Vinca Replacement

Ever since we moved here 7 years ago I’ve wanted to replace the Vinca (V. minor) from our shady driveway turn-around.  Because I was new to the Mid-Atlantic area I didn’t want to do a wholesale replacement with something I wasn’t sure would work in this mostly shady, dry environment.  So I took a piecemeal approach, trying a little of this and a little of that, leaving most of the vinca in place.  This year I’ve decided to get more aggressive with the replacement, adding some successful species and trying some more new ones.

This was the next area for vinca removal.  It gets morning sun and open shade later in the day. 
It is framed on the right and left with test plantings of Heuchera and foam flower.

My primary reason for getting rid of the vinca is that it is an invasive species.  It is able to creep out of managed landscapes and run rampant in forested areas forming a dense ground cover that excludes native species.  From an aesthetic standpoint, while verdant, it can be rather boring and lack personality. Because of its ability to form thick foliage mats it tends to block out other less competitive species and creating a monoculture, at least on the ground plane.  

Most of the plants I have tried have survived the dry shade, but only a few have competed strongly against the viney invasive.  In all, I have tried nearly 25 native species in this area.  Strong competitors include Jack-in-the-pulpit (Arisaema triphyllum), green and gold (Chrysogonum virginianum), hayscented fern (Dennestadtia puntiloba), bigleaf aster (Eurybia macrophylla), Heucheras (I’ve had success with H. villosa and the cultivars ‘Citonelle’ and ‘Palace Purple’), twinleaf (Jeffersonia diphylla), Virginia creeper (Parthenocissus quinquifolia), zig-zag goldenrod (Solidago flexicaulis), merrybells (Uvularia sessilifolia), golden Alexanders (Zizia aurea), and the low-growing shrub sweetfern (Comptonia peregrina).  Also the non-native variegated Solomon’s seal (Polygonatum odoratum variagatum) is doing well (I imagine the larger native P. commutatum would also do well).  These are able to grow and spread without much help from me.  

Species that survive the conditions but need some help to keep from being overrun include wild bleeding hearts (Dicentra eximia), Alleghany spurge (Pachysandra procumbens), hoary mountain mint (Pycnanthemum incanum), smooth aster (Symphiotricum laevae), foam flower (Tiarella cordifolia), sedges (white-tinged sedge Carex albicans and pensylvanica, and there are some more robust wild ones like loose flowered sedge, C. laxiflora, that do very well).  Barren strawberry (Geum fragarioides, formerly in the genus Waldsteinia) should work well under these conditions, but in my case it seems to struggle.

Species that would be overrun without intervention include Meehan’s mint (Mehania cordata), woodland phlox (Phlox divaricata), and Labrador violet (Viola labradorica).  The only total failure was partridgeberry (Mitchella repens).  This tough little plant does not like to be covered, so between the vinca and the pine needles piling up it didn’t stand much of a chance. 

In this year’s planting I’m adding another sedge, ivory sedge (Carex eburnea), also wild geranium (Geranium maculatum) and, though I’m doubtful about this one, wild columbine (Aquilegia canadense).  I also have some downy wood mint, Bleiphila ciliata, which I started from seed that should do well in dry shade.

On the west end of this planting which gets a little afternoon sun, you can see the
ground hugging green and gold (now in bloom) and the much taller golden Alexanders (to the right).
Other plants include wild black raspberry, which appeared on its own, and several
volunteer trees that need to be pulled out.  

One of the features of vinca that is hard to copy with many native species is that it looks good (that is, pretty much the same) throughout the year with relatively little maintenance.  This is a great attribute from a design standpoint, but that does not make up for its invasive tendencies and relatively low ecological value.  Of the native species mentioned here green and gold and the sedges are evergreen (or nearly so) and the heucheras and foam flowers look good for most of the year.  Where there is sufficient moisture golden ragwort (Packera aurea) would be a very good evergreen choice.  

In the foreground you can see how Pennsylvania sedge pokes through gaps
 in the Virginia creeper (5-leaflets).  The sedge remains green throughout the year,
but looks a little ratty come January.  Another strong presence here is the zig-zag goldenrod,
with its ovate leaves, in the left and center of this image. 

Clearing this area took about 45 minutes.  Much of the time was consumed 
separating the vinca from the good soil after it had been pulled.  The pulled vinca 
was segregated to dry out and die before being put onto the debris pile.

Clearing the new planting space was surprisingly easy.  Since the area was thick layers of decomposed pine needles, the soil was very loose and most of the vinca could be removed with a 4-tine garden cultivator.  What didn’t come out with the cultivator was hand pulled.  I’m sure some bits of vinca remain and these will be addressed as they pop back up through the mulch.  I like using the fork because it hooked on the vines and it minimized damage to the deeper tree roots. 

Most of the new plants are in.  The most obvious are the heuchera and foam flowers. 
In addition to the wild geranium, columbine and ivory sedge are more
zig-zag goldenrod at the back of the planting and Labrador violets to the front edge. 
You can see the garden cultivator I used lying to the left.

Another means of vinca removal is cutting it back low then covering with a layer of cardboard, then mulch or clean soil.  This method would be better where the vinca is more firmly rooted.  I’ve tried spraying it with glyphosate, but the kill rate seemed rater low.

Here's the completed planting from another angle.  The new plants are mostly on the right edge
(see the little white tags?)  In the center of this view are established heuchera and foam flowers.

Using a variety of plant species in this area allowed me to tailor the planting to fit the variations in the site conditions: deeper vs. partial shade, arid vs. average moisture, etc.  Using plants with a tendency to spread both above ground, like foam flower and green and gold, or below the surface, like hay-scented fern helps cover the ground more quickly and allows the plants to migrate through the site to find their best conditions.  The variety also increases the biodiversity, extends the periods of bloom and provides more variation in form and color. 

I think for the next phase of vinca removal I will move to the middle of bed and try some taller species like the great Solomon's seal, white wood aster and more hay-scented fern.

What's Up in April

The mild winter and warm spring have thrown off the normal times for plants to reemerge.  Most of may natives are at least 2 weeks, if not more early this year.  I found that I need to pay attention about how plants are coming along, because if I wait a couple of days I might miss some of the spring ephemerals.  So here are some of the botanical things happening with my native plants during the first two weeks of April.

These Celandine Poppies are heavy spring bloomers

The star of the spring this year are the Celandine Poppies, Stylophorum diphyllum, I planted last year.  The bright yellow blooms were opening at the same time as the foliage was coming out.  In the shady spot I have these in, they continued sporadic blooming all summer.  We'll see if they can keep up that pace this year.

The flowers are as white as
the flowers of Bloodroot.

I nearly missed the blooms on the Twin Leaf, Jeffersonia diphylla.  The incredibly white flowers are only open for a day, fortunately I spotted these at a distance and ran to get my camera.  I would not recommend growing these for the flowers, they don't last long enough, but the foliage is what really makes this a useful garden plant.  The leaves on this plant usually form a mound about 10" tall.  Also this one is growing under the Norway Maple, so it can handle some adversity.

Note the spotted foliage of the Trout Lily

I had to take this photo of the inside of the flower
with its raised petal.

This year I had 3 Trout Lilies, Erythronium americanum, come up, but only one bloomed.  I have these planted in with some tulips, so it is very easy to miss seeing the plant, since the leaves are of similar shape.  The Trout Lily does have subtle spots on the foliage that is the tip off.  Of course the flower is the real give away.  These flowers only last a few of days under normal conditions.





Last year I finally got good germination of Brown-eyed Susan, Rudbeckia triloba.  It takes a year to get established before it blooms, so I am looking forward to seeing it in action this year.  It has smaller, 'softer' blooms than the more common Rudbeckias.  I took these photos to document the difference between the Brown-eyed Susan and Black-eyed Susan, Rudbeckia hirta.

The arrow points to one of the three-lobed leaves.
As the plant grows taller this leaf form is harder to find.

Black-eyed Susan leaves are not lobed.  Also,
 you can see the stiff hair no the leaves (hirsute).

I have been trying to get some Woodland Sunflower, Helianthus divaricatus, to try under the Norway Maple for a number of years.  Last year I finally got some started.  The plant grew up to about 18", but did not bloom.  So I thought it was just settling in.  Looking in the area this spring I noted a number of seedlings that I am pretty sure are the sunflower.  So it appears that it has started colonizing already, even without blooming.  This can be a very aggressive plant and so far that looks to be the case.  But under this Maple, that is fine with me.

The form of these sprouts is consistent with Woodland Sunflower

Pennsylvania Sedge, in bloom.

I have also be experimenting with some native sedges, particularly Pennsylvania and Appalachian Sedges, Carex pensylvanica and C. appalachica.  These look pretty similar in leaf, but you can distinguish them by their flowers.  Pennsylvania Sedge blooms in early spring, right after it begins to green up.  Appalachian sedge blooms about a month later, after the foliage is well established.

I'll close with the Low Bush Blueberry, Vaccinium angustifolium.  Again, these are in a pretty marginal site, under the Maple.  The plants that are growing the best are the ones getting the most sunlight.  This year the blooming is better, so maybe I'll need to keep an eye out for a berry or two. 

Native Ground Covers - Part 2

In the last post I listed some of the herbaceous and small woody native plants that I have been using as ground covers. Sometimes you want that grassy look. There are a number of options for low maintenance grasses as alternatives to the Non-Native Kentucky Blue Grass and Perennial Ryes commonly used in residential lawn grasses.

One option to the conventional lawn is the use of fine fescue grasses.  These have a silkier appearance and tend to be a lighter shade of green than KBG.  Two commercially available seed mixes based on blends of fine fescue grasses are ‘No-Mow’ Mix from Prairie Nursery and Eco-Lawn from Wildflower Farm. These mixes contain a blend of creeping and clumping fescues, some of which are native to North America, which will tolerate a range moisture and light of conditions. Lawns of these grasses are reported to require very little mowing (1-4 times/year), little additional water and no fertilization.

Another option is to do a sedge lawn. Sedges, members of the genus Carex, number about 2000 species world-wide, with about 480 representatives native to North America. With so many species, there are some that are adapted to nearly any growing condition. In general, they look like average grasses. This genus can be distinguished in that sedges have triangular, not round, stems. When viewed down the stem the leaf blades radiate off at 120-degree angles. Sedge lawns are a better choice for wet conditions than fescues, however they do not tolerate foot traffic as well. Brooklyn Botanical Garden has a useful article on sedge lawns.

The first sedge that I became intrigued with was Rosy Sedge, Carex rosea. I saw this ‘in bloom’ in a friend's yard with its tiny (~1/8th inch) rose or star-like, tan colored inflorescences. These come in late spring. Otherwise, it just looks like grass. Unfortunately, I do not have a photo or these little flowers at this time, but here’s what it looks like without them. While it is naturally distributed over the eastern 2/3rds of the U.S., I do not know of a commercial source for this sedge.


Since first seeing Rosy Sedge, in 2006, I have become more interested in these plants. Two sedges that are available and well adapted for use in the Northeast are Pennsylvania Sedge (Carex pensylvanica) and Appalachian Sedge (C. appalachica).

Appalachian Sedge forms clumps with mid-green blades 8-24” long. These clumps do not produce rhizomes. The bloom time is in late spring, with seeds forming in late spring to early summer. Its native habitat is in dry to mesic deciduous forests and its native range includes the eastern states from Georgia to Canada. In my yard I have it growing successfully under a Sycamore Maple (another invasive tree). The foliage turns tan over the winter, but it greens up rapidly in the spring.

Pennsylvania Sedge is becoming much more available in the nursery trade. It is a little smaller than Appalachian sedge, with leaves at 4-18 inches. It is reported to tolerate occasional mowing (I haven’t mowed mine yet on purpose, anyway). Also it does spread slowly by rhizomes, a good trait for a lawn grass. The inflorescences appear in early spring as dark brown spikes, just above the foliage. These come before and are easily distinguished from the flowers of Appalachian Sedge. This sedge is found in well drained acidic, but rich soils in and along hardwood forest edges and openings. The native range includes the eastern states from Georgia to Canada to just west of the Mississippi River. My Pennsylvania Sedge is also doing well under the same maple tree. Mine is a bit larger than the Appalachian Sedge, but it has been in the ground a year or two longer. For me the beauty of both of these grasses is that they do well in DRY SHADE!!!

For more general information on growing alterative lawns check out the following links:
>Planting a ‘No-Mow’ lawn. This link also has a clear and concise statement on growing/encouraging moss.
>Native Grass Lawns: Lots of information on a variety of altenatives
>Planting a Native Grass Lawn. This is another useful link for the Brooklyn Botanical Garden site.
The book, Easy Lawns, edited by Stevie Daniels, gives information on growing low-maintenance native grass lawns appropriate to each region of the U.S.