Stiltgrass actions for Spring 2019

I have been battling Japanese stiltgrass, Microstegium vimineum, for the past 5 years or so.   Pulling stiltgrass out, particularly in late summer, in the shaded woodlands has been effective in reducing the amount of stiltgrass over several years.  Getting it out of the lawn is another matter.  I've tried raking it out in late summer, and over planting with more desirable grasses (particularly fine and tall fescues).  This has helped, but stiltgrass as a warm season annual, is very adept at filling any gaps in the lawn starting in mid-spring.  While I really like the look of the fine fescues,  particularly the no or low-mow fescue blends, these are slow to establish.  The tall fescues are more aggressive than the fine fescues.  When over-seeded in late summer, these do a better job of getting established and filling in the gaps. 

The area outlined in black has been burned with a garden torch in late summer for the past two years. 
The control patch in the middle was not burned; it has slightly less coverage with perennial grasses.

More recently I've used a garden torch in late summer to eliminate it before it can set seed.  This has been somewhat effective but that is not so practical for a large area.  

Last year I used a pre-emergent herbicide, like those you would use for crabgrass, for the first time.  It was very effective at suppressing the stiltgrass for an entire season.  (I should say that the chemical's effect is probably gone after 2-3 months, but by that time the stiltgrass germination rate has dropped.)  Other perennial grasses were able to start filling in.  I will expand the area of application this year and also test it in some of the meadow areas, as well.

The treated areas have a little more coverage with perennial, mostly cool season, grasses than the untreated areas. 
The brownish spots are mostly zoysia or nimblewill, both warm season species.

While Japanese stiltgrass has a very high rate of germination, I expect that there may be some that waits a season of two to germinate, so these pre-emergent herbicide treatments may need to be repeated for several years.  I will try to leave a small area that I treated last year  untreated this year to see how strongly the stiltgrass comes back. 

In a blog post last year I mentioned several pre-emergents that were effective.  This year I will be using the same as last year, dithiopyr, sold as Dimension.  It has the advantage that I could find it alone, without added fertilizers.  Also, it was less expensive than Preen garden weed preventer (trifluralin).  Timing-wise, the general recommendation is to put the pre-emergent herbicide down when the forsythia are in bloom.  Last year I did this on the early side, just before peak bloom.  This year I will wait just a little later.  My thought is that this will give the existing grasses a little more time to spread before I put down the herbicide, which works by inhibiting new root growth near the soil surface.  I recently found a website that give guidance on when to apply pre-emergent herbicides and other turf related IPM activities called GDDTracker.  A nice feature is that it compares the current and previous year's temperature histories.

I will also try the pre-emergent herbicide in an area that I mow only once a year then leave to grow as a meadow.  In one section I burned off the surface debris.  Half of this I will treat with the pre-emergent, the other half will be untreated (Burn Only).  I will also treat an unburned area with the herbicide to see if burning makes a difference.  The rest of the meadow will serve as the 'control' group.  I am a little concerned about using the pre-emergent herbicide in' wilder' areas.  It could have a negative effect on some of the native annuals there like sweet everlasting, Pseudognaphalium obtussifolium, and yellow fumewort, Corydalis flavula.  But, then again, the stiltgrass has a definite negative effect.

Here is a section of my 'Mown Meadow' where I will do a Stiltgrass/Pre-emergent experiment.  This will give me an idea of how much prep work is needing in this wilder area.

Another action that I will be doing is to plant some bottlebrush grass seedlings, Elymus hystrix, into areas that are infected with Japanese stiltgrass (some herbicide treated, others not).  Bottlebrush grass does particularly well in open shade, conditions that Japanese stiltgrass excels in.  Just removing the stiltgrass alone is not enough, I need to establish some desirable native species to keep the stiltgrass out.

Native Plant Information on Houzz

For the past 18 months I have been writing profiles of native plants for the mid-Atlantic region for the website Houzz.  While much of the content on this site is focused on interior design, they are making a concerted effort to spreading the news about native plant species and how to use them in residential design.  Also, many of the gardening and landscaping articles focus on responsible and sustainable design.

They have a number of writers from different parts of the U.S. doing profiles on useful plants native to their region.  Writers for other regions of the US include: Ellen Sousa for the Northeast, Benjamin Vogt for the Central Plains,  Heather Holm for the Great Lakes, and  Noelle Johnson for the deserts/southwest.  

Also on the website you can find articles on a number of specialty issues like drought tolerant plants, trees for wet soils, and native grasses to name a few. I encourage you to check out the resources on landscaping and native plants on Houzz.

Here are links to a few of my articles:

Great Design Plant: Pseudognaphalium Obtusifolium, or Rabbit Tobacco

Great Design Plant: Nyssa Sylvatica

10 Top Mid-Atlantic Native Plants

Fall's Second Season

Even though all the blossoms are gone there are still sights to delight the eye in the fall garden.  Rather than the purples and golds of aster and goldenrod flowers, we get whites and silvers from the seeds and seed heads of many of these same plants.  The lower angle of the winter sun magnifies this effect, causing them to nearly glow with reflected light.

This photo was taken on a mid-November morning.  Some of the plants from
left to right are little bluestem, New England aster, purple top (grass) and Canada goldenrod.

Sweet everlasting, Pseudognaphallium obtussifolium, has a particularly long-lasting presence in the garden.  Even after the seeds are dispersed the white, star-like sepals remain intact well into January.  This plant is an annual and depends on this seed finding a spot on the ground to continue its presence in the garden.

The spent flowers of sweet everlasting show off well in front of a dark back ground.
Mixed in here are the seed stalks of the native grass, purple top, Tridens flavus.

Virgin's bower, Clematis virginiana, is one of our native clematises.  It has a very long vining habit, growing to about 20 feet in sunny location in one season.  Many consider it weedy because its thin stems go just about anywhere.  I like it because it does a good job of covering  fences  with foliage without becoming heavy and damaging like the exotic sweet autumn clematis.  The flowers in the second half of summer are small and rather subtle compared to many cultivated clematises.  Where this plant shines (or glows) is in the fall when the feathery seed heads form.  

After the fluffy white seeds of New York ironweed are dispersed
these rust colored capsules will remain for several months.

Another fall star is New York ironweed, Vernonia novebaracensis.  By the end of October the magenta flowers are all gone, replaced with the rust-colored seed heads.  As winter wears on these breakdown and become less fluffy; however the star-like sepals remain into the new year.




Besides all these flowering plants, the grasses also make a graceful contribution to the fall and winter garden.  Last fall I wrote a blog post about fall grasses.  I won't go into a lot of detail again, only to say that some of them really do use the winter light to great effect, such as pink muhly (Muhlenbergia capilaris) and little bluestem (Schizachyrium scoparium).

Little bluestem also takes on a distinct copper hue that makes it easy to spot at a distance.  Northern sea oats (Chasmantheum latifolium) also has a distinctive form with its dangling seed heads and rich brown hues.  Also on the property I have several large patches of deer tongue grass (see last fall's post).  What I noticed this year was that, while not particularly beautiful in form, the stiff dried leaves made a very pleasant rustling sound when there was just a little breeze.

While leaving perennials and grasses standing over the winter offers some visual interest to an otherwise flat landscape, it is also a good practice for the ecologically minded gardener.  Seed heads left standing provide food for migrating and non-migrating birds.  Standing twigs provide winter cover for many small animals and insects.  The larvae of many butterflies over winter in the leaf litter.  Many insect predators overwinter in the ground cover.  By providing space for them you will have a leg up come spring on your pest control.  (There are situations were fall clean up is advised, particularly for plants battling a fungal or bacterial infection where spores can overwinter in the leaf layer.)

Appreciating plants in the fall is not just an outdoor activity.  We brought in a few to enjoy as a table center piece.  While pretty this has proven to get a little messy.  The seeds  on the little bluestem stick quite tightly to the table cloth and the hosta seed head is still shedding seeds.  Our biggest problem is that our cat likes to get in and rearrange things, even the spiny branches of the invasive wineberry (Rubus phoenicolasius).

Some of the plants from left to right, Northern sea oats, a wineberry stem, little bluestem,
false indigo pods, tall ornamental garlic, hosta and wild bergamot.

Collecting my own seed

I've been trying to figure out what to plant in the areas where I've been pulling out the Japanese stiltgrass.  I want to use native plants and I'd like them to be as local as possible.  As I was taking some autumn photos, suddenly it hit me.  Why not use the seeds that my native plants are producing right in my own backyard (duh)!!!  This is perfect.  By collecting seed from around my property I'm getting plants that are adapted to the local area.  I can also make a good guess at where the plants will grow well.  Of course not every seed I put out will germinate but the seeds are free and the investment in labor is minimal.  The seed I am collecting now are from late summer and fall blooming plants.

Here's what I've collected so far:

The ripe seed heads of this Sallow Sedge fell apart into individual
seeds when I touched them making them easy to harvest.

Sallow sedge, Carex lurida, is pretty common on my property.  It forms dense clumps that mature to 2-3' tall and wide.  It grows best in moist to wet soils and partial sunlight.  I have small clumps of it growing in the lawn, but these can't reproduce since they are getting mowed down regularly. The leaves are long and have a deep fold along the midrib.  This gives it a stiff texture.

I'll scatter the seeds along the woodland edges where the soil is moist and there are several hours of good sun each day.  It is also an area where I am trying to remove the invasive wineberry bushes, Rubus phoenicolasius.  The dense clumps may make it a little harder for these bushes to spread.

The seeds of bottlebrush grass are easily stripped off from
bottom to top.  Trying to go the other direction leaves most
of the seed still attached to the stem.

Bottlebrush grass, Elymus hystrix, is a common cool season grass of the northeastern quarter of the US.  Most of the plants I have were purchased, however I have seen some growing remotely.  So I may have some indigenous plants, or they are just really good at spreading.  This species is most noted for the flowers and seed heads that resemble a bottle brush.  The flowers appear in early summer and persist until fall.  

The plants grow from 2 to 5 feet tall and do well partial sun and soils with medium moisture levels.  I will plant these along the edge of a path where the soil drops away.  The height of these plants should still make them easy to see.

The seeds are relatively large.  One ounce typically consists of about 7,500 seeds

Ripe seeds are assisted in wind dispersal by the fluffy white appendages.
Some flowers still in bloom are at the lower right in the photo.

Tall Snakeroot, Ageratina altissima, formerly Eupatorium rugosum, is very common in this area.  It is particularly evident in my area along roadsides near the Potomac river.  It grows well in full to partial sunlight and a range of soil moistures.

It is tolerant of soil disturbance, making it a good candidate for an edge habitat where plants are occasionally mowed down.  I'll scatter these in some of the drier woodland edge areas.

The seeds are tiny, typically 150,000 per ounce. They require light for germination.  This is common for disturbance adapted plant species.

Here most of the fluffy seed of the Sweet Everlasting have 
been blown away, leaving the sepals as 'everlasting' flowers.

Sweet everlasting, Pseudognaphalium obtusifolium, is a native annual that depends on disturbance for survival.  It is most common recently cleared areas in full sun and dryish soils.  I have a recently cleared meadow area that will be perfect for these.

This plant is evident in a border because the fine hairs on the leaves and stems catch the sunlight and make it look like the plant is glowing.  The tiny white flowers never fully open but form white clusters of buds that show well.  After blooming long-lasting bracts remain giving the effect of an everlasting flower.

The seeds of this species are really tiny, coming in at 500,000 per ounce.  It is hard to find the actual seed, there is so much fluff attached. These seeds are quickly wind dispersed, so I need stay on top of harvesting them.

Short's Aster, Symphyotrichum shortii, is found in the mid-Atlantic and mid-western states.  This aster is the latest blooming species that I have growing.  It starts in about mid-September and continues to the end of October.  Besides its long and late blooming cycle, it is also tolerant of dry shade and alkaline soils.  This makes it an excellent candidate for deeper into the woodland areas where it can compete with the stiltgrass for patches of light and openings in the canopy.

Each seed of Small's Aster has an attached pappus that looks like a little umbrella that catches the wind.  The actual seeds are larger than the previous two species, with about 60,000 per ounce.

In the center are some ripe seeds with their fluffy pappus.
In the background you can see some or the lavender
flowers still in bloom.

So these are some of the later blooming species that I will try to 'seed' into the stiltgrass infected areas.  There no reason I shouldn't harvest some of my spring and early summer species and do the same.

White Flowers of Fall

Late summer and early fall is when the asters and goldenrods dominate the the landscape.  These are beautiful plants and provide tons of food for pollinators, but I was trying to think of other native plants that were actively blooming at this time.  I was especially interested in plants that are not too tall, ones that could be used near the front of a garden border.  One beautiful native that comes in late summer is Blue Mistflower (Conoclinium coelestinum), but it seems to be winding down now in my gardens.  I had hoped to have some sneezeweed (Helenium autumnale), but this is the first year for the plants and something ate off the tops (deer?).

Then, as I was walking through a meadow area some ideas literally hit me.  There at my knees was a clump of Sweet Everlasting (Pseudognaphalium obtusifolium) and around the bend was some tall snakeroot (Ageratina altissima).  Both of these plants stood out because of the large clusters of small white flowers.

The woolly hairs on Sweet Everlasting can catch
the light and brighten up the whole plant.

Sweet Everlasting is a native annual that grows well on medium to dry well drained soils.  Like many native annuals they grow well on disturbed sites, especially those will few other plants established.  Those growing in my yard are along the edges of mowed paths and in some of the drier planting beds.  The flowers consist of tightly bunched disk flowers only, no petals (ray flowers).  The narrow leaves are medium to light green on top and white-woolly on the bottom,  The stems are also covered with woolly hairs. As the name implies, the stems and flowers will last for a long time and can be used in dried flower arrangements.  When crushed the stems and leaves have a curry-like fragrance.

Ripe seeds have a fuzzy appendage that will catch the wind, helping with seed dispersal.  I have had some difficulty starting these from seed indoors.  They seem to do much better growing outdoors.  The tiny seeds need light to germinate so they should be sown on the soil surface and pressed in, not buried.

The leaves of Tall Snakeroot are held on long petioles, 1/2  to 2" and are disposed on
opposite sides of the stem.  The length of the petiole and the relatively
broad leaves distinguish it from related bonesets and other snakeroots.

I first noticed Tall Snakeroot (Ageratina altissima, formerly Eupatorium rugosum) growing in a shady area as I was clearing stiltgrass last year.  This year I am seeing it in multiple locations.  I don't know if it is spreading, or I am just getting better at finding it.  Similar to sweet everlasting, these flowers have only disk florets.  The bright white flowers are clustered together in broad heads, making them easy to spot at a distance.  While not a favorite plant for deer, I have noticed some nibbling of the leaves and flowers.

Normally growing 3' tall or more this may be a little tall for the front of a border, but some of mine have flopped over and they look fine at 8-12".  There is a selection named 'Chocolate', identified and developed at the Mt. Cuba Center.  It has burgundy toned foliage.

The 'deer-pruned' turtleheads are bushy and just the right height for the front of a border.

The last non-aster, white flower I came across this past week was White Turtlehead (Chelone glabra).  There grow well in medium to moist soils and part sun.  Under ideal conditions these will grow to about 3' tall.  This is a great plant for use in a rain garden.  It is generally deer resistant, but like with the snakeroot, my deer nibble on them a bit.  This was actually a benefit, after first flush of flowers had been chewed off, the plant came back lower and bushier, with more flowers.

Getting Aquainted

View upstream toward Harper's Ferry, WV a few days before Hurricane Sandy.

We've been in the new house for a little over a month now and we are starting to get into a new rhythm.  We are about a mile from the Potomac River, near Harper's Ferry.  As the leaves are falling it is easier to see the landscape features on the grounds and also identify some of the plants that were previously inaccessible through the brush.

The woolly leaves of Sweet Everlasting are similar
to those of Pearly Everlasting (see below). 

As I was tramping through the less explored areas, one familiar plant that stood out for me was the annual, Sweet Everlasting, Pseudognaphalium obtussifolium.  This can be distinguished by its nearly pure white flowers, compared to the yellow-centered flowers of the similar looking Pearly Everlasting.

The flowers of Pearly Everlasting have yellow centers.

The reddish-brown stipe of Ebony Spleenwort
is not as rigid as those of Christmas Fern.

As I made my way into the ravine at the back of the property I saw some familiar Christmas Ferns growing in the shade.  I turned around and saw another similar looking fern that turned out to be Ebony Spleenwort, Asplenium platyneuron.  These are both 'once-cut' ferns with boot-shaped leaves (pinnae), but the spleenwort has a reddish brown stem (stipe) and is generally more delicate in appearance.

One of the projects I have in mind is to 'develop' a portion of the property as a meadow area.   I was planning on covering the area with cardboard (a material I have an ample supply of after unpacking) to kill off the existing lawn.  However, a good portion of this area has been going wild for a couple of years and, on closer examination, I have found many of the desired grasses already present.  Now I think I will take a different approach, rather than starting with a clean slate, I will augment the existing native species and edit out the invasives.  This will be a tedious job, but  it would be a shame to remove the indigenous gene pool and replace them with the same species from some other ecoregion.  Currently in this meadow to be there are a lot of Multiflora Rose.  There also appear to be some other rose species.  I will need to wait for some fresh growth to make a determination of which rose is which.  

Multiflora Rose can be identified by the comb-like stipules.
Most native roses less complex stipules.

Anyone familiar with this plant?

There are a number of wildflowers growing in this area.  One that was still in bloom in October is what I believe to be a species of Helianthus.  I would appreciate any thoughts as to which species this is.  Since there was only one plant in bloom, I did not want to generalize too much based on one (partial) flower.  I'm leaning toward Jerusalem Artichoke, H. tuberosus, but there are so many other possibilities.

Some of the native grasses that are well represented in this meadow area are Little Bluestem, Switch Grass, and Deer Tongue Grass.  In the deciduous woods there are many clumps of Spreading Sedge, Carex laxiculmis.

Little Bluestem comes into its glory in the fall
when the seedheads glow in the low sunlight

Deer Tongue Grass stands out among the other grasses in the sunny meadow with its relatively short, broad blades.  The plume-like seed heads are lost early in the season.  

Clumps of Spreading Sedge are scattered
through the moist deciduous woodlands.

Fall projects include clearing out some of the fallen trees and thinning the River Grape vines and other overgrown shrubs from around the trees.

Winter Field Trip

So after writing about the 'Winter Weeds' around my house for a couple of weeks I decided to take a walk through a nearby meadow to see what's still standing.  For me the closest meadow is Rock Meadow, in Belmont, MA.  This erstwhile farm has been conservation land for the town of Belmont since 1969.  With decreasing maintenance budgets over the years this area was undergoing succession with open meadows being closed up with a variety of native and non-native, invasive species.  This severely  degraded its value as a bird nesting habitat and reduced it general value as a recreational space.  In 2005 the Friends of Rock Meadow worked with the town in securing funds to do a renovation.  Most of this work was completed between 2007 and 2009, with the removal of many invasive plants, clearing shrubbery from the meadow and improving trails.  So with map in hand I set out to see what interesting plants I could find...

The burrs on this Burdock catch the afternoon sun
as easily as they do to a passing hiker.

The first plant I came across was Burdock.  This old world introduction is a common weed of waste spaces, but its strong structure helps it persist in the winter landscape.  The burs on the seed pod are hooked which help them attach to passing animals, thus dispersing the seed to a wider area.







Next I walked by a thicket rich with Red Twig Dogwood.  I am assuming these are the native Cornus sericea (formerly, C. stolonifera), even with leaves and flowers some of these species are difficult to tell apart.

The Red-twig Dogwood was easily identified among
all the other brown branches in the thicket.

Large sections of Rock Meadow are consistently wet.  These areas are easily identified by their large populations of Cattails.  There are two common species in the Northeast, one with broad leaves and one with narrow (Typha latifolia and T. angustifolia, respectively).  I did not investigate which was present, or if both were there.

One of the wet areas in Rock Meadow that is home to Cattails

Steeple Bush, just upstream
of a wet meadow.

Steeple Bush (Spiraea tomentosa) is another native spirea.  Unlike the Meadowsweet I have growing at home, the flowers of Steeple Bush are held in tightly erect panicles.  Also I found it here, Steeple Bush prefers moister soils.

While not a true pre-Colombian native species, Queen Anne's Lace has become naturalized throughout North America.  Even without its flower petals, this plant still has a presence in the winter landscape.  

The bare bones of Queen Anne's Lace

The few remaining seeds on this Little Bluestem
still catch the  winter sunlight.

Little Bluestem is a widespread native grass.  It seems to look its best growing on really poor soils and is often seen growing along the highway.  In richer soils it gets tall and floppy.  In the fall and winter it can be picked out by its orangy appearance and the way that the fuzzy seeds catch the light.



One plant I almost passed right by was this Tower Mustard.  It just looked like some sticks poking out of the ground.  On closer examination I noticed the dimpled membranes that once held the seed in an alternating pattern.  I didn't know this plant at first, but I looked in my copy of  'Weeds in Winter' and it led me to the mustard family.  After that, I was able to locate the species by referring to my copy of Newcomb's.

The seed pods of Tower Mustard still show
the impressions of the seeds they held.

The opened seed pods of Evening Primrose
 look like dried flowers.

Evening Primrose is a plant that is easy to recognize in its dried form.  When I walked by I realized that I knew this plant, I just could not remember its name.  The stiff, four-parted seed capsules on the tall, upright stems are unique and hard to forget.  I quickly flipped through the field guide until I found a drawing that matched this plant dead on.

I'm pretty sure this is Sweet Everlasting.
Had I used my nose as well as my eyes I would no for sure.

After returning to the path I looked down and saw another familiar plant.  There was a single stem of what I believe was Sweet Everlasting (Pseudognaphalium obtussifolium).  However, it could also have been Pearly Everlasting (Anaphalis margaritacea) which also has woolly stems and leaves and persistent papery bracts.  Crushing a flower would have told me which, Sweet Everlasting has a sweet, tobaccoy scent, while Pearly Everlasting has no smell.  Also, the bracts of Sweet Everlasting have a dingy tone, while those of Pearly Everlasting are reported to stay white (forever?).

As I moved into a shadier area, a large patch of Raspberry vines became evident.  These stood out as a purple mass of branches against an otherwise dull brown background.  Closer examination showed the little red thorns on the purple branches.  A couple of years ago I attempted to ID some raspberries but was quickly overwhelmed by the possibilities.  Right now I will just appreciate their contrast to the shades of brown.

Raspberries of some sort; the thorns are too small to be Blackberry

When I first saw these berries I thought this might be an Arailia of some sort.
A little research indicated that this was actually Carrion-Flower.

Carrion-flower was a surprise find as I was heading back to the parking lot.  Most of the members of the genus Smilax are rather unpleasant to deal with, like Catbriar (Smilax rotundifolia), with its tangle of thorny branches.  Carrion-flower, S. herbacea, on the other hand, has few, if any, thorns and only grows to about 8' in length.  As its common name indicates, the flowers have an unpleasant scent.




While Rock Meadow has been cleaned up of many of its  invasive species, some still remain.  In the winter months Winged Euonymus is easily recognized by the little wing-like projections along its stems.  Another common invasive is Black Swallowwort.  It can be recognized by the remains of its seed pod that looks like a dried leaf.  This vine is very hard to eradicate since it will resprout from small fragments of roots left behind after pulling or digging.

The arrow in the photo points to some of the wings
on this Winged Euonymus.

The old seed pods on this Black Swallowwort looks kind of like those of Milkweed.  In fact these are both members of the Asclepiadaceae family.