I just made a quick video of this plot that's hard to reach because the Spice Plant is 'in front' of it.
Can the Spice Plant be moved behind it without breaking anything else? Or some other solution?
Stand in front of the garden. Hit "Enter" and select the garden. Use the arrow keys to select which plot of the garden you want to interact with.
You'll find that using the keyboard is much easier for most things, anyway. Especially gardening, if you have animals that like to walk in front of the garden.