Renovating an old garden can be a daunting task. In September of 2006, the Scott Arboretum received an endowment for the gardens of the West House from Barbara and Giles Kemp. For the past three years, the curatorial intern and volunteers have been renovating the garden to create a lovely example of a residential-style landscape with two intimate entertaining spaces. This fall our curator, Andrew Bunting, insisted I pay a visit to the West House to see the evolution the garden has undergone. I was not disappointed.

There are some simple steps to follow when approaching the task of renovating an old garden. These steps will help any gardener begin to tackle the often overwhelming process of revamping a mature garden.

1. Re-evaluate the site. Have new buildings been added to the site creating new microenvironments? Have the trees grow or fallen, adding sun or shade to an area? Test the soil to see if organic matter needs to be added.
2. Define objectives for the garden. In the case of the West Garden, the Arboretum wanted to create a residential-style garden. There needed to be strong winter interest because entertaining college guests occurs throughout the year. Two intimate entertaining spaces with ornamental interest during growing season needed to be established because the back of the garden is a popular place to entertain guests. A screen planting was also needed to hide view of the neighbors.
3. Evaluate the existing plants. Take a year to evaluated and identify the plants that are growing in the garden. Things are always easier to identify when they are blooming. As you cut back or remove overgrown plants, you will often discover hidden treasures. At the West Garden, an invasive, English ivy, Hedera helix, had consumed many of the beds. A planting of Tsuga canadenis was infested with wooly adelgid and scale along Elm Avenue. The previous residents had planted a bed of hybrid tea roses which do not perform well in the Delaware Valley. Throughout this bed there also was an infestation of Pinellia ternata.

Once you have evaluated the existing conditions and plants and have a new garden plan, you can begin the fun job removing, moving, and cleaning-up the plants. In the West Garden, the Tsuga canadensis were removed and variety of unique plants were planted to accent the front of the house including Stewartia pseudocamellia, Calliarpa dichotoma, Ilex verticillata ‘Winter Red’, Rhododendron ‘P.J.M.’, and Jasminum nudiflorum.

In the backyard garden, the English ivy was replaced with Hydrangea, Callicapra, several new Encore^TM Azaleas. Several ornamental containers were added to provide a great accent to the patio entertaining area. A rose planting in poor condition was replaced by a 75 foot perennial border to provide great interest throughout the year. This rich perennial mix contains Echinacea, Geranium, Heuchera, all plants which are better suited to be grown in the Delaware Valley.

Visit the West Garden to see the results of our volunteers’ and interns’ hard work. If you are overwhelmed by the task of renovation, take it one step at a time and enjoy discovery of hidden gems within the old garden.

By John McPhee

John McPhee wrote The Pine Barrens in 1967, when he went to explore the area of southern New Jersey because he “found it hard to believe that so much unbroken forest could still exist so near the big Eastern cities.” The Pine Barrens is an area rich in biodiversity as well as historical and cultural significance for New Jersey. It is home to a pygmy forest of miniature pine and oak trees, large scale cranberry harvesting, rare and interesting plants, and a unique history of industry, manufacturing, and becoming our country’s first National Reserve. McPhee wrote The Pine Barrens initially for the New Yorker. This book is one of the first examples of a style of writing for which McPhee became famous known as literary nonfiction. He blends geologic and environmental history with the intimate portraits of people he meets and experiences he has in this unique section of New Jersey. A really interesting aspect to reading this book now is to realize that while this book is over 40 years old, much of what McPhee observes and experiences is still relevant and accurate.

Check out this exciting title and many more at the Scott Horticultural Library!

]]> http://blogs.scottarboretum.org/gardenseeds/2008/09/the-pine-barrens/feed/ http://blogs.scottarboretum.org/gardenseeds/2008/09/semi-intensive-green-roof/ http://blogs.scottarboretum.org/gardenseeds/2008/09/semi-intensive-green-roof/#comments Fri, 26 Sep 2008 12:42:14 +0000 Becky Robert http://blogs.scottarboretum.org/gardenseeds/?p=454

Yesterday, we discussed how the majority of the Kemp Hall green roof was planted. Today, we will explore the remaining level and the excitement that a few more inches of growing media can bring. The remaining level was planted using a different technique because it is the semi-intensive section. This portion of the roof features mounds of the growing media eight to ten inches thick allowing for planting of perennials and bulbs, and a paver area to allow tours to step out onto the roof.

To plant this portion of the roof, plugs were used instead of cuttings. Plugs were chosen…

Yesterday, we discussed how the majority of the Kemp Hall green roof was planted. Today, we will explore the remaining level and the excitement that a few more inches of growing media can bring. The remaining level was planted using a different technique because it is the semi-intensive section. This portion of the roof features mounds of the growing media eight to ten inches thick allowing for planting of perennials and bulbs, and a paver area to allow tours to step out onto the roof.

To plant this portion of the roof, plugs were used instead of cuttings. Plugs were chosen because they allow the designer to create precise, highly individualized design. Using plugs of various types of sedums, large swathes of color were created radiating out from the paver section on the roof as seen in the sketch below.

As Ed Snodgrass describes in his book, Green Roof Plants: A Resource and Planting Guide, hardy succulents are the workhorse of extensive roofs.The Kemp Hall green roof puts these workhorses to the task on all five levels of the roof.

Throughout the semi-intensive level the following types of sedum can be found:

Sedum hybridum ‘MImmergrunchen’

S. album ‘Murale’

S. album ‘Coral Carpet’

S. rupestre ‘Angelina’

S. sexangulare

S. spurium ‘Schorbuser Blut’

S. spurium ‘Roseum’

S. spurium ‘White Form’

S. ‘Matrona’

Phedimus takesimense (aka Sedum takesimense)

Because this is the semi-intensive level of the roof, a variety of grasses, bulbs, and annuals were planted in the growing media mounds. Grasses add texture and motion to the roof landscape and a habitat for birds and insects as they do in a traditional landscape. The grass, Calamagrosits xacutiflora ‘Karl Foerster’, was planted to mimic the plantings on Alice Paul green roof which can be seen from Kemp Hall green roof. These grasses can also be seen blowing in the wind from the Chester Rd./Route 320.

Several types of accent plants were added to this portion of the roof as well. Accent plants do not grow as rapidly as groundcovers and offer seasonal interest. Accent plants also do not have as long a life expectancy as groundcovers, thus requiring periodically replenishing.

Listed below are the accent plants used on Kemp Hall green roof:

Talinum calycinum

Delosperma nubigenum ‘Basutland’

Campanula rotundifolia

Allium schoenoprasum

Dianthus carthusianorum

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On Monday, we completed the installation of the 3^rd green roof on the Swarthmore College campus by planting 15 different types of sedums and 7 other types of plants on the roof of the new dorm, Kemp Hall. Two different techniques were used to plant the five levels of this roof.

Four of the five levels were gently scattered with 100 lbs of 6 different types of sedum cuttings. These varieties were mixed by hand as seen in the image above.

Sedum is the most common plant chosen for extensive green roofs because it can tolerate and thrive in all of the unique conditions of growing on a roof. These include drought in a thin, free-draining growing media and periods of saturation of the substrate layer. High temperatures are found on roofs where there is no shelter from trees or shrubs and the surrounding concrete and stone absorbs and radiates heat. These roofs are also exposed to high winds which may cause physical damage to the plants and desiccate vegetation.

There are nearly 600 species of sedums with a wide variety of leaf colors and textures to choose from. Depending on your location in North America, sedum can produce a floral display from March to November. Hardy from zone 3a to 9, sedums are commonly known as stonecrop or orpine. This low-growing genus can have a flower color of pink, white, or yellow and some produce a red to evergreen rosette that changes color with the seasons.

A mixture of the following sedums was chosen for the 4 of the 5 levels of Kemp Hall roof.

Sedum kamtschaticum - green foliage blooms with yellow flowers in mid-summer

S. album ‘Murale’ - green and red foliage blooms with white flowers in mid-summer

S. reflexum - blue-grey foliage blooms with yellow flowers in mid-summer

S. sexangulare - green foliage blooms with yellow flowers in mid-summer

S. spurium ‘Schorbuser Blut’ - dark green foliage blooms with pink flowers in mid-summer

S. spurium ‘Roseum’ - green foliage blooms with pink flowers in autumn

After the cuttings were evenly distributed on top of the roof, they were raked into the growing media and watered. These cuttings will root and grow into an attractive green roof. This is the technique also used to plant the majority of the Alice Paul green roof.

Visit our blog tomorrow to learn about the other techniques used to plant the remaining level of Kemp Hall and the unique plants used. Click here to read past posts about the installation and design of the Kemp Hall green roof.

The volunteer who first introduced me to Pinellia described this invasive plant with a tone of loathing and detestation. If memory serves me correctly, I believe she described Pinellia as the “bane of [her] gardening existence.” At the time, I thought that was a pretty strong statement for such a small weed. But, after three months of first-hand experience with this seemingly ineradicable plant that always reappears with gusto, I now understand what the volunteer meant.

Pinellia ternata is native to Japan and is sometimes referred to as cow-dipper. The plant possesses trifoliate leaves and a flower typical to plants in the Araceae family (think of a jack-in-the-pulpit with its spathe and spadix flower). Similar to other Araceae plants, the flowers of Pinellia are hermaphroditic. One of the secrets of Pinellia ternata’s success is that its stem regenerates from a corm that resides inches below the soil’s surface. As a result, hand-pulling is nearly always ineffectual in ridding a garden area of Pinellia. The best method I have found for dealing with Pinellia is to push a hori-hori (Japanese digging knife) or other digging tool deep enough in the soil (a few inches) to excavate the entire plant. Success is achieved if the removed plant still has a spherical corm attached to its long white stem.

P. ternata thrives in the mid-Atlantic region and, left on its own, is capable of nearly doubling in population every year. However, with consistent and accurate weeding, it is possible to control the spread and reduce the pervasiveness of Pinellia in your home garden. Just be sure not to dump Pinellia in your compost pile; instead, tie it up in a plastic trash bag to prevent it from spreading its weedy ways.

Until next time, good luck in your weeding adventures and happy gardening!

When I first came to Swarthmore in the summer of 1986, I used to frequent the Taco Bell on Baltimore Pike (what can I say, I was an intern). One day I was parked in the back where the dumpster sits, and growing along the fence-line was a plant which had leaves similar in appearance to our native sassafras, Sassafras albidum. Some of the leaves were entire, others three lobed, and some had a mitten-shape. However, these were fuzzy, almost velvety to the touch. My new discovery was the paper mulberry, Broussonetia papyrifera, which is rarely found in cultivation, but considered an opportunistic and invasive weed. Later that summer on another culinary expedition I found one at the rear of the Burger King, also on Baltimore Pike!

Eighteen years, 6,000 Whoppers and 3,000 Burrito Supremes later I am thumbing through my favorite plant catalog, Heronswood Nursery when I discovered an entry for my old friend that had thrived on the fatty fumes of every fast food chain in Delaware County. However, this time it was a golden foliage selection, Broussonetia papyrifera ‘Golden Shadow’.

Plantsmen are notorious for finding special and coveted selections of plants most normal people would consider pernicious weeds. I remember visiting the J. C. Raulston Arboretum about 5 years ago and walking through the ’special’ hoop house which held all their treasures. Then Assistant Director, Todd Lasseigne got noticeably excited when he parted the packed-in plants and found a little variegated selection of crabgrass! Yes, the same crabgrass that major Fortune 500 companies have made billions creating herbicides to eradicate from your yard.

Suffice to say, I too got a little excited. Over the years I have grown a green and white variegated pokeweed; was smitten with a variegated plantain until it seeded all over the Terry Shane Teaching garden; and I’m still regretting ever putting a beautiful, purple, self-sowing (that is an understatement) member of the carrot family, Cryptotaenia japonica ‘Purpurea’ in my yard. So, why not try a golden foliage paper mulberry?

Perhaps it will turn out to be a mistake like the others, but 4 years into this experiment and the results are impressive. In March of each year I cut the main structure of this small tree/large shrub back to a twiggy structure of five feet. In the spring and through the summer large golden, felted leaves are produced. Many other golden-foliaged plants like Sambucus, Catalpa, Cotinus and Robinia lose the color intensity of their golden foliage as the summer progresses and the intensity of the sun increases. However, ‘Golden Shadow’ remains vibrant, lush and stunning.

I have heard that it has a propensity to sucker and colonize. I have noticed a sucker here and there, but nothing else yet. So far this bold-foliaged shrub has impressed all those who have walked by it. If you are looking for a bold plant for the garden with a distinctively tropical effect then ‘Golden Shadow’ might be worth your consideration.

It is a transition time for the seasons…I can feel and smell the autumn in the first part of the morning before the heat and humidity of the day set in. It is also a transition time in the gardens as well - with summer blooms fading and trees beginning to think about fall color. With the rain we have had in the last few days, leaves have plumped up again and the gardens, particularly in the Terry Shane Teaching Garden, feel lush and green. The varying shades and textures of green are set off here and there by touches of orange, yellow, brown and red. Not the showiest of plants, but adding to the mix of greens around campus, are the variety of ferns. An important element in the Shane Garden, Magill Walk, and the Glade Garden, ferns can act as a ground cover, backdrop and textural contrast to other bold foliaged plants. With fewer blooming plants showing off right now, ferns act as a filler and add green interest, setting off the few blooms that are on display in September.

A common but attractive grouping of native ferns is growing in the Glade Garden (this is a well-hidden garden below the Science Center that is worth seeking out after a good rain). Cinnamon fern, Osmunda cinnamomea; Christmas fern, Polystichum acrostichoides; and maidenhair fern, Adiantum pedatum are mixed with other plants native to the east of the Mississippi River in this quiet, green space. These native ferns will be featured in an upcoming Horticulture Seminar with Gregg Tepper and Marcie Weigelt of Mt. Cuba Center. My favorite in the Glade Garden is the cinnamon fern as it is works well in a grouping or as a specimen plant with its gold fall color and cinnamon-colored fertile fronds. The texture created by the fronds is the perfect effect to fill the one corner of this garden.

Our September class on native ferns has prompted the Scott Arboretum to add to its mix of ferns several other native varieties, which will be planted in gardens around campus this fall. In the meantime, be sure to make it over to the gardens after it rains (or even better, when it is raining!) to see the lush, tapestry of green throughout the Scott Arboretum.

The Scott Arboretum comprises the campus of Swarthmore College. If there was a way to quantify the most frequently visited spot on campus it would most likely be the pond in the Terry Shane Teaching garden. Children and adults alike find this to be both an intriguing and restful destination.

I, too, have always been attracted to water and water features in the garden. I am often attracted to the architecture of the water feature, whether it be an informal stone-edged pond like the one I have in my home garden or the formal architecture like the hills at Hestercombe in England or the fantastic new water works designed by Jacques Wirtz at Alnwick Castle in northern England. One of the most engaging and interactive of all water features is the relatively new installation at Millennium Park in Chicago by Jaume Plensa. Check out the video taken by Rhoda Maurer above.

I enjoy water in the garden for the sound because it is often a great foil for nearby traffic noise. However, I most enjoy it for the myriad of wildlife that it attracts, especially birds. Last year, I was lucky enough to attract a massive Great Blue Heron to my personal garden. To have such a majestic creature visit my garden was very exciting. The down side is that he feasted on a handful of goldfish in my pond!

Last Thursday we had the 5^th annual Crum Creek Clean-up. 38 people helped clean-up the creek and surrounding areas. Tasks included: trash removal, trail maintenance, and invasive and weed removal.

One group spent their time in and around the holly meadow pulling vines off of some of our native deciduous hollies (Ilex verticillata). They also removed several plants of purple loosestrife (Lythrum salicaria) that had established themselves in the holly meadow. They ended up with a whole dump truck full of weeds.

Three small groups set out in different directions throughout the trails of the Crum Woods to gather all sorts of trash.

Another group performed trail maintenance including the hard work of installing 5 water bars. Water bars are timbers that are buried into the trail at an angle across the trail with a low trench above the bar. They are intended to intercept and slow water runoff coming down the trail by diverting it to the lower side of the trail. The group also cleaned out sediment and debris above many existing water bars along the trail to improve their function.

Yet another group had the task of removing trash from the Crum Creek itself. These folks were up to their chests in the stream digging out tires, lumber, plywood, bottles and many other things. They worked mostly upstream from the SEPTA trestle at the holly meadow using rowboat and canoe to haul trash out of the creek to the trucks. Because the water was so low and still, it was easier to see and remove some of the deeper trash that we couldn’t get during previous spring clean-up events.

All together we collected the following trash:

22 tires

29 bags and 3 buckets of trash

3 plastic pipes

1 traffic cone

1 small appliance

Lots of wood

Shovel

5 pieces of fiberglass

2 bowling balls

1 tire rim

1 wooden crate

1 bike helmet

1 case recyclable bottles

1 angle iron

1 smashed TV

1 bike wheel

1 bike tire

1 galvanized garbage can

1 light off of traffic barricade

1 diamond ring

Thank you to all of the staff and volunteers who helped with another successful Crum Creek Clean-up.

If snakes or other predators don’t eat them, they will burrow into the ground and turn into shiny brown pupae. They will stay underground for one or two winters and then emerge in the spring as the adult royal walnut moth, also known as the regal moth. This moth is orange-striped with yellow markings and can have a wingspan of up to five and a half inches.

Be on the lookout for these amazing caterpillars this September!