*Solution* Use all three traits to filter for the processed version:
material: "quarry bush leaf"
item: "leaves"
trait: "cookable"
That gave me the right readouts, so I'm hopeful it will for you. Below's some of the data I got enroute to that.
--- Data gathering, from my current mess of a fort ---
With the stock screen listing these quantities:
225 quarry bushes [plant] (~approximately 85 itemstacks)
626 quarry bush leaves [leaf] (~approximately 140 itemstacks)
329 rock nuts [seed] (9 of which are planted)
(sums to 1180 quarry-bush-related items, in ~545 itemstacks)
I also have various other leaves (694 total, including quarry), plants (1768 total, including quarry, in z-Stocks; plain z-screen's "Plants" is 339), and seeds (2967 total, including rock nuts), along with uncounted roasts using quarry bush leaves as ingredients, which inevitably makes this harder to narrow down.
The conditions interface says I have:
1208 material-"quarry bush leaf" item-unspecified
1208 material-"quarry bush plant" item-unspecified
1208 material-"rock nut" item-unspecified
359 material-unspecified item-"leaves"
291 material-"quarry bush leaf" item-"leaves"
0 material-"quarry bush plant" item-"leaves"
0 material-"rock nut" item-"leaves"
1707 material-unspecified item-"plants"
0 material-"quarry bush leaf" item-"plants"
225 material-"quarry bush plant" item-"plants"
0 material-"rock nut" item-"plants"
2661 material-unspecified item-"seeds"
0 material-"quarry bush leaf" item-"seeds"
0 material-"quarry bush plant" item-"seeds"
320 material-"rock nut" item-"seeds"
626 material-"quarry bush leaf" item-"leaves" trait-"cookable"
So, it seems to sum together the quarry-bush-related materials (1208 is close enough to 1180, I'm assuming an active job or somesuch accounts for the discrepancy), until you start specifying items as well. Item type without materials seems to be approximately accurate for plants and seeds, slightly lower than the expected values - probably what jobs have reserved and not counting items still in the FarmPlots, which seems reasonable to me. Item type + material type also seems to work sensibly for seeds and plants. But in both cases, leaves are a mystery - where the 359 'leaves' and 291 'quarry bush leaf leaves' come from, I'm at a loss to explain. As well as why adding the restriction of "cookable" /increases/ the value it finds - I guess it means thinking of these as narrowing restrictions is the wrong paradigm, but what to replace that view with is an open question.
Unless you really want the rock nut oil, I can't think of a reason for growing quarry bushes.
You can get stacks of 20 leaves relatively easily, which classically was a very useful way to make larger-quantity roasts, much more reliably and 'easily' (ymmv, preferred playstyles/systems/industries, etc) than large meat stacks. I don't pay nearly as much attention to my roast outputs anymore (since, as you said, its easy to drown in food), but it stills seems to fill that niche rather well. (it was desirable both for stretching high value ingredients (titan meat, etc), and for consuming less stockpile space (if you avoid barrelling prepared meals, which is probably another outdated habit)).
(producing rock nut press cakes is neat to do as a challenge, but given how little it rewards, that actually rather /supports/ your point I think :p. Plus, with all the other seeds you can now turn into press cakes & oil, that's no longer a specific reason to pursue quarry bushes)