Origin and Habitat: Hoya davidcummingii comes from the Philippines and it was published in 1995. It has previously been incorrectly sold as Hoya gracilis.
Type locality: Bulusan Volcano National Park in Sorsogon Province (Luzon, Philippines).
Habitat and ecology: It grows along forest edges.

• Hoya davidcummingii Kloppenb.

Description: Hoya davidcummingii is a small climbing perennial herbaceous hoya with amazingly attractive rose-red perfumed flowers with yellow centers. Usually it starts blooming at an early age and flowers are produced through-out the year. It has previously been incorrectly sold as Hoya gracilis.
Derivation of specific name: The species name honors the Australian hoya collector David Cumming.
Stems: Thin, wiry about 2 mm in diameter with small aerial roots formed just below the nodes that helps the plant rooting in the substrate. Internodes about 3 to 4 cm apart.
Leaves: Thick, small, always opposite. Petiole ca.1 cm long. Lamina smooth, oblong, elliptical and pointed, about 4-6(-10) cm long and 1.5-2(-2.5) cm wide, concolour, above dark green with darker edges and the underside is lighter green.
Inflorescence: With10-15(-20) flowers in a hemispherical umbel. Peduncle approximately 2 cm long, green, smooth and glabrrous. This hoya do not drop the peduncle after flowering and it often flowers from the same peduncle again.
Flowers: Hermaphrodite, radially symmetrical, mostly flat, pentamerous, and each flower is about 8-9(-20) mm in diameter. The corolla is purple or pink and the corona is yellow with a red centre. The edges of the petals are sometimes a little reflexed (bent downward) when first opening, and often become strongly bent as they ages. It produces little nectar and the fragrance can be described as caramel like.
Blooming: Even though this hoya isn't all that easy to grow, it certainly flowers often and willingly and there always seems to be new ones on the way all the time. It even flowers during the winter. Flowers stay open about 5 days.

Bibliography: Major references and further lectures.
1) Anders Wennström und Katarina Stenman "The Genus Hoya – Species and Cultivation.", Botanova, Umeå 2008

Cultivation and Propagation: Hoya davidcummingii likes to grow on the dry side in dappled light. It is considered one of the trickiest hoyas to grow and is not suitable for Hoya beginners, but as long as it's not over watered it should be fine. If you see the leaves shrivel up, take cuttings and start over. Clusters of fragrant rose-red blooms with yellow centres and modest growth habit make this rare vining plant perfect for the windowsill and for hanging baskets. Hoya davidcummingii flowers often and sometimes already as a cutting.
It is a tropical plant that once again will do much better with some extra warmth.
Growth rate: This is a compact shrubby species that grows really well and strong in optimal condition.
Potting medium: Because it is an epiphyte benefits from being potted up in a very well-draining and porous potting medium that allows some air to get to the roots; typical mixes include, peat, with some fibrous soil and sand along with large-grade drainage material such as perlite, pumice, or ceramic balls. Often specialized hoya growers either use only chopped coconut husk or a good orchid potting mixture for growing their hoya plants. The medium needs to be moisture-retentive.
Fertilization: The plants should be fed regularly with a fertilizer suitable for epiphytic plants.
Watering: With its succulent qualities it's quite adapt at storing water for longish periods of time between waterings. Water regularly in summer, but do not overwater (wet-sensitively) and let the plants to dry out between watering and then water again. Its roots are easily lost in pots that stay damp for any length of time. Keep quite dry with ample airflow in winter (It would probably tolerate one watering a month). In the rest period no high atmospheric humidity. Care must be taken with watering as they tends to become swollen and untidy in growth habit if given too much water and shade.
Fertilization: During the growing season enrich the soil using a fertilizer rich in potassium and phosphorous, but poor in nitrogen, because this chemical element doesn’t help the development of succulent plants, making them too soft and full of water.
Exposition: This hoya species prefers bright light but no direct sun. Outside half shade to shade (filtered sunlight or afternoon shade tolerated), inside it will need a reasonably light room in order to actually grow, although it will still get by even in a shadier spot and can be positioned almost anywhere in homes or offices. It subject to sunburn if exposed to direct sun for too long. Tends to bronze in strong light, which encourages flowering and heavy leaves production.
Temperature: The optimal temperature is approximately 12-15° C in winter and 30-40 ° C in Summer (Outdoor zone: At least Zone 10, possibly cooler).
Spring: When winter ends and they begin to grow again, they will require much water and soaking the pots will no longer put the plants at risk for rot. In the spring they will grow well in partial shade and leaving them out in the rain may provide them with the water they need.
Summer: In the summer months they will tolerate heavy rain, but will be just as happy if the season is dry. They will tolerate hot weather outdoors as long as they are kept in strongly filtered light and this will encourage them to flower. They also enjoy some fertiliser. Moving the plants as they are developing buds may cause them to spontaneously abort the flowers all together.
Autumn: In the fall keep them outdoors until the night time temperatures drop below the 10°C.
Winter: Winter care presents no problems at 12° C with plenty of light. In winter be sure to take extra precautions to keep them dry, because damp cool conditions when the plants are resting is an invitation to fungal infections, but - according to temperatures –some occasional lit watering may be useful.
Maintenance: Prune the plant lightly to keep it tidy.
Repotting: In any season it's best to lay the stems out for several days before replanting them and then pot them only in dry soil and withhold any water until they begin to shrivel or start growing again. Re-pot every 2 years.
Pest and diseases: Hoyas are generally fairly easy to grow, especially if kept pest-free. They are very susceptible to stem and root mealy bug, which can be fought easily with common pesticides, and damage from these may well initiate fungal attack. Any time when there is a dead or dying stem in the pot it is important to remove it immediately and completely before other healthy stems can become ill too, isolate the healthy parts, dry them off, and re-root them in new compost.
Propagation: It can be tricky to root and to get a nice plant you need to put several cuttings in the same pot.