Question
I put Epsom salt on my hydrangeas.  One is doing fine, the other one has drooped way over.  I did a thorough watering to the root system.  Have I killed it?

Answer
Your Hydrangea is DROOPING?????

HOW MUCH of this stuff did you use, Deb?  2 cups?  2 teaspoons?  2 inches?  2 much!

First, go out -- right now -- and DRENCH THE SOIL that Hydrangea is in.  Wash out the Epsom salts!  Soak the pot for 5 minutes, dump the water, soak again, dump.  Rinse, soak again, dump.  Get it OUT of the soil.  See of this little shrub can recover.

Next, while you're waiting to see what happens to your poor sick plant, let's go over your technique.  Sit down.  Pour yourself a cup of coffee.  This is going to take a little time.

I too have used the Epsom Salts Trick on some of my garden plants, in the days when I experimented all over the place.  Epsom Salts seemed to be a great, cheap source of Magnesium.  Jerry Baker recommended it, I read about it a few other places, and it was a novel idea at the time.

Plants need Magnesium. Not much, but they need it.  Biggest reason:  Chlorophyll.  The chemical formula for Chlorophyll is C55H70MgN4O6.  See that molecule in the middle?  Mg?  Magnesium!  You CAN'T MAKE CHLOROPHYLL WITHOUT MAGNESIUM!

There is some information supporting your Epsom exercises on the internet:

epsomsaltcouncil.org

One other fact: Few chemical fertilizers have any Magnesium in them.  So people who grow Palms and certain other plants, which use a LOT of Magnesium -- a lot more than your Hydrangea -- and are grown in areas where Magnesium is NOT in the soil (sandy soils with a Low pH) have to be conscious of the Magnesium needs of their plants.  They cure their plants with Magnesium-packed Dolomite -- not Epsom Salts.

BUT...

Does your soil need Magnesium?  You wouldn't know if you haven't had your soil tested.  Bet you didn't know that Magnesium is the EIGHT MOST ABUNDANT ELEMENT in the Earth's crust!  There's absolutely NO good reason to buy it or to use it unless you NEED it.  In fact, TOO MUCH Magnesium is HARMFUL for your Hydrangea.

But maybe your Hydrangeas have a deficiency of Magnesium.  Here's a description of the symptoms according to the Asia-based Food & Fertilizer Technology Center:

'The characteristic symptom of Magnesium deficiency is Chlorosis of the leaves. (Chlorosis is a condition where the leaves turn pale. The color may be pale green, yellowish or almost white.)  The Chlorosis is seen mainly on the margins and tips of the leaves, and in the part of the leaf between the veins ...mainly in old leaves ...In severe cases, the leaves may fall early. The whole leaf blade may die, except the veins (middle ribs) and the bottom of the blade, which remains green. The green part of the leaf thus looks like an inverted V.'

You can read their entire essay here:

http://www.agnet.org/library/bc/52006/

Excess Magnesium can lead to shortages of Potassium and other nutrients.  Plus, since Epsom Salts is SALT, too much will damage or even kill your plants.

As you have learned the hard way.

Were you trying to turn your Hydrangea Pink?  or maybe Blue?  Or just trying to take good care of it?

Fact is, all of us gardeners has killed DOZENS of plants.  That's how we learn.

If you find that you have done some damage to your Hydrangea, it's a good lesson and the best way to learn.  Let me tell you a little about Epsom salts.  'Epsom Salts' (technically Magnesium Sulfate, or MgSO4) is one of just a few water-soluble Sulfate minerals, and it is a soluble salt -- a salt that dissolves in water.  ALL chemical fertilizers are also 'soluble salts'.  When Ammonium, Potassium, Chloride or Nitrate dissolve in water, they are soluble salts.  A little will fertilize the plants.  Too much will damage and sometimes destroy a plant.  That can happen quickly -- perhaps with your Hydrangea -- or it can take time and build up slowly.  THERE IS NO DIFFERENCE BETWEEN YOUR USE OF EPSOM SALTS AND THE USE OF A CHEMICAL FERTILIZER LIKE MIRACLE GRO.  I didn't know that back when I used Epsom Salts.  I know that now.

Now, why would I be anti-Epsom Salts?

I happen to think Jerry Baker is doing us all a big favor by trying to steer people away from the heavily advertised chemical fertilizers and pesticides, getting people to open their medicine and kitchen cabinet and use Epsom Salts, or Baking Soda, or Coca-Cola, or Borax.  But SOME of the things he says are not such a good idea.  And I don't think this Epsom Salts thing is a good idea.

Why?

Because ALL chemical fertilizers ARE SALTS.  Salts KILL microbes in your soil.  I love my microbes.  I love my soil foodweb.  I love all the beneficials down in the dirt.  One teaspoon of healthy soil holds MILLIONS of friendly microscopic organisms.  If salt hurts my microbes, it's got to go.

So there you are, Deb.  Some things are not as simple as they seem.  At the end of the day, if you are a better gardener, the day was a good one.

Now, if you want to know how to turn those Hydrangeas Blue or Pink, let me know.