# Giant Knotweed (*reynoutria sachalinensis*)

Giant Knotweed is a tall, leafy plant that can grow up to 10 feet high! Its huge green leaves provide shade and are fun to explore in nature.

- **Category:** [Plants](https://www.snappit.app/explore/categories/plant)
- **Rarity:** Common
- **Danger:** 1/5 · Very low
- **Habitat:** Giant Knotweed typically lives in riverbanks, wetlands, and disturbed areas.
- **Also known as:** Asian Knotweed, Sakhalin Knotweed

![Giant Knotweed](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/GiantKnotweed056.jpg&width=800)

Photo: Velocicaptor at en.wikipedia, Public domain · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:GiantKnotweed056.jpg)

## Appearance

The Giant Knotweed is a towering plant with hollow, bamboo-like stems, often red-speckled, and large, heart-shaped leaves. It features creamy-white to greenish-white flowers clustered in frothy sprays. Its immense size and thick stems make it visually distinct from most other herbaceous plants.

## Taxonomy

- **Kingdom:** Plantae
- **Phylum:** Tracheophyta
- **Class:** Magnoliopsida
- **Order:** Caryophyllales
- **Family:** Polygonaceae
- **Genus:** Reynoutria

## Interesting facts

- It was brought to Europe from far-off East Asia in the 1800s.
- Its strong roots can even push through cracks in concrete and pavement!
- People sometimes eat its young shoots, which taste a bit like rhubarb.
- This plant can grow over 3 meters tall in just one summer!

## Special abilities

- **Rapid Growth Spurt:** Giant Knotweed can grow incredibly fast, reaching towering heights quickly to outcompete other plants for sunlight and space.
- **Super Spreader Roots:** Giant Knotweed has a deep, spreading root system that helps it access water and nutrients and quickly colonize new areas.
- **Fragmented Rebirth:** Giant Knotweed can re-grow from tiny stem or root fragments, making it incredibly tough to remove once established.

## Measurements & details

- **Height:** 200-400 cm
- **Spread:** 100-300 cm
- **Flower Size:** 0.2-0.5 cm
- **Bloom Season:** Late summer to fall
- **Edible:** Yes
- **Toxicity:** None
- **Lifecycle:** Perennial
- **Pollination Method:** Insect

## Ecological connections

- **Pollinates:** European honey bee (*Apis mellifera*) — Bees collect nectar from its late-season flowers.
- **Eats:** Black bean aphid (*Aphis fabae*) — Aphids feed on the sap from its leaves and stems.
- **Eats:** Knotweed flea beetle (*Psylliodes chalcomera*) — Beetles feed on the leaves and stems of knotweed.

## Traits

- [Solitary](https://www.snappit.app/explore/traits/solitary): Solitary animals live alone for most of their lives, only interacting with others for mating or parental care.
- [Colorful](https://www.snappit.app/explore/traits/colorful): Colorful describes organisms or objects displaying a wide range of bright and distinct colors.
- [Herbivorous](https://www.snappit.app/explore/traits/herbivorous): This trait characterizes organisms whose diet consists entirely or primarily of plant material.
- [Forest](https://www.snappit.app/explore/traits/forest): Forest habitats are terrestrial environments dominated by dense tree cover, supporting a high diversity of plant and animal life.
- [Aquatic](https://www.snappit.app/explore/traits/aquatic): Aquatic habitats encompass environments where organisms live predominantly in water, including oceans, rivers, lakes, and wetlands.

## Collections

- [Plants](https://www.snappit.app/explore/collections/plants)

## Safety

**Danger:** 1/5 · Very low

No special safety notes yet.

## Frequently Asked Questions

### How to identify Giant Knotweed?

Start with the whole plant, then compare leaf arrangement, leaf edges, stems and any flowers or fruit. Opposite leaves grow in pairs; alternate leaves come one at a time along the stem. These details tell you far more together than a single green leaf does. Plant Identifier: upload a photo and compare the visible details.

### How tall is Giant Knotweed?

200-400 cm

### How wide does Giant Knotweed spread?

100-300 cm

### How big are the flowers on Giant Knotweed?

0.2-0.5 cm

### When does Giant Knotweed bloom?

Late summer to fall

### Is Giant Knotweed edible?

Yes

### Is Giant Knotweed toxic?

None

### What is Giant Knotweed's lifecycle?

Perennial

## Where to spot

- [Leschi Park](https://www.snappit.app/guides/places/leschi-park) — Washington, US · Park

## More Plants

- [white snakeroot](https://www.snappit.app/explore/white-snakeroot) (*Ageratina altissima*)
- [tree-of-heaven](https://www.snappit.app/explore/tree-of-heaven) (*Ailanthus altissima*)
- [western sword fern](https://www.snappit.app/explore/western-sword-fern) (*Polystichum munitum*)
- [common milkweed](https://www.snappit.app/explore/common-milkweed) (*Asclepias syriaca*)

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Source: [Giant Knotweed: Facts & Places to See — Snappit](https://www.snappit.app/explore/giant-knotweed)