Look for these common identifying features:

• Hollow, upright stems that can resemble bamboo
• Distinctive leaves that grow alternately along the stems
• Rapid, dense growth that can crowd out surrounding vegetation
• Small white to cream-colored flowers that appear in branching clusters
• Reddish or purple speckling on younger stems
• Extensive underground rhizomes that allow the plant to spread and return after being cut back

No. Cutting knotweed alone will not get rid of an established infestation. While cutting removes the above-ground growth, the extensive underground rhizome system remains alive and can produce new shoots. Cutting may help manage the plant's size, but effective control typically requires a long-term treatment plan that targets the knotweed over multiple growing seasons.

Yes, but treating knotweed near water requires extra care. Only herbicides specifically labeled for use in or around aquatic sites should be used in these situations. The right application method can also help minimize off-target exposure to water and surrounding vegetation.

Green Shoots® offers an Aquatic Kit designed for targeted herbicide application in areas where knotweed and other invasive plants are growing near water.

Always read and follow the herbicide label, including all restrictions and precautions for aquatic environments.

Yes. Stem injection can be an effective, highly targeted method for treating knotweed when the stems are suitable for injection. It allows herbicide to be placed directly into the plant, helping minimize application to surrounding vegetation.

Stem injection is particularly useful when knotweed is growing near desirable plants or in areas where foliar spraying may be difficult. As with any herbicide application, always follow the product label and use only products and application methods approved for your specific situation.

Yes. Knotweed can regrow after treatment, especially during the first few years of control. Its extensive underground rhizome system allows the plant to survive and produce new shoots even after above-ground growth has been treated.

This is why knotweed control should be viewed as a long-term process. Monitor the treated area for new growth and follow up as needed. With consistent treatment and monitoring, the infestation should become smaller and easier to manage over time.

Understanding how knotweed grows is an important part of developing an effective control strategy. What you see above ground is only part of the plant—the extensive underground rhizome system is what allows knotweed to survive, spread, and return after being cut back.

Fast, Aggressive Growth

Knotweed emerges in spring and can grow rapidly throughout the growing season. Dense stands can quickly reach several feet tall, shading out surrounding vegetation and creating large, uniform patches.

Spreads Through Rhizomes

One of knotweed's biggest advantages is its extensive underground rhizome system. These underground stems can spread horizontally and produce new shoots, allowing an infestation to expand beyond the original stand.

Above-Ground Growth Dies Back in Winter

After flowering and the onset of colder weather, knotweed typically dies back to the ground. The dead, hollow stems can remain standing through winter, while the plant's rhizomes survive underground and produce new growth the following spring.

New Growth Can Come From Small Rhizome Pieces

Knotweed can also spread when rhizome fragments are moved by soil, equipment, water, or other disturbance. Even small pieces can potentially produce new plants under favorable conditions. This is one reason why digging, mowing, or moving contaminated soil can make an infestation more difficult to manage.

Why Timing Matters

Knotweed's growth cycle can influence when and how it should be treated. Successful management requires targeting the plant when it is actively growing and following up on new growth that appears in subsequent seasons.