Photo: Daniel CahenCC BY 4.0via iNaturalistresized / cropped
Bastard Toadflax Plant Care
Thesium humifusum DC.
Updated · Sources · How we source care data
This plant's silver-gray leaves are its most distinctive visual feature, making it stand out among other species. Originating from Mediterranean regions, Thesium humifusum is highly sought after by plant collectors for its unique appearance and rarity in cultivation. Its delicate, intricate foliage adds an element of elegance to any garden or collection.
Every 7–14 days
Partial shade to full sun
60–75°F
40–60%
At a glance
How do you care for Bastard Toadflax?
Water Bastard Toadflax every 7–14 days, letting the top layer of soil dry out between waterings, and give it partial shade to full sun. It prefers temperatures of 60–75°F (16–24°C) and 40–60% humidity. Fertilize it every month during the growing season.
Where Is the Bastard Toadflax Native To?
- Algeria
- Angola
- Austria
- Belgium
- Benin
- Botswana
- Burkina Faso
- Burundi
- Cameroon
- Cape Verde
- Central African Republic
- Chad
- Côte d'Ivoire
- Djibouti
- DR Congo
- Egypt
- Equatorial Guinea
- Eritrea
- Eswatini
- Ethiopia
- France
- Gabon
- Germany
- Ghana
- Guinea
- Guinea-Bissau
- Ireland
- Kenya
- Lesotho
- Liberia
- Libya
- Luxembourg
- Madagascar
- Malawi
- Mali
- Mauritania
- Morocco
- Mozambique
- Namibia
- Niger
- Nigeria
- Republic of the Congo
- Rwanda
- Sao Tome and Principe
- Senegal
- Sierra Leone
- Somalia
- South Africa
- South Sudan
- Sudan
- Switzerland
- Tanzania
- The Gambia
- The Netherlands
- Togo
- Tunisia
- Uganda
- United Kingdom
- Zambia
- Zimbabwe
What Is the Bastard Toadflax?
Bastard Toadflax (Thesium humifusum) belongs to the Santalaceae family within the Thesium genus. Bastard Toadflax is native to western Europe and north-western Africa, known as bastard-toadflax.
Bastard Toadflax displays a low-growing perennial herb growth habit, reaching up to tall with a spread of approximately 1 ft. Bastard Toadflax produces small, inconspicuous flowers in clusters.
Leaf size: approximately 2 inches.
How Often Should You Water a Bastard Toadflax?
Thesium humifusum requires watering every 7–14 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 7–14 days
Let soil partially dry between waterings
What Light Does the Bastard Toadflax Need?
Bastard Toadflax thrives in partial shade to full sun.
Light Requirement
Partial shade to full sun
What Temperature and Humidity Does the Bastard Toadflax Prefer?
Thesium humifusum grows best at temperatures of 60–75°F. Bastard Toadflax prefers humidity levels of 40–60%.
Temperature
60–75°F
Humidity
40–60%
What Soil Mix Works Best for a Bastard Toadflax?
Well-draining sandy loam with added organic matter. Good drainage is essential for Bastard Toadflax to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Bastard Toadflax?
Feed Bastard Toadflax every month 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 month
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Bastard Toadflax?
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 Bastard Toadflax?
Bastard Toadflax can be propagated through seeds, division of root clumps. Similar propagation techniques also apply to bastard toadflax plant care, which shares the same genus.
Is the Bastard Toadflax Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Bastard Toadflax, 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 Bastard Toadflax?
Bastard Toadflax is susceptible to aphids, spider mites, scale insects. 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 Bastard Toadflax Need?
Bastard Toadflax grows outdoors in USDA Zone 7a – 10b. It survives winters down to planting zone 7a. Bastard Toadflax is native to western Europe and north-western Africa, known as bastard-toadflax.
Hardiness Zone
Zone 7a – 10b
Keep exploring plants
Bastard Toadflax 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 Thesium genus — compare its care with other Thesium species on PlantoScan.
Thesium is part of the Santalaceae plant family — browse all Santalaceae genera and species.
Bastard Toadflax thrives in bright light and direct sun — see other bright-light plants.
More Thesium Species
Other Thesium species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Thesium humifusum DC., family Santalaceae (first published in Fl. Franç. , ed. 3, 5: 366 (1815)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Bastard Toadflax, 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: Daniel Cahen, CC BY 4.0, iNaturalist — original.
- Hardiness zone: USDA Zone 7a – 10b, 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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