All out push to eradicate invasive sunflowers

Those following these posts know that we have been battling invasive sunflowers for some years. When we began savanna restoration, we had fairly small patches of sunflowers around the edges of the woods. Since we opened up the areas to more light, the sunflowers have flourished and are now forming large patches. Many of these patches are even coalescing, making even larger patches. Taxonomically, these are mostly Helianthus divaricatus, but a few are H. decapetalus. (The photo above is of a very small clone; most we are dealing with are many times larger!)

One problem with these sunflower clones is that the individual stems are so close together that virtually no other plants can grow. They are as weedy as garlic mustard!

There is virtually no scientific literature on sunflowers as invasive species, although two venerable Wisconsinites, Curtis and Cottam, reported at the University of Wisconsin Arboretum some early observations of toxicity (allelopathy) with showy sunflower (H. rigidus; now classified as H. pauciflorus).

We fiddled around for some years trying various "band-aid" approaches, such as handpulling, mowing, and one-time spraying. All of these methods got rid of the plants temporarily, but next summer they were back again, often even stronger.

Herbicide treatment was the best procedure, but even here we did not eradicate them, probably because some of their rhizomes escape the spray, overwinter, and grow again the following spring. (This species has an impressive underground rhizome system!)

I finally realized that we had to mark each patch carefully and return to it again and again, spraying all the survivors each time. We can't leave even one plant alive, or it will serve as a source of future infestation. In a sense, we have to "sterilize" the clone. (This is also what we do with garlic mustard.)

In order to get started on this ordeal, last August (when they were flowering and easiest to see) Amanda and Marci installed permanent numbered markers at over 95 GPS'd clones. I set up an Excel spreadsheet so that we can keep track of what we do with each of these clones and used ArcGIS to map them. The photo below is a low-resolution version. I can send a higher res version to anyone interested.



For the past week we have been spraying some of these clones with triclopyr 3A (we can't do all of them this year), attempting to hit every plant. In a couple of weeks we will return to those sprayed and treat any survivors or new plants. And we'll return again sometime in late July or early August. Finally, we will return again next spring and spray again (and again, if necessary).

The value of the permanent markers is that we can be sure we are getting all the plants in each clone.

Fortunately, these plants are very sensitive to triclopyr, and show a visible response within 24 hours, so we can discern fairly easily if we missed any plants.

I may sound paranoid on this, but we have evidence that some of these clones are even able to invade prairies. One clone actually sent rhizomes from a savanna under six feet of a mowed firebreak and into one of our prairies, where it set up housekeeping. Within a year there was a patch of 200 stems.

I'll report back on this project later in the summer, or early fall.

Plants on the south-facing slope

Since it heats up early, the south-facing slope at Pleasant Valley Conservancy is always the first area to be burned (this year on 23 March 2010), and also has early flowering plants. Plants like pussy toes, bird's foot and prairie violet, and violet wood sorrel flowered weeks ago. Wood betony is long finished and is starting to make seeds.

A plant that is just in full bloom now is Leonard's skull cap (Scutellaria parvula) (C value of 6). You have to be careful not to step on this tiny mint, which is now in flower all over the hillside. According to Cochrane and Iltis, this species is found mostly in the southwestern (Driftless) part of Wisconsin, where it is generally seen on steep hillsides and other dry places. On our south slope it generally occurs only as single tiny plants, but in one area that was slightly shady we found a large patch.

This is one of those species that one hardly ever collects seed from, since as soon as it is finished flowering it essentially disappears from view.




Another species that we find primarily on the dry hillside is alum root (Heuchera richardsonii) (C value of 7). I found the specimen shown while climbing up our rocky Ridge Trail. Usually we see only single specimens, but in this area there were several rather large patches. Its flower stalks are bare of leaves, which are only found as a lush rosette at the base. I'm not sure whether the specimens here are native to the site (we always had small amounts of this species even before restoration began), or whether they arose from planted seed. The area here (Unit 5) is part of the very steep hillside that we have planted with dry prairie species at least five times over the past 10-12 years.

Another species that we find growing right out of rocks is prairie dropseed (Sporobolus heterolepis), which is not the most common habitat for this highly conservative species (C value of 10!). According to Cochrane and Iltis, this is a tussock grass par excellence and is an indicator of unplowed prairie relicts. When we first started restoration, the only place we had this species was on our original ungrazed prairie remnant, but as our restoration has proceeded, it has spread (either on its own, or from seed we planted). The lush-looking tussock in the photo is growing right out of rocky ground, where tufts of little bluestem grass are also thriving.


This is a great time of year to wander the prairies, as lots of species are now starting to flower.

2010 interns

One of the big events at Pleasant Valley Conservancy in late May each year is the arrival of a new crop of interns. This program, that Kathie and I help manage for Madison Audubon Society, has been a great success, and we look forward to another fine summer!

Pleasant Valley Conservancy is part of the so-called "Prairie Partners" group, which involves five separate entities. The interns work one day each week at each site, thus getting to see a wide variety of habitats as well as different ways of carrying out ecological restoration work. The interns are at PVC each Tuesday. (The other sites are the Mounds View Grassland of the Prairie Enthusiasts, Pheasant Branch Conservancy, UW-Madison Lakeshore Nature Preserve, and Madison Audubon's Goose Pond Sanctuary.)

This program is open to students from all of Wisconsin, and although we always have some UW-Madison students, we generally get students from other campuses as well. This year we have three students from UW-Stevens Point.

Veiny pea

A few years ago I found a single plant of veiny pea (Lathyrus venosus) in one of our bur oak savannas. I lost track of it for a while but now it is back in full, having formed about an 8 X 8 foot patch. Although it is not an especially rare plant (it is found in almost all Wisconsin counties), it does have a reasonable high C value (6), and is fairly showy.

Although Curtis (Vegetation of Wisconsin) found this species to achieve maximum presence in prairies, according to Cochrane and Iltis it has more affinity for savannas.

It is growing in a fairly shady part of Unit 11B, near a stand of fairly large bur oaks and shagbark hickories. From a distance, it doesn't look like much, but up close the flowers look quite nice.

We have another species, Lathyrus palustris (marsh pea), in the Crane Prairie at the edge of our wetland.

Both of these species arose spontaneously, or, as Kathie says, "are native to the site."

First success with cream baptisia

We have always had a nice native population of the more common Baptisia alba, but none of the rarer cream baptisia (Baptisia bracteata). A few years ago we managed to acquire some cream baptisia seeds and raised transplants in the greenhouse. Since cream baptisia is a dry-site species, we planted these mainly in dry areas of Toby's and the Pocket Prairie. Some transplants survived and some disappeared. This year for the first time some of the transplants are flowering. Although we have only a few flowering plants, perhaps these will be the forerunners of a large population someday.

In 2006 I went on John Ochsner's TPE field trip to Butenhof Prairie in Green County, where there is a huge native population of cream baptisia. The photo below shows a typical plant from this site, literally "dripping" with flowers.


Greene Prairie at the UW-Madison Arboretum has a large population of cream baptisia (planted over 50 years ago by Henry Greene), living somewhat "out of place" in the lowland of this rather "wet" prairie. Now would probably be a good time for a visit. As Ted Cochrane states in his book on the Arboretum prairie plants: "...this Baptisia creates a stunning effect in the spring and early summer prior to growth of warm-season grasses."

Bur oak resprouts after fire

The upper part of our south-facing slope is a fine savanna with some nice large bur oak trees that are completely fire tolerant. They produce acorns, of course, which tumble down into the prairie remnant below. Some of the acorns germinate and make seedlings which are top-killed by our controlled burns. However, an important characteristic of oaks is the ability to resprout after fire.

What happens to these resprouts? They are killed again by the next fire, etc. etc. Will they ever turn into large trees? Eventually, one or more of these small seedlings may escape fire. If that happens a few years in a row, they may get large enough so that they become fire resistant. Bur oaks are noted for their thick, corky, fire-resistant bark.

Yesterday, I surveyed the south slope for resprouts of "bad" plants that needed spraying (brambles, buckthorn, honyesuckle, sumac, etc.). I was fascinated by the large number of bur oaks that were resprouting. The photo here shows an example. You can discern the corky bark even on these small plants.

An interesting thing about these resprouts is that the leaves lack the characteristic bur oak shape. They have rounded lobes, putting them clearly in the White Oak subfamily, but lack the deep indentations that are generally seen on leaves of larger bur oaks.

How old are these plants? We have been burning this part of the south slope for at least 10 years, which gives an upper limit for their age.

Although fire is keeping the stems of these oaks from reaching any significant size, the root system is another matter. Oaks are noted for their extensive root systems. Instead of starting over each year, as the stems have to, the roots can continue to grow and enlarge. Bur oaks in particular have very impressive underground root systems. (In 1932 the distinguished Nebraskan prairie research John Weaver excavated the root system from a small bur oak grove and published photographs of the underground network. His paper can be found in the Botanical Gazette, Vol. 94, pp. 51-85.)

Another correction: Sweet Indian plantain "is" present in the savanna

I've been going back and forth about whether I have sweet Indian plantain (Hasteola suaveolens), a wetland plant, in our savanna. My earlier post had a misidentified photo. It was Lion's foot instead of Hasteola. The milky sap was the deciding factor.

The photo below is definitely Hasteola (no milky sap, characteristic hastate leaves), and it was taken in our bur oak savanna, a long way from any wetland. This is the second savanna location that I have found Hasteola.

Spraying resprouts; big weekend

This is peak season for spraying resprouts, and Kathie and I have been keeping busy. We worked Friday, Saturday, and Sunday. Amanda has also been working all these days too.

Unfortunately, we still have lots left to spray. If they get ahead of us, the resprouts will be too big to spray without causing damage to nearby "good" plants, and we will have to use different techniques. This week will probably be the last for spraying resprouts.

Our main focus is brambles, but buckthorn, honeysuckle, grape, and sumac are also ready and we are spraying them also. (When we see poison ivy, we spray that also.)

All of the species we are spraying were top-killed during our extensive spring burns. One of the main reasons we burn is so that we can spray resprouts. As the photos show, the resprouts are small and thus can be sprayed without causing much peripheral damage. However, because they are small, they are often hard to find, but the challenge is worth it. As Amanda says, this is addictive work because it is quiet and easy. We have equipped our Solo backpack sprayers with special shoulder harnesses so that you can carry a sprayer all day long without effort.

Each of us deals with a single unit, starting at one corner and walking slowly back and forth, spraying anything bad. At the same time, you get to see the good plants. Sometimes it is a challenge to spray the bad without hitting the good. A little triage is sometimes necessary. A drop or two of herbicide on a good plant will probably not cause any damage. A casual survey the next day shows that this idea is probably correct. The sprayed target plants will show extensive visual damage, whereas adjacent good plants continue to look fine.

Grape vines are one of the more difficult plants to eradicate when they are larger, as they sprawl all over the area. Thus, spraying resprouts makes a lot of sense. The nice large leaves make them easy to see, and easy to spray.








Buckthorn resprouts are more troublesome, as they are small and often hidden among good things. Because we have been working on buckthorn eradication for so long, we have eliminated the large plants, so most of the resprouts are arising from really thin, short stems. These are often difficult to spot among all the other herbage. In the long run, it is easier to look for the resprouts themselves, such as shown in the photo here.


Finding sumac resprouts requires careful attention, as at present the divided leaves are still small and are close to the ground (photo below). This may not be the best time to spray sumac, and we will definitely have to return in mid summer to deal with those missed, but any sprayed now will not be a problem later.



One of the joys of this work is finding a hidden plant gem. Yesterday Kathie found several plants of a twayblade orchid (probably Liparis liliifolia). This orchid had been reported from Pleasant Valley Conservancy some years ago by Paul Michler, but disappeared. The small population, hidden among a patch of smooth brome, would have been difficult to find if Kathie had not had her eyes focused on the ground. These plants are mostly still in bud, with only a single flower yet open.

Frost damage to plants from recent cold snap

Folks who have lived in Wisconsin a long time are aware that you can't plant tender plants before May 15. But how about the native plants that thrive in our prairies and savannas? One might think that evolution has made sure that they don't start growing too early.

Last Saturday night the temperature dropped below freezing at Pleasant Valley Conservancy. Many species seemed not to notice, including some that were flowering well, such as golden Alexanders, blue-eyed grass, Robin's fleabane, columbine, and shooting star.

However, tick trefoil (Desmodium glutinosum), which was in full leaf, suffered severe frost damage. This was surprising, as this plant was not growing in the bottom land, where frosts usually accumulate, but in our upland savannas. As the photo shows, its leaves really got zapped.

Since we have a lot more tick trefoil than we really need, we aren't concerned about losing some, although it seems likely that the plants themselves were not killed.

Another species that showed frost damage was smooth sumac (Rhus glabra). Most of the stems of this species had been top-killed by our recent controlled burns, but resprouts were just coming up and were damaged.

I haven't done a survey to see what other species might have been affected. Those mentioned were observed during a round of spraying of bramble resprouts.

Lion's foot, not sweet Indian plantain

My post of April 21, 2010 entitled "A good plant out of place?" was incorrect. The plant in question was not sweet Indian plantain (Hasteola suaveolens) but lion's foot (Prenanthes alba). The leaves are fairly similar, especially when small, but Prenanthes leaves have milky sap and Hasteola leaves do not. The population I described in the post has milky sap.

My error. Thanks to Gary Birch for correcting me!

Dealing with burdock

We don't have a lot of burdock at Pleasant Valley Conservancy, but it is such a nasty plant that we give it careful attention.

Burdock, also called bardane, beggar's button, lesser burdock, wild burdock, or wild rhubarb, is Arctium minus. According to the UW-Madison Herbarium web site, it is an introduced and ecologically invasive biennial. It is found in every one of the 48 states, and in some of these states it is classified as a noxious weed. Some sources state that burdock may be native in some parts of its range.

Burdock forms a rosette of very large basal leaves. There is practically no root system in first-year plants so that digging is problematic at that time. Second-year plants have a thick tap root that runs deep into the ground. In its second year it sends up a long somewhat leafy flower stalk, with thistle-like flowers. Its fruits are large, sticky burs. According to one site: "Don't get to close to the plant as the fruiting heads grab onto nearly everything." (According to one source, these burs were the inspiration for Velcro!)

At Pleasant Valley Conservancy we have burdock in only two locations: the marsh south of the Barn Prairie; and on the small knoll among white oaks in Unit 13. These two sites are quite different ecologically and it is not clear why burdock has been only established here.

Some years ago we tried digging plants with a shovel but discovered that we never eradicated them in that way. Apparently, root fragments could send up new shoots the following year. We finally turned to herbicide. Presumably any broad-leaf-specific herbicide would work, but since we use Garlon 3A as a foliar spray for brambles, etc., we are using that.

Our goal is to deal with this plant in its first year, so that burs are never made. Occasionally, we miss one and find it only when pushing through tall foliage and find burs attached to a sock or pant leg.

Yesterday I spent about an hour spraying burdock plants in the wetland at the edge of the Barn Prairie. This was an area that had burned completely during the Fish & Wildlife Service burn of two weeks ago, and most of the surface vegetation had been consumed. About the first plant to reappear was burdock, and I counted over 200 plants, both small and large. This was ideal spraying, as there was practically nothing else present, so I did not have to worry about peripheral damage. The photo to the left shows two sprayed leaves.

The infestation in this area was extensive, with leaves of varying sizes, even including seedlings still at the cotyledon stage. I sprayed them all.

I am trusting that eventually we will be able to eradicate burdock, since the patch we had at the edge of the Barn Prairie, sprayed for the past 4-5 years, now seems to be gone.

Installing a boardwalk across our wetland

Everything finally gelled and with the help of a lot of great volunteers we were finally able to install the boardwalk across a section of our wetland. There is now dry access from the edge of the Crane Prairie to the edge of the creek. It is also possible to walk along the edge of the creek for quite a ways. Mostly this route is across areas that were burned in the Fish & Wildlife Service burn of April 27.

The boardwalk was designed by Jim Hess, who also supervised installation. It is a noninvasive design, making no modifications of the wetland itself. The individual boardwalk units rest upon sections of telephone poles that were donated to Pleasant Valley Conservancy by Madison Gas & Electric Company. Near the start the walkway crosses a small creeklet on a bridge fabricated by Wickcraft Company of Madison, who kindly installed the bridge without charge (thanks, Brian Kuehn!).

The bridge was installed on November 12, 2009, and we started fabricating the walkway sections soon after. However, the heavy snows of early December kept us from taking delivery of the lumber. We were finally able to do the major construction of the 18 boardwalk units on December 18, 2009. See this link for details on construction. However, more heavy snows kept us from moving the units to the walkway site until late March 2010. Then we waited until the Fish & Wildlife Service burn was completed before doing the installation. Yesterday the weather was great; cool but sunny, perfect weather for this heavy construction job.

Ten volunteers made short work of the job: Jim Hess, Paul Michler, Rex Sohn, Susan Slapnick, Amanda Budyak, Bill Walters, Chris Noll, Gary Birch, Kathie Brock, and I.

The photo below shows one of the boardwalk sections being toted to its final resting place. We made 18 sections, although we only needed 17 to reach the creek.


The photo below shows one of the telephone pole sections being toted to its site. Obviously, these are fairly heavy.


The next photo below shows one of the 10 foot sections being set into place. Since the wetland was fairly flat, each section matched fairly well with those on each side of it, although there was some jumping up and down to make the final match work.


The sections were connected together by 2 foot spacer boards, held in place with large bolts. The intent of the design was to permit the sections to move in relation to each other as the wetland underwent changes.

The photo below shows two sections bolted together. Once they were connected, the final floor boards were screwed in place.


When we reached the creek, we installed a "tee" section at right angles, so that viewers can spread out a little. We plan to install another unit to enlarge this viewing site.



What is going to happen when we get a flood? One of our neighbors is convinced that the whole boardwalk will float away. However, Jim Hess has planned for this eventuality. A ten-foot long metal tube has been driven into the wetland next to each unit, and fastened to the unit by a metal bracket.

This boardwalk has two functions. The first is to permit visitors to get "into" the wetland, for bird and butterfly watching, and enjoyment of the area. The second is to give us access to the wetland for restoration purposes. We have never been able to really control invasive brush properly. There are lots of large honeysuckles along the creek. Now we will be able to start to deal with them.

1st annual workers' bird list

Our diligent workers are currently spraying bramble resprouts. This is a surprisingly pleasant activity, as it is quiet and peaceful. While they are working, they are able to hear the bird fauna. Spearheaded by senior restorationist Susan Slapnick, yesterday they compiled a list of birds heard at Pleasant Valley Conservancy. The list is below: over 40 species.

Thanks, Susan, Marci, Megan, and Amanda!

Eliminating small buckthorn

Because of the extensive seed bank, buckthorn continues to send up new shoots for years after the original plants have been eliminated. I have tried lots of different ways of killing these small shoots, including foliar spraying and cutting and treating the cut stems. Both of these methods work, but have their own problems.

My new method, which works like a charm and is quick and economical, is basal bark treatment using a foam paint stick on a long pole. No stooping. Quite conservative of herbicide, and very easy to control.

I have discussed the foam paint stick technique in my web site, and in several blogs. Until recently, we were using this only for treating cut stems. But obviously the same device can be used for basal bark application of herbicide. Because buckthorn stems are small and smooth, the foam brush is easily used.

The photo above shows a group of buckthorn stems that have been treated. The zone where the herbicide was applied can be seen. It isn't necessary to apply herbicide all around the stem; just one side is enough. The herbicide is 20% Garlon 4 diluted in Bark Oil, with an oil-soluble red dye added.

The photo to the left shows a buckthorn stem that had been basal barked with the foam brush about 2 weeks ago. The bright green leaves have turned to a dirty gray and have curled up. In another week or so, the stem should be leafless.

I treated 24 marked stems and all 24 showed the same response.

This technique should be usable any time of year, although if used now the response is very easy to see.

We have been using foam paint sticks for several years. I'm not sure why I never thought of using them for basal bark treatment.