For example, blueberries, azaleas and rhododendrons do well in an acidic soil between 4.5 and 5.5. Lawns favor a pH of 5.5 to 6. Roses do best in soils with a neutral pH of 6.5 to 7.

The ideal pH for roses is a soil that tests between 6 and 6.5.When the pH falls below 6, the soil will hold potassium, nitrogen and phosphorus molecules captive.

In order to absorb the nutrients, roses need a soil with a pH that is slightly acid to neutral (6.0-7.0).