Growing the Desert Garden

Welcome to the Desert Garden, with garden coach Tyler Storey, where we talk about everything having to do with gardening and landscaping in the Desert Southwest. From composting to Cercidium and agaves to arugula — we'll cover everything you want to know to grow your own beautiful Desert Garden.

Wednesday, July 23, 2008

From the Inbox: Pruning Paint

From a Correspondent:

I hope you can help.  I have a huge fig tree growing in my backyard. Three of the limbs broke from being too heavy with leaves and fruit. I would like to know if I should apply either pruning paint or tree tar on the limbs that have been cut.  If the cut limbs need some kind of product put on them, could you recommend a product?
Thank you for your help.
Carson, California
Hi Aurora,

While I'm sorry to hear about your breaking fig tree, I do have good news: you don't need any kind of pruning paint or wound dressing.  More than that: you don't want any kind of paint or dressing.  

Trees, for the most part, do a wonderful job of taking care of themselves; the breaking of fruit-laden limbs reminds us that there are exceptions.  When it come to recovering from wounds, though, trees are best left to their own devices.  Pruning paint, sealing tar, and other kinds of wound dressings have been found to do no good in protecting the tree, and it appears that they may actually interfere with the tree's own process. 

Any time we prune a tree, whether to shape it or as a result of accidental damage, as with your fig tree, the tree is wounded and its outer protective covering (the bark) is compromised.  As when a person has a cut, this damage opens up the tree to the possibility of disease or insect damage.  Unlike a human or animal though, a tree doesn't really heal a wound; trees seal their wounds instead.  

The late Dr. Alex Shigo did extensive research which showed that trees undergo a process he called CODIT, an acronym for "compartmentalization of damage in trees."  The short version is that trees seal off their damaged areas from their undamaged areas, and eventually may also recover the outer area of the damage bark with a new layer; if you've ever gone back and looked at a tree you pruned a few years earlier, you have probably seen where the cut is now covered over with new bark.  

What does all this have to do with pruning paint?  I'm glad you asked.  Pruning paint or other wound dressings interfere with the natural sealing process of the tree and can actually prevent it from taking place.  Air exposure, sap weeping, decay organisms and all the other things we hope to "correct" with the use of pruning paint are all critical parts of the tree's sealing process.

Do go ahead and remove the ragged stubs where your fig's branches cracked, but other than that, you'll be best served by leaving the tree to recover on its own.  

Next year you may wish to thin the fruit a bit in advance, and consider cutting back on your frequency of watering if you think that might be contributing to over-vigorous growth and weak limbs.

I hope this helps,


1 comment:

cheryl said...

Would fig trees grow down by Palm Springs/Salton Sea? I would LOVE to grow one!