Parthenium Weed (Parthenium hysterophorus)

Photo: Dinesh Valke from Thane, IndiaCC BY-SA 2.0via Wikimedia Commonsresized / cropped

Parthenium Weed Plant Care

Parthenium hysterophorus Adans.

Updated · Sources · How we source care data

Parthenium hysterophorus is a species of flowering plant in the family Asteraceae. It is native to the American tropics. Common names include Santa-Maria, Santa Maria feverfew, whitetop weed, and famine weed. In India, it is locally known as carrot grass, congress grass or Gajar Ghas. It is a common invasive species in India, Australia, and parts of Africa.

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Water

Every 7–10 days

Light

Full sun to partial shade

Temp

60–80°F

Humidity

40–70%

At a glance

How do you care for Parthenium Weed?

Plant Parthenium Weed in full sun to partial shade (USDA zones 13a) and water a young shrub every 7–10 days until it is established. It tolerates temperatures of 60–80°F (16–27°C). Fertilize it every 6 months during the growing season.

What Is the Parthenium Weed?

Parthenium Weed (Parthenium hysterophorus) belongs to the Asteraceae family within the Parthenium genus. Parthenium Weed is native to the American tropics. Parthenium Weed is also known as Feverfew, Wild Carrot, White Snakeroot.

Parthenium Weed displays a low rosette, spreading ground cover growth habit, reaching up to 0.5 ft tall with a spread of approximately 1.5 ft. Parthenium Weed produces small white daisy-like flowers in clusters.

Leaf size: approximately 2 inches.

How Often Should You Water a Parthenium Weed?

Water a young or newly planted Parthenium Weed 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 Parthenium Weed Need?

Parthenium Weed thrives in full sun to partial shade.

Light Requirement

Full sun to partial shade

What Temperature and Humidity Does the Parthenium Weed Prefer?

Parthenium hysterophorus tolerates temperatures of 60–80°F. Parthenium Weed prefers humidity levels of 40–70%.

Temperature

60–80°F

Humidity

40–70%

What Soil Mix Works Best for a Parthenium Weed?

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

How Often Should You Fertilize a Parthenium Weed?

Feed Parthenium Weed every 6 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 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 Parthenium Weed?

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.

Parthenium Weed is suited to USDA Zone 13a.

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 Parthenium Weed?

Parthenium Weed can spread to about 2 ft (0.5 m) and reach about 1 ft (0 m) tall. Space plants about 2 ft (0.5 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 plant spacing calculator.

How Do You Prune a Parthenium Weed?

Prune Parthenium Weed 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 Parthenium Weed in Winter?

Parthenium Weed is frost-tender (hardy to USDA zone 13). 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 Parthenium Weed?

Parthenium Weed can be propagated through seeds, division of clumps. Similar propagation techniques also apply to grayleaf parthenium plant care, which shares the same genus.

Is the Parthenium Weed Toxic to Pets and Children?

Pet safety not verified

The ASPCA does not list Parthenium Weed, 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 Parthenium Weed?

Parthenium Weed 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 Parthenium Weed Need?

Parthenium Weed grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. Parthenium Weed is native to the American tropics. In cooler regions, grow Parthenium Weed as a houseplant or bring it indoors before the first frost.

Hardiness Zone

Zone 13a

Keep exploring plants

Parthenium Weed 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 Parthenium genus — compare its care with other Parthenium species on PlantoScan.

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

Parthenium Weed 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: Parthenium hysterophorus Adans., family Asteraceae — World Flora Online record.
  • Pet toxicity: Pet safety not verified: the ASPCA does not list Parthenium Weed, 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: Dinesh Valke from Thane, India, CC BY-SA 2.0, Wikimedia Commons — original.
  • Hardiness zone: USDA Zone 13a, 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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