Has your topiary gone from a lively fresh green Sphagnum Moss to not so fresh and the moss has turned brown like the one shown below?
Note that your Sphagnum Moss is like dirt to plants. To keep the moss alive, you will need to refresh the moss once to twice a year by mixing in new moss or planting live foliages to the topiary. It is suggested that you plant foliage within 6 months to get the moss to accept the plants for growth. If you just let the moss sit for a long period-of-time, the Sphagnum moss can dry out to a point where you can not save it.
Thus, you need to maintain the topiary and moss for longevity by adding plants or adding new moss in with the older moss. If you do not plan to revive or take care of the moss, we suggest that you use artificial outdoor boxwood foliage that needs little maintenance so you will not have to deal with the worn-out look as shown here. The outdoor boxwood foliages are UV protected and can last up to 8 years in torment weather conditions.
Here is a list of plants to consider for your topiary.
https://www.topiarytree.net/whitepaper/how-to-use-topiary-frames.html
