Szczepan Bialek wrote:
The "ground plane antenna" is also the monopole:
"To function as a ground plane, the conducting surface must be at least a
quarter of the wavelength (?/4) of the radio waves in size. In lower
frequency antennas, such as the mast radiators used for broadcast antennas,
the Earth itself (or a body of water such as a salt marsh or ocean) is used
as a ground plane. For higher frequency antennas, in the VHF or UHF range,
the ground plane can be smaller, and metal disks, screens or wires are used
as ground planes".

Note that it does not say that it is sufficient to connect one side
of the antenna to the ground with a wire.
A ground plane is something different than a wire to ground.