#TeachingTuesday: Liriope vs. Mondo Grass

Last week we had to cancel our usual training session due to extremely cold morning temperatures! We delayed our crews coming in for an hour and a half until the sun could come up and raise the temps. Fortunately, we’re not experiencing the current polar vortex dip like the Midwest is! We are hoping that everyone in the Chicago area stays safe and warm.

Today we covered an important topic with our maintenance crews: how to tell the difference between liriope and mondo grass, and which one should be cut back over the next month or so. There are two main types of liriope – clumping (Liriope muscari) and spreading (Liriope spicata). The neat clumps and broader foliage of L. muscari make it easy to tell apart, but L. spicata and mondo grass (Ophiopogon japonicus) look very similar. Both are very common groundcovers in NC, and ours crews will be spending a lot of time working with these plants on our clients’ properties as we start gearing up for spring.

Key Differences – ID Tips

• The leaves of mondo grass are more narrow than those of liriope.
• The berries of mondo grass are bright blue, while liriope berries are black.
• The flower stalks of liriope are usually quite showy, and stick out above the foliage. You will not usually see the flower stalks of mondo grass, as they are typically shorter and hidden beneath the foliage. Even in the winter once the flowers and berries are all gone, you will notice more old stalks on the liriope, and will not usually see any in the mondo grass.
• Mondo grass plants are typically shorter than liriope, and may be darker green.
• Mondo grass leaves are less likely to have winter discoloration or signs of insect or disease damage than liriope.

Winter Cutback

Because Mondo grass is less susceptible to winter discoloration and damage due to insects and diseases, it does not usually need to be cut back in the late winter/early spring. Liriope, however, grows very quickly and does best when cut back once every year. This also gives you a chance to remove fungal spores and scale insects that may be overwintering on the old foliage. Make sure to cut the foliage back BEFORE the new foliage begins to emerge–February is usually a good time of year for NC.

Liriope can be cut back in a few different ways, depending on how large of an area you are cutting back. For small areas, hands shears or electric shears may the easiest route, but for very large areas, a push mower may be used. Make sure to use a clean, sharp blade set no lower than 3″. Remove all of the cut foliage to prevent spread of insect pests or diseases. If the beds need to be mulched, make sure to not bury the plant crowns, as this will lead to crown rot.