Should I prune the long stems?

Yes, pruning encourages the plant to branch out and grow thicker. The cuttings root easily, so check your local regulations before propagating them, and never put trimmings or plant pieces in drains, ponds or waterways, because this plant is invasive in many regions.

Will it grow in full shade?

It can survive, but it will become very leggy and lose its vibrant color. Full sun is best for a healthy, dense plant.

Why is my Alligator weed growing so leggy? Causes and fixes

Check these first

Measure the light levels in your plant's current spot.
Check if the plant is leaning toward a window.
Look for signs of overcrowding in the container.

Likely causes

Insufficient Light
Most likely
How to tell: The stems are long and thin with large gaps between the leaves. The plant leans heavily toward the nearest light source.
What to do: Move the plant to a spot with full sun or bright, indirect light. If you are growing it indoors, place it within 12 inches of a bright window.
Crowding
Possible
How to tell: The stems are tangled and thin because they are competing for space. This often happens when the container is too small for the root mass.
What to do: Trim back the longest stems to encourage bushier growth. If the container is packed, divide the plant into two separate pots.

Leggy growth in other plants

Find out what's wrong with your alligator weed

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

It is not a health emergency, but it makes the plant look sparse. If the stems become too weak to support themselves, it is time to prune.

Stopping it coming back

Provide at least 6 hours of bright light daily to keep the growth compact.

Alligator weed: leggy growth? Check yours with a photo

Every plant is a little different. Take a photo of your alligator weed and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Should I prune the long stems?: Yes, pruning encourages the plant to branch out and grow thicker. The cuttings root easily, so check your local regulations before propagating them, and never put trimmings or plant pieces in drains, ponds or waterways, because this plant is invasive in many regions.
Will it grow in full shade?: It can survive, but it will become very leggy and lose its vibrant color. Full sun is best for a healthy, dense plant.

Why is my Alligator weed growing so leggy?