Seeing green this time of year is bad!

By late October most of the native species have either turned color or lost their leaves. Anything green now is almost certainly nonnative (bad). This is a great time to survey for invasive brush which, because they are still green, really stand out.

Buckthorn bush in the midst
of the S slope prairie 

Buckthorn and other nonnative shrubs: Buckthorn, in particular, really stand outs, as the photo shows. Note that this buckthorn plant is a new vagrant in a tall grass prairie that has been burned annually for the past 15 years. This shows two things: 1) Fire will not eradicate buckthorn; 2) The buckthorn rootstock has a long persistence, since this plant is new in 2015 in an area that had been cleared of buckthorn in 1998!

However, this is probably not a good time to use a foliar spray on this bush. At this late in the season, one can't be certain that the herbicide will still be translocated to the roots (which is essential if this bush is to be eradicated). However, basal bark with 20% Garlon 4 in bark oil will work 12 months of the year, and this is how Amanda dealt with this plant.





Nonnative herbaceous perennials still green: Lots of nonnative herbaceous perennials retain their green color long after native species have senesced. This includes such culprits as garlic mustard, hedge parsley, sweet clover (1st year plants), mullein, burdock, catnip, and motherwort. This is an excellent time to foliar spray these plants with 2-4% glyphosate. The rule is that only green leaves will take up glyphosate and translocate it to the roots. Since most native species have senesced, there is no danger of peripheral damage.

This time of year, all of our Solo backpack sprayers have been put away for the winter, but the Solo 2 gallon hand-held sprayer was still available and worked well on this small area. It took about 15 minutes to deal with this patch. A nearby patch of catnip was also treated.

Large motherwort patch near the parking area. This area was highly disturbed due to road building
and has been a difficult area for us to restore. Motherwort and catnip are continual problems.
Note the handy Solo sprayer. 

An exception to the "rule of green": A number of native species do exhibit the phenomenon of "fall regrowth" so a few native green plants may still be present. These are usually found as rosettes near to last summer's senesced stems. Generally, these are easy to spot and should obviously not be sprayed.

Upland boneset, a Special Concern species

Upland boneset (Eupatorium sessilifolium) is a Special Concern species in Wisconsin and Threatened in Michigan. As the Wisconsin State Herbarium map shows, it has a narrow distribution in the southern part of the state. It has a Coefficient of Conservatism of 9.

(Although it is a "classic" savanna species, for some reason it was excluded from the Cochrane/Iltis Atlas of the Wisconsin Prairie and Savanna Flora.)

Note that E. sessilifolium can be easily distinguished from the much more common tall boneset (E. altissimum) because of its sessile leaves (see photo below).

In the early days of restoration at Pleasant Valley Conservancy we had only a single stand of 5 stems at the SE corner of Unit 8. We raised seedlings in the greenhouse and planted transplants in likely areas in the Conservancy. Most of these transplants grew and we now have this species in a number of good savanna sites. In addition, it has spread on its own from the original stand and there are now many plants in other parts of Unit 8.

We have been working with upland boneset for over ten years now, and have found that despite the lush flowers and seed heads, germination of seeds is below 5%. However, the species transplants well, so that those seedlings we have been able to raise generally become well established. The population shown in the photos here was part of a transplant series that has flourished in Unit 19C.

This species may be more common in southern Wisconsin than the map below shows. (Because it is a State-listed species, detailed locations are not given in the Herbarium website.)

Update 26 October: Yesterday I discovered a new large patch of upland boneset just south of the South Firebreak in Unit 5. Kathie and I counted over 20 flowering stems. Nice to know this species is spreading on its own.

The sessile leaves are an unmistakable characteristic of Eup-sess.

Hazel (Corylus), gray dogwood (Cornus), and the problem of a woody legacy

This is the time of year when all restorationists are seeding red!

This is the best time to seek out invasive shrubs that can potentially cause trouble in a restoration project. Two shrubs that can cause major trouble are hazel (Corylus americana) and gray dogwood (Cornus racemosa). Although natives, they can be highly invasive, and can take over major parts of the restoration.

The leaves of both hazel and gray dogwood turn a rich red color in the fall, making them easy to find among prairies and savannas.

This hazel clone is easy to spot this time of year because of its lush red leaves.
Note the size of this clone, which is in a prairie/savanna remnant
that has been burned annually for the past 15 years.

Hazel is noted for the large thickets that it can form, especially in the absence of fire. The Public Land Office surveyors often recorded hazel in their notes, probably because of the difficulty that had plunging through a thicket with their measuring chain. (In contrast to hikers, surveyors were required to walk in an absolutely straight line!)

Despite some reports, hazel is definitely a clone-former, and can spread extensively, especially in the absence of fire. It is a major threat in Minnesota where extensive research has been done to control it. Research at Minnesota's Cedar Creek Science Reserve has shown that annual or biennial fires are essential to control hazel. By the third year without fire, extensive hazel thickets usually have developed, through which fire will generally not carry. Fire will top-kill hazel but will not eradicate it. 

Gray dogwood (Cornus racemosa) is another clone former that can often form large thickets. It is a common shrub in prairie and savanna remnants. In the absence of fire, it can literally "take over" a remnant. It is a major problem in Illinois, but is also common in Wisconsin. 

 These clonal shrubs are especially troublesome in remnant prairies and savannas where there is a legacy of woody vegetation. Such a legacy probably exists in almost all remnants found in southern Wisconsin because these remnants survived for many years without fire. It has only been since the mid 1980s that restoration work has begun in most remnants in our area, whereas fire had been mostly absent since the end of the 1930s.

Although annual or biennial fire can problem control these shrubs indefinitely, the only way they can be eradicated is by the use of herbicides. I have posted extensively on herbicide techniques for woody shrubs.

Note: There are situations where a woody legacy is not a problem. These are prairies that have been created from scratch from former agricultural fields. A field that has been in corn or soy beans for the last 10-50 or longer years no longer has a woody legacy. Thus, prairies created in such fields should not have any problems with woody encroachment. Burns at three-year intervals will likely be sufficient to maintain the prairie. However, even such prairies, in the prairie/forest border which is southern Wisconsin, will eventually become invaded with woody vegetation, as the example of Curtis Prairie on the UW-Madison Arboretum has shown.

Another way to eradicate Canada goldenrod

I have posted on Canada goldenrod eradication in the past.  My method was a leaf spritz with a low-volume high-concentration of Garlon 4 herbicide diluted in bark oil. [One part Garlon 4 and four parts bark oil.] A few leaves in the upper part of the plant are given a quick spray. This works well, but has the disadvantage that a small amount of herbicide mist might fall on "good" nearby plants.

Two-inch wide foam paint stick

Kathie has developed a modified procedure that permits better control of the herbicide. She uses a foam paint stick soaked with herbicide. Instead of spraying the leaves, she makes a gentle 6 to 10 inch "swipe" up the stem somewhere about waist high. To be certain that no stems are missed, she bends over the top of each stem as it is treated. She carries a small spray bottle to reload the foam from time to time.

The foam sticks are available at any hardware or paint store, in various sizes. A two-inch stick is ideal for this work.\

A Canada goldenrod clone treated about two weeks earlier. The kill rate is about 99%.
Note that there is no peripheral kill on nearby Desmodium glutinosum plants.

The ideal time to treat Canada goldenrod is from early August through early September, when the plants are in flower. At that time, the plants are large enough to find easily, no stooping is involved, and there is still time enough to return and treat any plants that were missed.

Multi-year studies with the leaf spritz method showed that it was possible to completely eradicate a clone. We anticipate the present modification will be equally effective.

Prairie plants on rock outcrops

In the Driftless Area there are many rock outcrops on which plants appear to be "struggling" for survival. If such an area is fairly large it might be called a "barren" or "bald", depending on its location.

The plants that are growing on rock outcrops are sometimes called "disturbance species", because they may also grow in areas that have suffered considerable human interference.

At Pleasant Valley Conservancy we have several rock outcrop areas, and they are never devoid of plants, despite the thin, almost nonexistent soil. The area that we call the East Overlook is the largest rock outcrop, and is an interesting area to visit. (The Mid Savanna Trail passes below and around the outcrop, continuing onto the Saddle and South Firebreak.)

When we first started restoration work, the East Overlook was heavily colonized with buckthorn, reasonable since this calciphile does well in dolomitic habitats. Years of work have eradicated the buckthorn, and now the site has only native species.

In the spring, small populations of pasque flower and prairie smoke are present. Later columbine can be seen, followed by hairbell and whorled milkweed.

A survey I made yesterday was interesting because there was a large population of hoary vervain (Verbena stricta). Kathie and I counted over 50 stems of this species in an area of about 10 X 20 feet.This beautiful plant is a classic example of a "disturbance species", since it is often found in areas highly disturbed by humans. The best population we have found was on an abandoned commercial site at the corner of County I and County V, just off Interstate 90/94. There was still lots of concrete remaining, and around the edges in the thin soil was a huge population of V. stricta. (Some people might ignore such a species, but it is a true prairie species and not highly invasive, since it probably cannot compete with the "nondisturbance" species.)

Verbena stricta shoots growing out of the very thin soil surrounding the bedrock of the East Overlook

V. stricta in a prairie. It usually thrives best at the edge,
perhaps adjacent to a path.

 Yesterday Kathie and I did a species list for this small rock outcrop. In addition hoary vervain, we found big blue stem, side oats, little blue stem, prairie dropseed, hairbell, whorled milkweed, Kuhnia, Carex eburnii, cream gentian, silky rye, and woodland brome. Also present was a single large eastern red cedar (carefully protected from fire) and several bur oak grubs. Thankfully, there was no buckthorn!

Anyone interested in rock outcrop communities would be advised to access the valuable book edited by Roger C. Anderson, James S. Fralish, and Jerry M. Baskin, 1999. "Savannas, Barrens, and Rock Outcrop Communities of North America." Cambridge University Press. It has 36 chapters that cover the whole of North America, from southern Florida to subarctic Canada. Although I bought this book because of its extensive treatment of North America savannas, I found the chapters on barrens and rock outcrops also interesting. If you are a "plant" person and do much travelling in North America, this is an excellent book to take along. Here are few examples: New Jersey Pine Barrens, Serpentine Rock barrens of Eastern and Western North America, Granite Outcrops of Southeastern  U.S.,  the Cliff Ecosystem of the Niagara Escarpment, Alvars of the Great Lakes Region, Southern Ontario Granite Barrens.

One of the areas Kathie and I visited was Mount Arabia, a site in the southeastern Piedmont region of DeKalb County, Georgia, where there was a large granite outcrop that had tiny islands of soil where primarily endemic species grew. Because of its endemic plants, this area has been protected in a state park.