The Acorus gramineus, or Japanese Sweet Flag, is a plant with many names. It’s also known as the Japanese Rush, Grassy-leaved Sweet Flag, and Grass-leaf Sweet Flag.
This plant is native to Japan, Korea, and eastern Asia. It often grows in wetlands and shallow water, making it perfect for water gardens and ponds.
Description of Japanese Sweet Flag
This shrubby plant has long, narrow, and slightly curved leaves. The leaves can grow up to 30 cm (12 inches) tall.
It can grow fully or partly in water, or in very moist soil. Yet, it will only flower if it’s at least partly in water.
Types of Japanese Sweet Flag
There are two types of this plant. The first is the var. pusillus, which has slightly shorter and more rigid leaves. These leaves are also glossy and green.
The second type is the var. variegatus, which has long leaves that are streaked with yellow.
Cultivating Japanese Sweet Flag
The Japanese Sweet Flag grows well by its rhizome. This means it can create a near-seamless ground cover where it has the right conditions.
Many people use it around the edges of ponds and water gardens. It’s also used in freshwater aquaria.
How to Grow Japanese Sweet Flag?
To grow this plant, you can divide the fleshy underwater rhizome and plant the base in shallow water.
This will help it grow and spread in the right environment.
Uses of Japanese Sweet Flag
In Japan, during the Heian period, people would gather the leaves of the plant for the Sweet Flag Festival.
This festival took place on the fifth day of the fifth month.
Sweet Flag Festival Traditions
- People would spread the Japanese Sweet Flag and Wormwood on the roofs of houses for decoration. This was also done to keep evil spirits away.
- Special herbal balls made of Japanese Sweet Flag were made for the occasion.
These traditions show how the Japanese Sweet Flag has been a part of Japanese culture for many years.
Today, the plant is still widely used in gardens and ponds for its beauty and versatility.