It might be tempting, but do not remove the thorns. You may however, remove any and every leaf which falls below the water level along with discoloured petals. Their blooms respond quickly to warmth, but their lifespan is extended when kept in a cool area.
In the event of premature wilting, trim the stems as before, and submerge the flower – petals, stem and all – in a water bath for at least half an hour to an hour.
Average vase lifespan: 3-10 days
Seasons for blooms: All year (varies from one variety to the next)