You don't have to put it in your garden! Mine grow happily in pots on the windowsill (but, incidentally, peyote is quite hardy and can survive light frosts if it's dry, as well as being submerged in water during the rainy season in its natural habitat - refer to the works of K. Trout for further details.)
If it's mescaline you're after, why aren't you choosing Trichocereus species? They have the advantage of a much faster growth rate, and there's a well developed body of extraction knowledge surrounding them.
Kash's A/B Mescaline ExtractionCIELOAre you sure you want the full-spectrum peyote alkaloids? You specifically state "mescaline content" - but that's only 50% of the peyote alkaloids. The rest of them, like pellotine and lophophorine for example, are more like hypnotics and ganglion blockers. And maybe several others have antiseptic properties.
I'd highly recommend you grow your own Trichocereus cacti instead.
“There is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
― Jacques Bergier, quoting Fulcanelli