Monday, December 8, 2014

Staphylea trifolia (American bladdernut)

Staphylea trifolia (American bladdernut) is a Kentucky native shrub that can be found in the wild throughout the state, but is all too rare in cultivation.  It is most commonly found growing in mesic deciduous woodlands, and to a lesser extent in floodplain woodlands and along riverbanks.   This is a handsome species whose paucity in home gardens may be due to being poorly known, or its growth habit which some gardeners may find untidy.  Bladdernut tends to form suckering colonies that spread slowly and may require additional maintenance.

Bladdernut ex situ
Staphylea is a member of the Staphyleaceae Family and takes its name from the Greek word staphyle (a cluster) which is a reference to the arrangement of the flowers.  The specific epithet ‘trifolia’ is also descriptive and means a three-part leaf.   The plant is rather easy to identify during the growing season based on the foliage; leaves are compound with three leaflets, and occur opposite on the stem.  The stems have longitudinal bands of black and gray making them quite attractive and distinctive.  Lastly, if you’re still wondering what a bladdernut is, the fruit develops into an inflated papery-bladder containing several small seeds.  Since there is no nutritive portion of the fruit, the seeds are most likely dispersed if the fruits are carried away by wind and water.

A bladdernut leaf is comprised of 3 leaflets

characteristic striped stems
pendulous flower clusters
maturing fruit
This ripe fruit has turned brown, note that the inside contains a few seeds but is otherwise 'hollow'.  These fruits may persist hanging from the stems well into winter and can be quite attractive.

The Walk Across Kentucky displays bladdernut in the Appalachian, Bluegrass, and Shawnee Hills regions.  Give it a try in your landscape if suckering stems are not a major concern and the site stays reasonably moist and shady.

Friday, October 24, 2014

Autumn Scenes

A cool and precipitous autumn has yielded some fantastic fall color on the Walk Across Kentucky.  It is the last hurrah for much of our 2014 foliage before what is purported to be an unusually cold winter.  We enjoyed a terrific growing season and are especially thankful to the many volunteers who helped expand the WAKY trails and exhibits.  Here are a few images from across the collection.

The Appalachian Plateau
Sassafras albidum, trail of pines exit

Symphyotrichum novae-angliae

The beech corridor (Fagus grandifolia)

Trail of pines entrance, Sassafras albidum

The Bluegrass
BG meadow: Symphyotrichum oblongifolium, Schizachyrium scoparium

Maple grove: Acer saccharum/nigrum

The Cumberland Mountains
Sorghastrum nutans

Castanea dentata

The Knobs

Rhus copallinum

Rhus glabra

Juglans, Fraxinus, Quercus grove

West Knobs transition
The Mississippi Embayment
The new Ash trail, Fraxinus profunda still holding leaves

Liquidambar styraciflua

The Pennyrile
Sassafras albidum

Pennyrile trail entrance: Quercus stellata & marilandica

Pennyrile prairie

Rhus & Acer

The Shawnee Hills
Rock Berm #2

Taxodium distichum

Shawnee Hills Meadow

The Woods

Thursday, July 31, 2014

Shawnee Hills Floodplain Forest


The Shawnee Hills Floodplain forest is one of the new exhibits along the Walk Across Kentucky.  Planted during the spring and summer of 2013, it has quickly become established with some exceptional native plants from western Kentucky.  Presently, this area is overflowing with blossoms and pollinators.  In particular, the cardinal flower (Lobelia cardinalis) and its pollinator, the ruby-throated hummingbird (Archilochus colubris) are a sight to see.  

This specific site is a low-lying depression planted as a grove of willow oak (Quercus phellos) in 1991.  The area sees a substantial amount of surface water collect and flow through during heavy rain events.  Because the canopy of the oaks was so dense, there was minimal vegetation on the ground, and as a result this site was prone to erosion.  What may seem to be a location unsuitable for gardening is actually an ecosystem that is quite common, especially in the Shawnee Hills region of Kentucky.  Often referred to as a floodplain forest, areas such as these typically contain hardwood trees such as the pre-existing willow oak grove at The Arboretum.  The plant community is adapted to wet soils, often deep shade, and extended periods of submersion.  

The stunning transformation of this exhibit in the past year is a testament of the dynamism of native plants when planted in favorable locations.  Not only does this highlight that there truly is a right plant for all locations, but it shows how quickly (and relatively simply) sites such as these can be established.

Here is a look back at the development of this exhibit:
'before'; a very dense grove of Quercus phellos, complemented by false indigo (Amorpha fruticosa - front left) and eastern gamagrass (Tripsacum dactyloides - front right)
Step 1. Allowing visitor access required some pruning of the oaks for clearance as well as a boardwalk, since the area is prone to flooding.  This boardwalk was part of an eagle scout project.
The completed boardwalk in autumn, 2012.  The oaks had recently dropped their leaves, but the absence of ground vegetation causes them to wash away during winter floods.
Spring 2013, the Native Plant Volunteer group begins initial planting of the Floodplain forest.  This included removal of hidden patches of purple wintercreeper (Euonymus fortunei), a significant invasive species.

Autumn, 2013.  Over 500 perennial plant plugs were planted over the course of the summer, including blue star, iris (4 species), spider lily, ferns (3 species), Lobelia (2 species), starry campion, wood poppy, Elymus (2 species), and many others.  Also planted were some shrubs and small trees, including hearts-a-burstin', wahoo, american snowbell, swamp holly, and ironwood.  A willow oak was removed in the center of the grove to allow some filtered sunlight to enter the garden.  The trunk and limbs of the tree were left to help prevent washouts and provide shelter for the turtles that nest here.

Winter, 2014.  The floods arrive.  During heavy rain events this area stays flooded for days at a time.  The new boardwalk allows access through the garden, and the newly established vegetation helped to control soil erosion 
Spring, 2014. After concentrating energy on root growth the previous year, the perennials exploded in 2014.  The blue stars, trillium, phlox, beardtongue, and iris were extremely floriferous in early spring.
Summer, 2014. (today) 
Lobelia inflata (left), Lobelia cardinalis (right).
Swamp milkweed in a sunny spot at the entrance to the boardwalk, just beginning to open.
This informational sign was designed by Arboretum intern and UK Landscape Architecture student Will Coleman, and installed on the edge of the boardwalk.
A look back towards the WAKY, cardinal flower in all directions.  A pair of hummingbirds were taking full advantage of the red flowers but moving too fast to photograph.

Thursday, July 3, 2014

Rubus odoratus (flowering raspberry)

When it comes to summer flowering shrubs, one of the hidden gems on The Walk Across Kentucky is flowering raspberry (Rubus odoratus L.).  Of course, all raspberries flower, but Rubus odoratus blossoms are particularly showy.  The 2” diameter flowers are fuchsia in color, and are borne on terminal panicles throughout the course of the summer.  A member of the rose family (Rosaceae), the flowers are very similar in appearance.

In Kentucky, Rubus odoratus is quite rare, found predominately in the Cumberland Mountain region, though it may grow as an escape further west.  Of ~9 species of Rubus native to Kentucky, R. odoratus is the only species with simple leaves.   The leaves are palmately lobed and get quite large, with a size and texture similar to Hydrangea quercifolia.  Another nice benefit of this raspberry (unlike many) – it is thornless!

Culturally, this species prefers slightly acid, well-drained soils in sun to partial shade.  Like most species of Rubus, R. odoratus is a colonial plant that will sucker and spread, and must be kept in check in certain garden situations.  Cultivated plants can benefit from rejuvenative pruning every few years, and this should be done shortly after they have finished flowering.  Mature plants will reach 6’ tall.  

There are 3 accessions of flowering raspberry on the Walk Across Kentucky, near the Trail of Pines in the Appalachian region.  Their flowers, fruit, and architecture provide food and shelter for wildlife throughout the year.  

WAKY Trail of Pines

Tuesday, June 10, 2014

Keep on Rocking in the Free World

In April, the Walk Across Kentucky received an exciting new addition to the Shawnee Hills region: 40,000 lbs of rock.  More specifically, the rocks were sandstone boulders, seven of which accounted for an entire flatbed truck-load.  This delivery was made possible by the College of Agriculture, Food and Environment, as well as our dear friend Neville Crawford, a volunteer from western Kentucky who sourced the boulders for us.

The original master plan for the Walk Across Kentucky called for the use of various geologic features from across the state, including glades, cliffs, and other outcroppings.  We are slowly implementing these features as time and funding allow, for they truly bring their own unique character to the physiographic regions.  

Our new sandstone boulders can be seen from inside the visitor center.  Due to their imposing size they have begun to serve as a beacon, luring visitors southward beyond the rose garden.  It was no small feat moving and placing these boulders, the largest of which has a mass of nearly 5 tons.  We believe these rocks were formed over 400 million years ago when Kentucky was rising out of the ocean.  These sandstone monuments will become part of a future garden in the Shawnee Hills region, and surely last for many years to come.  

Here are a few images of the 200 mile journey from Mclean County to Lexington:

Mclean Co. Stones are assembled for loading.
Mclean Co.  Flatbed truck is fully loaded
Arboretum parking lot.  Stones are moved one at a time to the WAKY.
Shawnee Hills Region of WAKY.  Stones installed
View northward toward the Dorotha Smith Oatts Visitor Center
'Rock #1' in situ Mclean Co.
'Rock #1' ex situ and rotated 90 degrees
stones in the meadow

Even more recently, we had two other additions to the WAKY collections of the non-photosynthetic variety.  These installations were made possible by a donor in Jessamine County who allowed us to collect local limestone rocks from an excavation project.  These stones are far older than the sandstone, as they were formed when Kentucky was still underwater.  It is exciting to be able to display more of Kentucky's diverse geology, for it is geology that has played a major part in defining physiographic regions and plant communities across the state.

Here are the other two new installations, which should change dramatically as plants are added in the coming weeks:  
Bluegrass Scree Garden (above).  Limestone fragments form a skirt around a young Gleditsia triacanthos.  This area is well suited for plants that require dry soil and full sun.  Expect to see Opuntia, Manfreda, Yucca, and others planted here.

Bluegrass Fern Garden (below).  This enlarged sinkhole is the direct opposite of the scree bed, for it has moist soils in full shade.  Limestone was used to form artificial ledges, outcroppings, and a staircase to lead visitors into the pit.  This shady damp site has been planted with Hydrophyllum, Polymnia, and Elymus, and will be the site of a future bluegrass fern collection.  The limestone staircase can be accessed from a new mulched pathway that leads through a dense planting of maple, oak, and buckeyes.