Borinquen Thoroughwort (Chromolaena borinquensis)

Photo: Teunie at Dutch WikipediaCC BY-SA 3.0via Wikimedia Commonsresized / cropped

Borinquen Thoroughwort Plant Care

Chromolaena borinquensis (Britton) R.M.King & H.Rob.

Updated · Sources · How we source care data

This plant's most distinctive visual feature is its large, heart-shaped leaves with striking purple undersides. Originating from Puerto Rico, Chromolaena borinquensis is highly sought after by plant collectors for its unique foliage and rarity in cultivation. Its vibrant colors and unusual leaf shape make it a standout addition to any collection.

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Water

Every 7–10 days

Light

Full sun to partial shade

Temp

65–85°F

Humidity

40–70%

At a glance

How do you care for Borinquen Thoroughwort?

Plant Borinquen Thoroughwort in full sun to partial shade (USDA zones 11a–12b) and water a young shrub every 7–10 days until it is established. It tolerates temperatures of 65–85°F (18–29°C). Fertilize it every 4 months during the growing season.

Where Is the Borinquen Thoroughwort Native To?

Native range1 country

What Is the Borinquen Thoroughwort?

Borinquen Thoroughwort (Chromolaena borinquensis) belongs to the Asteraceae family within the Chromolaena genus. Borinquen Thoroughwort is native to the island of Puerto Rico. Borinquen Thoroughwort is also known as Eupatorium borinquense, Osmia borinquensis.

Borinquen Thoroughwort displays an upright, spreading shrub growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Borinquen Thoroughwort produces small white or lavender flowers in clusters.

Leaf size: approximately 6 inches.

How Often Should You Water a Borinquen Thoroughwort?

Water a young or newly planted Borinquen Thoroughwort every 7–10 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established shrubs mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Watering Frequency

Every 7–10 days

Until established; then in dry spells

What Light Does the Borinquen Thoroughwort Need?

Borinquen Thoroughwort thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Borinquen Thoroughwort Prefer?

Chromolaena borinquensis tolerates temperatures of 65–85°F. Borinquen Thoroughwort prefers humidity levels of 40–70%.

Temperature

65–85°F

Humidity

40–70%

What Soil Mix Works Best for a Borinquen Thoroughwort?

Well-draining sandy loam with added organic matter. Good drainage is essential for Borinquen Thoroughwort to prevent waterlogging, which leads to root rot and fungal issues.

How Often Should You Fertilize a Borinquen Thoroughwort?

Feed Borinquen Thoroughwort every 4 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established shrubs 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 4 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 Borinquen Thoroughwort?

Choose a spot with full sun to partial shade and well-draining sandy loam with added organic matter. Avoid low spots where water collects after rain.

Borinquen Thoroughwort is suited to USDA Zone 11a – 12b.

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

How Far Apart Should You Plant a Borinquen Thoroughwort?

Borinquen Thoroughwort can spread to about 2 ft (0.6 m) and reach about 3 ft (1 m) tall. Space plants about 2 ft (0.6 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 plant spacing calculator.

How Do You Prune a Borinquen Thoroughwort?

Prune Borinquen Thoroughwort 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 shrub in one year.

How Do You Care for a Borinquen Thoroughwort in Winter?

Borinquen Thoroughwort 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 Borinquen Thoroughwort?

Borinquen Thoroughwort can be propagated through seeds, stem cuttings. Similar propagation techniques also apply to bigelow's thoroughwort plant care, which shares the same genus.

Is the Borinquen Thoroughwort Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Borinquen Thoroughwort, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.

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 Borinquen Thoroughwort?

Borinquen Thoroughwort is susceptible to aphids, spider mites, whiteflies. 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 Borinquen Thoroughwort Need?

Borinquen Thoroughwort grows outdoors in USDA Zone 11a – 12b. It survives winters down to planting zone 11a. Borinquen Thoroughwort is native to the island of Puerto Rico. In cooler regions, grow Borinquen Thoroughwort as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 11a – 12b

Keep exploring plants

Borinquen Thoroughwort 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 Chromolaena genus — compare its care with other Chromolaena species on PlantoScan.

Chromolaena is part of the Asteraceae plant family — browse all Asteraceae genera and species.

Borinquen Thoroughwort thrives in bright light and direct sun — see other bright-light plants.

More Chromolaena Species

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

Sources

  • Scientific name & taxonomy: Chromolaena borinquensis (Britton) R.M.King & H.Rob., family Asteraceae (first published in Phytologia 20(3): 199 (1970)) — World Flora Online record, IPNI name record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Borinquen Thoroughwort, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
  • Photo: Teunie at Dutch Wikipedia, CC BY-SA 3.0, Wikimedia Commons — original.
  • Hardiness zone: USDA Zone 11a – 12b, estimated from the plant's typical growing conditions.
  • 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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