April 28, 2012

1 - Pitch that flows from pruning wounds in conifers is a material that helps seal the wound and conserve water.

Yard & Garden
April 28, 2012

Q. :

My Arizona cypress tree has sap running constantly from where branches were trimmed off. Do you know a way that I can stop the sap running or cause it to close up its wounds and stop? Can it be bandaged and changed often? My cat keeps getting it in her underside and it is a constant battle to cut her hair and get sap out of furniture. The tree is not in a place where I can put a fence around it, and if I was 20 years younger I would just cut the tree down. I saw your website and figured you were the best person to ask. I hope you can help.

- Janet


A :

The "sap" is really "pitch". This is a material conifers make to serve as scabs after they are wounded (pruning cuts, broken branches, wind-induced cracks in the bark). It helps these arid-land trees conserve water. The drip will stop in time, but for now you may consider trying a variation of the old trick used when men cut themselves while shaving (a small piece of tissue paper to absorb the blood and encourage drying). You can put something on the drip from the tree to help the sap congeal. In the case of the tree, you can try a scrap of fabric. Choose a color that will not be unsightly. Burlap or old torn clothing will be OK. This should help in the same manner that a small scrap of tissue helps stop bleeding from shaving cuts. It should absorb some of the pitch and allow more rapid drying to form the dry pitch cover (scab).

If the drip continues, put another scrap over the first until you have enough layers to dry the pitch so that the pitch seals the wound - stopping the leak.

I hope this works for you. You could try blotting the drip, but that would not let the pitch seal the wound as quickly.

For gardeners experiencing oozing of true sap due to slime-flux (wet-wood) disease, this trick will probably not be helpful. In the case of wet-wood disease washing the wound periodically to remove the sap can help, but not stop the problem since this is due to the incurable disease inside the tree (unlike the case discussed above regarding the Arizona cypress tree). In cases where the sugars in the oozing sap is being fermented by yeasts and bacteria on the surface of the tree, scrubbing with a 10 percent chlorine bleach solution will help reduce the foul odors produced by the fermenting sap. This is a temporary solution and must be repeated.

We do not recommend pruning sealers (pruning paints) to close wounds in either case. The pruning sealer can often increase the problems or create new problems. If you are a person who must "just do something" to deal with the wound, you can use a thin, water-based (latex) paint to cover the wound, but this will not stop the pitch flowing from the cypress nor will it stop the sap flowing from wet-wood infected trees.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

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