German-knotweed
Scleranthus annuus
Last reviewed: August 2026
Toxicity unknown
German-knotweed (Scleranthus annuus) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
part shade
Water
low
Size
2"–12" H × 2"–6" W
Bloom
May, Jun, Jul, Aug, Sep
Native alternatives to German-knotweed
German-knotweed is not native to the United States. These natives fill a similar role in a planting, matched on bloom season, bloom color and mature size.
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.
Find rebates in your areaGerman-knotweed is a small, low-growing annual herb that forms compact mats of tiny, narrow leaves. It produces inconspicuous greenish flowers from late spring through fall and typically grows in poor, sandy soils.
In an HOA neighborhood
German-knotweed takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Very small and inconspicuous appearance lacks ornamental appeal
- Annual nature means gaps and bare spots each year
- Name includes 'knotweed' which has negative associations
Wildlife value
This plant provides minimal wildlife value as it has very small, wind-pollinated flowers that don't attract significant pollinators or other beneficial insects.
Common questions
- How much sun does German-knotweed need?
- German-knotweed grows best in part shade conditions.
- When does German-knotweed bloom?
- German-knotweed blooms in May, June, July, August, and September.
- Is German-knotweed HOA-friendly?
- German-knotweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
If something looks wrong
Common plant problems, and what to check first
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow German-knotweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Planning a bed around it? Start a free plan with this plant
Not sure where to start? Take the 2-minute yard quiz