The common name for Acorus gramineus 'Ogon' is golden sweet flag. Golden sweet flag is originally from the wetlands of China, Japan, Korea, India, the Philippines and Thailand.
Originally the Acorus gramineus 'Ogon' was assigned to the arum family which also includes the lily. Nowadays the Acorus gramineus 'Ogon' has been assigned to its own family called Acoraceae.
Gramineus means grasslike and refers to the grass-shaped leaves.
The Acorus gramineus 'Ogon' is a plant that likes boggy conditions. It likes very moist soil or even shallow standing water (approximately 4 inches (10 cm) deep). This makes it a very suitable plant for along the waterside. Also in a drier spot the golden sweet flag does well. This perennial will then stay smaller and grow slower. If the conditions are too dry the leaf tips will turn brown.
The Acorus gramineus 'Ogon' forms a low tuft or mound and purifies the water. It has firm grasslike leaves that are yellow with green stripes. The leaves emit a sweet smell when pinched or bruised (hence its common name). Although Acorus gramineus 'Ogon' looks like a grass, the golden sweet flag not a member of the grass family.
The flowers are insignificant and have no ornamental value. In our climate in The Netherlands the golden sweet flag hardly ever form red berries after flowering. It is a very strong plant that has no serious insect or disease problems and is tolerant to salt.
The golden sweet flag is not an invasive plant. It spreads slowly by powerful rhizomes. I tried to contain the Acorus gramineus 'Ogon' in one place with a thin plastic foil. Because the rhizomes are pretty powerful they ‘marched’ over that foil. Because the golden sweet flag spreads slowly it is not necessary put anything around it.
The golden sweet flag is quite hardy. Leaves or leaf tips may die with frost but in spring new leaves will form. You can cut or pull away de died parts to enjoy the new leaves. In mild regions de golden sweet flag is evergreen.
If the centre of the plant thins out you can dig it up and divide it in spring.
Deer resistant: yes
Exposure: sun/part shade
Foliage color: green/yellow
Flower color: green
Flowering time: June - July
Hardiness: -4 ºF/ -20 ºC
Height: 16 inches/ 40 cm