See tender perennial . Hedges, topiaries, and trees are perennials that do not die back, although the deciduous ones do go dormant. Phosphorous promotes strong roots and stems. Bone meal is a good source of phosphorus. To remove the growing tip of a stem.
Potassium promotes healthy fruit .
Seaweed and greensand are common sources of potassium. I am still confused, however on the merits of soluble vs. insoluble potash. R. phaseoli specializes in peas and beans and is available in garden centers. A perennial that cannot tolerate freezing weather. Tender perennials are usually listed as annuals , to the everlasting confusion of those of us who live in the tropics.