Matthew Sarver » Pennsylvania

Knocking Out Knapweed

Matthew Sarver — Fri, 07 Aug 2009 04:44:42 +0000

Another July has come and gone, but not all of the fireworks are over. The striking pink display of spotted knapweed, Centaurea stoebe ssp. micranthos, is still going strong in rangelands and old fields and along highways and railroad grades across the country. Native to Europe, spotted knapweed was introduced accidentally to North America in the late 19th century, and has since become a problematic invasive weed, especially in the west.

The pinkish-violet blossom of spotted knapweed.

I first noticed knapweed blooming on our wildlife sanctuary property in Pennsylvania about five years ago, at the same time that I started to seriously consider the possibilities for habitat management on the site. Knapweed control was one of my first projects on the property. Since I knew that mowing was counter-productive (causing the plants to flower at a lower height), I decided to pull the knapweed by hand. I’ve repeated the process for four years, and have eliminated spread of the plant while steadily reducing the seed bank at the main introduction site. Because spotted knapweed seedlings assume a low-growing rosette form during their first year and don’t bolt and bloom until their second year or later, I’ve been able to track my success by noting a significant reduction in rosettes (a few dozen this year compared to countless hundreds during the first year of two of treatment).

Unfortunately, Spotted Knapweed is a highly favored bee plant, used heavily by native bumblebee species. It’s always emotionally taxing for me to pull, bag and dispose of the knapweed with bumblebees crawling all over the blossoms as I work. This brings me to one of my take-home messages in invasive species control and restoration: in degraded habitats, native species often rely heavily on invasive plants because the diversity of native plants has been reduced. It is important to know what native insect and wildlife species rely on the invasive plant you are removing. Then, when planning a restoration, try to plant (or enhance habitat for) native plants that provide resources at the same time of year as the invasive. In my case, I’m working on restoring some meadows that will hopefully make up for (from a bee perspective) the eventual disappearance of my knapweed stand.

Spotted knapweed is an invasive plant, but is used extensively by native bumblebees

Since I’ve been working on this population for several years with a good deal of success, I thought I’d share a brief description of my spotted knapweed manual removal method.

Here are a few important points:

Get a good digging tool – I have tried various things – heavy clawhammers to grab and yank roots, various hand tiller/weeder/fork type things, etc. I’ve recently settled on a well-balanced, heavy-duty, and inexpensive digging tool (see the photo below) that I picked up at the friendly neighborhood home improvement warehouse.
Pull plants during their bloom period and before they’ve gone to seed. Be sure to bag and dispose of the plants in a landfill, to avoid dispersing seed or root fragments. A good rain just before (or even during) pulling makes the job much easier.
Be patient when pulling and learn to stop and dig more when you feel that the root is about to snap. Pieces of root left in the ground will sprout the following year.
Don’t dig right at the base of the plant – you risk cutting through the root, which often twists to one side or another a few inches down. Instead, loosen the soil about 5-6 inches from the base of the plant.

Here’s the process illustrated:

This is my tool of choice: a beveled, pointed blade on one end (used the most) and a straight blade on the other. The pointed blade sinks well into the shale soils where my infestation occurs.

Many stems usually radiate from a single root crown of older Spotted Knapweed plants. It's important to gather all the stems up to get a good grip on the plant for pulling.

Strike the ground about 5-6" from the base of the plant and loosen the soil, prying up with the tool while pulling straight up on the plant. Pulling at an angle makes it more likely that you'll break the root.

The root system should pull up cleanly if you loosen the soil enough and slowly pull upward on the plant.

The root crown can be quite broad on robust plants, or much smaller with fewer fibrous roots on stressed plants.

Please let me know if you have had success with other spotted knapweed control methods. I have considered trying Milestone, a selective herbicide that is supposedly quite effective on both knapweed and thistles. So far, I haven’t needed to resort to spraying though, since manual removal has been working well and at this point only takes me about a day each year to complete. Now if only I could eliminate my crown vetch, smooth brome, and reed-canary grass this easily!

Pennsylvania Passes Prescribed Burning Act

Matthew Sarver — Thu, 23 Jul 2009 15:52:45 +0000

Many ecological communities in Pennsylvania (including native grasslands, oak-hickory forests, and serpentine barrens) depend on periodic fires to maintain their plant community composition and structure. In an even wider range of habitats, fire can be a tool to help combat invasion by non-native plant species. But conducting prescribed burns on private land has been a challenge in the state because of liability concerns. While other regions of the country have embraced the modern use of prescribed fire in managing habitats, Pennsylvania has long been stuck in the Smokey the Bear fire suppression mentality, with only a few organizations conducting regular prescribed burns on private land.

All that changed on July 14th 2009, when Pennsylvania Governor Ed Rendell signed House Bill 262, establishing the Prescribed Burning Practices Act. Introduced by Rep. Gary Haluska, the new law authorizes the state Department of Conservation and Natural Resources to establish standards for the conduct of prescribed burns in the state. The state will begin regulating burning practices by certifying burn managers and requiring state approval for burn plans. In exchange, the law limits the criminal and civil liability of landowners and burn managers, so long as the regulatory process is followed:

No owner of property who contracts with or authorizes a prescribed burn manager to conduct or permit a prescribed burn on the property pursuant to the requirements of this act shall be subject to civil or criminal penalty for damage or injury caused by the fire or resulting smoke, unless negligence is proven.

- PA House Bill 262

The passage of this law is a major step forward in facilitating the use of prescribed fire as a management tool on private conservation lands in the state. I hope to be able to use fire to manage the grasslands at my own wildlife sanctuary property in southwestern Pennsylvania at some point in the future.

Another exciting step forward is the establishment of The Pennsylvania Prescribed Fire Council, an organization created “to promote the exchange of information, techniques, and experiences of the Pennsylvania prescribed fire community, and to promote public understanding of the importance and benefits of prescribed fire.”

PPFC has named Matt Boss of The Nature Conservancy as the Council’s first Training Coordinator. You can join the effort to promote prescribed burning in Pennsylvania by becoming a member of PPFC.

Down on the Farm

Matthew Sarver — Mon, 22 Jun 2009 04:28:08 +0000

I recently returned from spending several days hard at work on my “farm”. Why the quotation marks? Well, the 116-acre property, which has been in my family since the early 1900s, doesn’t grow crops or livestock these days, but does produce both Grasshopper Sparrows and Henslow’s Sparrows on 80+ acres of reclaimed strip mine.

Situated on the western slope of Chestnut Ridge, the property climbs over 400 feet in a little over half a mile. The walk from the stream bank of Laurel Run to the top of a high, grassy knoll on the eastern end of the property tests the aerobic fitness of most visitors, myself included.

Once atop the hill, a panoramic view to the west awaits. Sunsets here are magnificent, and on clear days the towers of the Pittsburgh skyline some 35 miles distant are clearly visible. Because our parcel is only part of a 200+ acre reclaimed strip mine, the property has hosted area-sensitive grassland birds for many years. Recently, however, Black Locust, Tree-of-heaven, Autumn Olive, and other woody vegetation have been gradually shrinking the available habitat for these grassland specialists.

To combat the loss of grassland habitat to succession, fight invasive species, and plant natives, we enrolled in the USDA Natural Resources Conservation Service Wildlife Habitat Incentive Program (WHIP). The cost-share assistance provided by this program has allowed us to begin restoring habitat on the property. We’re in the fourth year of our WHIP contract, and the restoration work is steadily progressing. I’ve added a new page, titled Sanctuary, to the main site, with a PayPal button so you can contribute to our efforts if you’d like to help us out!

Look for more on the restoration progress and the biota of the property in upcoming posts!