Hi dmoore: here's a previous thread on increasing one's NPK with organic matter:

http://forums.gardenweb.com/discussions/3528532/npk-and-ph-of-organic-matters?n=149

Maybe you've done plenty already.

The Bottom Line
• Ideal soils, from a fertility standpoint, are generally defined as containing no more than 5% OM
by weight or 10% by volume
• Before you add organic amendments to your garden, have your soil tested to determine its OM
content and nutrient levels
• Be conservative with organic amendments; add only what is necessary to correct deficiencies and
maintain OM at ideal levels
• Do not incorporate organic amendments into landscapes destined for permanent installations;
topdress with mulch instead
• Abnormally high levels of nutrients can have negative effects on plant and soil health
• Any nutrients not immediately utilized by microbes or plants contribute to non-point source
pollution

https://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/soil-amendments-3.pdf

I dig the hole for the rose, remove the soil and mix with espoma rosetone. Would you add more to the soil at that point?