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Sap on a Mesquite tree

Posted by jill_frances AZ (My Page) on
Thu, Jun 5, 08 at 13:47

I have a mesquite tree in my front yard, about 7 years old (planted by builder). It now has some kind of sap or bee deposit on it, in a couple of globs, and dripping down. It looks like sap, anyway. Has anyone ever seen this, and is it something to worry about?

Follow-Up Postings:

RE: Sap on a Mesquite tree

Have you pruned it recently? Mesquites (and most other trees) will put out sap in order to seal off wounds (like if you cut a branch off). If the sap is clear and healthy looking, not black and nasty, I would not worry... but still keep an eye on it, it should stop after the wound is healed.

RE: Sap on a Mesquite tree

Just noticed my mesquite tree is dripping black sap. What is wrong? It is probably 6-8 yrs old ( it was here when we bought the house 4 yrs ago) The black sap has poured down from the "Y" of the tree and a branch from up above. Noticed it on the bench underneath. It has a large spread of branches and beautiful. We also noticed that it was a slow/late bloomer this year. Could it be from lack of water being we just noticed that our sprinkler drip system has not been working. Last week we let the water hose drip all night, only one night. Should we continue to water it that way a few more times?

RE: Sap on a Mesquite tree

The black sap is just some bacterial baddies working it's way out from a wound area. The tree usually makes it out just fine and it's not uncommon, especially in areas with high wind. You can sometimes see the black sap splattered like tar on understory plants.

If you prune wait until the heat is kicking because it lessens the chance of the "black sap."

They also tend to sap up when they're breaking dormancy and going into their growing season.

RE: Sap on a Mesquite tree

Black sap from a "V" or branch crotch could be a sign of included bark. Mesquites are notorious for forming close branch attachments (less than 45 degrees), and instead of the bark being pushed up creating a ridge it folds under into the "V". This indicates an area of weak attachment and also where bacteria that create diseases like Slime Flux can weaken the wood.

Left alone, this weak union will usually fail and often causes huge wounds and ripping bark. If this is the case it is probably a good idea to remove one the branches.

Mesquites often drip sap from pruning wounds and this is pretty normal.

If you decide to do any pruning, don't use sealants on the wound. They trap bacteria and fungi inside creating more problems. Just leave the wound open to the air and if you have made the cut at the right location, the tree will heal itself.

Here is a link that might be useful: Pruning Planting and Care

RE: Sap on a Mesquite tree

  • Posted by zzini Sunset 13 (My Page) on
    Fri, May 7, 10 at 21:50

I had two trees with dripping sap - one tree looked like it was headed for the great beyond. I went to one of the large box stores to ask about it and the guy told me to immediately call an arborist to come out and deal with the really bad bugs that he swore were going to kill my trees.

I had a vision of hundred-dollar bills floating out of my wallet so I went to my friendly neighborhood nursery (that specializes in native plants - and where I should have gone to at the beginning!) and the guy there said exactly what aztreelvr and nc-crn said.

I left both trees alone and both are thriving - and my wallet is much happier!!!

RE: Sap on a Mesquite tree


I've relocated to AZ after about 20 years back east. Was an ACN here way back when. The house I purchased here was vacant for about 2 years and had 4 overgrown Mesquites in the front. All of them I trimmed last fall shortly after moving in.
One of them has been and continues to drip a lot of sap. I really just thought it was related to much of the above description in regard to the trimming. However, upon closer examination it's coming from many places. It's mostly clear and is quite a large blob where it was dripping. Knocking off a sap blob will cause fresh sap to come out. Otherwise all of the trees appear healthy. Just had them trimmed and thinned and the guy that did it (seemed well experienced and knowledgeable) had no idea why this one was doing it and why it was coming from where it was coming. Any ideas? I'd like to share a pic but can't seem to add it here.

RE: Sap on a Mesquite tree

Kmacn - Mesquites do that. Stop picking the scab off and let it heal. Also, if you can. decrease the water it gets.

The "gum" they are exuding will dry to a clear, crystalline mass that smells wonderful when you burn it. This fall, try knocking some of the dry stuff off and toss it on a BBQ.

RE: Sap on a Mesquite tree

Or leave it for a thousand or so years so someone can make jewelry out of it >smile< ....

I'm glad this thread was revived, I had the exact same question about my mesquite.

RE: Black spots under Mesquite leaves

I have two mature Mesquites (30 yrs) and noticed green leaves dropping which have black spots on the underside and sappy stems. I also noticed a tiny black beetle crawling out of one leaf. The lower limbs appear brown and very thin vegetation. Any idea what is going on with them? Thanks.

RE: Sap on a Mesquite tree

piperflyer - What you report is typical for mesquite at this time of year.

They shed a bunch of leaves in the late fall, and if it gets too cold, will shed the rest of them.

They also die off at the bottom, putting most of their energy into branches with better sun exposure. . Look at a wild mesquite and half or more of the lower and inner branches are dead.

The "sappy stems" may be because you are overwatering. If they are 30 years old, they don't need supplemental watering.

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