Pond Academy

How to Plant Yellow Flag Iris in a Pond (Care & Grow Guide)

Pond Academy is reader-supported. Buying through links on our site may earn us an affiliate commission. As an Amazon Associate I earn from qualifying purchases.

The Yellow Flag Iris or Iris pseudacorus is a perennial, herbaceous, aquatic plant and a prominent member of the Iridaceae family. Also known as water flag or yellow iris, this flowering plant is native to three different continents – northwest Africa, western Asia, and Europe.

You will find it growing about 2-4 feet tall along shores in shallow water. The flowers of the yellow flag iris are usually distinct, with a bright yellow color that helps them stand out along the edge of the pond's water.

But that is the sweet part – the yellow flag iris can also be destructive. Its invasive nature makes it a menace in different states and other countries.

And beyond its invasiveness, it can have negative effects on humans and animals alike. On contact with human skin, the resin content of the plant can cause skin irritation. Plus, it can potentially sicken animals when eaten which is why herbivores avoid them as much as possible.

Planting yellow flag iris is subjected to local regulations. Even when you are allowed to plant, you must not release these types of irises in any form into waterways or pubic water bodies.

How to Plant Yellow Flag Iris in a Pond (Care & Grow Guide)
Yellow Flag Iris - 3 Live Plants in 6 Inch Pots - Iris Pseudacorus

Yellow Flag Iris - 3 Live Plants in 6 Inch Pots - Iris Pseudacorus

Price:
Buy Now on Amazon

Clicking this link to make a purchase may earn us a commission at no additional cost to you.

Psst! Pin This Page For Future Reference

Yellow Flag Iris Quick Look

Common Names

Yellow iris, yellow flag, water flag, iris pseudacorus

Plant Type

Bog plant

Light Requirements

Full sun to partial shade

Hardiness Zones

USDA 5-9

Bloom

May to June

Grow Up To

2 to 4 ft. tall

Flower Color

Yellow

How To Plant Yellow Flag Iris In A Pond

When it comes to planting yellow flag in a pond or water garden, the key part is the rhizome or root. Start by positioning the root in the aquatic planting media, with the cut end tuber standing against the side of the planting container, rather than the middle.

This positioning ensures the root is well spaced to spread across the entire planting container. For best results, do not use bagged potting mix or similar lightweight soil – they end up floating and clouding your pond water.

The planting container should be placed on the planting shelf at about 6 inches into the water.

Yellow Flag Iris Care Guide

It is recommended to prune and trim the leaves and flowers of your yellow flag as soon as they turn brown. Removing and discarding these parts completely will minimize the excess organic material in your pond.

As winter sets in, the leaves and stems of the yellow flag iris start dying. If you have planted yours in a bog area, it is best to leave the plant alone once you have trimmed off the dead foliage, up to 1-2 inches above the top of the water.

If your yellow flag is on plant-shelves or planting containers, you only need to trim them to 1-2 inches before lowering them gently into the deeper parts of the pond. 

In Spring, once the ice has thawed completely, withdraw all the plants submerged in water. This must be done before any plant growth occurs.

If you live in Zones 6 and warmer areas, you can leave your plants as is – they can survive the weather conditions.

Yellow Flag Iris - 3 Live Plants in 6 Inch Pots - Iris Pseudacorus

Yellow Flag Iris - 3 Live Plants in 6 Inch Pots - Iris Pseudacorus

Price:
Buy Now on Amazon

Clicking this link to make a purchase may earn us a commission at no additional cost to you.

FAQs

Is yellow flag iris invasive?

Yes, the plant is classified as an invasive ornamental perennial plant in several states and countries. It’s non-native to the United States and can cause harm to animal health by sickening them when ingested and to humans as the resin content of the plant can cause skin irritation.

How do you control yellow flag iris?

The best control method is manual removal using your hands. However, it is best to have your gloves on for this process because the plant’s resin can cause skin irritation. Dig the plants up and carefully but thoroughly remove all the rhizomes before disposing of them responsibly.

An alternative control method is the use of herbicides, especially when hand removal is not feasible.