How To Grow Thryallis (Galphimia glauca) In Your Garden

Galphimia glauca, often referred to as Thryallis or Shower-of-Gold, is an evergreen shrub. It carries profuse, yellow, star-shaped flowers. These bloom nearly all of the year round in tropical climates.

Thryallis reach a height and spread of about 4 to 6 feet (1.2 to 1.8 meters).

Galphimia glauca plant in bloom
Galphimia glauca photograph by Forest and Kim Starr; CC.

The plant is grown for its cheerful, long-lasting blossoms, and its suitability for small spaces, border planting, and butterfly gardens. It thrives in USDA hardiness zones 8 to 11.

How to Grow Galphimia glauca in the Garden

Galphimia glauca prefers to grow in a sunny to partially shaded position in the garden, with the most abundant flowering occuring when there is more sunlight.

It is able to adapt to a variety of well-drained soil types. Plants can tolerate a wide soil pH range, from mildly acidic through to mildly alkaline.

Thryallis flower close up
Thryallis image by Miltos Gikas; CC.

Plant out Thryallis during spring or early fall. Use a hole that is about the same depth as the root ball, and double the width. Once the Thryallis has been set in place, backfill the hole with soil, and then water thoroughly.

This plant is relatively drought-tolerant once established, but appreciates regular watering in dryer climates.

Applying abalanced, slow-release fertilizer in early spring will promote vigorous growth and blooming.

Prune lightly after blooming. This will help tomaintain a compact, tidy form. It will also help to stimulate the next round of blooms.

Though it is generally disease-resistant, keep an eye out for common pests such as aphids and scale insects. Maintaining airflow between the plants, will aid in preventing these issues.

Galphimia glauca can make a delightful addition to any garden, brightening the landscape with its prolific, sunny blossoms. Its relatively compact size, and low maintenance needs, make it an ideal choice for novice and experienced gardeners alike.

Quick Galphimia glauca Growing and Care Guide

Scientific Name: Galphimia glauca.

Common Name(s): Thryallis, Rain of Gold, Shower-of-Gold.

Growing Zone (USA / UK Hardiness): USDA Zones: 9-11.

Best Used For / Garden Location: Hedges, borders, mass plantings, or specimen plants.

Plant Details

Life Cycle / Plant Type: Evergreen.

Plant Height: 4-6 ft (1.2-1.8 m).

Plant Spread: 3-4 ft (0.9-1.2 m).

Blooms: Spring through autumn.

Flower Details: Golden-yellow, star-shaped flowers.

Leaf Foliage: Glossy, dark green leaves.

Fruit: Small, dry capsules.

Growing Conditions and Location

Best Light Conditions: Full sun to part shade.

Suitable Soil Types: Well-drained soil; can tolerate sandy, loamy, or clay soils.

Sowing / planting: Sow seeds in spring after the last frost.

Germination time: Germination usually takes 2-4 weeks at 70-75°F (21-24°C).

Propagation: Semi-ripe cuttings in summer.

Plant Care: Water regularly but avoid waterlogged conditions; prune to maintain shape.

Growing in pots and containers: Can be grown in pots with proper drainage.

Growing as a House plant: Not typically grown as a houseplant due to light requirements.

Further Information

Miscellaneous: Attracts butterflies. Tolerant of air pollution and salty conditions.

Pests and diseases: Generally pest-free, but watch for aphids and scale.

Common Cultivars / Varieties: Galphimia glauca 'Aurea' features particularly vibrant golden-yellow flowers.

Family: Malpighiaceae, the Malpighia family.

Native: Native to Mexico.

References and Further Reading: University of Florida, IFAS Extension; Missouri Botanical Garden; Wikipedia.

Common Questions

Does Galphimia glauca make a good garden or landscaping plant?

Yes, Galphimia glauca can be a good choice for gardens and landscapes, especially in warmer regions. It is a small evergreen shrub that displays bright yellow flowers for extended periods.

Is Galphimia glauca a fragrant plant?

Galphimia glauca is not really known for a strong fragrance, but it us beloved for its vibrant, golden-yellow flowers that bloom nearly year-round.

What is the perfect location to grow Thryallis?

Thryallis prefers a sunny to partly shaded location of the garden. This should have a well-drained soil. It is drought-tolerant once established.

Is Galphimia glauca invasive in the USA, if so in which states?

Galphimia glauca is not considered invasive in the USA.

How do I remove Galphimia glauca from my garden?

Removing Galphimia glauca involves cutting back the plant and digging out its root system. Be sure to remove as much of the root system as possible so as to prevent regrowth.


Galphimia glauca is a tropical evergreen shrub that thrives in well-drained soil and full sun to part shade. It's known for its bright yellow flowers that bloom most of the year, offering continuous color to gardens.

I hope that you have enjoyed reading this guide on how to grow Galphimia glauca. You may also enjoy the following the following yellow-flowered growing guides: How to grow Yellow Star, Helianthemum nummularium, and Lysimachia plants in the garden.

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