If the culms are smooth it's not Aureocaulis, as all forms of this have a rough,sandpapery surface. Allgold dose have green stripes but there usually very narrow and very sparse, I've never seen one with that ammount of striping. I'd have a go on Vivax, seems to fit you're description and photo quite well.

THANK YOUUUUUUU! I'd forgotten how :)

Oops, I meant to ask--is there any other way, besides that tag, to identify it? What can I look for, if anything? Thank you.

Options include: another deciduous tree that's already 5+ feet tall. conifers: Green Giant (widely available/affordable), Cryptomeria, Junipers. fast growing broadleaf evergreen: privet (ligustrum), American Holly (lots of choices) . A mixture is ideal, based on space, soil, sun. Enjoy!