I verified that all the orchard questions were really orchardcms questions and retagged them. There are currently no orchard questions.
However, creating the "orchard" synonym for the "orchardcms" tag requires more than 2500 reputation and a total answer score of 5 on the tag.
See Top Users for orchardcms. There is currently only one user who qualifies! (User Sohnee)
You might invite him into a chat and ask him to propose the synonym. But there currently only 2 other users who can up-vote it if he does. It requires 4 up-votes to get approved.
Alternatively, you might flag this answer and ask a moderator to do it. Note that meta moderators and SO moderators are not necessarily the same, IIRC.