Common knotweed
Also known as
Common knotweed, equal-leaved knotgrass, prostrate knotweed, mat grass, oval-leaf knotweed, stone grass, wiregrass and door weed
Taxonomy
Polygonum arenastrum
Polygonum
Polygonaceae
Caryophyllales
How to care for Common knotweed
Water
How often to water your Common knotweed
every 9
Common knotweed needs 0.5 cups of water every 9 when it doesn’t get direct sunlight and is potted in a 5" pot.
Use our water calculator to personalize watering recommendations to your environment or download Greg for more advanced recommendations for all of your plants.
Water 0.5 cups every
9
Light
Check the growing potential in your area
A plant's growing potential is determined from its location, the time of year, and current local weather.
Select a city to check sunlight intensity
Finding light for Common knotweed in your home
a window
Common knotweed love being close to bright, sunny windows 😎.
Place it less than 1ft from a south-facing window to maximize the potential for growth.
Common knotweed does not tolerate low-light 🚫.
Select your region to see how the current weather in your area affects the placement of Common knotweed in your home 🏡.
Nutrients
How to fertilize Common knotweed
Most potting soils come with ample nutrients which plants use to produce new growth.
By the time your plant has depleted the nutrients in its soil it’s likely grown enough to need a larger pot anyway.
To replenish this plant's nutrients, repot your Common knotweed after it doubles in size or once a year—whichever comes first.
FAQs
Common knotweed prefers for the soil to dry out between waterings and should be watered regularly. Use our water calculator to personalize watering recommendations to your environment or download Greg for more advanced recommendations for all of your plants.
Sunlight Needs
Common knotweed requires abundant, bright and direct light. Place it less than one foot from a window to ensure it receives enough light to survive 💪. Select your region to see how the current weather in your area affects the placement in your home 🏡.
Toxicity
Greg does not have confirmed data on this plant’s toxicity. If you, a family member, or a pet consumes plant material of unknown toxicity, it’s always best to consult a medical professional.
If you or someone else ingested this plant, call Poison Control at US (800) 222-1222. If a pet consumed this plant, contact your veterinarian or the ASPCA at US (888) 426-4435.
Soil
Common knotweed is very sensitive to dry soil, so choose a potting soil that retains moisture. A good soil will still drain well and contain lots of organic matter such as coco coir or sphagnum moss.
Fertilizer
Common knotweed grows very slowly and doesn’t require added fertilizer. Replacing your plant’s potting soil once a year should provide them with more than enough nutrition. Remember, plants get their energy from sunlight, not fertilizer!
Growing Outdoors
USDA Hardiness Zone
Common knotweed can be grown outdoors in USDA Hardiness Zones 4a-8b. Find your local hardiness zone here.
Care Summary for Common knotweed
Common knotweed
Greg recommends:
Water
0.5 cups every 9 days
Placement
< 1ft from a window
Nutrients
Repot after 2x growth
Based on the 4” pot your plant is in, and that it doesn’t get direct sunlight.
