
Photo: Eric HuntCC BY-SA 4.0via Wikimedia Commonsresized / cropped
Smooth Ragwort Plant Care
Packera glabella (Poir.) C.Jeffrey
Updated · Sources · How we source care data
Packera glabella (formerly Senecio glabellus) is one of several plants with the common name butterweed, this one has also been called cressleaf groundsel and yellowtop. It is native to central and southeastern North America. It is toxic when eaten by humans.
Every 3–5 days
Partial to full shade
50–75°F
40–60%
At a glance
How do you care for Smooth Ragwort?
Plant Smooth Ragwort in partial to full shade (USDA zones 12a) and water a young shrub every 3–5 days until it is established. It tolerates temperatures of 50–75°F (10–24°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 Smooth Ragwort Native To?
What Is the Smooth Ragwort?
Smooth Ragwort (Packera glabella) belongs to the Asteraceae family within the Packera genus. Smooth Ragwort is native to central and southeastern North America. Smooth Ragwort is also known as Smooth Senecio, Senecio carolinianus, Senecio densiflorus.
Smooth Ragwort displays a low rosette, spreading growth habit, reaching up to 1 ft tall with a spread of approximately 2 ft. Smooth Ragwort produces small yellow daisy-like flowers in clusters.
Leaf size: approximately 4 inches.
How Often Should You Water a Smooth Ragwort?
Water a young or newly planted Smooth Ragwort every 3–5 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 3–5 days
Until established; then in dry spells
What Light Does the Smooth Ragwort Need?
Smooth Ragwort thrives in partial to full shade. The optimal light range is 100–500 lux. Avoid placing Smooth Ragwort in direct, harsh sunlight for extended periods, as this can scorch the foliage.
Light Requirement
Partial to full shade
100–500 lux
What Temperature and Humidity Does the Smooth Ragwort Prefer?
Packera glabella tolerates temperatures of 50–75°F. Smooth Ragwort prefers humidity levels of 40–60%.
Temperature
50–75°F
Humidity
40–60%
What Soil Mix Works Best for a Smooth Ragwort?
Moist, well-draining soil with high organic content. Good drainage is essential for Smooth Ragwort to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Smooth Ragwort?
Feed Smooth Ragwort 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 Smooth Ragwort?
Choose a spot with partial to full shade and moist, well-draining soil with high organic content. Avoid low spots where water collects after rain.
Smooth Ragwort is suited to USDA Zone 12a.
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 Smooth Ragwort?
Smooth Ragwort can spread to about 2 ft (0.6 m) and reach about 1 ft (0 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 Smooth Ragwort?
Prune Smooth Ragwort 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 Smooth Ragwort in Winter?
Smooth Ragwort is frost-tender (hardy to USDA zone 12). 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 Smooth Ragwort?
Smooth Ragwort can be propagated through division, seeds. Similar propagation techniques also apply to small-headed ragwort plant care, which shares the same genus.
Is the Smooth Ragwort 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 Smooth Ragwort?
Smooth Ragwort 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 Smooth Ragwort Need?
Smooth Ragwort grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Smooth Ragwort is native to central and southeastern North America. In cooler regions, grow Smooth Ragwort as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Smooth Ragwort 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 Packera genus — compare its care with other Packera species on PlantoScan.
Packera is part of the Asteraceae plant family — browse all Asteraceae genera and species.
Smooth Ragwort copes with lower light than most plants — browse the full list of low-light plants.
More Packera Species
Other Packera species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Packera glabella (Poir.) C.Jeffrey, family Asteraceae (first published in Kew Bull. 47(1): 101. 1992 [28 Feb 1992]) — World Flora Online record, IPNI name record.
- Pet toxicity: Smooth Ragwort 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.
- Photo: Eric Hunt, CC BY-SA 4.0, Wikimedia Commons — original.
- Hardiness zone: USDA Zone 12a, 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.
