Hoya obscura is a fast-growing hoya from the Philippines. Characterized by medium-sized veined leaves that range from deep green when grown in shade, to a deep reddish color when grown in sunlight. This hoya is very easy to grow.
- Growing habit: Viny and compact, leaves fairly close together along new shoots. Very fast grower in optimal conditions. Extremely floriferous.
- Sap color: milky.
- Leaf size: 2 cm to 10 cm.
- Epiphytic: Epiphytic to semi-epiphytic in the wild. Readily adapts to pot culture.
- Fragrance: Intense and pleasant, remarkably like a buttered cinnamon roll for the plant pictured. Wafts a considerable distance. Many people have likened the fragrance to Froot Loops cereal.
- Soil conditions: Must be moist but well-drained and airy. The specimen pictured is generally allowed to dry completely between waterings, and is rootbound in a 3-inch terra cotta pot.
- Outdoor zone: At least Zone 10, possibly cooler.
Care And Growing Guide
- Light: Bright but indirect filtered light. Leaves will burn and shrivel in intense direct sun.
- Water: Water moderately during the growing season, allowing the top layer of soil to dry out between watering. In their rest period (winter), water lightly to prevent the plant from drying out but don’t overwater.
- Humidity: This variety of Hoya especially likes moderate-high humidity.
- Temperature: Hoyas can tolerate temperatures ranging between 15°C-29°C. Be careful of draughts and hanging near open windows and do not allow temperatures to drop below 10°C. This particular Hoya grows at higher altitudes in the wild so can handle cooler nighttime temperatures.
- Soil: A free-draining organic potting mix or a 1:1:1 ratio of cacti soil, orchid bark and perlite will keep your Hoya houseplant very happy.
- Fertilizer: Use a balanced fertiliser twice a month during the growing season (Spring and Summer) and be sure to dilute correctly as over-feeding can cause some damage to the plant. If the potting medium is particularly dry, water lightly before feeding to avoid fertiliser burning the roots. If your Hoya is about to bloom, you can use a feed that has more phosphorus in it.
- Repotting: Hoyas don’t require frequent repotting, and do tolerate being slightly root-bound. Once every year or so is completely fine; the ideal time to re-pot is early Spring when the plant has actively started growing after its winter rest. Roots ‘circling’ around the bottom of the nursery pot is an indication that repotting is needed. Increase pot size by just a few centimetres.
- Pruning: You can give your Hoya linearis a haircut to tidy your plant up if it gets too long! Use a sterile blade and cut back any dead, dried stems. Be careful not to cut the peduncle (which can look a bit woody) where the star-shaped flowers will grow from. To take cuttings you can propagate, trim a few centimetres underneath a node. Be careful of the white latex sap that will leak out here; wear gloves as this can be an irritant.
- Propagation: The two most effective ways to propagate your Hoya linearis are rooting stem cuttings in either water or sphagnum moss. Propagation can take a number of weeks, particularly these ones with fuzzy leaves. It is beneficial to keep the humidity high at this point so cover your cuttings in a propagator / humidity dome…or plastic bag!
- Scorched/ shrivelled leaves : Your plant is getting too much sun and not enough humidity; move to somewhere more shaded and humid (a bright bathroom would be great!).
- Limp or wilting leaves: This is a sign of a watering issue and could be a result of either root rot or prolonged under watering. Inspect the roots of your Hoya to determine the cause. If the roots of have been very wet and started to rot, you should take cuttings of your Hoya linearis to propagate and create a new plant. If it’s excessively dry, increase watering gradually.
- Sudden leaf drop: can signal shock from cold temperatures… be aware of hanging in cold windowsills and draughts in winter! Hoya’s can’t handle temperatures below 10°C, so ensure your plant is placed somewhere warmer with enough humidity.
- Shrivelled up foliage: The plant isn’t getting enough water or humidity (or both); gradually increase both. This particular Hoya requires more humidity than some others.
- Very long ‘stretched’ stems/internodes: This is called etiolation and means that your plant isn’t getting the correct amount of light; stems will be especially ‘stretched’ and leaves smaller in size.
- No flowers: The main reason is that your Hoya isn’t getting enough light. Another consideration is that some Hoyas often flower as a sign of stress; so keeping things slightly root bound could encourage those lovely ‘porcelain flowers’ to make an appearance!
- Pests: Incorrect care and lack of humidity are the main reasons pests may appear, and the Hoya linearis can be susceptible to mealy bugs or aphids in particularly dry conditions. Be sure to closely check the fuzzy leaves and if pests are present, the plant can be treated with insecticidal soap. Repeat weekly and keep the plant in isolation until completely pest-free.