lime tree

Hi - about this time of year the lime tree in my garden starts dropping sticky deposits - no problem. But this year I notice it also sheds some form of black substance that coats all plants, grass and my new patio with a black stain. Any idea of whether this is normal, what it is, if I can prevent it, and how I can wash it off my patio!? Thanks

 

yes very common on limes, the sticky deposits are what is called honeydew, (basically aphid sh*t) and the black substance is sooty mould growing on the honeydew. can't prevent it, keep patio funiture covered and using a power washer is all i can suggest, GG.