Rhododendron calceolarioides Plant Care

Rhododendron calceolarioides Wernham

Updated · Sources · How we source care data

Rhododendron macgregoriae is a rhododendron species native to Indonesia and Papua New Guinea at altitudes of 500–3,350 m (1,640–10,990 ft). It is an evergreen shrub or tree purportedly growing to 15 m (49 ft) in height, with leaves that are ovate-elliptic or obovate-elliptic, 40–140 × 25–50 mm in size.

🌿Shrubs
Water

Every 7–14 days

Light

Partial shade to full sun

Temp

40–70°F

Humidity

40–60%

At a glance

How do you care for Rhododendron calceolarioides?

Plant Rhododendron calceolarioides in partial shade to full sun (USDA zones 11a) and water a young tree every 7–14 days until it is established. It tolerates temperatures of 40–70°F (4–21°C). Fertilize it every 6 months during the growing season. It is reported as toxic to pets, so keep it out of reach of pets.

Where Is the Rhododendron calceolarioides Native To?

Native range2 countries

What Is the Rhododendron calceolarioides?

Rhododendron calceolarioides (Rhododendron calceolarioides) belongs to the Ericaceae family within the Rhododendron genus. Rhododendron calceolarioides is native to Indonesia and Papua New Guinea at altitudes of 500–3,350 m (1,640–10,990 ft).

Rhododendron calceolarioides displays an upright, spreading shrub growth habit, reaching up to 6 ft tall with a spread of approximately 6 ft. Rhododendron calceolarioides produces showy clusters of large, colorful blooms in various shades.

Leaf size: approximately 6 inches.

How Often Should You Water a Rhododendron calceolarioides?

Water a young or newly planted Rhododendron calceolarioides every 7–14 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established trees mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Watering Frequency

Every 7–14 days

Until established; then in dry spells

What Light Does the Rhododendron calceolarioides Need?

Rhododendron calceolarioides thrives in partial shade to full sun.

Light Requirement

Partial shade to full sun

What Temperature and Humidity Does the Rhododendron calceolarioides Prefer?

Rhododendron calceolarioides tolerates temperatures of 40–70°F. Rhododendron calceolarioides prefers humidity levels of 40–60%.

Temperature

40–70°F

Humidity

40–60%

What Soil Mix Works Best for a Rhododendron calceolarioides?

Well-draining, acidic soil with high organic matter content such as peat moss, pine bark, and perlite. Good drainage is essential for Rhododendron calceolarioides to prevent waterlogging, which leads to root rot and fungal issues.

How Often Should You Fertilize a Rhododendron calceolarioides?

Feed Rhododendron calceolarioides every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established trees in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

Fertilizing

Every 6 months

During the growing season

The PlantoScan app can remind you when to water and when to fertilize each plant.

Where Should You Plant a Rhododendron calceolarioides?

Choose a spot with partial shade to full sun and well-draining, acidic soil with high organic matter content such as peat moss, pine bark, and perlite. Avoid low spots where water collects after rain.

Rhododendron calceolarioides is suited to USDA Zone 11a.

Plant container-grown or balled-and-burlapped trees in spring or early autumn, setting the root flare at soil level, and water well after planting.

How Far Apart Should You Plant a Rhododendron calceolarioides?

Rhododendron calceolarioides can spread to about 6 ft (1.8 m) and reach about 6 ft (2 m) tall. Space plants about 6 ft (1.8 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the tree spacing calculator.

How Do You Prune a Rhododendron calceolarioides?

Prune Rhododendron calceolarioides while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the tree in one year.

How Do You Care for a Rhododendron calceolarioides in Winter?

Rhododendron calceolarioides is frost-tender (hardy to USDA zone 11). In colder areas grow it in a container and move it to a bright, frost-free place before the first frost.

How Do You Propagate a Rhododendron calceolarioides?

Rhododendron calceolarioides can be propagated through stem cuttings, layering, grafting. Similar propagation techniques also apply to southern indica azalea plant care, which shares the same genus.

Is the Rhododendron calceolarioides Toxic to Pets and Children?

Toxic (caution)

Reported as toxic in our plant data. Not verified by the ASPCA.

This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.

See all plants toxic to cats and plants toxic to dogs.

What Pests and Diseases Affect the Rhododendron calceolarioides?

Rhododendron calceolarioides is susceptible to aphids, lace bugs, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

What USDA Hardiness Zone Does the Rhododendron calceolarioides Need?

Rhododendron calceolarioides grows outdoors in USDA Zone 11a. It survives winters down to planting zone 11a. Rhododendron calceolarioides is native to Indonesia and Papua New Guinea at altitudes of 500–3,350 m (1,640–10,990 ft). In cooler regions, grow Rhododendron calceolarioides as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 11a

Keep exploring plants

Rhododendron calceolarioides is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.

It belongs to the Rhododendron genus — compare its care with other Rhododendron species on PlantoScan.

Rhododendron is part of the Ericaceae plant family — browse all Ericaceae genera and species.

Rhododendron calceolarioides thrives in bright light and direct sun — see other bright-light plants.

More Rhododendron Species

Other Rhododendron species in PlantoScan's care catalogue share similar watering, light, and soil preferences:

Sources

  • Scientific name & taxonomy: Rhododendron calceolarioides Wernham, family Ericaceae (first published in Trans. Linn. Soc. London, Bot. 9: 95 (1916)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Rhododendron calceolarioides is reported as toxic to pets in our plant data (not verified by the ASPCA), so treat it with caution. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
  • Hardiness zone: USDA Zone 11a, calculated from the plant's minimum temperature.
  • Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.

Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.

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