Common Knotweed

Also known as

Common knotweed, equal-leaved knotgrass, prostrate knotweed, mat grass, oval-leaf knotweed, stone grass, wiregrass and door weed

Taxonomy

Scientific name

Polygonum arenastrum

Genus

Polygonum

Family

Polygonaceae

Order

Caryophyllales

How to care for Common Knotweed

💦 Water

How often to water your Common Knotweed

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

Does your plant get direct sunlight?

No Yes

Select the pot size

☀️ Light

Finding light for Common Knotweed in your home

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

Nutrient, fertilizer, and repotting needs for Common Knotweed: repot after 2X growth

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

💦 Water Needs

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

Common Knotweed is not known to cause harm to humans or pets. Regardless, if you, a family member, a cat, or dog has ingested any plant material, please consult a doctor or a veterinarian.

🪴 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 3a-9b. Find your local hardiness zone here.

🍂 Yellow Leaves

Yellow leaves aren’t always a reason to panic, and can be a normal part of a plant’s life cycle. Unless brand new leaves are turning yellow or all the leaves change color at once, it’s likely just your plant shedding old leaves.

Overwatering and root rot are the most likely cause of problems in Common Knotweed, since they are sensitive to wet soil. The leaves may also appear to be curling or drooping. Less often, yellow leaves are caused by underwatering, nutrient deficiencies, or pests.

Replace soggy soil with fresh, dry soil and download Greg to make sure your plant never gets overwatered again!

🧐 Troubleshooting

When troubleshooting a sad-looking houseplant, start by checking for signs of distress in its leaves, such as yellowing, browning, or drooping, which can indicate overwatering or nutrient deficiencies.

Inspect the soil moisture; too dry or too wet soil can cause problems.

Ensure the plant is getting the right amount of light, as too much or too little can stress it.

Finally, consider environmental factors like temperature and humidity, and adjust care routines accordingly to revive your plant.