlogged depressions.
- Do not prune deep into old, brown, leafless wood.
- Do not over-fertilize, as this species has low nutrient requirements.
Seasonal Care Calendar
| Task | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fertilize | ||||||||||||
| Mulch | ||||||||||||
| Pest Check | ||||||||||||
| Prune |
Watch Out For
Pests & Diseases
Common Pests
Common Diseases
In the Garden
Landscape Uses & Companions
Landscape Uses
Companion Plants
Multiply
Propagation Methods
Good to Know
Common Questions
Kōwhai questions
What zones can Kōwhai grow in?
Kōwhai is hardy in USDA Zones 8–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.
Is Kōwhai deer resistant?
Not reliably. Deer may browse Kōwhai, especially tender spring growth — plan on repellents or fencing where pressure is high.
When does Kōwhai bloom?
Kōwhai typically blooms in late winter through mid spring. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.
Does Kōwhai need full sun?
Kōwhai does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.
Is Kōwhai drought tolerant?
Yes — once established (usually after the first full season), Kōwhai handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.
More Sophora to compare
Keep exploring
Explore the genus
Hardy in your zone?
Grow Kōwhai with confidence
See it in a design of your actual yard, get zone-matched care reminders, and track it season by season in your garden journal.