Photo: Matt BergerCC BY 4.0via iNaturalistresized / cropped
Knotweed Spineflower Plant Care
Chorizanthe polygonoides Torr. & A.Gray
Updated · Sources · How we source care data
Chorizanthe polygonoides, also known as the San Diego spineflower, is a unique plant with small white flowers that bloom atop thin stems. Its distinctive feature is its narrow lance-shaped leaves that are green in color.
Every 7–14 days
Full sun to partial shade
50–80°F
40–60%
At a glance
How do you care for Knotweed Spineflower?
Water Knotweed Spineflower every 7–14 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 40–60% humidity. Fertilize it every 2 months during the growing season.
Where Is the Knotweed Spineflower Native To?
What Is the Knotweed Spineflower?
Knotweed Spineflower (Chorizanthe polygonoides) belongs to the Polygonaceae family within the Chorizanthe genus. Knotweed Spineflower is native to California and Baja California.
Knotweed Spineflower displays a low spreading groundcover growth habit, reaching up to tall with a spread of approximately 1 ft. Knotweed Spineflower produces small clusters of inconspicuous flowers.
Leaf size: approximately 2 inches.
How Often Should You Water a Knotweed Spineflower?
Chorizanthe polygonoides 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 Knotweed Spineflower Need?
Knotweed Spineflower thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Knotweed Spineflower Prefer?
Chorizanthe polygonoides grows best at temperatures of 50–80°F. Knotweed Spineflower prefers humidity levels of 40–60%.
Temperature
50–80°F
Humidity
40–60%
What Soil Mix Works Best for a Knotweed Spineflower?
Well-draining sandy soil with low to moderate fertility. Good drainage is essential for Knotweed Spineflower to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Knotweed Spineflower?
Feed Knotweed Spineflower every 2 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 2 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 Knotweed Spineflower?
Repot every 2-3 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 Knotweed Spineflower?
Knotweed Spineflower can be propagated through seeds, division of rhizomes. Similar propagation techniques also apply to short-horn spineflower plant care, which shares the same genus.
Is the Knotweed Spineflower Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Knotweed Spineflower, 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 Knotweed Spineflower?
Knotweed Spineflower 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 Knotweed Spineflower Need?
Knotweed Spineflower grows outdoors in USDA Zone 8b – 10b. It survives winters down to planting zone 8b. Knotweed Spineflower is native to California and Baja California.
Hardiness Zone
Zone 8b – 10b
Keep exploring plants
Knotweed Spineflower 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 Chorizanthe genus — compare its care with other Chorizanthe species on PlantoScan.
Chorizanthe is part of the Polygonaceae plant family — browse all Polygonaceae genera and species.
Knotweed Spineflower thrives in bright light and direct sun — see other bright-light plants.
More Chorizanthe Species
Other Chorizanthe species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Chorizanthe polygonoides Torr. & A.Gray, family Polygonaceae (first published in Proc. Amer. Acad. Arts 8: 197 (1870)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Knotweed Spineflower, 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: Matt Berger, CC BY 4.0, iNaturalist — original.
- Hardiness zone: USDA Zone 8b – 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.
Identify Plants Like the
Knotweed Spineflower Instantly
Scan any plant with your phone camera and get instant ID, care tips, water and fertilizer reminders, and health checks — all in one app.
Free
to download
iOS & Android
platforms
Light & dark
mode
100,000+
species