Azalea macrostemon Plant Care
Azalea macrostemon Kuntze
Updated · Sources · How we source care data
Rhododendron japonicum, the Japanese azalea, is a species of flowering plant in the family Ericaceae, native to Japan. A deciduous shrub reaching 8 ft (2.4 m) but usually half that, it is found in grasslands and open scrub, never in dense thickets or woodlands.
Every 4–7 days
Filtered sunlight or partial shade
45–75°F
40–60%
At a glance
How do you care for Azalea macrostemon?
Plant Azalea macrostemon in filtered sunlight or partial shade (USDA zones 11b) and water a young tree every 4–7 days until it is established. It tolerates temperatures of 45–75°F (7–24°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 Azalea macrostemon Native To?
What Is the Azalea macrostemon?
Azalea macrostemon (Azalea macrostemon) belongs to the Ericaceae family within the Azalea genus. Azalea macrostemon is native to Japan.
Azalea macrostemon displays a compact, mounding shrub growth habit, reaching up to 5 ft tall with a spread of approximately 5 ft. Azalea macrostemon produces showy, colorful blooms in various shades of pink, red, white, or purple.
Leaf size: approximately 2 inches.
How Often Should You Water a Azalea macrostemon?
Water a young or newly planted Azalea macrostemon every 4–7 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 4–7 days
Until established; then in dry spells
What Light Does the Azalea macrostemon Need?
Azalea macrostemon thrives in filtered sunlight or partial shade. Avoid placing Azalea macrostemon in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Filtered sunlight or partial shade
What Temperature and Humidity Does the Azalea macrostemon Prefer?
Azalea macrostemon tolerates temperatures of 45–75°F. Azalea macrostemon prefers humidity levels of 40–60%.
Temperature
45–75°F
Humidity
40–60%
What Soil Mix Works Best for a Azalea macrostemon?
Well-draining acidic soil with high organic matter content, such as peat moss or pine bark. Good drainage is essential for Azalea macrostemon to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Azalea macrostemon?
Feed Azalea macrostemon 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 Azalea macrostemon?
Choose a spot with filtered sunlight or partial shade and well-draining acidic soil with high organic matter content, such as peat moss or pine bark. Avoid low spots where water collects after rain.
Azalea macrostemon is suited to USDA Zone 11b.
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 Azalea macrostemon?
Azalea macrostemon can spread to about 5 ft (1.5 m) and reach about 5 ft (2 m) tall. Space plants about 5 ft (1.5 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 Azalea macrostemon?
Prune Azalea macrostemon 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 Azalea macrostemon in Winter?
Azalea macrostemon 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 Azalea macrostemon?
Azalea macrostemon can be propagated through softwood cuttings, layering, seeds.
Is the Azalea macrostemon Toxic to Pets and Children?
Toxic (caution)
Reported as toxic in our plant data. Not verified by the ASPCA.
Toxic to pets, mild toxicity to humans if ingested
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 Azalea macrostemon?
Azalea macrostemon is susceptible to spider mites, lace bugs, caterpillars. 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 Azalea macrostemon Need?
Azalea macrostemon grows outdoors in USDA Zone 11b. It survives winters down to planting zone 11b. Azalea macrostemon is native to Japan. In cooler regions, grow Azalea macrostemon as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 11b
Keep exploring plants
Azalea macrostemon 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 Azalea genus — compare its care with other Azalea species on PlantoScan.
Azalea is part of the Ericaceae plant family — browse all Ericaceae genera and species.
Azalea macrostemon thrives in bright light and direct sun — see other bright-light plants.
Related Plant Care Guides
Closely related plants with similar care requirements:
Sources
- Scientific name & taxonomy: Azalea macrostemon Kuntze, family Ericaceae (first published in Revis. Gen. Pl. 2: 387 (1891)) — World Flora Online record, IPNI name record.
- Pet toxicity: Azalea macrostemon 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 11b, 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.
