Just going by this picture it could either be R. multiflora itself or a hybrid of it, of which there are both named garden cultivars being planted intentionally as well as random hybrid seedlings coming up. Also if anything in her planting was grafted on R. multiflora rootstock that could have thrown up its own stems from the base. Otherwise, if there is R. multflora growing nearby that could have seeded into her rose bed.

Compare to ZZ plant, Zamioculas zamiifolia.

In right conditions, they grow quite large. I would think that in ground, as yours, even bigger. In pots, the size would be more limited. Too bad other one was thrown away! These are desirable by some ppl - I don't think I saw crested aeonium for sale around my area (but I do not 'stalk' stores :) - only some other succulents. According to what I read, it is flat, like yours, if cresting starts early. This will explain better than I can - many articles about this mutation are available, here is just one of them.

Sorry for the poor quality of the photo I'll try to get you a better picture. It is not Solenostemon scutellarioides ( now Plectranthus scutellarioides ) its trunk is woody, the opposite leaves and with colored bracts