On Gardening: Japanese sweet-flag grasses are ornaments for all seasons

December 29, 2014

Ogon, the leading variety of dwarf Japanese sweet flag, lends a fine textured grass-like element to beds and mixed containers.

Leave it to Ogon to be the most thrilling plants in the foggy landscape. Ogon, which means gold, is a great selection of Japanese sweet flag that seemed to literally glow through recent fog and mist, and it can do the same for your landscape. You no doubt have seen Ogon and probably thought it terrific looking ornamental grass, which is precisely how we use it in the landscape or mixed containers.

Ogon, the leading variety of Japanese sweet flag, is known botanically as Acorus gramineus. Proven Winners has to be given the credit for its dramatic rise in popularity when it was introduced into the Fall Magic line pf plants a few years ago. Not only it bring us Ogon, or Golden Japanese sweet flag, but also another called White Japanese sweet flag, Acorus gramineus variegatus.

Prior to these introductions, Acorus calamus was perhaps the best-known of the sweet flags, with its larger leaves that give off an aromatic scent. The foliage and rhizomes are used today to make the Oil of Calamus.

The Acorus gramineus group is not nearly as aromatic, but they do give us some great new grass-like choices for flower beds, borders, rock gardens and mixed containers. Ogon is one of the more stunning selections because of its bright golden color combined with green variegation. They are cold-hardy from zones 5-9.

I love how the dwarf sweet flags work tucked among rocks in creek beds, whether dry or flowing with water. In fact, all water gardens need some at the edge. They are choice plants for pocket planting in mixed containers of flowers and greenery. The golden variegated leaves literally shine, drawing your eye to gaze in its direction. They also look at home in combination with bamboo, umbrella plants and Louisiana iris.

But this time of the year, those of us in the South grow them in clusters as pansy partners and the perfect complement to purple flowering kale and cabbage.

The Japanese sweet flag spreads from the tips of rhizomes, similar to the way an iris spreads. They can reach about 10 inches tall and as wide. This gives you the option of using it as a ground cover. Performance seems best if they get a little filtered shade during the heat of the day.

Plant yours so that the rhizome is showing slightly above the soil line, then water thoroughly. Since it likes moist soil, be sure to apply a good layer of mulch and water during droughty periods. The soil should be fertile, organically rich or loamy, and retain moisture well. Tight clay soils will not make you or the sweet flag contented.

While ugly liriope leaves need cutting back virtually every year, sweet flags grown in good moist locations may keep the leaves attractive for more than a year. From time to time, you will want to trim leaves or clumps that have lost their effectiveness. On the other hand those that dry out or get to much sun will scorch, requiring a little more leaf pruning.

Lastly, donít forget about the super dwarf golden selection called Minimus aureus. This one only gets about 3 inches tall and then curves slightly toward the ground giving a gold carpet look. This one can look breathtaking when grown in front of blue hydrangeas.

Spring planting season will be here before you know it. Make plans to use dwarf sweet flags as a fine-textured grassy element throughout your landscape and as you design your mixed containers.



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