Can I use Magnesium Aspartate on my garden?

I have about 100 Magnesium Aspartate tablets (vitamin supplements) which had been sitting at the back of the cupboard and have expired. Meanwhile, some of the plants in my garden are suffering from mild magnesium deficiency (eg. gardenias, lemon tree). I usually use Epsom salts, but was wondering whether I could just sprinkle these tablets around the plants and the magnesium would leach into the soil. Or does Magnesium Aspartate require human metabolism to free up the magnesium for absorption? I'm intending to post this in both Garden and Chemistry...