Try for Free
tab list
PictureThis
English
arrow
English
繁體中文
日本語
Español
Français
Deutsch
Pусский
Português
Italiano
한국어
Nederlands
العربية
Svenska
Polskie
ภาษาไทย
Bahasa Melayu
Bahasa Indonesia
PictureThis
Search
Search Plants
Try for Free
Global
English
English
繁體中文
日本語
Español
Français
Deutsch
Pусский
Português
Italiano
한국어
Nederlands
العربية
Svenska
Polskie
ภาษาไทย
Bahasa Melayu
Bahasa Indonesia
This page looks better in the app
picturethis icon
Instantly identify plants with a snap
Snap a photo for instant plant ID, gaining quick insights on disease prevention, treatment, toxicity, care, uses, and symbolism, etc.
Download the App for Free picturethis icon
Continue Reading
Yellow flag
Also known as: Dragon flower, Paleyellow iris
Yellow flag (Iris pseudacorus) is a flowering perennial plant native to Europe, Asia, and Africa. In temperate climates throughout the globe, yellow flag is cultivated as an ornamental plant. Yellow flag contains the toxin tannin and can irritate the skin. It's considered and invasive aquatic species.
Scientific classification
Instantly identify plants with a snap
Snap a photo for instant plant ID, gaining quick insights on disease prevention, treatment, toxicity, care, uses, and symbolism, etc.
Download the App for Free
Toxic to Pets
Toxicity
Perennial
Lifespan
Herb
Plant Type
Mid spring, Late spring, Early summer, Mid summer
Bloom Time
Late summer, Early fall, Mid fall
Harvest Time
1 m to 1.5 m
Plant Height
60 cm to 90 cm
Spread
Green, Yellow
Leaf Color
7 cm to 10 cm
Flower Size
Green
Fruit Color
5 - 32 ℃
Ideal Temperature
Spring, Summer
Growth Season
Rapid
Growth Rate

Images of Yellow flag

Distribution of Yellow flag

Distribution Map
Yellow flag is a widely distributed plant that is native to various regions across Europe, Western Asia, and Northern Africa. Its natural habitats have expanded due to cultivation to other continents, including parts of Asia and South America. Although actively cultivated for its ornamental value, yellow flag is sometimes thought to be a competing species in certain areas outside its native range. In particular ecological zones such as in oceanic climates, yellow flag may have an impact on ecosystems, whereby it establishes presence in wetlands, potentially affecting local flora and fauna.
Native
Cultivated
Invasive
Introduced
No species reported
Discover plant distribution and habitat
Gain insights into where plants thrive and how they adapt, helping you identify, cultivate, and protect them with essential information on habitats, distribution maps, and climate trends.
Download the App for Free
Habitat
Damp marshy areas, swampy woods, shallow water, wet ground on the edges of rivers and ditches
Hemisphere Trend Curve
Flowering
Fruiting

Culture

Garden Use
Yellow flag is highly popular as a wetland perennial in warmer climates. It is very easy to grow and produces a lot of flowers. However, it should not be planted near waterways that feed into wild areas because it can spread and become invasive. Gardeners should stick to using it in wet soils, or by enclosed ponds. Plantain lilies, Bistort, and Solomon's seal provide a good backdrop for this pretty flower.
Symbolism
Faith, Valour, Wisdom
Interesting Facts
In areas where it is not native, the yellow flag is considered a nuisance that shows up uninvited, staying longer than necessary and chasing all the old and familiar plants away. But even the most obnoxious plants tend to have good qualities. This plant has been used to remove heavy metals from waterways.
Name Story
Yellow flag: The specific epithet pseudacorus meaning "false acorus" refers to the similarity of its leaves to those of sweet flag that is featured with prominently veined mid-rib and sword-like shape. Since the flowers are yellow, it is called a yellow flag.
Get quick plant knowledge with a snap
Snap a photo for instant plant identification and learn about its name, symbolism, interesting facts, uses, and more.
Download the App for Free

Toxicity

Yellow flag poses a moderate toxicity risk to humans. Ingestion causes nausea, vomiting, and diarrhea; contact can cause skin irritation. Yellow flag is toxic to cats and dogs; ingestion of parts, especially leaves, leads to symptoms ranging from gastrointestinal issues to more severe signs. Immediate medical or veterinary attention is crucial if poisoning occurs.
Identify toxic plants in your garden
Find out what’s toxic and what’s safe for humans and pets.
Download the App for Free
RELATED: Toxicity of Yellow flag

Weed Control

Yellow flag is native to northern Africa and Eurasia that has been introduced in much of the world. It is considered invasive in eleven countries such as Australia, Japan, New Zealand, and the United States. It is considered a weed in much of North America. In the area of the Great Lakes, in particular, it has been cited as shrinking native habitats that house waterfowl, reducing the food supply for fish, and outcompeting other irises for pollinators. However, its vibrant flowers make it a popular garden ornamental. It is poisonous, so very few birds or mammals will eat it. In China, it is utilized to absorb cadmium and copper from contaminated waters. When necessary, yellow flag can be removed via the use of glyphosate and imazapyr herbicides.
How to Control It
The best season to control or restrict yellow flag is generally late winter to early spring, before it begins its rapid growth and flowering stages.
  1. Manual removal: Carefully dig out the rhizomes with a shovel or hand trowel, ensuring to remove as much of the root system as possible to prevent regrowth.
  2. Mowing: Regularly mow the area where yellow flag grows to prevent seed formation and spread.
  3. Mulching: Apply a thick layer of organic mulch, such as wood chips or straw, around the base of yellow flag to suppress growth and seed germination.
  4. Water management: Restrict water access as yellow flag thrives in wet conditions; maintain dry soil to inhibit its growth.
  5. Plant competition: Introduce competitive native plants that can outcompete yellow flag for resources, reducing its dominance.
Identify toxic plants in your garden
Find out what’s toxic and what’s safe for humans and pets.
Download the App for Free

Quickly Identify Yellow flag

1
Vibrant yellow flowers reaching 1-2 feet (30-60 cm) in height.
2
Sword-shaped leaves up to 3-4 feet (90-120 cm) with parallel venation.
3
Distinctly shaped, dry 3-sided capsule measuring 1.5–3 inches (3.8–7.6 cm) in length.
4
Stout, upright stem reaching 3-4 feet (90-120 cm) with smooth, unbranched structure.
5
April to June blooming period with lance-shaped petals in fan-like distribution.
Identify plants with a snap
Instantly identify plants with AI: Snap a photo, and get accurate results within seconds.
Download the App for Free
RELATED: How to identify Yellow flag

Care Guide for Yellow flag

Every week
Water
Full sun
Sunlight
5 - 32 ℃
Ideal Temperature
Garden Soil
Soil Type
Water: Yellow flag prefers high humidity and grows in wetlands, tolerating balanced moisture levels. Weekly watering is essential for optimal growth. It can endure fluctuating soil conditions and temporary flooding, thriving near bodies of water.
Fertilize: Fertilize yellow flag seasonally with balanced N-P-K fertilizers for optimal growth. Use high phosphorus formulas in early spring, applying every 4-6 weeks. Transition to low-nitrogen options in late summer to prepare for dormancy. Avoid overfertilization to prevent growth imbalances and environmental harm.
Pruning: Yellow flag features tall, yellow flowers and sword-like leaves. Prune dead leaves in early spring and remove spent flower stalks post-bloom to control size and prevent seed spread. Regular maintenance promotes health and aesthetics. Refer to local guidelines for tailored care advice.
Propagation: Yellow flag thrives in moist environments, showcasing vibrant yellow flowers. Propagate through rhizome division in late summer or autumn. Provide full sun to partial shade and consistently damp soil for optimal growth and to maintain its sword-shaped leaves and blooms.
Repotting: Repot yellow flag every 2-3 years in early spring to support its rhizomes. Use a deep, wide container for water immersion. After repotting, maintain high moisture and provide full sun to partial shade. Utilize heavy soil and ensure shallow water for optimal recovery.
Get tips and tricks for your plants.
Keep your plants happy and healthy with our guide to watering, lighting, feeding and more.
Download the App for Free
RELATED: How to Grow and Care for Yellow flag
Plant disease auto-diagnose & prevention
AI-powered plant doctor helps you diagnose plant problems in seconds.
Download the App for Free
close
close
Your Ultimate Guide to Plants
Identify grow and nurture the better way!
product icon
17,000 local species +400,000 global species studied
product icon
Nearly 5 years of research
product icon
80+ scholars in botany and gardening
ad
ad
Botanist in your pocket
qrcode
PictureThis Ios DownloadPictureThis Android Download
Scan the QR code with your phone camera to download the app