Acorus gramineus Ogon - Variegated Japanese Sweet Flag

Acorus gramineus 'Ogon' is a lovely perennial plant that thrives in moist, marshy soil. It can be grown in fully submerged conditions, under 10 to 15 cm (5.9 in) of water, in full sun or partial shade. The plant's variegated foliage is dense and delicate and remains decorative for most of the year.

Emerging from the slightly trailing base are leaves that resemble an iris but are narrower and are of a beautiful chartreuse green colour highlighted with bright yellow. The green flowers are almost invisible and are grouped in a small, short spadix that appears at the beginning of summer. This plant is also known as the Japanese variegated Sweet Flag, and it quickly forms a large clump that complements Japanese irises, Asian primroses, or willowherbs on the banks of a pond. You can also plant it in a trough or a garden with particularly heavy and moist soil.

We have added a type of plant similar to Acorus gramineus 'Ogon' in one of our ponds, which has semi-evergreen leaves and is very useful as most waterside plants tend to disappear in winter. Although Acorus gramineus is known to be non-hardy, it has been outside for more than 20 years without any damage caused by the cold. However, in areas with colder winters, it is advisable to overwinter it in a cold greenhouse or a well-ventilated and bright space, protected from frost while keeping the soil consistently moist.