Photo: KENPEICC BY-SA 3.0via Wikimedia Commonsresized / cropped
Glaucous sowthistle Plant Care
Sonchus glaucescens Jord.
Updated · Sources · How we source care data
Sonchus asper, the prickly sow-thistle, rough milk thistle, spiny sowthistle, sharp-fringed sow thistle, or spiny-leaved sow thistle, is a widespread plant in the tribe Cichorieae within the family Asteraceae.
Every 4–7 days
Full sun to partial shade
50–80°F
40–70%
At a glance
How do you care for Glaucous sowthistle?
Water Glaucous sowthistle every 4–7 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 50–80°F (10–27°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
What Is the Glaucous sowthistle?
Glaucous sowthistle (Sonchus glaucescens) belongs to the Asteraceae family within the Sonchus genus. Glaucous sowthistle is also known as Sonchus asper, Sonchus giganteus, Sonchus graecus.
Glaucous sowthistle displays an upright, branching herbaceous plant growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Glaucous sowthistle produces small yellow daisy-like flowers in clusters.
Leaf size: approximately 6 inches.
How Often Should You Water a Glaucous sowthistle?
Sonchus glaucescens requires watering every 4–7 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 4–7 days
Let soil partially dry between waterings
What Light Does the Glaucous sowthistle Need?
Glaucous sowthistle thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Glaucous sowthistle Prefer?
Sonchus glaucescens grows best at temperatures of 50–80°F. Glaucous sowthistle prefers humidity levels of 40–70%.
Temperature
50–80°F
Humidity
40–70%
What Soil Mix Works Best for a Glaucous sowthistle?
Well-draining, fertile soil with added compost or organic matter. Good drainage is essential for Glaucous sowthistle to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Glaucous sowthistle?
Feed Glaucous sowthistle every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Glaucous sowthistle?
Repot every 1-2 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Glaucous sowthistle?
Glaucous sowthistle can be propagated through seeds, division of root ball. Similar propagation techniques also apply to species plantarum plant care, which shares the same genus.
Is the Glaucous sowthistle Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Glaucous sowthistle, 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 Glaucous sowthistle?
Glaucous sowthistle is susceptible to aphids, caterpillars, slugs. 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 Glaucous sowthistle Need?
Glaucous sowthistle grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. In cooler regions, grow Glaucous sowthistle as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Glaucous sowthistle 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 Sonchus genus — compare its care with other Sonchus species on PlantoScan.
Sonchus is part of the Asteraceae plant family — browse all Asteraceae genera and species.
Glaucous sowthistle thrives in bright light and direct sun — see other bright-light plants.
More Sonchus Species
Other Sonchus species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Sonchus glaucescens Jord., family Asteraceae (first published in Observ. Pl. Nouv. v. (1847) 75. t. 5.) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Glaucous sowthistle, 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: KENPEI, CC BY-SA 3.0, 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.
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