Progress on Japanese Stiltgrass Removal - 2017

My 4 year long battle with Japanese stiltgrass, Microstegium vimineum, is continuing and it must be a continuing fight to remove this invasive grass from my property.  Since this is an annual grass the goals are to keep it from producing a new crop of seed and to eventually deplete the seed bank so that it won't crop up again from older seed.  Since this grass is all around I will need to take the fight to the neighborhood and beyond.  This will be easier if I can demonstrate to  other that this is a battle that is worth fighting.

One approach to Japanese stiltgrass removal is to nuke the site with round-up or a grass selective herbicide.  Despite it being effective on the current year's growth, this would still be a multiyear approach to deplete the seed bank.  I'd rather not kill everything because I have a number of interesting plants that I want to keep and I am generally opposed to the indiscriminate use of herbicides or pesticides. 

The key to non-toxic approach to stiltgrass removal is good timing.  Pulling the grass in late summer as the flowers are forming (late July to early September in Maryland) is the best time to concentrate your efforts.  Early season pulling helps, but if some plants remain they will expand to fill the void and you will need to return to pull again.  Stiltgrass pulled before seed has formed can be composted, though I usually segregate it from the rest of my garden scraps just in case.   Any grass pulled after flowering should be bagged or at least segregated and covered so that seed can not escape.

Here's a woodland edge area in 2013 when I started pulling/whacking stiltgrass

In 2014 coverage is not as dense, but still dominant.

In 2015 other plants are showing up.  Also I had seeded in some Virginia rye in 2014.

Now in 2017 stiltgrass is no longer dominant.  In the foreground is
Virginia rye, Elymus virginicus, drying out after seeds have matured.  

 The photos above show the progress that has been made over 4 years.  For the first two years this site was weed whacked to near ground level and then raked out.  As the stiltgrass density dropped I switched over to hand raking and pulling for the past two years.  These methods were more selective and allowed me to avoid the more desirable plants that were coming back in.

Mature Japanese stiltgrass, note the
location of the cleistogamous flowers.

In lawns, mowing stiltgrass is done to control its spread.  Unfortunately stilt grass has the ability to form cleistogamous flowers near the base of the stem.  These flowers are enclosed in a leaf sheath about an inch off the ground and can survive most mowings.  It has been reported that these flowers mature earlier in stiltgrass in regularly mown lawns.  To address this Russ Anderson, a West Virginia forester has suggested allowing stiltgrass to grow freely through July and then mow it closely to the ground in August as the flowers begin to develop.  The expectation is that there will be fewer cleistogamous flowers and by cutting it back late in the season there is not time enough for the grass to regrow.  I have been doing a variation of this in an isolated area where I am growing fine fescue.  Instead of mowing, I use a manual grass whip.  This rips out the stiltgrass and leaves more of the fine straight blades of the fescue intact.  After doing this for two years the amount of stiltgrass in the area has decreased, but I still have a few years to go.  

Another technique that I have been using  to remove stiltgrass from the lawn is to briskly rake the lawn after a rain to try and catch the lateral stems (stolons) of the stiltgrass.  Using a spring or bamboo rake does tear out a lot of stiltgrass, but it also tears up the soil and can damage the bunch and perennial grasses as well.  I also found that after doing this in early July, even though I removed a great deal of stiltgrass, much of it had regrown to fill the gaps in the lawn.  Inspection of the stiltgrass at this time did not show evidence of the cleistigomous flowers. 

This area was raked over with a steel garden rake.  Nearly all this debris is stiltgrass.

What appears to have worked better is a stiff steel garden or bow rake that is pulled along the surface of the ground.  It catches and pulls out the stolons of the stiltgrass and since the action is not so vigorous, most of the other bunching grass are left intact.  I did this in mid-September so there is not enough time for the stiltgrass to regrow.  Even though the soil was dry, the stiltgrass pulled out easily.  Inspection of the stems showed that there were some cleistogamous flowers forming at this time.

Areas that are blackened were burned with the torch (next to watering can). 
I kept a full watering can nearby just in case the fire got out of hand (it didn't).  I left a small area
in the middle un-burned as a 'control group'.

These mechanical methods are helping reduce the number of stiltgrass plants in the lawn but there are still a number that escape the raking and pulling.  A new approach that I am trying out this year is fire.  Burning stands of stiltgrass is not effective early in the season while new plants are still germinating, or in the off season when plants are already dead (stiltgrass seed is relatively fire resistant).  However, burning in late summer as the stiltgrass is beginning to flower may be a way to successfully battle a stiltgrass invasion.  This method was suggested to me by Joene Hendry, who writes the blog  Joene's Garden.  The process I am trying is to first mow the area close to the ground (about an inch), then allow a day or two for the grass to dry out.  Next use a garden torch to burn the remaining stems, this should get at those hidden flowers.  While this may seem extreme, any perennial  grasses with good root systems will bounce back in a week or two, but the stiltgass is not able to recover.   I did try burning without mowing first, but stiltgrass holds a lot of moisture and it takes a long time to completely burn up such a moist plant.  Mown plants, without a lot of leaves, were quickly burned up.

Another element of stiltgrass removal is to fill in the gaps with desirable vegetation.  Since I am located in the cool season grass zone I have been using a fine fescue blend (like Eco-lawn) in the shadier areas and tall fescue blends in the sunnier spots.  I do have some zoysia grass growing in the sunnier spots.  This warm season grass grows thickly and excludes most of the stiltgrass.  It's unfortunate that there are not more native options for turf in this area (although red fescue, Festuca rubra, is technically a native species).  By avoiding the use of broad spectrum herbicides I do allow the native sedges, violets and other species a chance to repopulate.

I did get an early start over-seeding this fall and I hope to have the new plants established before it gets too cold.  If these desired grasses get established I will experiment with some pre-emergent herbicides.  These act by  interfering with root development after seed germination.  These are particularly effective on annual species such as Japanese stiltgrass and crabgrass.   I imagine a year without stiltgrass competition should help develop a thicker lawn. 

Red, White and Blue for the Fourth and other times, too

Happy Fourth Of July!  When I think of the 4th it's all about red, white and blue.  In the garden these colors are not usually used together, unless you are doing a theme planting or a flower arrangement.  Occasionally it happens, though, by accident.

This mostly native arrangement has 'Annabelle' Hydrangea for white,
Monarda didyma and non-native Salvia splendens for red, and the blue
 is supplied by Campanulastrum americana and Salvia farinacea 'Victoria blue'.
The green fireworks are bottlebrush grass, Elymus hystrix.

While I didn't plan this color scheme, this combination of
blue flag iris, Iris versicolor, and the red and white striped flowers
of myrtle-leaf mountain laurel, Kalmia latifolia 'Minuet'
made a pretty nice display in late May. 

Here are some North American native plants that can supply you with red white and blue flowers for each season of the year.

Reds:

Scarlet sage is not hardy here so I grow it as an annual.
However, its seed will overwinter with a little protection

 In picking out these plants I looked for true reds rather than the many pinks and purples that are out there.  Roughly in the order of bloom from spring to fall  there is red trillium (Trillium erectum), wild columbine (Aquilegia canadensis), Indian pinks (Spegelia marilandica), fire pink (Silene virginica), red beebalm (Monarda didyma), various red salvias (Salvia ssp.), standing sypress (Ipomopsis rubra), turkscap (Malvaviscus arboreus), scarlet  rosemallow (Hibiscus coccineus) and cardinal flower (Lobelia cardinalis).

Cardinal flower makes a strong statement in late summer in sunny moist locations

White:

The pure white flowers of bloodroot are one
of my favorites in early spring.

There seems to always be something white in bloom. Here are 10 native plants with white flowers roughly in order of appearance:  Bloodroot (Sanguinaria canadensis), Phlox (all species have some white forms blooming from early spring to late summer), beardtongue (Penstemon digitalis), elderberry (Sambucus canadensis), hydrangea (H. arborescens and quercifolia), summersweet (Clethra alnifolia), swamp rosemallow (Hibiscus moscheutos, often with a scarlet center), tall snakeroot (Ageratina altissima), white turtlehead (Chelone glabra) and various asters.

Elderberry has large flat flower clusters
for nearly a month in late spring.

Blue:

There are also native blue flowers throughout the growing season.  These plants tend to prefer shady locations.  Also their blue flowers show better in part shade than they do in full sun.  Many of the blues tend toward lavender or purple, I've tried to select more mid-range blues.  Here are a few, again in order of bloom:

Virginia bluebells carpet moist ground in early spring.

Virginia bluebells (Mertensia virginica), Jacob's ladder (Polemonium reptans), Ohio spiderwort (Tradescantia ohioensis), blue flag iris (Iris virginiana), American bellflower (Campanulastrum americanum), gayfeather (Liatris spp.), mealycup sage (Salvia farinacea), blue mistflower (Conoclinum coelestinum), great blue lobelia (Lobelia siphilitica) and various blue asters.

This smooth aster is one of the bluer (less purple) native asters in the eastern US.
(Should be Syphyotrichum laeve, sorry)

There are many other red, white and blue blooming natives out there and I would appreciate hearing what your favorites are.  And again, Happy 4th!!!

Building a Container Water Garden

One of the challenges to creating a pollinator friendly garden is to include a water source.  We have a few static birdbaths, but ours are out of the way and often ignored.  To prevent mosquito breeding in these still ponds we throw in a 'mosquito dunk' which kill their larvae.  Having visited a few gardens with elaborate water gardens I was inspired to bring those home, in a scaled down version.

The finished product 2 days after completion.

What I have assembled is a container water garden that sits on our deck in easy view of the front door.  While I really wanted to include a lotus, they require a lot more space (min. 6 sq.ft.) to do well.  Instead I found a miniature water lily with 3" leaves that are in good scale with my container.  For a vertical element I chose squarestem spikerush, a native species that grows to 2' tall.  Anything taller would be out of scale.

Let me run you through the features of this container garden and the steps to build it.  The tub itself is a plastic planter bought from Costco for under $20.  The top is 2' in diameter and it holds about 20 gal. of water.  The depth is 15-18" which allow for the lily to be about a foot under water.  The bluestone rocks are partly for decoration but some are porous enough to be a butterfly watering station.  The rocks are stacked to create a small waterfall, powered by a small fountain pump.  For this sized tub, 20 ghp is sufficient. Since waterlilies do not like moving water the waterfall is directed to the side and into the rushes to slow the flow to a ripple.  The reason for the waterfall is to add a sound element to the garden and to create enough flow to keep mosquitoes from breeding in the otherwise still water.

The steps for constructing this garden are pretty easy.  Here the parts I used are shown.  They include the container, this one is plastic but a galvanized metal tub would work as well. There are also a small submersible pump, a timer, and about 3' of flexible hose to route water for the waterfall.  The concrete blocks create a flat base for the plant pots and the decorative stones.  Since I wanted a waterfall, at least one of these stones is concave to channel the water.

The 'hardware' for the water garden.

Next there are the plants.  We are fortunate to live not too far from Lilypons Water Gardens in Adamstown, MD.  They have been in business for a 100 years supplying water garden plants, fish and supplies.  There I was able to get some advice and select plants appropriate to my needs.  Since my container only has about 3 sq. ft. of surface I needed to look at smaller sized plants.  I selected the 'Helvola' hardy waterlily, with its smaller leaves and flowers it would not look at all crowed in my small container.

Here I measured the length of the stems so that
 I could place the pot at the proper depth in the container.
Turned out the setting directly on the bottom
 was the perfect spot.

Here's the square-stemmed spikerush.  The stems have a
flat membrane at each corner that catches the light.

Here I used the concrete blocks to elevate
 the spikerush so that it would not be too deep.

After placing the plants I added a couple of more concrete blocks to create a base for the decorative rocks and waterfall.  I put the pump behind the rocks to hide the cord and minimize turbulence.  The pump hose was was positioned on top of the waterfall rock and additional stones were used to press the hose in place.

Now with everything in place I filled the tub with water until the leaves of the waterlily were floating loosely on the surface.  The water was hazy for a couple of hours, but by the next day it was clear as seen above.  

Most water lilies like full sun, some like 'Helvola' tolerate part sun.  In its present location this container gets about 4 hours of direct sunlight.  Since the flowers open in response to sun (and close up in the evening) a sunnier site will keep the flowers open longer.

Learning My Sedges

Identifying grasses is tough.  While each species is different in some way, these differences are often subtle and often evident only when the grass is in bloom or when the seeds are ripe.  Looking out on a meadow or fallow field we often see 'grass', but in North America there are about 5000 species of plants that look like grass.  Most of these can be lumped into 2 groups.  The largest is the grass family (Poacea), with over 3000 taxa in North America followed by the sedge family (Cyperaceae) with about 1400 North American taxa.  Common characteristics of grasses are that they have round hollow stems and there are joints, or a thickening, at the leaf nodes.  Most sedges have triangular stems that you can often feel when you roll the stem between your fingers.  When viewed from above the leaves are 120 deg. apart, corresponding to the triangular stem.  Unlike grasses these stems do not have joints.

On our property in rural Maryland we are blessed with a number of different sedges.  Most of these have eluded identification because I have been looking at them in mid-summer when the foliage was big and strong but there were no flowers or seeds in sight.  Last fall when I renovated a garden bed I transplanted in several of these 'mystery' sedges.  Now, closer to the house I could keep an eye on them and catch them in bloom.

The bloom time for the sedges varies by species and growing conditions.  This year they started in early spring and some are still going strong in late May.  Some species that bloom early in the season are Pennsylvania sedge (Carex pensylvanica), Appalachian sedge (C. appalachica), and white-tinged sedge (C. albicans).  Among the sedges that bloom in mid-spring are rosy sedge (C. rosea) and broad loose-flower sedge (C. laxiflora).  Sallow sedge (C. lurida) is one that blooms in early summer.

In the past I have used a book by Lauren Brown, Grasses, an Identification Guide, to try to figure out what I had.  This book is nice in that you can get close to an identification without dissecting the plant.  However, it is limited in the number of species it covers.  This year I used the on-line key at GoBotany developed by the New England Wildflower Society.  I was pretty useful but it requires that you have detailed information about the flowers or seeds to make much progress through the key.  It also provides links to botanical terms and has good photos of each species when you get to the end.  It's limitation is that it only covers species native to the New England states, but that is still an awful lot of plants.

Here are some of the species that I am pretty sure I've identified or confirmed this year:

Rosy sedge is a reliable shade tolerant sedge.  Here its growing in a
woodland bed with strawberry bush (Euonymus americanus)
and American alumroot (Heuchera americana).

Rosy Sedge (C. rosea) is one I have been pretty sure about, but I just wanted to confirm.  It grows really well in moist shady areas and its mounds of fine textured foliage create a peaceful mood.  It's growing along a path that is used by both humans and deer. It can handle a little foot traffic and somewhat compacted soils.

Broad looseflower sedge name becomes clear
when it is allowed to go into flower.  Its leaves
get wider and the flowing culm flops over as it grows.

Broad loose-flower sedge (C. laxiflora) is very common here.  It is essentially evergreen and seems to survive out in the lawn even with weekly mowings.  This year I finally caught it in bloom and was able to run it through the identification key.  What stands out to me is that the leaf blade is folded along 3 veins giving it 'W' shape in cross-section.  In the past I may have ID'd this one as spreading sedge (C. laxiculmis).

Here, some smooth sheathed sedge is in flower in open shade.
The other grass at ground level is nimblewill (Muhlenbergia schreberi)
and a mayapple (Podophyllum peltatum) that was added in, is behind.

Smooth sheathed sedge (C. laevivaginata) is unassuming when not in bloom.  Its foliage resembles that of loose-flowered sedge in that it has a 'W' fold. In bloom it has a tall stalk topped with several tightly packed florets.

This group of weak stellate sedge is growing in an upland meadow/woodland edge
partly shaded by a mulberry tree and many taller perennials.

Weak stellate sedge (C. seorsa) looks like a much larger version of rosy sedge early in flower development (early May).  As the seeds develop they get much larger.  My sample looked similar to photos on the internet, but there some minor differences, such as lacking a bract (narrow leaf) just below the lowest floret.  I am 80% sure of this assignment.

Growing next to the stellate sedge is what appears to be pale sedge (C. pallescens).   This one stood out from other nearby sedges because the spikelets are on short stems rather being held tightly to the main stem.  This is a more northern species, not too common in Maryland.  For that reason I am a little skeptical about this assignment.

An important feature to note when using this identification key is where do the male flowers appear.  They can be on a separate spike at the top of the stem, they could be mixed in a spikelet with the female flowers, either above or below, or they could be on separate plants.  Another important feature to note is whether the pericarp (where the seed is formed) is divided into sections of two or three.

I often get too wrapped up with trying to name a plant.  Sometimes I just need to chill out and enjoy the plants for how they look and how they work in the garden.

It looked like a mild winter until...

We've been having a pretty mild winter this year.  The average temperature in the U.S. in February 2017 was 7.3 F above the 20th century average.  Comparing photos I'd taken in 2014 and 2015 with this year indicates that this year we are 2-4 weeks ahead, based on the blooming of the crocus and forsythia.  On March 14th we finally got a good dose of snow in our neck of the woods (west-central Maryland).

This late snow is out of place with the forsythia that has been blooming since late-February this year.

About a week before the snow storm I took a walk around the woods to see what was starting to come up.  The first thing I checked on was the spicebush.  It usually begins blooming shortly after the forsythia.  This year, while the forsythia had been in bloom for a couple of weeks, the spicebush was just getting started.

March 10th and the flower buds on the spicebush were just opening.

The next plant I checked was the pussy willow, Salix discolor.  This native tree/shrub is one of the earliest blooming native plants and is an important source of pollen to early season native bees.  Since this species is dioecious, only the male plants are sources of pollen; however both male and female flowers have nectar.

The buds of this pussy willow are just opening.  When fully in
bloom the flower buds of this male plant will be covered
with yellow pollen-bearing anthers.

Looking down on the ground in the leaf litter I found a number of Virginia bluebells, Mertensia virginica, that had just come up.  Sometimes the new leaves have a purple tinge to them, but that color quickly fades to green.  The spikes of flower buds follow quickly after this first flush of leaves.

These Virginia bluebells have just come up.

Also showing up on the ground was white avens, Geum canadense, which is pretty common in this area.  While its not particularly beautiful in bloom, it does fill in gaps in the shady understory and its wispy white flowers break up the sea of green leaves.  In the early spring it is by the light colored veins on the deeply divided leaves.

The leaf markings on this white avens rival those of some Heucheras;
however, as it matures the dominant leaves will be smaller and the veination less noticeable.

The plant to the left in this photo is purple deadnettle, Lamium purpureum.  This introduced species is scattered throughout the shady areas.  While weedy, it does not appear to be causing too much trouble with the other plants.

These violets look a little like garlic mustard, ...

Also noted among the fallen leaves were fresh leaves of some native violets, probably woolly blue violet, V. sororia.  These nearly round leaves have finely serrated margins (crenate) and fairly smooth leaves.

They can be distinguished from the over-wintering garlic mustard rosettes that have longer, slender petiole and leaves that are deeply veined and more deeply toothed serrate leaf margins.

Garlic mustard has deeply veined leaves that
look tired, having been out all winter.

Garlic mustard is not the only invasive species that is evident right now.  In fact late winter is a good time to spot some invasive species since they tend to come to life a little before most of the native species.  Multiflora rose and barberry are both leafing out now making them stand out in the woods.  Since the soil was soft I was able to pull a number of these bad guys out of the ground.  This is also a good time to spot Japanese honeysuckle growing up in the trees.  Now is a good time to  cut these climbing vines and deny the roots an early burst of energy.

Most native honeysuckles have the two terminal leaves fused together
like this just below the flower bud.

While not growing with the same vigor as the Japanese honelysuckle at this time, the native coral or trumpet honeysuckle is also leafing out. Flower buds are beginning to form, though the normal bloom season is closer to mid-spring.

New Plants for 2017: Just Getting Started

The seed and plant catalogs have been coming since late December and I've made a few selections already.  Here's a run down on seeds and shrubs that I have ordered so far.

The tubular flowers of fireweed mature into long
seed pods, as seen on the lower right.

Fireweed, Chamerion angustifolium (formerly of the genus Epilobium) is a tall perennial that puts out hot pink flowers in mid-summer.  Growing in part to full sunshine and average soil moisture this will be a welcome addition to the small meadow that I am developing.  The tubular flowers are very attractive to a number of native bees as well as hummingbirds.

Fireweed is named for its tendency to appear in great numbers after fire has cleared the competing vegetation.

The tiny seeds, ca. 1 mm long, need to be cold-moist stratified for 60 days for good germination.  The tiny seeds also need to be surface sown, as they need light for germination.  I started the stratification in damp sand last week, so I should be able to get them into trays in early April.

When stratification is done, I'll just smear the damp sand/seed mixture on top of the soil.

Another new species for me will be goat's rue, Tephrosia virginiana.  This member of the legume family likes dryish sandy soils in part to full sun light.  It has feathery foliage and puts out pink and yellow pea-like flowers in early to mid-summer.  Since this plant has a deep taproot, I will use it on an embankment that I want to stabilize.

Relative to fireweed, the seeds of goat's rue are huge, 3-4 mm long and about half as wide.  These seeds have a thick outer coating and will need to be scarified before giving it about 2 weeks of cold-moist stratification.  In addition to this I also got a packet of inoculum that contains the bacteria this plant needs to fix nitrogen from the air. I'll mix this with the seeds prior to starting the stratification process.  I think seeds will germinate with it, but not having the right bacteria can compromise their development.  

I have encountered this with another legume, partridge pea, Chamaecrista fasciculata, where I saw much better growth from seeds that had been treated with inoculum than for those sown without it.

In addition to these I got some additional seeds for rose verbena, Glandularia canadensis, and spotted beebalm, Monarda punctata.  I was pleased with the rose verbena I planted last year.  While it does not call for it, I moist stratified the seed for a month and got excellent germination rates.  It formed a nice ground cover and bloomed well with clusters of deep magenta flowers.  I purchased more seed because it is listed as marginally hardy in zone 6 and I was afraid that there would not be enough seed produced last season to produce another crop for this year.  Since our winter low temperatures this year have not dropped below 15 F, we are having more of a zone 8 winter, this species may make it through until spring.  In any case I'll have more plants to fill in and maybe share a few with others.

Rose verbena as it's looking in mid-February.  It's taken some damage,
but it's looking good close to the ground level.

The spotted beebalm I had a few years back has petered out.  I think it lost out to more competitive plants around the vegetable garden.  It is a short lived perennial and relies on having good places for new seed to germinate to continue in the garden.   For this new crop I will put it in spots with leaner soil and where its seed can germinate without being covered by other plants.


As far as shrubs, I'm just reinforcing some of what I got last year:
Eastern Red Cedar, only one from the three I planted last year was successful.  This year I'll get them in the ground sooner and do a better job of clearing away competitive plants.

Chokecherry, I'm 1 for 2 on this species.  For these I will need to clear a larger space so they can get established.  Once established they should grow quickly on their own.

American hazelnut, these are surviving well in somewhat shady locations.  I have identified several other woodland edge areas where it would be nice to have this native shrub fill in.