Question of the Week – Number 2: December 12, 2019
“Do you ever trim Asian jasmine and mondograss groundcover plantings? If so, when and by how much?”
Trimming these two popular groundcover choices is not something I do very often, but yes, I’ve been known to do it a couple of times in each case. That’s over a 43-year period of growing them in our current landscape.
This is a vine that we typically use as a low-growing groundcover. Even then, however, it tends to build up on itself to a height of 8 or 10 inches. If we trim or mow it at 4 to 5 inches it can be kept neat and tidy and smooth-topped. That will also discourage it from climbing up and into shrubs and onto the sides of our downspouts and fencing. Trimming is also a great and quick way to clean up a planting that’s been turned brown by extreme winter cold if you happen to live in the northern half of the state.
If you have a mower that can be set to mow at 4 or 5 inches, that’s one way to trim Asian jasmine. Try a couple of square feet in an out-of-the-way part of the bed to see if you’re happy with the way the bed looks after you mow. If you are, then you can proceed on to do the rest of the planting.
If your mower won’t cut that high, use a gasoline-powered hedge trimmer to cut the groundcover. It will be able to handle the woody stems. Take care to hold it level 4 or 5 inches off the soil surface. You don’t want to cut too low.
Whichever way that you do the trimming, late January is the best time to make this kind of a cut. That lets the jasmine invest all of its new spring growth in filling in the voids. It will look great by mid-spring.
This is my favorite shade-loving groundcover. That’s because it’s easy to propagate, it holds the soil well, and it tolerates shade perfectly. But most of all, it’s very easy to blow fallen leaves out of mondograss.
You’ll almost never need to trim it. In 43 years of growing it around our house, I’ve only trimmed ours one time. That was seven or eight years ago following a really serious ice storm. We live north of DFW, and ice had rested on top of the mondograss for almost a week. It matted the leaves and actually froze them. When things started to warm up in the spring the mondograss looked ragged.
I knew it would come back, but I also saw how badly it looked, so I decided to try mowing it high. It was tough work for the mower, but we eventually got through it. Sure enough, a few weeks later, up came all the “candles” of new shoots and the mondograss was back in the race.