Any kind of garden roses are generally far prettier in the vase than florists' roses. Florists' roses admittedly last longer in water but they are often stiff and formal, standing to attention in the vase with barely any character or charm, and usually no perfume at all. With a little care, most garden roses can be kept in water for the best part of a week.
Select buds with two or three layers of outer petals beginning to unfurl. Varieties with few petals should be cut tighter than varieties with many petals.
Cut stems as long as possible in the cool part of the day and plunge them immediately in cold deep water, preferably overnight.
When making the vase arrangement use water with flower food dissolved in it.
Strip the foliage leaving the lower 75% of the stem leafless. Make a clean new cut at the base of the stem leaving white pith then slice a 5cm strip of bark and pith from the base of the stem.
After 2 or 3 days change the water. Make a fresh base cut and slice a new 5cm strip from it.
Dedicate some roses to cutting. Plant them away from areas where flowers are needed to stay in the garden. Vegetable gardens are good for this.