Skip to Content

Support MinnPost

The Metropolitan Council generously supports MinnPost's Earth Journal coverage; learn why

Letter From Skunk Hollow: An invasion of gooey tree squids

MinnPost photo by Ron Meador
Behold, the invading orange tree squid from outer space.

Spring greenup is surging this year, thanks to all the rain pounding our part of western Wisconsin. One morning the woods out back had a gauzy green mist of new foliage; a week later you couldn’t see 20 yards into the trees. A day after that the grass out front was a foot high in places.

Sallie and I took a three-mile walk along a favorite road last Friday, noticing for the first time in our eight years here the density of scrubby crabapples in bloom along one shoulder.

And coming back down the other side, on Tuesday evening, we encountered the invading force of orange tree squids from outer space.

* * *

Sallie studied botany and can tell you without having to look it up, for example, that a lichen is the offspring of an algae and a fungus. We like lichens and are forever stepping off the path to inspect all the other things that grow on trees and shrubs — bracket fungus, epiphytes and mosses, the vast array of parasites and galls — as well as the mushrooms and other stuff popping from the forest floor.

Neither of us had seen anything like these before.

The first, small ones looked like blobs of gooey mucus that had oozed out of evergreen branches (some kind of sap hemorrhage?). They seemed to have formed on the top, then dripped or drooped downward.

Then we spotted some as large as a human hand, with a couple of dozen tentacles as long as my fingers. These jiggled like Jell-O when poked, gelatinous but not sticky. I pinched off a piece the size of a kidney bean and smooshed it in my fingers, finding it odorless and viscous, not quite slimy.

The forager in me really wanted to taste one but Sallie said, persuasively, that this really ought to wait until I had some idea what I was eating.

The first ones were on cedar trees, and we quickly noted these clues: They were only on the cedars. They were on every single cedar of the 50-plus we checked. They were so numerous in stretches that it looked as if my neighbors who decorate the roadside trees at Christmas had forgotten to take some ornaments down.

(At one point I thought I saw a squid on a red pine, very near a different kind of alien growth on a cedar branch, redder and more upright in shape. But a closer look established that we’d merely found a pine and a cedar growing so close together that their limbs were enmeshed, with the cedar’s branch sporting the alien and the pine’s a brand-new baby cone.)

We spoke of them as extraterrestrials — I suppose because we grew up on “The Twilight Zone” and “The Outer Limits” — until Sallie signaled that the joke had run its course for her.

 “OK,” I said, “but if they’re still here in the morning, and we don’t see any signs of our neighbors, I’m loading all the guns.”

* * *

We had a mystery on our hands, but compared to the pink fuzzball wasp galls, this was a case quickly closed. Just Google <orange slime cedar> and you’re home with the first few hits.

The culprit is Gymnosporangium juniperi-virginianae, the fungus responsible for cedar-apple rust, a disease whose cycle requires two very different hosts.

In spring, it needs an Eastern red cedar (which is actually a juniper, Juniperus virginiana). These cedars are common all over this part of the country, especially along roadsides where their drought tolerance and overall toughness are advantages.

In summer the fungus needs an apple, crabapple or hawthorn of the Rosaceae family; it’s not so picky as to species in that relationship. (There are also fungal cousins that grow on the cedars in the spring and on quinces, hawthorns and pears in summer.)

MinnPost photo by Ron Meador
The blobs are the fruiting bodies of the rust fungus.

The orange squids, I mean blobs, emerge somewhere each spring, for a few days to a week, in response to the right rainfall and air temperatures. So far as I could learn, however, their appearances are difficult to predict with any precision.

My neighbor Denny, who has lived in the neighborhood for decades and walks his dog every day, had never seen them before this week’s eruption, which left him awestruck and perplexed. As people all over the country tend to be when the blobs show up.

From Ellen Nibali’s Garden Q&A in the Baltimore Sun  last Saturday:

Help, I have an orange octopus on an evergreen in my front yard! What is it and what do I do with it? Now I see about 5 or 6 with orange tentacles on the tree; there may be more.

Weird looking, aren't they? These are cedar-apple rust galls that grow on our native Eastern red cedar… The number of galls depends on weather conditions each year. Wet rainy springs encourage them. It's not cause for concern on your evergreen tree, but it is a pest during the other half of its life affecting apple trees within a half mile… There is nothing you need to do. Just enjoy the weirdness.

The blobs are the fruiting bodies of the rust fungus — as morels are the fruiting bodies of the soil-dwelling Morchella fungi — and their function is to fill the air with spores that can drift to apple trees and set up the next stage, which scars the leaves and can make the fruit unsaleable. But the evergreens aren’t damaged much.

And I can report from a very small sampling that the blobs, unlike morels, may have no flavor at all.

* * *

From Michelle Grabowski’s May 1 post at “Yard and Garden News,” published by University of Minnesota Extension:

These rust fungi overwinter as infections in woody branches of junipers. Cedar apple rust and hawthorn rust result in round woody galls. Juniper broom rust causes a cluster of small branches, or a broom, to form, and quince rust directly infects the branch.  

In wet spring weather, these rust fungi come out of dormancy and produce gelatinous orange spore producing structures on rainy days….  The orange fungal structures on juniper can dry out and rehydrate several times in the spring, releasing spores each time they are wet.

So there’s the good news for you, if you’re interested in seeing these oddities — you stand a good chance in the days ahead if you go looking in the right places; they’re easily big and bright enough to spot from a passing car.

Back in Skunk Hollow, I’ll be heading out with a camera after each rain because the pictures you see here were made on Wednesday, after the drying had begun; the growths are considerably brighter and bigger when fully hydrated and who knows when they’ll come again.

Once they start to fade for good, the process goes pretty fast. You can see a cool time-lapse video of the growth and retreat, produced by the extension service at Purdue University, here.

* * *

Personal aside: Today’s Earth Journal is my 500th for MinnPost since I began the feature in September 2011, and while I love this work I want a break from it. So I’m taking a few weeks off to read, relax and reflect on subjects for the future. See you all again sometime in June.

Get MinnPost's top stories in your inbox

Related Tags:

About the Author: