Marsh planting set for Saturday July 10th
We met the truck from Spence Restoration Nursery at Jarvis today and unloaded over 1700 plants. Most of them are destined for the marsh, a few for the ponds, and a few others for other locations. A Peoples Energy grant through the Nature Conservancy paid for most of them, with the Chicago Park District picking up the tab for the rest. So bring your trowels and tall rubber boots (or even waders) if you have them, and let's get these guys planted. This is the beginning of a whole new marsh...
Now for the rest of the story. We started working on the marsh last summer. We've been aware for some time that Iris pseudacorus (yellow flag iris), which is native to Europe but a widely planted ornamental in the states, was taking over the marsh, even outcompeting the cattails, which are weeds in their own right.
With the help of a large crew from Aramark, CPD contractors for natural areas maintenance, over several days we cut and herbicided most of the iris is the marsh. However, we discovered this spring that much of the iris was in fact only top-killed, and that the many man-hours we spent had only set the plants back a bit. While searching for a more effective technique, we received a recommendation that we wait for the results of a trial that was being done at another location, before going back in and using more of the same herbicide we used last summer. This was in late May, and time was running out. We pushed back the planting date from the end of June to July. In the interim, we worked at removing the iris physically - by digging it up - from a small area at the north end of the marsh where we discovered a colony of Sagittaria latifolia (broadleaf arrowhead) last summer. This native species seems to have gotten here on its own, as we had no record of it and never planted any.
There have been a few other native species discovered in the marsh.
Years ago, Teri Radke discovered sweet flag, Acorus calamus (aka A. americanus, but see Sue Thompson's note in "Plants of the Chicago Region" by Swink and Wilhelm regarding that name). We now have a fairly large stand of this plant in the south end. We've also had common water plantain, Alisma subcordatum, which probably was seeded from plants we installed at the east end of the large pond. There's Sium suave, tall water parsnip, and just last year we found Epilobium coloratum, cinnamon willow herb. In the past we've found Lycopus americanus, common water horehound, but it seems not to have persisted.
Back to the trial. The results came back mixed, but were encouraging enough to spur me to undertake a trial of my own, using the same herbicide but with a slightly different formulation. I sprayed the iris growing in Beaver Flat, where we are planning to install much of the Saururus cernuus (lizard's tail) we've received. It seemed like an ideal spot for that species, but for the iris.
So at the beginning of June, I sprayed the iris there with this herbicide solution. I came back ten days later, and was amazed to see all the iris that I had thoughly sprayed was gone. The what remained of the leaves had mostly disintegrated; in many spots, it wasn't easy to tell that the iris had been there at all. Finally, some success.
In anticipation of spraying the rest of the iris in the marsh, we turned off the water supply to the Sanctuary at the last workday on June 26th. The hot weather and lack of rain caused to water levels to drop quickly, and the marsh had virtually no standing water when I joined our local Aramark crew of Erin and Zack on july 2nd to spray the rest of the iris. It has mostly had the desired effect, with much of the iris turning completely brown by July 8th.
Now we're set to add 20 new species to the marsh, although one of them - Pontederia cordata, pickerel weed - was just discovered growing there last Friday by Erin while herbiciding iris. He noticed 2 plants growing in the northwest corner. They'll be joined by about 150 more.
We didn't receive 5 species that we requested, but additional plants of the ones that were available were substituted. That means were a little short on bulrushes, and we also won't have lake sedge (Carex lacustris) or golden ragwort in this year's planting. I'm hoping that we can get some for next year, and maybe add a few shrubs like St Johns wort and meadowsweet. and perhaps even add a tree like sour gum to the mix. We'll see.
We are sure that next year we'll go back in to mop up the remaining iris, and also we'll work on removing the introduced Typha angustifolia (narrowleaf cattail). All this work is leading up to re-introducing frogs and toads to the Sanctuary, which have been absent for many years. We were hoping that 2011 would be the year, but it's looking more like 2012 now. When we're certain that the Iris pseudacorus is gone - which will probably take several years - we'll look to bring in Iris virginica shrevei, the native blue flag iris.
That'll keep us muddy for the foreseeable future!
Pictures from the plants.usda.gov web site.
Iris pseudacorus: J.S. Peterson @ USDA-NRCS PLANTS Database
Acorus calamus: R.A. Howard @ USDA-NRCS PLANTS Databas
Pontederia cordata: William S. Justice @ USDA-NRCS PLANTS Database