How do I run systemctl command on root mount

On my Arch systemd install, the name of the root mount unit is -.mount. (It is not listed in /etc/fstab, rather, it get the details of the root mount for the kernel options specified in the boot manager.)

If I try run any systemctl command on this unit, e.g:

systemctl show -.mount

I get this error:

systemctl: invalid option -- '.'

It is confusing the unit name for a option argument. How do I do this? Is there some why to escape the name so that it is not confused for a option argument?