In Rob wrote:
I would also like to add that it is better NOT to mix in alfalfa in de
planting hole, as it might damage the roots when it decomposes.

Not meaning to be rude, but how, exactly?

Additionally, most rosarians recommend NOT to add any fertilizer when
you plant a bareroot rose. Other than damaging the plants roots, the
abundance of nutrients will make the rose think that it has enough
roots already and slow the development of its root system: it will
make your rose lazy.

I agree that quick release fertilisers and manures will burn roots, but
Osmocote and other organic types (alfalfa included) are great in small
quantities. The idea that roses would become lazy around the presence
of nutrients is an absurd concept.