Hi. I plan to mulch a patch of black mondo grass (Ophiogogon planiscapus ‘Nigrescens’) to protect it from winter burn this winter. I was planning to make a small ‘wall’ with low stakes with burlap attached all around to surround the grass about 6″ above the highest parts of the grass. I plan to fill this area with leaves that fall in my yard until the grass it totally covered. What do you think of this plan? Do you think it will ensure less winter burn? Is it fine to use the whole leaf or do I have to render the leaves into smaller bits with a lawn mower? Are there any types of leaves that should not used?
Thank you for contacting the Toronto Master Gardeners regarding winter protection for Black Mondo Grass. Toronto is on the edge of the hardiness zone for Ophiopogon planiscapus ‘Nigrescens’. It sounds like you already have a good plan in place, however, the burlap wrap and leaf mulch should only be applied after the ground has frozen. Support stakes for the wrap can be installed now and be sure that the plants are sufficiently watered before freeze up. Using whole leaves as mulch will be fine as long, as the individual leaves are not overly large in size. I would recommend avoiding Norway Maple leaves as they are too large for this purpose and may carry spores of a fungal disease known as Anthracnose which could infect your plants.
For more information, please see this link to a post from our archives regarding winter protection for Black Mondo grass https://www.torontomastergardeners.ca/askagardener/winter-protection-for-black-mondo-grass/