Linda, depending on how much you applied to the area you could have significantly lowered the soil pH and increased the salinity, which could influence successful planting of the shrub. The changes and dissipation are dependent on many things, so to be safe I would recommend a soil test. Alternatively you might consider conducting a bioassay by planting something pretty sensitive in the area, like lettuce, to see if it germinates and grows normally. It would be best to compare this treated soil to untreated soil.