Hoya, the wax plant, is a climbing or trailing houseplant with thick, waxy leaves and clusters of fragrant, star-shaped flowers. Iowa State University Extension recommends bright, indirect light and a wet-dry watering cycle, and NC State’s plant database tags Hoya carnosa as non-toxic to cats, dogs and horses.
Hoya (Wax Plant) at a glance
| Type | Houseplant |
|---|---|
| Season | Perennial |
| Sun | Bright indirect light |
| Plant spacing | 12 in |
| Row spacing | 12 in |
| Per square foot | 1 |
| Seed depth | At surface |
| Days to maturity | Most bloom at 2–3 years old |
| How to start | Give hoya bright indirect light and a chunky fast-draining mix, water thoroughly then let it dry almost completely, and never remove the flower spurs |
| Water | 1 in per week |
These are the same numbers our plant spacing, square foot and harvest date calculators use. See every crop in the plant database.
When to plant hoya
Hoya can be started or repotted any time it is actively growing. Iowa State says young plants may need several years to mature and flower; NC State says most plants do not bloom until 2 to 3 years old. Flowers typically appear in summer. Prune in early spring and repot only when the plant is not in bud or flower.
How to plant hoya
- Light: bright, indirect light, bright enough to cast a shadow or read a book by. Leaves can scorch or turn red in intense light; low light gives thin, stretched growth and little or no flowering (Iowa State).
- Soil: a chunky, airy, fast-draining mix, for example potting soil with orchid bark and perlite or pumice. NC State says a loose, organic-rich mix in a pot with drainage holes.
- Repotting: only when outgrown or the mix has broken down, and only one pot size up (NC State: no more than 2 inches larger). Hoyas often flower better slightly potbound.
Caring for hoya
Water thoroughly, then let the mix dry almost completely before watering again; water more in bright, warm months and less in winter or low light. Use room-temperature water, as cold water can shock the plant (NC State). See the overwatering checker.
Ideal indoor temperature is 65–80°F; avoid anything below 55°F, including cold windows (Iowa State). Average indoor humidity of 40–60% is fine. Feed lightly in spring and summer at half or quarter strength and do not fertilize in winter.
Flowering: do not deadhead. Flowers grow from persistent spurs (peduncles), and many species rebloom from the same spur. Once buds form, keep light, water and temperature consistent to avoid bud blast.
Companion plants
| Grow nearby | Houseplants with similar bright-indirect-light needs |
|---|---|
| Keep apart | Cold windowsills and overly large pots that stay wet |
Mealybugs, scale and spider mites are the main pests; see the pest identifier. Check other pairings with the companion plant finder.
Common problems
| Problem | What you see | What to do |
|---|---|---|
| Yellow leaves | Yellowing leaves and root decline | Overwatering is the cause named by Iowa State. Let the mix dry almost completely between waterings; try the yellow leaf identifier. |
| Wrinkled, soft leaves | Leaves look shriveled or soft | Underwatering per Iowa State. Water thoroughly, then resume the wet-dry cycle. |
| No flowers or dropped buds | Thin growth, no blooms, or buds fall off | Low light, a very young plant, or changes in water, temperature or light once buds form (bud blast). Do not remove the old flower spurs. |
| Mealybugs, scale or spider mites | Cottony clusters in leaf axils, small bumps or webbing | Common hoya pests, with mites more likely in very dry air. See the pest identifier. |
Not sure what you are looking at? The plant problem identifier ranks likely causes from the symptoms you see.
When and how to harvest
Hoya is grown for its foliage and flowers. To propagate, take stem cuttings with at least one or two nodes, remove the lowest leaves and root the node in water, moist sphagnum or a light mix; roots often form within weeks. A leaf cutting usually will not vine unless a node is attached (Iowa State).
Plan your hoya
- Plant spacing calculator: how many plants fit your bed
- Planting calendar: sowing and transplant dates for your frost dates
- Frost dates by ZIP code: your last spring and first fall frost
- Harvest date calculator: when your crop will be ready
Frequently asked questions
How far apart should I plant hoyas?
Space hoyas 12 inches apart in rows 12 inches apart. In a square foot garden, plant 1 per square foot.
How deep do I plant hoya cutting?
Pot it at the same level it was growing; repot only one size up.
How long do hoyas take to grow?
Most hoyas bloom at 2 to 3 years old (NC State); young plants may need several years (Iowa State).
How much water do hoyas need?
About 1 inch of water a week, from rain and watering combined. Water thoroughly, then let the mix dry almost completely before watering again.
Why isn’t my hoya blooming?
Usually too little light or a very young plant. Also do not cut off the old flower spurs.
Is hoya toxic to cats and dogs?
NC State tags Hoya carnosa as non-toxic to cats, dogs and horses; check other species before assuming.
How do I propagate hoya?
Take a stem cutting with at least one or two nodes and root it in water, moist sphagnum or a light mix.