j tunney

I have read that, topically, your body will absorb, through the skin, only what it needs.  That supplements can overload your body, trying to get rid of the excess.  We have been using a topical spray (in a drought, baths are a luxury) Magnesium Chloride oil by Life-flo on the soles of our feet at night, and can definitely feel a difference. (Not an ad)  There is a lot of information on earthclinic.com regarding Magnesium and all it's benefits, as well as the specific compounds that are beneficial, and those that are not, also it's companion, Calcium.  That info is a whole lot different than what we see elsewhere.  

I am extremely interested in reintroducing Magnesium into our soils, and wondering if there is a way other than buying Epsom Salts to throw onto the land, so that it is available to what we are growing.  Seaweed?  What else?

It would help to know where you are.  "Chokecherry" tends to apply, regionally, to several different trees.  The one in our area is pretty much only located in the coastal chapparal of California (Prunus ilicifolia) which has tough, shiny, spiny leaves and a cherry sized fruit - thin skinned and a huge seed.  Honestly, it looks more like a type of hackberry.  They were considered 'trash' trees in the yard (when I lived in Texas), as they were prolific, fast growing, and tended to seed anywhere you didn't want one.  That said, the berries are edible.  I just came across this link looking for info -  http://www.homestead.org/MicahJanzen/Hackberry/HumbleHackberry2.htm