Garden Notes

Garden Notes

Sassafrass

Just as cities become known for their monuments and architecture (like Paris and the Eiffel Tower or New York and the Statue of Liberty) for plant people, places can become linked with iconic plants that grow there.  Over the years, Nantucket has become well-known for some of the Asian plants that are widely planted and naturalized around the island like blue hydrangeas (Hydrangea macrophylla) and beach rose (Rosa rugosa).  Although there is a lot to love about these plants, I sometimes think it’s a shame that more people don’t remember the island for the wide variety of native North American plants that grow here.  For instance, we are lucky to have one of the largest collections of American Elms (Ulmus americana) in any town in the United States.  These stately trees are undeniably amazing as they tower over the cobbled streets and historic buildings that downtown is known for.  In the less developed areas of the island there is a much wider variety of humble trees and shrubs growing together in the natural ecosystem that has developed here over thousands of years.  They may not be as striking as blue hydrangeas or as breathtaking the stately elms, but their quiet beauty is nonetheless amazing.  One of my favorite native trees is the American Sassafrass (Sassafrass albidium).

Colonies of Sassafrass are easily identified from a distance by their “Dr. Seuss-looking” growth habit of more or less upright, wiggly trunks and branches.  Up close, the youngest twigs are a shiny green while more mature branches and the trunks become grayish and furrowed over the years.  In early May, yellow flowers seem to burst out of the tips of the twigs, filling the whole canopy in a bright sunny haze.  Another easy way to identify these trees is by the leaves.  While most trees have leaves that are all the same shape, these trees have a set of three different leaves that appear throughout the canopy at the same time: a simple ovoid shape, a “mitten” shape and a shape with three lobes, resembling a trident.  During the growing season the leaves are a medium green, but they take on hues of brown, maroon, orange and deep scarlet in the fall.

Sassafrass is a medium-sized tree, averaging a height of more than 35′ on the island, depending on exposure.   They can be found growing in a variety of conditions, from the windy “Nantucket Serengeti” in the middle moors, to lower-lying areas like Squam swamp.  Their adaptability and unique look lend them well to use in many landscaped areas.  Consider planting them in groups of varying sizes to get the most naturalistic effect or use one to punctuate a focal point.  No matter where they are grown, they always make a great conversation starter!

All parts of the plant are fragrant when crushed, emitting a sweet, spicy smell that is difficult to explain to those that haven’t had the opportunity to enjoy it yet.  The roots have traditionally been used to make root beer and the dried and pulverized leaves (known as file powder) are used to flavor and thicken the popular Cajun dish, Gumbo.

Because these trees are difficult to cultivate in the field, there aren’t many tree farms that are able to supply them for us.  If you are interested in using some in your landscape, make sure to plan ahead and leave plenty of time for us to source them.  If you want to get a grove started in an economical way, we just received some well-grown #3 gallon containers that can get you off to a great start!


Get a Head Start on Spring, Plant in the Fall!

Now that Labor day has come and gone, it’s a great time to think about planting again.  Shorter days and cooler nights push plants to ready themselves for winter.  Transpiration (water loss) also slows to a minimum as leaves begin to senesce and drop, making watering far less of a concern than during the summer months.  While growth above ground slows and eventually stops, most plants continue to grow roots underground, in preparation for the next flush of growth in the spring.

 

Root development in woody plants has been been extensively studied over the years.  Scientists have found that the roots of woody plants continue to grow during the fall and winter, as long as the soil is not frozen solid.  As the ground seldom freezes on Nantucket before Christmas, and often thaws for long stretches in the winter, we have the luxury of being able to plant woodies almost year-round.

Best planting practices should be used to insure success with late season planting.

 

  • Carefully consider the site, being sure to choose plants that will thrive in the conditions present.  Pay particular attention to how much sun the area receives and the quality of the native soil; whether it is sandy, clayey, dry or overly wet.
  • Choose healthy plants, that have a strong root system
  • Dig a hole as wide as possible in the shape of a broad saucer to allow rapid root growth in the top 12″ of soil.
  • Be sure that the hole is not deeper than the root ball is high.  It is better that root ball of any plant rests on undisturbed soil and that the crown is slightly higher than grade once planted.  Loose soil at the bottom of the hole can settle over time, leaving the plant too low in ground.
  • If planting amendments are used, keep them to a minimum.  Making a small pocket of overly rich soil next to the base of the plant can discourage root growth into the native soil.  If fertilizers are used, consider going organic, and avoid additional phosphorous. Fertilizer should not be applied after mid-October on Nantucket.
  • Balled and Burlapped plants are best “wet-set”.  Place the plant in the hole.  Back fill the plant by half.  Next, fill the hole with water and allow it to drain.  Finally, complete the planting and lightly tamp around the plant, without overly compressing the soil.
  • Mulch is recommended for most new plantings, but keep it away from the trunks of trees and the crowns of grasses and other perennials.  Mulch piled up onto plants can cause them to decline over time.  Three inches should be a sufficient thickness for most jobs.  Bark mulch should not be considered a permanent design element, but more as a way to protect and enrich the soil as properly-spaced plants fill in and create a “living mulch” over time.

Mountainmint

Having been in business for 25 years on Nantucket, we have seen many trends in the islands’ landscape community come and go.  When I started at the nursery 14 years ago, there was a huge demand for ‘Knock Out’ series roses, for example – but today we only sell a modest number of shrub roses of any type.  When I was actively landscaping, many projects called for broad swaths of hydro-seeded, exotic, love grass but now (thankfully) landscape architects are using a wide variety of native grasses for those applications.  In fact, incorporation of native grasses, shrubs and perennial plants in the landscape is a massive trend that we don’t see slowing down.  Unfortunately, we’ve also seen an incredible increase in deer pressure across the island, which has spurred the movement toward planting only the most deer-resistant plants available.

We’ve seen that many of the native plants recommended for our climate are no longer deer-resistant at all.  For shrubs, we still recommend Myrica pensylvanica (Bayberry) and Baccharis halimifolia (Groundsel) as the backbone of a native planting plan.  Native grasses like Panicum virgatum (Switch Grass), Schizachyrium scoparium (Little Bluestem), Sporobolus heterolepsis (Prairie Dropseed) and Deschampsia sps. (Hair Grass) are a good choice as well.  Recently, I’ve been impressed with the various species of Pycnanthemum (Mountainmint) for good deer and rabbit resistance.

There are several species of Pycnanthemum in the trade that can be planted in a variety of conditions.  All are native to North America, and attract a wide variety of pollinators.  They look great mixed with other native plants and grasses in meadow gardens but are also a great addition to butterfly gardens and traditional perennial borders.  These herbaceous perennials are members of the mint family, with fragrant foliage and varying degrees of hairy leaves and stems.  They are generally 3-4′ tall and flower in shades of white and pale lavender in high summer to early fall.  Mountainmint grows in spreading clumps that are enlarged by runners; when they are happy, they can spread quickly, but the edges of the clumps can be easily managed by spading and pulling up the runners once or twice a year.

Some of the most commonly available species are listed below:

Pycnanthemum curvipes (Stone Mountainmint):  2-3′ tall.  Ovate silvery/green leaves with purple-spotted white flowers.  Native to rocky outcrops, bluffs, dry hillsides, open rocky woodlands and fields of the South Eastern United States.

 

 

 

 

Pycnanthemum flexuosum (Appalacian Mountainmint):  2-3′ tall.  Ovate green, hairless leaves with white/pale laender flowers.  Native to South Eastern United States where it occurs in a variety of conditions.

Pycnanthemum muticum:  2-4′ tall.  Ovate silver/green fuzzy leaves with pale lilac flowers and showy bracts.  Native to moist woods and meadows of the North Eastern United States.

 

 

 

 

 

Pycnanthemum tenuifolium (Narrowleaf Mountainmint):  3′ tall.  Narrow green, hairless leaves with clusters of tiny white flowers.  Native to a wide variety of conditions in the North Eastern United States.

 

 

 

 

 

Pycnanthemum verticillatum var. pilosum aka P. pilosum (Whorled Mountainmint):  1-3′ tall.  Grey/green leaves with clusters of white flowers.  Native to forests and meadows of a wide swath of the Eastern and Central United States.

 

 

 

 

Pycnanthemum virginianum (Virginia Mountainmint):  2-3′ tall.  Narrow lance-shaped leaves with white flowers dotted in lavender.  Native to moist woodlands and wetlands of Eastern United States.


Milkweed

There are many reasons to plant a garden: to add beauty to your surroundings, grow food or medicines, add value to your home, etc.  In recent years, islanders have become more and more interested in gardening to support our native ecosystem by providing shelter and food for native fauna.  Butterflies are always at the top of the list of insects that gardeners would like to support.  Many are amazingly beautiful, but also in real need of our help as their habitat is ever-shrinking due to human activities like development and farming.

Loads of native plants are a food or nectar source for caterpillars and butterflies, but we get the most questions about milkweed this time of year.  There are several species of milkweed that are native to the northeast, with more cultivated varieties in the trade as well.  We love these plants because they are easy to grow in full sun with average garden conditions.  The most popular of these is butterflyweed, Asclepias tuberosa, but we also stock others.

All milkweeds ooze a white latex sap when the leaves or stems are broken that prevents many insects from eating them.  However, monarch butterfly caterpillars have evolved to use milkweed as their only food source.  Many species of butterflies and other insects use the flowers as a source of nectar as well.  Milkweeds produce copious viable seeds in pointy pods.  When the pods mature and dry out in the fall it’s super fun to break them open and dispel the fluffy seeds on the wind!

Notable characteristics of the most commonly available milkweeds are listed below:

Asclepias incarnata – Swamp Milkweed.  The tallest milkweed that we stock at 36-48″ tall.  This plant is naturally found in sunny, moist areas like wet meadows and swamps with organically rich soil, but it adapts well to average garden conditions.  Flowers appear in July and August, varying in color from deep to light pink or even white.  The leaves of these plants are long and narrow, with a medium green color.

 

 

 

 

Asclepias syriaca – Common Milk Weed.  34-36″ tall.  This plant is found all over the island along roadsides, fields and disturbed areas.  They thrive in average soil in full sun.  The globe-like composite flowers appear in late June, persisting through summer.  The leaves are a dusty green, and wider than swamp milkweed.  This plant tolerates a wide variety of growing conditions, but is useful in areas with little supplemental water, as they are very tolerant of drought when established.

 

 

 

Asclepias tuberosa– Butterfly Weed.  The shortest of the common native milkweeds at 24-36″.  Found in sunny dry meadows, this plant makes a fantastic garden plant in dry areas without excessive irrigation. Make sure to plant it in full sun in average soil, and it will be happy for many years.  It has a bushy habit and narrow, ovate leaves.  The orange flowers appear in early July and persist for weeks in the height of summer.  Perennial plant of the year 2018!

 


Bluestar – Amsonia

Bluestar is one of my favorite plants of all time.  I like them because they are easy to grow with few, if any, pest and disease issues.  If sited correctly, they are super low-maintenance – just cut them down along with your other perennials at the end of the growing season or in early spring.  They have beautiful flowers, but also look great before and after flower, with disease-free green foliage in summer and yellow fall color.  Their bitter latex sap is said to make them unpalatable to deer (but the deer at 91 Somerset Road seem to like them just fine).  Several species and selections are available, each with its own characteristics.

Amsonia are long-lived herbaceous perennials that are native to the southern and south eastern United States.  Found in open meadows and fields as well as near lakes and wetlands, they tolerate a wide range of growing conditions.  In part sun, they tolerate less water, but planted in full sun, they benefit from consistent moisture.  Although they prefer fertile, well-drained soil, I’ve had good luck planting them in average garden soil with no additional fertility.  If the taller varieties are planted a shadier spot, they may benefit from a trim after flowering to promote a stockier habit that won’t flop open.

Their common name, bluestar is the perfect description of their flowers.  In late spring / early summer, these plants produce clouds of delicate, periwinkle blue, star-shaped flowers, each with five petals.  They don’t require deadheading, and look clean and tidy as the flowers fade.  These plants are right at home in the perennial border, but are also workhorses in prairie or meadow-style gardens.  The narrow-leafed varieties ‘String Theory’ and hubrichtii, in particular, contrast beautifully with bolder flowers like Echinacea, Shasta daisies, Black-eyed Susan’s, Crocosmia and the like.  Planted in a bright woodland situation, they would be excellent companions to Hostas and Heuchera as well.

The following plants are most commonly available:

Amsonia tabernaemontana:  Eastern Bluestar – 2-3′ tall and wide, with ovate leaves.

Amsonia tabernaemontana ‘Blue Ice’:  More compact than the species at only 12-18″ tall and 18-24″ wide.  Deep blue buds and lavender flowers.  Ovate leaves.

Amsonia 'Blue Ice'
Image courtesy Walters Gardens, Inc.

 

 

 

 

 

 

 

 

Amsonia tabernaemontana ‘Storm Cloud’: This Proven Winners selection emerges with near black stems and deep green leaves.  24″ tall by 38″ wide at maturity.  Periwinkle blue flowers.  Stems become green as season progresses.  Ovate leaves.

Amsonia 'Storm Cloud'
Image courtesy Walters Gardens, Inc.
Amsonia 'Storm Cloud' Black stems
Image courtesy Walters Gardens, Inc.

 

 

 

 

 

 

 

 

Amsonia x ‘Starstruck’: This hybrid bluestar blooms up to 2 weeks later than ‘Storm Cloud’.  It’s also more compact at 20″ tall x 30-38″ wide, with broader ovate leaves.

Amsonia 'Starstruck'
Image courtesy Walters Gardens, Inc.

 

 

 

 

 

 

 

 

Amsonia hubrichtii:  Thread-leaf bluestar.  Narrow leaves appear needle-like, but soft and fluffy.  2-3′ tall.

Amsonia hubrichtii
Image courtesy Walters Gardens, Inc.

 

 

 

 

 

 

 

 

Amsonia x ‘String Theory’:  A Proven Winners introduction.  Much like A. hubrichtii, but more much more compact.  18-22″ tall x 30=36″ wide.

Amsonia 'String Theory' fall color
Image courtesy Walters Gardens, Inc.
Amsonia 'String Theory'
Image courtesy Walters Gardens, Inc.

Hardy Kiwi

A great many years ago, I was visiting a friend’s farm back home in Nova Scotia and noticed a wild-looking plant covering a shed at the edge of the property. It was a huge tangle of broad leaves and tendrils from the soil up past the roof line. I had never seen anything like it, so I asked her what it was. She told me that it was a kiwifruit.  The only kiwi I was aware of were brown, fuzzy, tropical fruit that you could buy at the grocery store, so I just assumed she was off her gourd and moved on.  Since then, I have learned a lot more about plants and have grown to really appreciate the hardy kiwi species that are available for gardeners in the northern hemisphere. We have offered both Actinidia kolomikta (Arctic Kiwi) and Actinidia arguta cultivars in the past.

Hardy Kiwi are native to Eastern Russia, Korea, Japan and parts of China. These plants are extremely vigorous vines with twining tendrils that require strong support.  Their leaves are generally glossy-green and oval shaped, but there is variation among the cultivars and species.  Some are more serrated, or with red leaf-stocks and vines, others are even variegated with pink and white splotches.  Hardy kiwi have no particular pests to speak of (which is a marvel for a fruiting plant).  These kiwis are smaller than the typical grocery store kiwi, but the skin isn’t fuzzy, so they can be eaten right off the vine.

Like hollies, bayberry and many other plants, hardy kiwi is dioecious.  So, just like people, they have separate male and female plants.  In order to get fruit, it is important to plant either a self-fertile variety like ‘Issai’ or both a male and female of the same species. ‘Kens Red'(female), for example, should be planted along with another male Actinidia arguta in order to fruit.  They do require specialized care to produce fruit dependably, so it’s a good idea to do some in-depth research if fruit is the major goal.  Proper pruning and trellising can really help with getting a consistent crop.  That being said, I’d highly recommend growing them just for their ornamental value.

If fruit-set is just a bonus, why not give one or two a try and just see how they do?  Any garden situation where a Wisteria would be the traditional choice could absolutely handle a hardy kiwi vine.  They are equally, if not more, vigorous but with more handsome leaves.  They would look stunning covering a pergola or trained up along the side of a building. If allowed to grow across the slats of a pergola, this vine would provide quite a lot of shade below.  They could also do a great job of beautifying the fencing around a tennis court or pool, while providing good screening.

Including edible plants in primarily ornamental landscapes has been gaining in popularity over the last number of years.  As hardy kiwis are both attractive and productive, I think they are a perfect addition to the wisterias, roses and clematis that most gardeners are used to planting.  So, if you are up for a little challenge, and have some room – hardy kiwi is a great new(old) plant to try!


Thoughts on Pruning

I have to admit it – I love pruning.  There is something really great about the sound of my pruners clipping through the branches of plants that I’ve been growing all year.  After a long season of spacing, watering, fertilizing, deadheading and primping our shrubs to keep them salable, it gives me a weird glee to whack them back down to size.  For nursery stock, this is an essential part of keeping plants healthy and looking good, with top-growth in the right proportion to the roots.  It’s a little different with plants in the garden.

Novice gardeners often ask why pruning is important at all?  They look at the trees and shrubs in nature and figure they do just fine without pruning of any kind.  Why put in the work?  That’s a fair enough question.  The thing is, we expect a lot from the ornamental plants we grow in our yards and gardens.  We want them to look good and last a long time.  We want shade, but not too much shade.  We want them to fill their allotted space, but not overgrow it.  They need to be dense and flower profusely.  Plants in nature don’t have to live up to such high expectations.

If you think about a deciduous forest, under story shrubs are spindly and gawky, reaching up for as much light as they can get under the wide canopy of trees.  When a tree falls, light shines onto the forest floor and those spindly shoots take off, spreading up and out.  Shrubs that grow in meadows or at the edge of forests or wetlands, where sun is more available, tend to grow in tight-knit communities where they crowd each other, never achieving a balanced form.  As gardeners, we get to decide the spacing for our plants, giving them enough light and space to achieve the form we want.  We can plant them densely, as hedges, or further apart to allow them to grow into the shape their genetics want them to be.

Of course, ample water and nutrition are very important.  But good pruning can help a great deal to keep plants looking good and behaving the way we want them to behave.  With proper pruning, shrubs can be kept healthy and dense, with good form and produce the maximum show of flowers year after year.

We have lots of pruning resources on the website.  If you have questions, try using the search function in the top right hand corner of our website to find videos and written material that answers common questions.

 


Sweet Gale aka Bog Myrtle

I’m always on the look out for “new-to-me” plants that I think would work well for gardeners on Nantucket.  From time to time, we have big successes with those plants, but more often, landscapers just don’t know what to do with them.  When I came across Sweet Gale, Myrica gale, I thought it would be the perfect addition to our line up of native plants with some deer-resistance, so we brought some in.  They look great, but they don’t seem to be selling at all.  Sometimes we can encourage sales of lesser-known plants by putting them in a prominent spot so that customers will notice them.  I decided to make a display in front of the armillary in the courtyard, to see if that would drum up some interest, but to no avail.

You guys!  I really think these are great plants for us. You gotta give them a shot!  The cultivar we’ve stocked is called ‘Low Boy’.  These are compact (2-3′), rounded shrubs in the bayberry family.  They have semi-evergreen blue/green waxy leaves that are similar to common bayberry, but prettier.  ‘Low Boy’ is a male selection, so it won’t get fruit, but these plants are all about the aromatic leaves.  Sweet gale naturally grows in wet or moist soils in salt marshes and wetlands, so it would be perfect on Brandt Point or any low-lying area of town.  That being said, these plants will do well anywhere they are properly irrigated in full to part sun.  Although I haven’t seen them planted yet, I think they should have good deer resistance, to boot.

The texture, shape and size of these plants is so pleasant that they would work well in a number of design styles and a wide rage of applications.  Sweet gale is the perfect plant for use in loose, coastal gardens paired with summer sweet, switch grass, native sedges, and rose mallow.  But they would also make a great component in a naturalistic matrix planting or used as a vast drift in the New American Landscape style.  I could even see them used to create a super cool minimalistic, planting with purple smoke bush as a back drop.

Try a few!  You’ll like them.


Crape Myrtle Trees

Everyone loves flowering trees.  When in bloom, they can change the entire look and feel of the landscape, especially if there are many trees planted throughout a property.  Ornamental cherries and pears make up the vast majority of the flowering trees that we sell at the nursery, but there are lots of lesser-used trees that are also very beautiful.  In recent years, we have had more and more customers including Crape Myrtles in their gardens.

The genus Lagerstroemia has more than 50 species, but most of the landscape-worthy plants we offer are within the species indica and fauriei or hybrids of those.  These deciduous trees and shrubs are native to India and Asia, including China, Japan and Korea.  They prefer full sun and fertile, moist, but well-drained soils.  Crape Myrtles come in a wide range of sizes and flower colors.  The leaves are a deep, lustrous green, and often turn amazing shades of red and orange in the fall.  Most cultivars have handsome bark, that exfoliates, giving the trunks an interesting mottled appearance.  The enormous paniculate (botanical jargon for many flowers joined together on a branched central stalk) flower clusters are borne on the tips of the branches and generally open in September on Nantucket.

Because these trees are technically marginally hardy here, we always suggest planting them in a protected spot in town.  In reference to Crape Myrtles, the authority on woody landscape plants, Dr. Michael Dirr states, “…-5 to -10 F is about the breaking point between a woody plant and herbaceous perennial.”  However, there are quite a few large Crape Myrtles on the island that have survived some of the colder winters we had a few years ago.

Crape Myrtles flower on new wood, so they are often pruned severely while dormant, forcing a lot of new growth annually.   That being said, I much prefer the look of a tree that is artfully pruned to a balanced framework instead of heading the entire plant back to an arbitrary height.  When pruned this way, they can have a lovely shape that is nice to look at, even when the branches are bare in winter.

We’ve had many cultivars over the years, but a few of the most common are listed below with their attributes:

  • ‘Biloxi’:  Pale pink flowers on a 20′ tall tree.
  • ‘Centennial Spirit’:  Wine red flowers on a 10-20′ tall tree.
  • ‘Hopi’:  Light pink flowers on a semi-dwarf tree – 7-10′ tall.
  • ‘Muskogee’: Lavender flowers on a large shrub or small tree – 15-20′ tall.  Britt’s favorite!
  • ‘Natchez’: White flowers on a vigorous, small tree – 20′ or more tall.
  • ‘Sarah’s Favorite’: White flowers on a vigorous, small tree – 20′ or more tall.  Anecdotally, a better plant than ‘Natchez’.
  • ‘Sioux’: Dark pink flowers on a large shrub or small tree – 14′ or more tall.
  • ‘Tonto’: Fuschia-red flowers on a semi-dwarf tree – 6-8′ tall.
  • ‘Tuscarora’: Coral-pink flowers on a large shrub or small tree.  15′ or more tall.

 

 


Ornamental Grasses 201 – Nice Natives

Although most of the garden-worthy grasses we sell as ornamentals are exotic, there are many beautiful native grasses to choose from in commerce.  Whenever possible, we like to encourage our customers to try using native grasses.  They grow well, require little care, and have evolved with the natural vegetation of the island.  Native plants contribute to the overall beauty and health of our planted landscapes as well as the native ecosystem.  They also support the fauna that has developed here over thousands of years.

There are many native grasses found here, growing in a wide variety of habitats; from the shore line into the more fertile interior areas of the island.  The most popular species of native grasses that we sell is Panicum virgatum, commonly called Switch Grass or Panic Grass.  There has been a lot of work done with these grasses over the years, so there are many cultivars to choose from with a variety of heights, habits and colors to the foliage.  For more information on some of the various Panicum grasses check out this post: https://surfinghydrangea.com/switch-grass-2086

Another of our naturally-occurring grasses that is slowly becoming more popular is Schizachyrium scoparium, Little Bluestem.  If you walk your dog at Tuppancy Links, you are very familiar with this grass: it’s one of the predominant species found growing on the links, especially beautiful in the fall when it takes on coppery-red, orange and auburn hues.  Backlit by the sun at the end of the day, it’s magic.  Little bluestem grows best in full sun on moderately fertile, well-drained soils without much additional water.  The narrow bluish foliage appears in mid to late spring from the base of mostly clumping plants.  By August, the plant reaches its full height of about 2-3′ and begins to flower.  The flowering stems rise above the foliage, producing tight sprays of fluffy flowers.  Gardeners have found that when little bluestem is over-irrigated or grown with too much fertility it can get floppy – avoid this problem by planting it in un-amended soil and only watering during establishment and prolonged periods of drought.

Whether planted in drifts or sprinkled here and there among perennial flowers, this is a wonderful addition to almost any island landscape.  Several cultivars are available including ‘The Blues’ whose blue foliage is steaked with purple and accented with red stems.  ‘Standing Ovation’ is another great cultivar that is touted to be reliably sturdy with an upright, non-flopping, habit.

For a plant that will tolerate shadier conditions, try Carex pensylvanica, Pensylvania Sedge.  Although, it’s not technically a true grass, this short (6-12″) plant has a delicate, grassy look with arching foliage and spreads by rhizomes to make a pretty ground cover.  It looks especially nice in dappled shade under deciduous trees but grows well in fully shaded areas.

Several other grasses native to North America are also well-worth planting.  For a fine textured, loose look  consider Sporobolus heterolepsis, Prairie Dropseed, Deschampsia cespitosa, Tufted Hair Grass or Descampsia flexuosa, Crinkled Hair Grass.