That is indeed a rust disease but that is not a Hemlock (which has short, smooth, soft-to-touch, non-prickly needles).

It is our native Juniperus virginiana, also known as Eastern red cedar.  Hemlocks are native too, but unfortunately, we are not seeing many of them anymore due to an invasive sucking insect called the Hemlock Woolly Adelgid that kills them. Here is our page where you can see the tree needles and pest: 
https://www.extension.umd.edu/resource/hemlock-woolly-adelgid-trees/

Rust diseases are unusual because they spend half of their life on one plant (junipers) before transferring to another family of plants (apple, crabapple, hawthorn, serviceberry, quince). Here is our page on them: 
https://www.extension.umd.edu/resource/rust-diseases-trees/


There isn't much to be done as damage to either host is not severe enough to warrant fungicide applications. 


Christine

Hello Cathy,

There are several species of rust fungi; we don't have pictures of them all (yet) on our web page, since the Cedar-Apple Rust type featured is more commonly seen by gardeners when infecting flowering trees like serviceberry. The linked Ohio State University article shows good examples of the varieties of rust in the photos on that page.

The type you have is probably Cedar-Quince Rust, and despite the name differences, both can infect a similar and overlapping group of host plants. There is no cure for a rust infection like this in junipers. While the juniper host sometimes seems to live for many years after an infection began, not very troubled by the rust, the fungal spores will be spreading every spring to rust-vulnerable species like serviceberry, apple, crabapple, and hawthorn. Cedar-Quince Rust causes somewhat different-looking infection symptoms on those hosts and could kill its twigs, in comparison with Cedar-Apple Rust which tends to only affect fruit (berries) and sometimes cause leaf spots.

If this is a young juniper plant not in a suitable location for long-term growth (it would potentially heave-up some of those bricks as it matures, given they can reach 20+ feet tall when older), we suggest you remove the plant to spare nearby plants a source of rust inoculation. It's not a foolproof measure -- fungal spores like rust can be carried some distance on the wind from other infected plants -- but it might save a nearby tree from significant infection each spring.

Using vinegar on the fungal fruiting bodies (the equivalent of mushrooms for this fungus, which is the orange crust or goo) will not kill the fungus and is not recommended. The fungus "body" is growing inside the tissues of the juniper itself, and only the visible orange part on the surface is producing spores to spread it to other plants. The orange structures can be unnoticeable for part of the year on an infected plant, and the infection in the pictured juniper might have actually begun a year or more ago.

Miri

Cathy,

It's hard to tell without photos, but your young juniper tree might have more than one kind of rust infection if the orange ooze now has a drastically different appearance. In either case, they are not curable and removing the visible spore-releasing growths will not accomplish much -- it won't help the tree, and it won't prevent more spores from being released at other times or from ooze that you didn't notice elsewhere on its branches or trunk. Plus, if you cut into the bark by accident, that could pose a serious risk of dieback or wood decay for the plant that is similarly untreatable. (Too many trunk cuts can also kill a tree.) The living layer of tissue in a trunk lies just underneath the bark, which can be fairly thin on young plants and in certain species, and easily damaged.

The structures on fungi that produce spores as they reproduce are somewhat like flowers or seeds/fruits on a plant. In other words, their function is to propagate and spread the organism to new areas, but removing those parts does not remove or kill the entire organism itself. Think of it like picking a flower or fruit off a plant -- you remove the plant's ability to spread (at least in part) but you're not doing anything to get rid of the plant itself. The main part of the fungus (its "body," essentially) is living inside the wood of the juniper -- it can't be scraped off or taken away physically -- so taking off any visible parts that are only dispersing spores won't resolve the issue, other than improving the tree's outward appearance for a very short period of time.

We do not recommend the use of detergent or any type of household soap on plants. They can include ingredients that may damage plant tissues, pollute the soil, or render the application ineffective against the pests or diseases that non-scientific books or websites might recommend them for. Detergents and soaps not formulated for specific use on plants for pest/disease control can strip the protective wax or lipids off the surface of leaves and other plant parts, resulting in them drying out, becoming infected by other diseases, or being much more vulnerable to sunburn. Penn State has a good article about why home remedies like this are not a good idea to use in the landscape/garden.

Miri

You're welcome.

We don't see rust infecting ornamental cherry as often as other species (serviceberry, crabapple, and hawthorn are the major victims). Still, since the tree would mature too large for that location (if it lives long enough), either way it would be best to move or remove it. The spore-producing structures on rust fungi swell and wither tied to the weather in spring. Like a flower opening in sunshine and closing on a cloudy day, rust fungi make that orange gooey ooze on damp days and not on drier days. Its activity will slow and cease as we move into late spring since that part of the infection cycle (spreading spores) will be over.

If you like growing Eastern Redcedar (that native juniper type), there might be some individuals more resistant to rust infection if you wanted to plant a new one elsewhere, but unfortunately they are untested/unknown when it comes to cultivars on the market for sale, so it's pot-luck as to whether a new planting remained uninfected or not. Anecdotally, we tend not to see evidence of rust on the dwarf, blue-gray shrubby cultivar called 'Grey Owl,' but that isn't a guarantee it will remain rust-free, and it has a different look than the upright, greener form you currently have.

Miri

You're welcome!