
Here are some links to articles that should be helpful to you in growing your rosebush in a pot or container.
https://www.gardeningknowhow.com/ornamental/flowers/roses/container-roses-growing-roses-in-pots.htm
https://www.gardeningknowhow.com/ornamental/flowers/roses/miniature-roses-containers.htm
For feeding the rosebush, use approximately 1/3 the amount listed on the rose food of choice that is called for when feeding the roses outdoors in a rose bed or garden, in most containers.
https://www.gardeningknowhow.com/ornamental/flowers/roses/best-rose-fertilizer.htm