Mistletoe

We’ve been tied up with a big Mulberry trimming job for three days (plus a rain day in the middle of the week). It is finally finished, and we can move on to some other work! I’ve got a couple interesting pictures of this job at the end of this post. I’ve also been working on this post about mistletoe. I hope you will find the information interesting and helpful!

There are two basic types of mistletoe that grow in our area. The first, and most common, is desert mistletoe (Phoradendron californicum et al – up to six species in this group) which infests typical Sonoran Desert leguminous trees and shrubs. This is the mistletoe that we see growing in mesquite (Prosopis sp.), palo verde (Cercidium sp.), sweet acacia (Acacia farnesiana) and catclaw acacia (Acacia greggii).

Desert Mistletoe - Phoradendron californicum et al

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 and in older neighborhoods with pecan or ash as street trees.

Christmas Mistletoe - Phoradendron macrophyllum

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.

Arizona Ash (Fraxinus velutina) infested with Christmas Mistletoe

Mistletoe is spread by seeds, like other plants. The seeds are whitish-pink berries that are sticky. They are a favorite food the Phainopepla which is a black bird with a Cardinal-like crest and with white in the wings. They are never far from a clump of mistletoe. The berries either pass through them, or the seeds are wiped from their bills onto a branch. If the seeds end up on any thin-barked (ie. young) branch of a suitable host they will probably grow.

I have a missionary friend in Nicaragua who was telling me one day that you can always tell what plants are good to eat by watching the animals and birds to see what they eat. If they like something, it is safe for us to eat. I told him he is WRONG! Surprisingly, he has not had any problems yet!  For your information, MISTLETOE BERRIES ARE POISONOUS TO PEOPLE!!!

Desert Mistletoe Berries

Having many clumps of mistletoe in a tree is like setting up a bird feeder. The more berries there are, the more birds will come – wiping and excreting seeds on more branches as well as adjacent trees.

Because the clumps are unsightly and having seeds in the area encourages more plants, I like to keep mistletoe trimmed out of trees wherever possible. It is always advisable to cut out the clumps while they are small. There are usually 5-10 times as many clumps as you can see.

When trimming out mistletoe, the recommendation is to remove the branch back to a fork [as explained in this post], 12” to 18” below the clump. This should ensure removal of the haustorium inside the branch, putting an end to that clump. Simply pulling off the clump of mistletoe will retard its growth, but will not kill it. Sometimes when the mistletoe clump is within a few feet of the ground on the main trunk of a tree, the only options are removal of the tree or repeated stripping of the mistletoe growth. If the mistletoe is kept stripped off, there will be few berries and little incentive for Phainopeplas to visit.

Because mistletoe is a plant, and not a bacteria or fungus, it is not necessary to clean tools in bleach water between cuts (sterilize them). Mistletoe cannot be spread this way.

The Great Purple Hairstreak (Atlides halesus) is a beautiful butterfly whose larvae use christmas (and other) mistletoe as a larval host. I have seen these butterflies at the Hassayampa River Preserve “hilltopping” on Lykes Lookout. This is a behavior where the males stake out a territory at the top of a hill. We were able to stalk them and get some reasonable photos.

Great Purple Hairstreak hilltopping at the Hassayampa River Preserve

Mistletoe has its place in the Creation. There are plenty of wild areas where it will continue to grow and provide food to the creatures who rely on it – you might as well control it in your yard!

Now for a couple pictures from our latest job. First, a photo of the APS service man re-connecting the service to the house where we were working. He dropped the line for us to do our work and came back to put it up after we were finished. They are very helpful in this regard. We need to stay 10 ft away from all wires!

APS helped us by taking down the service line into the house.

Next is a picture showing the lift in a really tight spot! I had to drive it through the car port and set it up inside a block walled porch. I needed to get it in this position so I could reach over the roof to remove some overhanging branches. I couldn’t swing the boom far enough to get everything, so I ended up dropping Shannon off on one limb and worked with him to cut and lower some pieces. The roof was a very old tile that was brittle and couldn’t support a person’s weight!

The lift in a tight spot!

I’m working on a post related to tree planting that I hope to get up soon – check back!