Tom's Blog

Monday, July 14, 2014

Turning an abandoned house site into prairie

The farm house near our cabin was burned down by a former landowner. The land under and around the house was ignored until we removed the debris about 15 years ago. By the time we started restoration work here, the land had become a major weed patch. Wherever there weren’t conventional weeds, day lilies had run amok.

Once we started, it took us 12 years to eradicate all the bad plants and to get a lush, diverse prairie established. Although not a Superfund site, the legacy of the house structure undoubtedly made this restoration difficult. Our experiences might be useful for those trying to establish natural areas in urban areas.

Before planting, the herbaceous vegetation and the brush were treated with 2-3% glyphosate (foliar back-pack sprayers) and the dead vegetation burned off. In November 2002 the site was planted with a prairie mix suitable for dry-mesic to mesic conditions.

Although prairie plants became established, there still remained a lot of undesirable vegetation. The principal undesirables were day lilies, brambles (mainly black raspberries) and sumac, with occasional honeysuckle.

We got started with serious eradication work in 2006 and finally, in 2014, we seem to be finished. Although this seems a long time, I suspect it is typical of what one can expect when restoring such a very bad site. Since it was a small site (less than 1 acre), complete canvassing the site could be done, ensuring that no invasive plant was missed.

We burn this site every year, usually in mid- to late-March. As soon as the invaders started to appear they were sprayed, several times during the early growing season. The goal was to have all the invaders sprayed before prairie vegetation got too big. Further details are given below.

Day lilies. There were lots of these, and they had spread all through the site, as well as into other areas nearby. Because this is a monocot, glyphosate was used. Fortunately, these plants show early so we could kill them before “good” species got too big. However, day lilies have a deep, persistent rhizome system, making them difficult to kill. We discovered that for success we needed to use a high concentration of glyphosate (8%).

Brambles. These generally don’t begin to appear until early May, but continue to show throughout most of the month. We attempted to catch these at the rosette stage, using a foliar spray of 3-4% Garlon 3A. Any plants that were missed in the May sprayings were allowed to grow until they were several feet tall (so we could sure we weren’t missing any), and then killed by basal bark treatment with 20% Garlon 4 in oil. Complete eradication took so long presumably because of the extensive rhizome system.

Sumac. This shrub also has an extensive rhizome system, but has the additional problem that it root suckers extensively. Thus, after the above-ground plants are killed with Garlon, root suckers form and will continue to appear until late summer. Those shoots appearing in early June can be sprayed with Garlon but those missed or arising later are best allowed to wait until they are large enough so that they can be treated by Garlon 4 basal bark. Like brambles, eradication of sumac took quite a few years.

Even though the prairie plants had become well established over the first 3-5 years after seeding, it took at least 10 years to eradicate day lilies, brambles, and sumac.

Ragweed and other annuals were hand pulled before flowering, generally by mid-summer.

Because this site was small and was near the cabin, it could be monitored easily, which was a real advantage.

The photo shows what the site looks like now.

Part of the Cabin Prairie that was planted on the old house site.
A diverse flora has been established, including both forbs and grasses

Saturday, July 12, 2014

Nice oak savanna video from Oregon

I stumbled across a link to this video while editing the Oak Savanna page on Wikipedia. Well worth watching this 8 minute video. Although the species are different in Oregon than in the Midwest, the habitat seems very similar.

Oregon oak savanna video (It may take a few seconds to load.)

The principal oak here is the Oregon white oak or Garry Oak, Quercus garryana, named for Nicholas Garry, a deputy governor of the Hudson's Bay Company in the early 1800s. This species ranges from southern California to southwestern British Columbia, growing mostly at lower altitudes.

Friday, July 11, 2014

Mowing roadside weeds

Those battling weeds in natural areas can't help being depressed as they drive along and see large populations of enemy plants. Late summer is especially bad as these weeds start setting seed.

Some of these weeds are biennials, and can be controlled if they are mowed at the right time. Over the last few years the mowing crews seem to have realized this and now are trying to work at the right time. Unfortunately, with the large mowers they use they can't get next to sign posts, guard rails, and other permanent structures at the edge of the highways.

Road crews are unable to mow next to guard rails and other permanent structures in the right-of-way
Kathie and I did a brief survey of the unmowed weeds present along this particular Dane County Highway KP guard rail. The diversity was not surprising. What was disturbing was the number of perennial species, since these cannot be controlled by mowing. They must be sprayed with a broad-leaf-active herbicide.

Weed along guard rail
Life style
Bird’s foot trefoil
Canada thistle
Common ragweed
Giant ragweed
Queen Anne’s lace
Trifolium (short white clover)
White sweet clover
Wild parsnip
Yellow sweet clover

Some of the shorter weeds, such as bird's foot trefoil, "like" to be mowed. That is, because of their short stature the mower misses them, and since competition from the taller-growing weeds no longer occurs, they flourish. This is why bird's foot trefoil is so common on mowed median strips in urban areas. 

Despite the diligence of road crews, I am not encouraged that significant control of our roadside weeds can be developed. There are too many ecological and political problems. 

Friday, July 4, 2014

Butterfly milkweed having an especially great year

Black Earth Rettenmund Prairie State Natural Area is always one of the great sites for the showy butterfly milkweed (Asclepias tuberosa), but this year is especially nice. I counted 180 plants, mostly fairly large, in a small (1 acre) patch which is representative of most of the 16-acre prairie remnant. The photo here, of the South Unit, is typical. The area we call the "Saddle" is also especially nice, but the whole prairie is in full bloom.

This species does especially well in dry mesic prairies such as Rettenmund, where it is found in association with lead plant, Coreopsis palmata, prairie rose, compass plant, rosin weed, big bluestem, needle grass, prairie dropseed, and rough blazing star.

Those following these posts may remember that butterfly milkweed was also doing well at this site in 2012. However, soon after that post was made, the effects of that summer's drought made themselves felt, and many of the plants started to senesce. Seed set that year was very poor. Although the species snapped back in 2013 it was nothing like this year.

The following observation indicates that butterfly milkweed self-seeds well. Adjacent to Rettenmund Prairie is a 3 acre pasture that has not been grazed in about 20 years. When grazing was discontinued there were no prairie plants at all.

We have been burning this pasture biennially since 2002. Nothing has been done to this pasture except burning, yet as the years have gone by it has turned into a prairie remnant dominated by little bluestem, with a few scattered forbs. About four years ago, butterfly milkweed plants started to appear, and the number has gradually increased. This year the number of milkweed plants is quite large, as the photo below shows.

Former pasture now rich in milkweeds. Subjected only to biennial burns. 
This is a dramatic example of the ecological power of fire!

An interesting fact about butterfly milkweed is that in contrast to all the other milkweeds it does not have a milky sap.

Wednesday, July 2, 2014

Long-term success with smooth brome eradication on a prairie remnant

Although it may take a while, it is possible to replace smooth brome with a high diversity of native prairie species. In the early days of our restoration work on the road-cut of our south-facing slope, while we were concentrating on brush/tree removal and wild parsnip/sweet clover control, smooth brome got started. Due to ignorance, we ignored it! Within a few years it had become well established, and native species had become scarce.

In contrast to the south slope as a whole, which was (and is) a fairly good prairie remnant, the road cut was virtually barren with only a few "good" species. I assume this is a legacy of road construction, since Pleasant Valley Road was re-aligned sometime after World War II. Also, the road cut is steeper than the rest of the hillside, and hence more xeric.

In 2005, five years after we had cleared the road cut and the whole south slope, we carried out an eradication of smooth brome on the road cut by early-season glyphosate spraying. This technique is described in some of my earlier posts. The photo here shows the spraying we did on April 14, 2005.

Pleasant Valley Road being sprayed with glyphosate by the local Co-op in 2005. The green is virtually "pure" smooth brome.
About a week after the road cut was sprayed, it was hand-planted with a complete prairie mix. Some of the species appeared within a year or two, but many of them took some years to get established. Although a few plants of lead plant were found after 6-7 years, this year, 9 years later, we now have dozens of plants. Since lead plant is a fairly conservative prairie species (C value of 7), and a virtual indicator of dry prairies, it is satisfying to see so many now well established.

Lead plant (Amorpha canescens) now well established on the Pleasant Valley Road cut.
Yesterday my brief survey came up with the following species now established on this road cut. Since this wasn't an exhaustive survey, I'm sure there are more.

Latin name
Common name
Amorpha canescens
Andropogon gerardii
Big bluestem
Anemone cylindrica
Prairie thimbleweed
Asclepias tuberosa
Butterfly weed
Astragalus canadensis
Canada milk vetch
Baptisia alba
White wild indigo
Dalea purpureum
Purple prairie clover
Desmodium canadense
Showy tick-trefoil
Desmodium illinoense
Illinois tick-trefoil
Echinacea pallida
Pale purple coneflower
Erigeron strigosus
Daisy fleabane
Heliopsis helianthoides
Ox-eye sunflower
Kuhnia eupatorioides
False boneset
Lysimachia ciliata
Fringed loosestrife
Monarda fistulosa
Wild bergamot
Ratibida pinnata
Yellow coneflower
Rudbeckia hirta
Black-eyed Susan
Schizachyrium scoparium
Little bluestem
Silphium laciniatum
Compass plant
Sorghastrum nutans
Indian grass
Thalictrum dasycarpum
Purple meadow-rue
Tradescantia ohiensis
Common spiderwort
Verbena stricta
Hoary vervain

During the years since 2005, the road cut has only been managed by annual dormant season burns and brush control at about 3-4 year intervals.

This year brush on the whole south slope was controlled by basal bark treatment with our standard method, 20% Garlon 4 in bark oil.

Due to the steepness of the road cut, work there requires a bit of special skill. Thanks to Susan, Amanda, two Chris', Kathie, Heisley, Marci, Dan, Sara, Willis, and perhaps others for managing to stay upright while planting and doing careful brush control work!

Saturday, June 28, 2014

Sweet clover: why is it so prevalent on our prairies?

Sweet clover (Melilotus alba; M. officinalis) is probably the most expensive weed that we deal with in prairie restoration work. In contrast to garlic mustard and reed canary grass, the control cost per person hour per acre is quite high, and most infested areas are almost impossible to eradicate. The principal reason is the historical legacy of former sweet clover agricultural use.

As part of my interest in historical ecology I dug into the early agricultural literature on sweet clover.

Sweet clover is native to Central Asia but has spread around the world. The Greeks wrote about it and it has been in Central Europe since the Middle Ages. It spread to North America in the 1600s. (One of the early ways it arrived here is in soil used as ship ballast.) Although an agricultural crop, it spreads well on its own and in the late 19th Century it was extensively present on roadside, waste lands, and other disturbed areas. In fact, it was so prevalent that in 1893 it was declared an “official” noxious weed in Wisconsin and Illinois.

However, many farmers objected to calling it a weed and a love/hate relationship soon developed.

Here is a report from Illinois in 1916: “When the sweet clover started to come into our state our people rose up in arms as they thought it was a catastrophe that had fallen upon them and they aroused the Legislature and passed a law placing sweet clover on the list of noxious weeds. The law passed and people were compelled to get out on the roads with scythes, grub hoes, etc. to cut down the sweet clover. They tried very hard to destroy it but the more they waged war against it the more the plant would come on and it has gone from the southern part of the state to the northern part of the state and wherever it has gone it has paved the way for the plant which is still better than the sweet clover---alfalfa. [Sweet clover] has carried the proper germs [root nodule bacteria] necessary for the growth of alfalfa. It has taken possession of the roadsides in many parts of the state, but it has been instrumental in crowding out bad weeds along these roadsides….It has performed an important mission and after we woke up and found that the sweet clover was a true friend, they rushed back to the Legislature and had it taken off the list of obnoxious weeds….there is a future for the sweet clover plant in our state.” (Annual Report Vol. 21, Illinois Farmers’ Institute. 1916)

In the period from about 1910 through the early 1940s sweet clover became a widely used crop, especially in the North Central area of the U.S. (In 1929 Illinois had 757,000 acres of sweet clover growing. And in the early 1930s over 50,000,000 pounds of sweet clover seed was produced in the U.S., an indication of the acreage being planted. U.S. Bureau of Agricultural Economics for 1932)

Here were some of the many advantages of sweet clover as a crop:
  • Among most productive crops available if handled properly
  • Bees love it and it is a great honey plant
  • Used in roadside mixes because drought-resistant and hardy (can survive road salt)
  • Very useful in the reclamation of eroded and degraded land
  • Used as a green manure for soil improvement
  • Cover crop for grass
  • Hay
  • Silage
  • Seed production (for market)
  • Food plots for wildlife

During the period when sweet clover was widely used, it readily “escaped” and moved not only into roadsides and waste lands, but sunny natural areas such as prairie remnants.

Although presently sweet clover is no longer widely used, we are left with the legacy of earlier times. Listed below are the botanical and ecological characteristics responsible for the problems that sweet clover gives restorationists:
  •  Drought tolerance
  • Ability to live on poor soils
  • Nitrogen fixer
  • Prolific seed producer
  • Seed characteristics
    • Each plant can produce many seeds
    • Seeds can remain viable in soil for many years (>100 yrs)
    • Hard seeds difficult to germinate
      • But heat from prescribed fire brings about germination
  • Allelopathic, preventing  the growth of native plants

 It is important to note that sweet clover will only grow in soils with pH 6.5 or higher. This means that for agricultural purposes it often needs lime. In many areas of Wisconsin, especially in the Driftless Area, sandy soils and those that have developed on sandstones (such as St. Peter Sandstone), are too acidic so that they will not support prolific sweet clover growth. Thus, sweet clover may not be a problem in all prairie remnants.

Today, whenever a prairie remnant is restored in our area, fire is one of the first tools that is used. Although fire is obligatory for prairie restoration, it also induces sweet clover seeds to germinate. Especially after the first burn in virtually any remnant, there will be a major “flush” of sweet clover plants. Although these new plants can (and must) be eradicated, they are an “indicator” that likely sweet clover once flourished in this site and left a seed bank that has the potential for lasting many years. If such a sweet clover flush occurs, it guarantees that the restorationist is at the start of a lengthy task.

How about former agricultural lands? It depends. Some of these fields may have been used to raise sweet clover many years ago, and viable seeds may still be present. Although most of these seeds may be well below the surface, scattered seeds may be near the top and may be induced to germinate by prescribed burns. Although sweet clover will likely not be a problem, this is not guaranteed, so that any planted prairie should be monitored. Even without fire, it is inevitable that some buried seeds will germinate. However, it does seem probable that sweet clover eradication will be easier in former agricultural fields than on remnants.

Despite its strong reputation as a highly invasive plant, and the large amount of money spent by restorationists to eradicate it, regulation in North America of sweet clover as a noxious weed is very spotty. Here is a list of what I have found:

Official declaration in the 21st century established or considered (mostly unenforced):
  • New England
  • Iowa
  • Colorado
  • Texas
  • Australia
  • Quebec
  • Alberta
  • Various counties, Washington
  • Lake Tahoe basin, California
  • Town of Middleton: Dane County, Wisconsin
  • Others?
  • Not listed in Wisconsin’s new regulation NR40 (but neither is crown vetch, bird’s-foot trefoil, or reed canary grass!)

Monday, June 23, 2014

Butterfly trip at Pleasant Valley Conservancy

On Saturday, June 21, 2014, a butterfly field trip (24 participants) was held at Pleasant Valley Conservancy led by Ann Thering and Kathie and Tom Brock. This trip was held under the auspices of the Prairie Enthusiasts, Madison Audubon Society, and the Southern Wisconsin Butterfly Association. This was the fourth year this trip has been held and it is almost becoming a "regular". We are pleased that Pleasant Valley Conservancy has become a great site for butterfly conservation.

Due to time constraints, only the wetter areas of the Conservancy could be visited. Thus, species found primarily in the oak savannas or dry prairies are probably missing from the list below. The count was provided by Ann Thering.

The Baltimore Checkerspot is one of the species of most interest, since it is not that common in southern Wisconsin. As the "count" shows, Pleasant Valley Conservancy is a great site for this species. The photo shows a "tame" mating pair of this small but attractive species.