There are many excellent low-maintenance roses available nowadays. Select ones that are highly resistant to black spot, a fungal disease that often defoliates susceptible roses. The Knock Out Series of roses, Easy Elegance Series, and OSO Easy Series of roses all fit the bill for roses that are easy to grow. The type and amount of fertilizer to use depends on the fertility of the soil that you grow them in. If you have good loamy organic soil, you may need very little supplemental fertilizer. (Amend your soil with compost or other organic matter to build it up.)
Earthworms are beneficial in aerating the soil and converting organic matter into humus, so they should be encouraged to grow and thrive in the soil.