Hoya puom ‘Siam Ruby’ is a stunning and rare Hoya cultivar originating from Thailand, prized for its vivid, jewel-toned flowers and handsome foliage. Like all Hoyas, it belongs to the Apocynaceae family and is adored by collectors for its combination of colourful blooms, fragrant scent, and easy-care nature.

The leaves are medium-sized, oval, and glossy, deep green in colour, often with faint veining or light silver speckles. Under strong light, they can develop subtle reddish tinges, adding a warm tone to the foliage. However, the true showstopper is the flower: ‘Siam Ruby’ produces umbels of star-shaped, waxy blooms in rich ruby-red tones with a creamy-yellow corona. Each flower has a glossy finish and emits a sweet, pleasant fragrance, particularly in the evening.

With its trailing or climbing growth habit, Hoya puom ‘Siam Ruby’ makes a perfect choice for hanging baskets, trellises, or trailing displays.

Hoya puom ‘Siam Ruby’ – Care Guide

Light

Thrives in bright, indirect light. A few hours of gentle morning or late-afternoon sun enhances foliage colour and promotes flowering. Avoid harsh midday sun which can scorch leaves.

Watering

Water when the top 2–3 cm of soil feels dry. Like most Hoyas, it prefers to dry slightly between waterings. Avoid waterlogging, which can cause root rot. Reduce watering during winter when growth slows.

Temperature and Humidity

• Temperature: Prefers 18–28°C. Protect from cold draughts and avoid prolonged exposure below 15°C.

• Humidity: Benefits from moderate to high humidity (60–80%), though it will adapt to average household conditions. Increased humidity encourages lush growth and prolific flowering.

Soil and Potting

Use a chunky, airy, and free-draining epiphytic mix – orchid bark, perlite, coco husk, and a small amount of peat-free compost works well. Repot every 2–3 years, as Hoyas prefer to be slightly root-bound.

Feeding

Feed monthly during spring and summer with a high-potassium fertiliser to promote flowering. Stop feeding in autumn and winter.

Pruning and Maintenance

Prune long vines to maintain shape and encourage branching. Do not remove peduncles (flower spurs), as Hoyas rebloom from the same sites each year.

Growth and Maturity

A moderate grower that develops climbing or trailing vines up to 1–2 metres long. Flowers appear once the plant is mature and established in bright, stable conditions.

Common Issues

• No flowers: Insufficient light or pruning off flower spurs.

• Yellowing leaves: Overwatering or poor drainage.

• Shrivelled leaves: Extended drought.

• Pests: Occasionally mealybugs, aphids, or spider mites.

Background and Benefits

Originating from Thailand, Hoya puom ‘Siam Ruby’ is one of the most colourful flowering Hoyas in cultivation. Its ruby-red blooms set it apart from paler species and cultivars. Easy to grow and reliable once mature, it is a favourite among collectors who appreciate dramatic, richly coloured flowers.

✅ Quick Care Summary

• Light: Bright, indirect; tolerates gentle morning sun

• Water: Allow topsoil to dry slightly between waterings

• Temperature: 18–28°C; protect below 15°C

• Humidity: Moderate to high (60–80%)

• Soil: Chunky, airy, free-draining epiphytic mix

• Feed: Monthly in spring/summer; high-potassium fertiliser

• Growth: Climbing or trailing vine; glossy green leaves; umbels of waxy ruby-red flowers with creamy-yellow centres and sweet fragrance