Pasture grasses for horses, and serpentine soils?

Asked March 11, 2019, 2:50 PM EDT

Hi - We are moving back to the Illinois Valley after 4 years away. When we lived in O'Brien for 17 yrs we had an old flood plain valley and good grass. Here in Maine we have learned a lot about Orchard Grass and Bluegrass, and have learned just what is involved in making good weed-free hay. Now that we are looking again I'm wondering if we end up on serpentine how that might affect the horses. What are the best pasture grasses we can grow in Oregon? I don't expect to still make hay, but I know knapweed will be a problem, and I hope not star thistle. In Maine we learned the only way to eliminate bedstraw was to spray. As I recall that was also the case in Oregon with knapweed & star thistle. Any publications you can steer me to or advice you can give, will be appreciated! Thanks, Kathy Ethier, Harmony, Maine

Somerset County Maine

5 Responses

Hi Kathy,

Thanks for reaching out. Tall fescue and orchardgrass are the most common forage grasses in Southern Oregon and some pastures have a fair proportion of perennial ryegrass but it generally does not persist well through our hot summers. These can all grow on serpentine soils but not very well.

If I were aim to grow high quality horse hay and had not yet purchased land, I would avoid the serpentine dominated soils. They are generally lower in fertility and can contain toxic heavy metals such as nickel and chromium as well as asbestos. These soil minerals can both limit plant growth as well as be a potential route for the ingestion of those toxic materials by both horses and humans.

Yellow star thistle is a troublesome weed in non-irrigated pastures and hayfields, but poses little difficulty in irrigated settings. Here is a good resource on managing starthistle if you're interested.

If you have specific parcels in mind, you can check a soil map to evaluate soil mineralogy and predict the likelihood of challenges from serpentine parent material. The web soil survey is the place to look up specific soils:
I can help with soil mapping if needed.

Please let me know if you have other questions.

Hi Gordon - Didn't realize I found you thru a 3rd party, hope that's not a problem!
I appreciate your info on soils etc. We had good loam on Wood Creek, but I remember we looked at what is now the Tycer Crossing area and steered clear. From reading a Josephine county soil survey I think we probably need to look for a valley area to get the better soils. I've seen a few places where pot growers have been, and don't like the iron looking stuff. We usually do improve whatever we end up on; just have to see what we can find.
I found the survey pages daunting, so am still looking for a map of Illinois Valley soils. Is it possible there's one out there that would outline the best areas for me? Thanks, Kathy E.

Hi Kathy,

You're right that the valley and floodplain soils are better suited for farming, but I'm not sure if there is one map already made which will show you those lands in the Illinois Valley

Do you know about the Web Soil Survey? (

It's the most up-to-date place to find soil information about a parcel or region. The tool can be a bit daunting to use, but there are instruction available on their home page and in YouTube tutorials. For the quality of farmland, you would want "Farmland Classification" under the "Land Classification" under the "Suitabilities and Limitations for Use" tab.

Let me know if you need help with this.

Hi Gordon - One more question, and I'm still not comfy with the soil survey!
Some of the places we're looking at have that reddish, gravelly soil, mostly out the west side of 199 on Naue Way and Lone Mtn Rd. I think it may be a later stage of the breakdown of serpentine?
So I suspect a lot of iron in there, maybe too much for horses, and not enough other nutrients. Wondering if I could amend such a soil as to at least graze it, then buy hay for winter. Looking at pretty small parcels for my remaining 2 horses. If I can establish two 2 or 3 acre areas to rotate I'll be content.

Hi Kathy,

Would you send me an address or two from properties you're considering or ones with the soil you describe? With a specific street address, I can look up the soils and provide an answer to your question about iron and pasture growth.