Exploring New Milkweed Meadows in Rigdon

Jenny studying the plants in the still-green seep along the edge of the west meadow. The lush shrub at the top of the photo was a very healthy poison oak!

Back in February, I was invited to a Zoom meeting set up by Walama Restoration and the Middle Fork Ranger District to discuss ongoing restoration projects in the area and further work on purple (or heartleaf) milkweed (Asclepias cordifolia) and monarchs (if their population bounces back) in the Rigdon area. At that meeting, I learned that last summer the district hired some surveyors to check out special habitats (I think that includes anything that isn’t forest!) on the west side of Hills Creek Reservoir and the Middle Fork of the Willamette. They surveyed a number of south-facing openings that I’d seen on Google Earth but never explored. I was very excited to hear that they found two new populations of milkweed! And these were farther north than any of our other sites, making them the new northern boundary of its range. Jenny Moore, the current district botanist, didn’t know much more about the sites or the milkweed itself there, so we discussed going up there together to see them for ourselves once the milkweed started blooming.

After seeing the milkweed starting to flower at Big Pine Opening a few weeks earlier (see Relaxing Day in Rigdon), I figured it was time. The weather was supposed to get hot again, so I was happy that Jenny was able to go out with me on Friday, May 28 before it got too hot for a steep bushwhack up low-elevation, south-facing, rocky meadows around 600′ above the road.

Beautiful spreads of woodland phlox (Phlox adsurgens) bloomed along the edge of the both the paved road and the gravel one we walked on.

We drove south on Road 21 and turned right just before the bridge crosses the reservoir, continuing on a mile and a half or so until we reached the bermed and gated-off road along Windfall Creek. We only had to walk about a third of a mile, but there were a number of fallen trees to climb over. The road bank is pretty steep except in one spot where it comes down to the road directly beneath the middle of the four openings uphill. Unfortunately, the poison oak was particularly bad here. We managed to skirt around the mostly low-growing clumps of poison oak as we climbed up steeply through the woods. Using the maps on our smartphones to head toward the easternmost meadow, where one of the milkweed populations had been found, we eventually spotted the opening. I stopped to look at it through binoculars and was thrilled to see a great many milkweed plants. Unfortunately, once again, the poison oak grew to shrub-sized proportions just where I wanted to access the meadow. There was a steep downhill drop otherwise. I managed to get by it but no doubt brushed by some of the rash-inducing leaves. Once in the meadow, I discovered some painful object had gotten in my shoe and had to take it off. This is when I realized I really wasn’t prepared as I had to touch my shoes, which were no doubt swimming in poison oak oil. I should have brought some Technu with me. While I did wash all my clothes (including my shoes) and showered with Technu and Dawn when I got home, it wasn’t enough. The following week was an itchy one!

The slope looked really steep in the east meadow, but it wasn’t as hard to wander about as it appeared at first, so we were able to count the many milkweeds.

But on to the “good” plants! We were really pleased to see what a large and healthy population of purple milkweed was growing on this steep rocky slope. We made a count and totaled well over 300 plants. And they were large, healthy plants. We also spotted many small, young plants, so it was also reproducing well. The one recent rain had refueled a lush seep along the west edge of the meadow. It was still colorful with rosy plectritis (Plectritis congesta) and monkeyflower (Erythranthe sp.—probably microphylla, but the new taxonomy still has me confused). No doubt during a wetter spring, the whole area would have been showier; it was mostly pretty dried out for May. In the rockier areas, the ground was covered with the leaves of snapdragon skullcap (Scutellaria antirrhinoides), and Jenny finally spotted the first few beautiful purple flowers in bloom. I was also happy to see some white-flowered threadleaf phacelia (Phacelia linearis) coming into bloom. It is scattered around the area, including at Youngs Rock and Heckletooth Mountain, but it isn’t very common.

There were several pale swallowtails as well as tiger swallowtails and cedar hairstreaks nectaring on the milkweed. Trying to follow them up and down the slope was a challenge!

I was super excited to see a snowberry clearwing moth also nectaring on the milkweed, but I only managed a few long shots before it disappeared.

The distinctive inflorescences of many-stemmed sedge have male flowers at the top and a few female ones on the bottom. The wiry foliage could be mistaken for a rush (Juncus).

After surveying the area for milkweed and compiling a plant list, we headed uphill to the uppermost meadow, following the seep through a short stretch of woods. Just as we entered the forest again, I spotted a sedge I recognized (not many of those, I really need to learn them), having seen it recently at the Sacandaga Bluff area next to the campground. That had been the most northerly site for this distinctive species, many-stemmed sedge (Carex multicaulis), but this area is almost 7 miles further north. So this is the most northerly site for both the uncommon sedge and the milkweed. How had I never checked this area out before?!

The uppermost meadow was much larger and shaped somewhat like an hourglass, narrowing greatly between the upper and lower sections. The seep—though dry here—ran down through the center, funneling all the moisture from this area to the one we had come from. Drying up clovers and other moisture lovers attested to it probably looking much showier earlier in the spring. We didn’t have time to go to the upper section of meadow, especially since no milkweed had been spotted here. Instead, we cut over to the westernmost opening, missing the middle one entirely.

I had noticed the distinctive gray-green polka-dot pattern on Google Earth, so I was expecting to see buckbrush (Ceanothus cuneatus) in the upper and western meadows. It seems to appear in meadows that have burned.

The western one was even steeper and rockier than the first. It was also more exposed. There was milkweed here, and although the plants were large, there were far fewer. I believe Jenny counted somewhere around 70 plants. Perhaps it was drier here and couldn’t support as many large plants. Many of the other plant species were the same as the east meadow, including both the skullcap and the threadleaf phacelia. I also found a patch of many-stemmed sedge in the woods just above the meadow—while I have limited knowledge of this species, that seems to be its preferred habitat. We also noted several species we hadn’t seen yet, including blooming northern buckwheat (Eriogonum compositum) and broadleaf stonecrop (Sedum spathulifolium).

The west meadow was much steeper than the east and had no obvious source of moisture. Both the junegrass (Koeleria macrantha) and the milkweed were well spaced out.

Snapdragon skullcap and Indian dream fern (Aspidotis densa) in a gravelly area of the west meadow.

Time was running out before we had to leave so Jenny could return the Forest Service vehicle on time. I thought it would be faster going down than coming up, but I was mistaken. Heading down the steep slope through the woods, climbing over branches and around poison oak took a lot of care and time. I used a stick to push some of the tall poison oak out of the way. I was relieved when I spotted the road below, but, as I had feared, the road bank was just too high to go straight down. So close and yet so far! We had to head farther east through the woods until we reached the spot we initially ascended. The poison oak was still extra thick there, but at this point, I just had to get back onto flat ground. It was a really interesting and successful trip, and I would love to see it when more is in bloom, but I will definitely have to be better prepared for the poison oak next time!

4 Responses to “Exploring New Milkweed Meadows in Rigdon”

  • Lon Otterby:

    Tanya, Wow, I am looking forward to the Southern Willamette Forest Collaborative restoration project on the west side of Rigdon. Those high up meadows are so important. Thanks for the preview!!
    Lon Otterby

  • ernst schwintzer:

    Have you seen any monarch butterflies recently? I have showy milkweed in my yard and have not seen any monarchs in over two years.

  • Hi Ernst,

    Unfortunately, the western monarch population crashed in the last couple of years. Hardly any made it to Oregon last year. We’re keeping our fingers crossed and hoping they can recover, but in spite of many efforts on the part of monarch lovers, it isn’t looking good. Some interesting information can be read here: https://baynature.org/2020/01/16/with-no-sign-of-monarch-rebound-butterfly-experts-and-enthusiasts-meet-and-plan/

  • Becky Riley:

    Thanks for the interesting post–and all the scrambling and poking around looking for milkweed. So interesting (and encouraging) to know about all this A. cordifolia up on these west-side, low elevation rocky meadows.

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