So, what exactly is a Grandiflora? If we look at the name we would assume it means something along the lines of "Big Flowers". But perhaps it would be slightly more accurate to say "Lots of flowers", as that is one way to distinguish a Grandiflora from a Hybrid Tea rose.
A Grandiflora is a cross between a Hybrid Tea and a Floribunda. It inherits the best of both... the high centered blooms of the H.T, and the multiple flower sprays of the Floribunda. They also tend to be very vigorous, and often grow much taller than a Typical Hybrid Tea. Here in North West Victoria, Australia, we have long hot summers and some of the Grandifloras can get up to 2-3 meters tall.
Since they do tend to grow large, be sure to provide enough space for your grandifloras. In tougher, less forgiving areas give at least two feet of space, more in warmer climates as they will get bigger there. Grandiflora roses are rated from zones 4-9 but tend to be a little more cold tolerant than H.T roses.
You can generally do well with propagating these via grafts, but some people have noted they've done well with own roots. Clip dead flowers and you should get continual blooming.
Fire 'n Ice, a popular red/white blended Grandiflora, suited to the cut flower trade.
Wild roses, Hybrids, climbers, miniatures and more. Make some sense of the multitude of rose varieties with our handy guides.