The effects of herbicides

About a month ago I noticed something odd about our Redbud (Cercis) trees.  The newest leaves were opening up all shriveled, deformed and partially yellow.  I had not closely watched leaves unfurling in the past, but I was pretty sure they opened as little hearts folded in half and just grew larger with time.  They didn't start out as these strange, malformed stingrays.

Deformed Redbud leaf

Deformed leaves

I asked some of my expert plant friends about this, especially those that live near me and are familiar with Redbuds.  One of them said that it looked like damage from herbicides.  I was pretty sure it couldn't be from herbicides since I don't use them myself and because these trees are in my backyard, which is pretty well surrounded by bushes and trees.  Also, the nearest house to these trees has been vacant for 7 years now.  None of our immediate neighbors have the immaculate monoculture lawns of those who spray their lawns with weed killers and fertilizers.  I did notice that the tree in the front yard across the street from our house also had the same pattern with their newest leaves, although to a lesser extent.

Regular, healthy leaves

More recently the trees have been putting out regular leaves again, leaving a very clear set of affected leaves along each branch.  I took more photos and sent these to my friends.  The same friend who had guessed herbicide damage found an excellent article on Redbuds that explains they are very sensitive to pre-emergent herbicides, the kind people spray on their lawns just before the grass comes out in the spring.  The photos were eerily similar (see page 6).

Deformed leaves surrounded by healthy growth

It seems as though our trees are suffering from someone that sprayed their lawn down the street, most likely on a windy day.  It's not surprising that a chemical whose purpose is to kill weeds would also negatively impact other plant life.  I like my yard to look nice - grass not too high and not too many weeds - but I have never given in and hired one of those companies to spray my lawn.  This is mostly because of the cost, but also because I don't like chemicals being used when they aren't necessary.  Now I have an additional reason to dislike these unnecessary chemicals.  The good news is that the damage is limited to some ugly leaves - at least as far as I can tell.  Hopefully there isn't enough of this being used that it is getting into our water supply at high concentrations.  We stopped drink tap water a couple of years ago.