Answer: I am wondering if your shrub is by any chance a boxwood? If so, this is the normal aroma, although not all people interpret it that way. If it is some other shrub, then perhaps it has become a marking target. You might be able to discourage the animals by using a repellent spray on the shrub, either a home-made pepper and/or garlic type or a commercially prepared spray formulated specifically to repel cats. Another approach is to try spreading thorny branches beneath it to make it less welcoming or to cover the soil (or mulch, a favorite litter box substitute) with a layer of wire mesh to make it impossible to dig there.
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