The Best Soil and pH for Roses
Roses are not truly fussy, but they perform best in rich, well-drained soil that is slightly acidic. Getting the soil right up front prevents most problems later.
What roses want from soil
The ideal rose soil is a fertile, well-drained loam with a slightly acidic pH of about 6.0 to 6.5 — the range at which the nutrients roses need are most available to their roots. Heavy clay and pure sand can both grow good roses once improved with generous organic matter.
Adjusting pH
To lower pH (make soil more acidic), incorporate elemental sulfur or acidic organic matter. To raise pH (reduce acidity), add garden lime. Change pH gradually over seasons rather than all at once, and re-test to track progress.
Improving drainage and fertility
The single best amendment for almost any rose bed is compost or well-rotted manure, worked in before planting and top-dressed each year. In poorly drained sites, consider raised beds so roots never sit in water.