Japanese Spurge

(Question)

Large city maple tree in front yard that had roots spread along entire surface of the front yard. Consulted with Amandeep Tiwana arborist at Bartlett Tree care and created a 10″ raised bed around entire front yard. Tree was never planted properly- had a “volcano” around it. Leveled out the entire bed.Planted an entire front yard of Japanese spurge in September 2019. New triple mix soil plus mulch on top. Watered every third day with multiple sprays for 25 minutes. Plants have rooted, some did flower but not many. Are yellow with some spots on them. Want to make sure this bed growns in! Any help would be appreciated. Thanks Mary

(Answer)

Hi– Thanks for contacting the Toronto Master Gardeners and for sending along the photos. Japanese spurge (Pachysandra terminalis) is a good choice for growing under maple trees. Maples have a shallow root system which really pulls the moisture out of the soil. While Japanese spurge prefers a medium moist soil it is moderately drought tolerant once established.

Japanese spurge will turn yellow if it receives too much sun.  However, in your case, I think the brown lesions showing on the leaves indicate the presence of a leaf blight possibly Volutella blight, the most common fungal disease that affects Japanese spurge.  Fungal diseases are promoted by prolonged wetness on the leaves so you may need to change your watering practices.

We had a similar question from another gardener. Our response to that question outlines both how to treat the disease and going forward how to keep your Japanese spurge healthy.  Click here to reach this information.  With some care, you should be able to return your plants to health. Note that Japanese spurge is slow growing so it will take a few years to create a weed-smothering carpet of green.