Why can't I plant a tree in moshi monsters?

Answer 1

If you are asking about Rox plants, they are random. You can not plant to get a Rox flower.

Otherwise, you plant seeds in your Moshi Monster garden. The seeds grow into flowers and, if the flowers and colors are the correct combination, you will attract a moshling.

If you are not able to plant seeds and you are a Basic member (free), you may have your limit of moshlings and will need to let one go before you can plant any more seeds. Basic members are only allowed two moshlings in their house and one in their garden.