Sunset at Big Hollow Main Prairie

The Xeric Limeston Prairie Garden

XLP garden plot

This year has been the first growing season for three garden beds planted with locally collected prairie seeds.  The process of preparing these gardens started last growing season with the spraying of the garden beds.  I sprayed the beds with 3% glyphosate solution several times throughout the growing season in order to kill persistant perrenials and to start to deplete the seed bank of various annual species.  This practice of spraying throughout the season takes patience and persistance, but having a seedbed free of competing vegetation makes establishing a garden from seed very simple.

All three of these beds contain a similar mix of species.  The grass component of the seed mix includes (listed in order of abundance), sideoats grama, little bluestem, poverty oatgrass and arctic brome.

Chinese mantis: Tenodera sinensis

 The forb component was planted separately in early February to allow time for the forb seed to stratify.  Most forb species seed will not germination without exposure to a cold moist enviroment over a period of about two months.  The february sowing seemed to be adequate for breaking seed domancy of most the species planted which includes, Rudbeckia hirta, Eupatorium altissimum, Asclepias tuberosa, Asclepias verticilliata, Asclepias viridiflora, Solidago juncea, Solidago nemoralis, Allium cernuum, Trichostema brachiatum, Heliopsis helianthanoides, Pycnanthemum incanum, Blephilia ciliata, Desmodium paniculatum and Aster laevis.  At the time of sowing the seeds were simply scattered evenly of over the soil surface, and were buried over time by the heave/thaw action of the winter time soil.

maryland senna: Senna marilandica

Pictured above is my maryland senna seed production patch I planted in spring of 2011.  To prepare them for germination I pulsed the extremely hard seeds in a blender to chip and scarify the seed coat.  Senna seeds will not germinate without mechanical scarification or weathering in the soil over a period of a couple years, so I choose the short term option.  These plants originated from seed collected from several small plants growing in a Juniata County XLP under very dry rocky soil conditions.   Growing them out in this double dug vegetable garden allowed these plants to reach their current size and produce a similar amount of seed in their first year of growth from seed.

sideoats grama: Bouteloua curtipendula

This is my sideoats grama seed production bed.  It was established from seed from several prairies in Centre County in 2012.  This plot is also located in a old vegetable garden bed and the grasses have managed to bloom and set quite a bit of seed in their first season of growth.  The red colored parts of this plant are the pollen producing anthers.

This garden was previously planted in virginia wildrye along with some other flowers. In midsummer before the wildrye set seed I applied gylphosate throughout the bed.  Since the initial application I made several isolated follow up treatments. I decided to the leave the exotic Buddleia or Butterfly bush as it smells so nice and pollinators love it.  It does have the ability to self sow, but not to an unmanagable degree.  Beside the Buddleia, I left three eastern redcedars in the bed to provide some evergreen cover and to create some of the physical structure of the local prairies.  This plot gets more shade from the nearby walnut canopy and will probably have no true prairie grasses seeded.  Im considering using bottle brush (Eylmus hystrix) as the dominant graminoid in the background areas of this plot, with the shorter poverty oatgrass (Danothonia spicata) planted in drifts in the foreground area.

Slender lady's tresses: Spiranthes lacera var. gracilis

The slender lady's tresses started blooming about a week ago at the Main Prairie. These flowers are fairly abundant this year.  I would estimate a total of 20 to 30 flowering stems are blooming throughout the Main Prairie.

Before today I have never seen butterflies utilizing spiranthes for nectar.  Pictured above is a pearl crescent butterfly.  In this same area I spotted 2 small hairsteak butterflies which were also actively feeding on this orchids flowers.

Stiff goldenrod: Solidago rigida

The stiff goldenrod and gray goldenrod populations at the Main Prairie are responsible for the prairies current color scheme.

Back to the Main Prairie

The Main Prairie at Big Hollow

 

Compared to mid July the Main Prairie has entered a lull period in its flower phenology.  The slight haze of yellow in places foreshadow the flowering of several species of goldenrod later in August.

and has

Cirsium discolor patch

 

 

In areas along the woods edge field thistle has started blooming. These areas have become a fixture for nectar foraging insects.

Hemaris thysbe: Hummingbird Clearwing

Big Hollow Mesic Prairie

Northern blazing-star: Liatris scariosa

The Liatris scariosa plants at the Mesic Priairie at Big Hollow are blooming presently. 

Heliathus strumosus

Pictured above is a large colony of sunflowers that grow out onto the footprint of a sewer line right of way.  This area looked more less like bare mineral soil last winter from heavy equipment activity.  Fortunately the disturbance in this area was very superficial and the prairie and this adjacent sunflower patch were not damaged.

The Sporobolus Grassland

Today I visited a unique grassland not far from the Big Hollow Prairie.  I've come to call it the Sporobolus Grassland, be cause poverty dropseed or Sporobolus vaginiflorus is the dominant graminoid at this site. 

Allium cernuum was blooming in abundance

 Poverty dropseed leaves are long and wiry and create a beautiful wispy texture in grasslands where it predominates.  Unfortunately this seems to be last remaining dropseed grassland in the area.  Most grasslands in Pennsylvania are not stable and are changing to woodland and invasive shrub thickets.  Black walnuts are encroaching upon this grassland.  In addition, the exotic invasive bush honeysuckles and autumn olive are problematic invaders at this site as well.

Flowering spurge: Euphorbia corrollata

Flowering spurge is blooming in abundance in this habitat.

A small colony of Pale indian plantain: Cacalia atriplicifolia, grows at this site

Siphium trifoliatum

Above is a photo of Silphium trifoliatum at the main prairie.  The main prairie contains many of these plants but most years only a few of them will bloom.  This year I have counted 15 blooming plants at Big Hollow's Main Prairie. Deer herbivory on this Silphium population has always been voracious, but this year the deer seem to have held back a bit.  I will guess that this can be attributed to two changes from the previous seasons.  Wetter weather (up until July) has increase plant biomass, but also clearing the woodlands surrounding the prairies of exotic shrubs and vines has removed a lot the cover the deer need to feel secure in the area.  Clearing the surrounding woods has been a win-win situation for the Silphiums at Big Hollow, reducing deer herbivory and releasing many established plants from deep shade.