|Red yucca overgrown near a sidewalk. It is possible to gently dig them up in the fall or early spring, divide them and replant smaller plants or 'starts' that will again fit in this space.|
|Red yucca younger and occupying a smaller space.|
If you were to dig red yucca out, divide them and replant a start from your divisions you could have kept them in that sized area. Normally you would have divided them in the early spring, around early February, or mid-fall months around the first of October.
Tree roses require special pruning techniques and may not be the easiest rose to plant there. Regular hybrid teas or floribundas would be a better choice there. If you do go with roses just make sure that the soil is covered with wood mulch.
By the way, red yucca is not a yucca at all. It just looks kind of like one.