This is the time of year when a particular parasitic plant gets a lot of attention, and is even brought into some of our homes.
If we’ve learned nothing else from Christmas movies, we know that people accidentally end up under a sprig of mistletoe at a holiday party and then have to kiss — and then end up living happily ever after.
Many of those movies are set in places where those holiday parties happen during a lovely Christmastime snowfall. But there is a type of mistletoe for us desert-dwellers, too.
To learn about it, The Show spoke with Kelsey Yule, project manager for the National Ecological Observatory Network Biorepository at Arizona State University.
Full conversation
MARK BRODIE: Kelsey, what exactly is desert mistletoe?
KELSEY YULE: So desert mistletoe is a species of mistletoe that is located across the entire Sonoran Desert and a little bit of the Mojave Desert, so into California, but across, you know, obviously found across all of our southern Arizona habitats at the lower elevation where we see that desert scrub.
So mistletoes are parasitic plants that grow up in the canopies of their host trees. Desert mistletoe infects the legume trees in our region, so most commonly that would be the mesquites or the palo verdes, the iron woods. And from those host trees, it takes its water and many of its other nutrients, and then it, you know, converts that into its own growth, and it produces flowers and fruits that are used by a lot of our native wildlife.
BRODIE: What does it look like?
YULE: So it actually looks a lot like the mistletoe that we think of as part of the holiday season. It's a green clump up in the tree canopies, and it produces a lot of reddish or whitish berries, like we think of with the Christmas mistletoe.
But unlike the typical or stereotypical Christmas mistletoe that you know grows in Europe or in the eastern United States, it does not have big leaves. So it looks a bit more stringy than the typical mistletoe, but it's a big clump up in the canopy of our most common trees here in the desert.
BRODIE: How common is it ? Like is this the kind of thing where, like, if you just look up and know to be looking for it, you'll probably see it. Or is it less common than that?
YULE: It's very common. So it's not very often, like in town or in the city, although you can occasionally see it, but it's very common, especially if you go out to desert washes.
And it really it just depends on where you find the seed dispersing birds mostly. It's our most common host tree species that it can grow on, and it'll be really patchy across the landscape, but kind of wherever you find its main seed dispersing bird, the phainopepla, you can find the mistletoe.
BRODIE: So you mentioned, it is a parasitic plant. Does it actually kill its host, or does it just take its water and some of its other nutrients?
YULE: It just takes some water and other nutrients. Generally, a parasite doesn't want to kill its host because it will die too. The mistletoe can't survive if it's not, you know, right tapped into the branches of a host tree.
People often ask me about how to remove mistletoe from the trees in their yard, and my answer is always, if you love birds and pollinators and the native wildlife here in the Sonoran Desert, there's no reason to remove it. It doesn't have strongly negative effects on the host trees, and it's really an important food source for a lot of our wildlife.
BRODIE: Does desert mistletoe bloom this time of year? Like, is this the kind of plant that people might choose to cut down and put in their house around Christmas?
YULE: Yeah, so it is blooming around this time of year. The flowers are super small. They're like a millimeter in diameter, but they are quite fragrant. So that's nice. I think they kind of smell like spice apple cidery, so that's very cool.
But the reason why someone might bring it in is pretty similar to why they might think that the typical Christmas mistletoe is pretty they do have these like beautiful red berries and tons of them on a single plant.
BRODIE: And as you said, it is fairly similar in many ways to other kinds of mistletoe, right?
YULE: Yeah, so the Christmas mistletoe is the same plant family, same origin and the eastern mistletoe that is often used here in the U.S. as the Christmas mistletoe is the same genus of plants. So very closely related.
BRODIE: Does this plant have a particular use other than the way that some people use it around this time of year?
YULE: Yeah, so the Seri and O'odham indigenous communities have long used the berries as food, and although all the green parts of the plant are toxic, the fruits are not, and they can often be kind of sweet.
And one of the coolest things, I think, is that the Seri and O'odham people recognize that the berries actually taste different depending upon the type of hostry they're on. You know, mesquite versus palo verde versus acacia and so certain plants from certain host trees are, you know, preferred for use as food. So I've always really thought that was cool.
BRODIE: That is really interesting, that the, as you say, that the parasitic plant kind of takes on some of the characteristics of its host.
YULE: Yeah, absolutely. And then for my research, I actually looked a lot at how the mistletoe was different depending upon what host it grows on, and we see some genetic differences there too. So it's really borne out on all levels how this, this mistletoe, has adapted to its host species.
BRODIE: So I have to ask. I mean, do you happen to bring desert mistletoe into your home around the holidays?
YULE: I actually never have brought in cuttings during the holidays, but I have tried to grow it on the trees in my yard. It's very slow growing, so I don't have any beautiful fruiting plants yet to show for that, but I would love to someday.
