My mesquite tree is oozing black sap in several places where it was pruned. It's staining my new patio stone. It's been doing this for the past 3 years--it's not slime flux, as it has no odor. How can I divert this sap to drip on the soil next to tree instead of patio? I have put containers to catch some of the sap but it is a mess and people will trip on them. This particular mesquite tree is very old--probably 60 years or so. There is no odor to his sap and it's more watery than sticky. The patio was installed this past summer so it previously dripped on the soil where it was absorbed and was not a problem.