Essentials
At a Glance
Plant Type
Shrub
Height
72 inches
Width
72 inches
Light
Full Sun
Zones
9
Water
Low to medium
Humidity
Tolerates a wide range
Lifespan
Long-lived perennial shrub
Native To
Mexico and Central America
Toxicity
May be mildly toxic if ingested
The Story
Plant Bio
Galphimia glauca, commonly known as Thryallis or Gold Shower, is a tropical evergreen shrub celebrated for its nearly year-round display of bright yellow, star-shaped flowers. It has an airy, fine-textured appearance with attractive blue-green foliage. Its exceptional heat and drought tolerance, combined with a very long blooming season, make it a workhorse in warm climates for hedges, foundations, and container plantings.
Bloom Period:
Uses & Benefits:
Marketplace
Where to Buy
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Planting
How to Grow
- Choose a location that receives at least 6 hours of direct sun.
- Ensure the soil is very well-drained.
- Dig a hole as deep and twice as wide as the pot.
- Set the plant in the hole and backfill with soil.
- Water thoroughly after planting to settle the soil.
- Water regularly until established, then only during prolonged drought.
Pro Tip
For the bushiest growth and most prolific flowering, prune it back by about one-third in late winter or early spring.
Keep It Thriving
Care Guide
Do
- Provide full sun for best flowering.
- Allow the soil to dry out slightly between waterings.
- Prune annually to maintain a compact shape.
- Plant in a location with good air circulation.
Don't
- Do not plant in heavy, waterlogged soil.
- Avoid planting in shady locations, which reduces flowering.
- Don't overwater, as this can lead to root rot.
- Avoid heavy fertilization, which can promote foliage over flowers.
Seasonal Care Calendar
| Task | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Fertilize | ||||||||||||
| 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
Thryallis questions
What zones can Thryallis grow in?
Thryallis is hardy in USDA Zones 9–10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.
Is Thryallis deer resistant?
Yes — Thryallis is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.
When does Thryallis bloom?
Thryallis typically blooms in early summer through late fall. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.
Does Thryallis need full sun?
Thryallis does best in full sun (6+ hours).
Is Thryallis drought tolerant?
Yes — once established (usually after the first full season), Thryallis handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.
Keep exploring
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Hardy in your zone?
Grow Thryallis 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.
