Name:Rose, various species of Rosa. You can use any strongly scented rose.
Family: Rosaceae, rose family
Used part: petals
How: tea, tincture, elixir, vinegar, oil, salve, ... syrup, jam, ...
For what: gives courage and, if needed, an ability to display barbs to the world. Gives gentleness, love for self and others. Calms, makes you smile.
Externally: wonderful in a bath!
Used part: you can if you so wish use the green parts as rose family astringents, and you can if you so wish use the flower bottoms as a sort of apple-tasting tea, but these parts and their uses are unimportant in comparison with the petals.
Used part: fruit - the rosehip
How: soup, tea, jam
For what: contains vitamin C and flavonoids, among other things.
You'll find itchy hairs in the rosehips, which you'll have to get rid of one way or the other. Having spent one fall trying all different ways to detach the itch from the fruit, I've come to the conclusion that it's best to buy already de-itched dried berries ... they're widely available by the pound, in grocery stores.
Note: Storebought rosehip sauce can contain tomato sauce.
Note: While you'll find rosehips in storbought rosehip tea bags, the taste and colour come from roselle, the fruit flesh of a hibiscus (Hibiscus sabdariffa). If you want the same colour from your homemade tea, you'll have to use a large amount of ripe rosehips; the half-a-teaspoonful you'll find in teabags will net you a rather too watery experience.
Other: Rose beads are absolutely lovely.
Make curtains from rose hips: string them onto longish strings and hang a lot of them side by side at a window. Note: during rainy summers rose hips have a tendency to mold on the inside, instead of drying properly. They'll dry better if you leave the small flower-side leaves attached. So they're decorative, but not all that useful.
Roseroot is a different plant entirely, not even in the same family: it's Rhodiola rosea. Don't dig up your roses in the hope of getting roseroot.
Warnings: Don't use sprayed or commercial roses. No other warnings.