Mistletoe

We’re going to be working all week in Scottsdale for a homeowners association doing mistletoe control. One of the board members found my previous blogs on mistletoe and started asking questions. One thing lead to another and and resulted in us  going through the washes and N.A.O.S. (natural) areas taking out all the mistletoe we could find. I had to submit a request for a permit from the City of Scottsdale to work in the N.A.O.S. areas and they require a Certified Arborist to do the work.

We came upon this clump of desert mistletoe (Phoradendron Californicum et al) in a Palo Verde tree (Cercidium). It was about 3ft long and basically filled a garbage can by itself. The teardrop shape was perfectly uniform and there were no dead spots in it. Although our goal is to take out all the mistletoe in the area, I had to appreciate this plant! It was the most incredible clump of mistletoe I have ever seen!

Christmas Mistletoe

The second is Christmas Mistletoe (Phoradendron Macrophyllum) which infests cottonwood, ash, black locust, hackberry, maple, pecan walnut, sycamore and willow. We typically see this mistletoe along the Hassayampa River in older neighborhoods with pecan or ash as street trees.

Both types of mistletoe are plants which have “roots” called haustorium within the branches of their host tree. Mistletoe has chlorophyll in their stems and leaves, so they are able to make food for themselves. But they are parasites in that they take water and nutrients from their host.

Control of mistletoe can be difficult. Some horticulturists do not feel that mistletoe harms their hosts that much, so advise that we should not worry about it in our trees. I have seen fairly young mesquites that were so full of mistletoe that they certainly will not survive many years.

Both types of mistletoe are plants which have “roots” called haustorium within the branches of their host tree. Mistletoe has chlorophyll in their stems and leaves, so they are able to make food for themselves. But they are parasites in that they take water and nutrients from their host.



Control of mistletoe can be difficult. Some horticulturists do not feel that mistletoe harms their hosts that much, so advise that we should not worry about it in our trees. I have seen fairly young mesquites that were so full of mistletoe that they certainly will not survive many years.

Mistletoe Seeds Sprouting!

I was looking at my Screwbean Mesquite (Prosopis pubescens) today and noticed some desert mistletoe(Phoradendron californicum) seeds sitting on some of the horizontal branches and in forks. I immediately started rubbing them off, when I noticed some little red “roots” (called radicles) sticking out one end! I wished I had not removed them all, because I thought it would make an interesting picture. Well, there were a couple more seeds down on the main trunk and I got a shot of one of them!

Look at how that radicle is going right for the crack in the bark instead of downward like a normal root! I rubbed this one off too – I hope I got it off in time.

The seeds are tiny, about 1/8″ long and 1/16″ wide, usually with a little red residue from the fruit on them. They are fairly distinctive and easy to see once you have the correct “search image”. I would advise checking your native desert trees (Palo Verde, Acacia greggii [Catclaw] and Mesquite) for seeds and getting them off as soon as possible. They could be sprouting RIGHT NOW!

The seeds of Desert Mistletoe are spread by birds in their droppings, and when they wipe the sticky seeds off their bills. The Phainopepla (Phainopepla intense) is the primary one that spreads the seeds. I do not believe the seeds on my Screwbean Mesquite were deposited by Phainopeplas as we have not seen them in our year or immediate area very often. The tree is frequented by many other birds, as it is near a feeder, so there a lot of likely suspects.