The term clade (rhymes with played) would work for your purposes. From University of California (Berkeley) Museum of Paleontology's Understanding Evolution:
A clade is a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor. Using a phylogeny, it is easy to tell if a group of lineages forms a clade. Imagine clipping a single branch off the phylogeny — all of the organisms on that pruned branch make up a clade.
There can be multiple smaller clades within a larger clade, so it is a more general term than the taxonomic ranks such as "family". In some cases a clade may contain multiple families, but conveniently the family rosaceae is considered a single (basal) clade in the rosales order (which is a "super-clade" containing two other sub-clades comprising eight other families, as well) (Wikipedia).
Technically, you would probably call this the rosaceaea clade, but I think biologists/horticulturalists would understand you if you called it the rose clade.
There is an adjectival version of the word clade, cladistic, but that has more to do with the system of classification rather than a particular clade (M-W). However, I don't believe you would need to change the form of the word; rather, you would use the compound noun rose clade as a modifier, just as rose itself can be a modifier in phrases like rose arbor or rose print or rose clade. So you could say both
I'm allergic to pretty much everything in the rose clade.
I'm allergic to all rose clade foods.