Hoya linearis

Meet the plant

A hoya that only hangs. Many thin strands fall from the pot, clothed in soft, narrow, slightly hairy leaves up to 5 cm long, more like a curtain of green needles than a wax plant (RHS profile, Steve's Leaves). It grows on trees in the mountains from Nepal and the eastern Himalaya to south-central China and Indochina (Kew POWO, RHS profile), hanging from the branches much as Spanish moss does (Ohio Tropics). The RHS gives it an Award of Garden Merit and recommends it for hanging pots (RHS growing guide).

Its reputation is mixed. Vermont Hoyas and Steve's Leaves call it one of the hardest hoyas to grow (Vermont Hoyas, linearis, Steve's Leaves); Ohio Tropics finds it easy once its conditions are right (Ohio Tropics). Those conditions are the whole story. Its leaves are thin for a hoya, so it cannot sit dry for weeks the way a wax plant can; yet it rots readily in a pot that stays wet. The answer growers agree on is a setup that dries fast: a small pot, a gritty mix, bright light, moving air, and cool nights (Ohio Tropics, Vermont Hoyas, linearis). This guide calls it demanding for that reason.

No poison-centre list names it; the ASPCA lists its relative the wax plant as non-toxic to cats and dogs (ASPCA). The milky sap can irritate skin, so wear gloves when you cut it (Ohio Tropics, RHS growing guide).

You will usually buy a small pot of rooted strands, and it may shed some needles in transit (Steve's Leaves). What to expect in a year: in good conditions, a lot. Vermont Hoyas saw a plant roughly triple over one summer (Vermont Hoyas, linearis), and strands can in time reach well over a metre (Ohio Tropics). Little in winter.

Light

Bright light, right in front of a window. Ohio Tropics grows it at a north and east window and finds morning sun a real help, especially in winter (Ohio Tropics); the RHS asks for bright indirect light with shade from hot sun, and lists east, south and west aspects (RHS profile). Steve's Leaves sells it as a plant for shade to partial shade (Steve's Leaves). The cautious path is bright light with gentle morning sun and a sheer curtain against hot afternoon glass in summer, because good light is also what lets the pot dry fast (Ohio Tropics).

Too little light shows as long gaps between the needles and thin strands (Ohio Tropics), and as no flowers: Vermont Hoyas saw no blooms for years at a dim window, and buds that formed only matured once the plant went under lights (Vermont Hoyas, linearis). Too much hot sun bleaches the needles.

Water

Check first. Push a dry finger as far into the mix as it will go, and lift the pot: learn what it weighs wet and dry (Ohio Tropics, Vermont Hoyas, watering). Dry all the way down and light means it is time. Any dampness means wait. In a hard, gritty mix the finger and the weight can both be hard to read (Vermont Hoyas, linearis); a wooden skewer pushed to the bottom and pulled out after a minute shows damp where it comes out dark. The needles help too: limp, soft needles hanging straight down are asking.

The rule: water thoroughly, until it runs out of the bottom, then let the whole mix dry before the next watering, and set the plant up so that happens quickly (Ohio Tropics). Never in sips (Vermont Hoyas, watering). Sources differ. The RHS waters moderately in growth and keeps the compost just moist in winter (RHS profile); Steve's Leaves lets only the surface dry and warns the plant is quite sensitive to overwatering (Steve's Leaves); Ohio Tropics lets the whole mix dry fairly quickly, and Vermont Hoyas suspects it prefers very dry conditions (Vermont Hoyas, linearis). This guide takes the drier side, almost dry, because rot is the way this plant is usually lost, but it pairs that with a fast-drying setup, because a long dry spell costs it needles (Ohio Tropics).

Thirsty: limp, soft, shrivelling needles on a dry, light pot, and after a long spell older needles yellowing and dropping. A soak brings the rest back within a day or two. Overwatered: needles yellowing and dropping while the mix is still wet, strands blackening where they meet the mix (Ohio Tropics, Iowa State Extension). If the needles say thirsty and the soil says wet, believe the soil and look at the roots.

How often that lands depends on the pot, the mix, the light and the room. In a small pot of fast-draining mix in bright light in summer it often comes round about once a week, which is what Vermont Hoyas settled on (Vermont Hoyas, linearis); in a heavier mix or a dim spot it stays wet far longer, and that is the danger. In winter, with less light and cooler rooms, the mix dries more slowly and waterings space out (Ohio Tropics, UF/IFAS Gardening Solutions); dry heated air can still empty a pot faster than you expect (Vermont Hoyas, watering). Treat the numbers as a reminder to check, not as the instruction.

Soil and pot

A gritty, very fast-draining mix. Ohio Tropics uses a cactus or succulent compost with extra perlite; Vermont Hoyas has seen it thrive in a hard bonsai mix that water runs straight through; the RHS uses a fast-draining, loam-based compost with extra organic matter (Ohio Tropics, Vermont Hoyas, linearis, RHS profile). The general hoya mix of equal parts orchid bark, peat-free compost and coarse perlite also works (RHS growing guide). Lean toward the grittier end.

The pot needs a drainage hole and should be small, usually a hanging one. Hoyas like being root-bound and resent being over-potted (Ohio Tropics, Clemson HGIC), and the RHS says they resent repotting and can stay in one pot for many years (RHS profile). When you do move up, go one size, 2 to 4 cm wider (Vermont Hoyas, repotting). Terracotta dries faster, which this plant may welcome; plastic lets you judge the weight. Either works if you check before you water.

Repot in spring, never in bud or bloom, and handle the strands as little as you can: they are brittle and the needles shed (Steve's Leaves). Soak it in, then wait until the new mix is nearly dry before watering again: the first two months are when overwatering does the most harm (Vermont Hoyas, repotting). Hold the feed for five or six weeks (RHS growing guide).

Feeding

Lightly. A balanced liquid houseplant or orchid feed at half strength every four to six weeks from spring to early autumn, and nothing in winter (Iowa State Extension). Sources differ: the RHS gives a balanced liquid feed monthly in growth (RHS profile), Ohio Tropics feeds very dilute at most waterings and stops from autumn to late winter (Ohio Tropics), and Iowa State feeds at a quarter or half strength. This guide takes the weaker monthly rule. Every few months water through with plain water to wash out salts (RHS growing guide).

Flowering

Small clusters of ten to thirteen white stars at the strands (RHS profile), with a lemony scent, sometimes with a touch of cinnamon, lasting two weeks or more (Vermont Hoyas, linearis, Ohio Tropics). Unlike most hoyas it flowers late: late summer and autumn (RHS profile). Vermont Hoyas saw buds form at the end of summer and open a few weeks later.

What it takes: light above all, then a snug pot and a few drier weeks before the flowering season (Ohio Tropics). Sources disagree on age: Ohio Tropics says a plant two or three years old, while Vermont Hoyas finds it flowers at a very young age from cuttings (Vermont Hoyas, linearis). Most hoyas that never bloom are not getting enough light (UF/IFAS Gardening Solutions).

Two things never to do. The flowers come again from the same spurs, so when you trim a long strand, avoid cutting a spur (Ohio Tropics, RHS growing guide). And once buds appear, do not move or turn the plant until the flowers are over; a moved hoya drops its buds (Iowa State Extension).

When something looks wrong

Look at the soil first, then at how fast it dries.

• Limp, soft or shrivelled needles. Check the mix. Bone dry: soak it, and the needles firm up within a day or two. Wet for a long time: look at the roots for rot (Ohio Tropics).
• Needles yellowing and dropping, strands going bare. A pot kept wet, a pot left bone dry for a long spell, or a cold draught (Ohio Tropics, Vermont Hoyas, linearis). Correct the water, move it out of the draught, and set it up to dry within days: small pot, gritty mix, more light.
• Strands blackening at the base. Rot from a mix that stays wet (RHS growing guide). Cut away every dark soft root, repot in fresh, barely damp gritty mix in a small pot, and root healthy strand tips straight away: a plant this far gone often does not recover (Ohio Tropics).
• Long gaps between the needles. Too little light (Ohio Tropics). Move it right in front of a bright window; trim the leggiest strands in spring and root the tips.
• Bleached or scorched needles. Hot afternoon sun (RHS profile). Filter the summer sun and keep the morning sun.
• Strands snapping, needles falling when touched. Normal for this brittle plant (Steve's Leaves). Hang it out of the way and root the broken pieces.
• Brown crisp tips. Dry air, most likely in heated winter rooms. A humidifier or a pebble tray, with air moving around the strands (Ohio Tropics).
• No flowers. Light first, then the pot (too large?), the spurs (were they cut?) and a few drier weeks before late summer (Ohio Tropics).
• Buds drop before opening. The plant was moved, or the watering or temperature changed suddenly (Iowa State Extension). Leave it where it is.
• Mealybugs. White cottony tufts among the needles (RHS profile). Dab each one with a cotton bud in rubbing alcohol, spray the whole plant with insecticidal soap, and repeat weekly even after they seem gone (Ohio Tropics, Clemson HGIC).
• Spider mites. Pale speckling and fine webbing in dry warm air (Clemson HGIC). Rinse the strands under a gentle shower every few days, spray with insecticidal soap or neem weekly, and raise the humidity.

Propagation

By stem cuttings in spring or summer, or by layering. Take strand cuttings with two or three nodes, strip the needles from the lowest node, and push them into a light mix with plenty of perlite, kept just moist under a clear bag out of direct sun (Ohio Tropics); in moist perlite, hoya cuttings usually root in four to six weeks (Vermont Hoyas, propagation). Some growers root them in water. The RHS layers strands in spring or summer, pinning them to a pot of mix beside the plant until rooted, or takes semi-ripe cuttings with bottom heat in late summer (RHS profile). Wear gloves for the sap. Several rooted strands in one small pot make a fuller plant sooner.