Is the plant indoors? Probably too dry for moss so it goes dormant. In the summer, trees do best transitioned slowly outdoors by first putting them in shade for a week. They probably put that moss on just before send the plant to the store for sale.

That's not live moss so not revivable, sorry :-( It is just used as a decorative topping or mulch and the color does fade and the moss becomes dried out over time.

I agree with jon and gardengal48 as to the use of the collected moss for decorative use.

But mosses are funny and can be quite resilient. If there is any chance on keeping them

alive you would have to remove them from the planter and place them inside a deep pot that has a thin layer of aquarium filtering material covered by a inch or less of clean fresh water sand.

Place it outside in a cool shady protected spot and water only with distilled water every day using a spray bottle and give them a good soaking. Give it a year. Perhaps some of them will

have made it. Main thing is coolness and dampness that drains off rapidly with a daily dose of

distilled water. Good luck