Yuo can not graft a cannabis scion or a Stem with root system to Tomatos,Nettles,Hops what I know ,but you ve good chances to graft cannabis to Humulus-scanden/japonicus aka Japanese hops.
=netxt brother of Cannabis + a one saison plant as Cannabis are .
This realy works I read many times + the root system of the Jap Hops can be very powerfull too.
-But the result will grow different as graftet with cannabis I think:=different rootstem-system of Jap Hops = different trais by the way how the graftings grows and flowers!)
-But the pollen of bouth are will not be fertile,-because of the fast genetic drift of bouth species = unpossible