Stiltgrass management, part 2

After trying to remove as much Japanese stiltgrass as possible in late summer, the next step is to fill in the gaps with more desirable plants. My approach last year of seeding in native grasses like Canada and Virginia ryes did not work out too well.  There were some good reasons for my disappointing results.  I needed to plant  these relatively large seeds more deeply to get better germination.  Also these new grass seedlings need 2-3 years to establish before mowing back, or using as pasture.  It would be better to use these big perennial grasses in a meadow planting where mowing is done only once a season.

This year I am trying a more conventional route with the filler grasses.  I will be using commercial turf grasses that are selected for rapid growth and formation of a dense turf layer.  This is what I need to exclude the stiltgrass.  By planting these cool season grasses in the fall they have a chance to germinate and fill in before the stiltgrass starts growing in mid-spring.

I divided up the stiltgrass infected areas into full sun, part sun and mostly shade and selected a seed mixture appropriate for each condition.  For full sun I selected a blend of tall fescues with just a little Kentucky bluegrass.  For the part-sun areas I have a blend or both tall and fine fescues with a little perennial rye and Kentucky blue grass.  For the shade areas I am using a blend of fine fescues selected for low maintenance.  This year I am using Eco-Grass from Prairie Moon, but there are other blends such as No-Mow from Prairie Nursery and Eco-lawn from Wildflower Farm that should work as well.

Most commercially available cool-season turf grasses are not native to North America with the exception of some of the fine fescues, in particular red fescue (Festuca rubra).  You can find detailed information about which turf grasses are appropriate for your region from your state's cooperative extension.  For example the Maryland Extension Service has a listing of recommended grass cultivars that were tested locally.

Before buying seed this year I shopped around to see what specific seed cultivars were used in each of the blends.  There is usually a tag with the detailed seed composition somewhere on the bag. When I went out to buy the one I liked, I found that that specific blend was no longer available even though the product name on the bag was the same.  Frustrating!!!  I imagine that the retailers are still trying the produce an equivalent performing product, but it still, that was a frustrating experience.

The first step in the reseeding process is to remove the stiltgrass thatch in the lawn.  This opens up spaces for the new seed and may help remove some undispersed sitltgrass seed.  Since late in the season much of the remaining stiltgrass has had a chance to set seed, this thatch needs to be segregated from regular compost and the regular brush piles.  I have a couple of piles dedicated to stiltgrass so that it does not get mixed up with the regular yard waste and I can monitor it for spreading.  Another option would be to landfill it in thick plastic bags.  You do not want to let the stiltgrass get out and spread its seed.

Late September is when the stiltgrass begins to die back.  The brownish areas are easy to spot.

Once the area was clear of thatch I applied the new seed.  I used the back side of a bow rake to press the seed into the soil.  The nice thing about the conventional turf seeds is that they do not need to be planted deeply.  After sowing, it is necessary to keep the new seed bed moist until the new seedlings are established. I usually try to time my seed sowing with coming rains.  That way I don't need to water it in (I'm really lazy in that way).  Besides the cooler temperatures, autumn is a good time for lawn seeding because it is usually a rainier then too.   I usually see good levels of germination in 10-14 days for the Eco-grass.  This year is working out well (so far).  The soaking rains in early October saturated the soil and I have only needed to add a little additional water to keep the soil moist.

The area between the piles has been (mostly) cleared of stilt grass and is ready for seeding.
I used a leaf rake for this, but a stiff garden rake would have been
more effective for tearing out the stiltgrass plants.

While the standard instructions on the seed bag recommends fertilization at the time of seeding, it is best to do a soil test to determine if added fertilizer is needed.  If you use a mulching mower to return your grass clippings and leaves to the soil your fertilizer needs will be much lower (or non-existent). The risk of over-using fertilizer is that it will stimulate weed growth and that run off of excess nutrients will damage the environment.  Since we are in the Chesapeake watershed I try to use the minimum of fertilizer possible.  That usually means none.  In fact, for the fine fescues fertilization is not recommended.  If fertilization is needed, fall is the best time for cool season grasses.  Spring fertilization will stimulate growth of warm season weeds (and stiltgrass) as well as the cool season grasses.  In the fall only the cool season plants are actively taking up nutrients.

In this full sun area tearing out the stiltgrass exposed a lot of bare ground.
This spot was seeded with the full sun blend.  Just to the back left
 is a full shade area where I planted the Eco-grass mix.

One new thing I learned about tall fescue, Lolium arundinaceum, is that some cultivars are infected with an endophytic fungus that produces loline alkaloids that are toxic to many insects and mammals that feed on the grass.  This endophytic fungus also reduces biodiversity around the infected fescue.  while this is great for the fescue it is bad for the wider plant and animal communities.  The widely used and inexpensive cultivar K-31 has a high rate of infection.  So far I have not been able to find out which cultivar have low infection rates, however this may be more common in southern states.  One way to lower the effects of infected fescue on the environment is to keep it mowed so that it stays in a vegetative state, i.e., not going to seed.  Hopefully its ability to form a good turf and exclude the stiltgrass will outweigh it negative environmental effects.
..

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.

Stiltgrass is in bloom - The time to act is now!

The flower heads of Japanese stiltgrass are just opening up.
The weedy plants have just had a growth spurt
bringing some of them to nearly 4' tall.

I am in midst of a multi-year battle to get rid of, or at least control, the Japanese stiltgrass, Microstegium vimineum, on our property.  Last year I came up with a plan to bring this invasive species under control.  The key element is to prevent this annual grass from setting seed.  Eventually (5-7 years) the seed bank will be depleted.  Also I am encouraging the existing native plant population to back fill the gaps to suppress re-invasion.

In late August stiltgrass goes into a growth spurt as the flower heads develop.  It is critical to cut it down or pull it out before seed set begins.  By killing the plant before the seeds can mature, you can dispose of the plants by composting.  Otherwise the plants would need to be segregated (e.g. bagged and sent to landfill) to prevent another generation of seed from spreading.  The taller stiltgrass is easier to find and pull than it is earlier in the season.  You should try to remove the plant close to the ground since it also produces a second hidden (cleistogamous) flower in the lower stem.


The following two photos show a moist shady area just before I removed the stiltgrass.

One year after close cutting stiltgrass in late August (2103) the growth is still rather dense.

After two years of cutting there appears to be more gaps in the stiltgrass converage.

In a couple of areas I was weed whacking and composting in place.  After 2 years of this I am seeing some minor decreases in the density of the stiltgrass coverage.  This year I raked the cut grass off and into a pile.  By removing the dense thatch I am hoping to seed some other species move in.  I have another large area where I will leave the cut grass in place.  We'll see if that makes a difference.

American germander blooms in late July and the seed is still maturing,
so I'd like to keep these standing a little longer.

One of my challenges is to remove the stiltgrass while leaving as much native vegetation in place.  Many of the earlier blooming natives, such as the beebalms (Monarda sp.) and tick trefoils (Desmodium sp.) have already gone to seed.  However, there are a number of later blooming species that I'm trying to preserve by carefully hand-pulling around them.  These include American germander, (Teucrium canadense), Virginia knotweed (Persicaria virginiana), white vervain (Verbena urticifolia), white avens (Geum canadense), and the native annual, clearweed (Pilea pumila).  While not beautiful plants on their own these species do fill the woodland edge with a variety of colors and textures largely obscured by the invasive stilt grass.

Clearweed is a fairly common native annual found in shady moist sites.
Currently in bloom, the flowers are yellow tassels in the leaf axils.

Here I'm halfway done with a section revealing some American germander (center).  To the left is my new grass whip.

I recently got a double edged grass whip which does a great job of ripping stiltgrass out of the ground while leaving single bladed grasses largely intact.

This low-growing sedge was hardly disturbed as the weed whip tore out the stiltgrass.

I am also finding a number of native grass species under and within the stiltgrass.  These include the evergreen, spreading sedge (Carex laciculmis) and deer-tongue grass (Dichanthelium clandestinum).

Botanizing Weverton Cliffs

I am very fortunate to live close to the Appalachian Trail.  One of the nearby highlights is Weverton cliffs.  At  about 850 ft elevation they stand over 500 ft above the Potomac River and provide beautiful views toward Short Hill Mountain in Virginia to the south and west.  I took the easy way and parked at the trailhead in Weverton so the climb was only about 400 ft.  The hill side was heavily forested and there were not many long views until you make it to the actual cliffs so I focused on trying to recognize the variety of plants along the trail.

View from Weverton cliffs to the southwest overlooking the Potomac river.  At the far right is the Shenandoah river.

Most of the lower slopes are moist with rich soil. As you climb the soil gets rockier and drier.  This is reflected in the type of vegetation you see along the zig-zag trail.  Being mid-July there were not a lot of flowers in bloom.  On the way up I passed by patches of bellwort, Jack-in-the-pulpit, and false Solomon's seal.  There were also a surprising variety of ferns, a few I figured out and some that remain a mystery to me.

There were many clumps of lady fern (Athyrium filix-femina) along the way.  One of the first ferns I need to look up was a Massachusetts fern (Thelypteris simulata).  One ID clue is that the blade is broadest in the center and slightly taperd at the base.  The other fern here was harder to ID.  I think it is mountain woodsia (Woodia scopulina).    

A Massachusetts fern (right) and possibly mountain woodsia (left) growing next to the trail.

Here is the back side of what I believed to be a Woodsia.  

On further checking and finding more of these I'm pretty 

sure that this is log fern, Dryopteris celsa.

I would need to go back with a fern ID book in hand to be more certain about this one.  (I would appreciate any help on figuring this one out.)

In some of the sunnier openings there were large masses of a coarse leafy plant.  It looked like an invasive species the way it monopolized the space.  Each large leaf was divided into 5 coarse lobes and the flowers  had no petals to speak of, though there were 5 green sepals around each one.  I was able to key this out as Small-flowered leafcup, Polymnia canadensis, a woodland native found in much of the East and Mid-West.

The small-flowered leaf cup appear to have no petals on the flowers.
It may have been a little early as the buds were just opening up.

 As I approached the top of the ridge the soil became thinner and rockier.  The plant population began to change in response.  I noticed some ericaceous plants like low bush blueberries and mountain laurel.  At the top of cliffs the dominant tree is the Table Mountain Pine (Pinus pungens).  This is a two-needle pine with short, slightly twisty needles.  This Appalachian native is a beautiful, sculptural tree.  Its twisted form is enhanced by the weather at the top of the ridge.  Although, I have seen one in a protected location that shared some of this sculptural character.

Table Mountain Pine is adapted for growing in thin, rocky acidic soils.

One of my favorite plants is the native annual false pennyroyal (Hedeoma pulegioides).  I was pleased to find some growing up at the top of the cliffs.  It is often found in disturbed areas, such as along paths, where you can pick out its intense sharply minty scent when it is disturbed.

False pennyroyal, a member of the mint family,
has opposite leaves and an intense smell when touched.

I didn't think I would find anything new on the way back down, but I was wrong.  The change in perspective revealed almost as many new plants as on the way up.  The first one I noticed was narrow-leaved Houstonia (Houstonia tenuifolia).  What I noticed were the bright little flowers seemingly floating in space.  The leaves are so narrow you could easily miss seeing them.

Narrow-leaved Houstonia has white to pale lavender flowers.
The broad leaves on the ground belong to a different plant.

Another plant that revealed itself on the way down was fringed loosestrife (Lysimachia ciliata). The most noticeable flowers were on a long panicle held above the foliage.  

Each of the yellow flowers were nodding, defying an easy photo op.

Back at the trail head I continued on toward the river to see what was growing in this more 'civilized' environment.  There were many more non-native and invasive species like Japanese stilt grass, tree of heaven and rose of Sharon.  Mixed in were a some native species.  On a large rock near the US 340 underpass was a large patch of common polypody (Polypodium virginianum).

Common polypody is an evergreen fern commonly found growing on rocks,
particularly in shaded, north-facing areas.

Since my first vist there was so productive, I will make a point of going back in a couple of months to see how it has changed.  I'm pretty sure I saw a number of goldenrods and asters.  these are hard to distinguish when not in bloom.

Green Milkweed

I've been planting more milkweeds (Asclepias sp,) around our property with mixed success.  Butterfly milkweed, A. tuberosa, has done well and looks great with its showy orange flowers.  Swamp or rose milkweed, A. incarnata, has had trouble.  My deer, for some reason, seen to like to eat up the young plants I put in.  I've resorted to putting wire cages around them so the have a change to get established.  On the wild side we have a small patch of common milkweed, A. syriaca, which are ignored by the deer and doing quite well.

The other day while mowing I was surprised to find a different species of milkweed.  Not as tall as common milkweed and with drooping green flower clusters, I was sure this was something new (to me).

Green milkweed is noted for it's thick oval leaves and
green nodding flower clusters that hang from the leaf axils.

I checked a couple of guide books and am pretty sure what I found is Green Milkweed, A. viridiflora.  This is a fairly common species, usually found in dry lightly shaded locations, including roadsides, prairies and clearings.  My plant is near the edge of a wooded are, mostly in the open with average moisture soil.

While not showy for us, it does attract pollinators, particularly bees to its sweetly scented flowers and it does provide food for the monarch butterfly caterpillars.  So far I've only seen this one, but I'm watching for more.

A Surprise Bug

A few weeks ago a deer broke off a branch from one of the smooth sumac that I have been trying to establish on my property.  Rather than tossing it out I put it in some water to see if it would root.  After two weeks, I inspected it closely for any growth and found none.  This is no surprise, stem cuttings are not recommended for propagating smooth sumac.  What I did find was what looked like a new bud, but it was facing the wrong way.  On closer examination I saw that it was a small insect.

If this bug were turned around on the branch, I may not have distinguished it from the sumac's leaf bud.

The general shape of this insect brought leafhoppers to mind.  Looking at similar insects on the web brought me to conclude that this was the nymph of a two-striped planthopper, Acanalonia bivittata.  

The white plume coming from the rear of this insect is a waxy compound that helps prevent desiccation
 and may protect it from predators.

While I really love my plants, there are some pretty amazing looking insects out there.  All them with a role to play in a healthy ecosystem.

Wildflowers on the Potomac

Way back in late April I set aside some time to see some of the nearby native species on a guided walk with the Maryland Native Plant Society (MNPS).  We visited the limestone cliffs along the Potomac river near Sharpsburg, MD.  In this area are a number of plants rare to Maryland, such as northern white cedar (Thuja occidentalis) and bulbet fern (Cystopteris bulbifera).  Our leader that day was Christol Fleming (co-author of Finding Wildflowers in the Washington-Baltimore area), who really knew the area inside and out.

Following are some of the many photos I took that day (roughly in the order seen moving downstream from Snyder's landing):

Coarse foliage of Virginia waterleaf is spotted with white.
Its blooming period is a little later in May.

It's difficult to tell Dutchman's breeches and Squirrel corn (Dicentra cucullaria and  D. canadense)
apart when not in bloom.  Here, side-by-side, you can see that Squirrel corm has a blue-green cast.

These blue cohosh were not in bloom yet, but the layered foliage of this mass
created the effect of a green mist coming down the hillside. 

Up on a limestone cliff  we saw this lyre-leaf arabis (Arabis lyrata) and
 wild columbine (Aquilegia canadensis) on a rock outcrop.
These two species are well adapted to growing in thin soiled habitats.

Shooting star is a species found in rich calcareous soils
prevalent in this area along the Potomac.

Many Virginia bluebells were in bloom at this time throughout the region.  

Mixed in here are some of the rarer white ones.

In some places the floor of shady woods were covered with the white flowers of meadow rue.
It was formally of the genus Anemonella.

There were two kinds of trillium in bloom at this time. The red trillium (T. erectum),
shown here, and toadshade (T. sessile).

When I think of violets, shades of blue and purple come to mind.
This downy yellow violet, though common, really caught my eye.

There were many more species growing there than I've shown here, some like the hepatica had already bloomed out, and others like the dwarf larkspur and mayapples had not yet popped.

I would like to pay a visit to this area in early summer to see the massive banks of the native smooth hydrangea (Hydrangea arborescens) in bloom; however Cristol warns in her book that this area has been overrun with garlic mustard and Japanese honeysuckle at that time of year.