My purple sand cherries (I have 3) have done great for 3 years now. Today I noticed VERY small black spots on all the branches and sap dripping away off of the branches. Any ideas what this is? It seems to be all over all three of my bushes. Thanks for any help!

Here is a pic, if it is what I suspect;

http://www.hiltonpond.org/images/CherryBlackKnot01.jpg

If so it is called black knot, which is unfortunately very common on cherry and plums.
It is a fungal disease which is vectored in by insects.
Once infected it is very hard to eradicate the disease. If you can catch it early and prune out the infected branches, you can lesson the damage to the tree. If it is let go, it is a death sentence for the tree. It will weaken slowly as it spreads from branch to branch and eventually die.
Here is a link from UW that you may find to be helpful.
http://www.uwex.edu/ces/wihort/gardenfacts/X1056.pdf#search='black%20knot'

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Mike Maier
aka
The Plant Doc

Sounds to me like APHIDS.....

I have a regular cherry tree *sour*
and each year I had them coverrrrrred in aphids'..
I diligently squeezed every year, but they'd do a bit of damage...

I finaly figured out *I think why* the tree was never pruned right and I had 3 leaders in the trunk and that's not supposed to be...

I am not sure of your growing conditions, on your particular type of tree...

but growing conditions, many vary, are the reason why a plant/tree/shrub/bush etc. gets aphids...

Let us take a peak at it and double check to make sure, if it' is aphids', we'll see what's your next step to getting it growing right....

*my niece lives near Philly*


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Weezie

Don't forget to be kind to strangers. For some who have
done this have entertained angels without realizing it.
- Bible - Hebrews 13:2





http://photobucket.com/albums/y250/weezie13/