Why Lawn

Lawn maintenance consumes an incredible amount of time and money.  But what is the purpose of a lawn, and could those resources be put to better use?

Let’s first start with the question:  Why have a lawn?  There are some practical reasons.  Recreation - lawns are often used as open and safe places for children, and some adults, to play.  Protection - having open sightlines around your dwelling, with few hiding spaces can make one feel safer.   Buffer space - keeping nature at a ‘safe’ distance.  This could be to control insects or wildlife, or, in fire prone areas, an open, healthy, lawn can protect a dwelling from fire. Status - a perfect lawn is often equated with ones class.  Going back a century or so, if you had the resources to expend on maintaining a perfect lawn then one must be pretty well off.  

A pretty common sight: large lawns on multiacre lots.  

In his 1841 treatise on landscape gardening, A. J. Downing advocated for the need of having a proper lawn to have a tasteful and civilized property.  He translated the Romantic style of late 18^th-century English landscape architects into a form more suited to the United States, particularly in the Hudson Valley and Mid-Atlantic.   Downing was extremely influential in setting the course for American landscape design into the 20^th century.  Another key event in making the lawn a standard feature was around 1870 when the reel lawnmower, which had been invented in England, came to the US.  This made keeping a mown lawn more practical. 

Achieving the ‘perfect’ weed-free lawn was made much easier with the development and marketing of the herbicide 2,4 D (1944) for residential use.  A lawn treated with this was made free of nearly all non-grass (dicot) plants.  This meant that most flowering plants which could support pollinators (e.g. clover, fleabanes and heal-all) could be eliminated from lawns.  The result was a nearly flawless (one could say featureless) green carpet of only grass-like (monocot) plants.     

Considering the history of landscape design from earliest times, there seems to be a need for humans to exert control over nature, despite the costs.  People, in general, feel much more comfortable in a landscape that is readable or understandable.  These are places where they can see the ins and outs and how to move through the space.  Think of the composition of a photograph or painting.  There are elements that draw the eye through the piece to a focal point.  Crisp or well defined edges are also important in creating readability.  I’ll admit that I do feel a sense of satisfaction when I look back on an evenly mown and edged green carpet. 

Let’s look at some data about lawns in the United States:

Acreage of lawns   Looking on the internet I found figures of between 40 and 50 million acres of residential turf grass in the US.  Compare that to the total amount of land used to grow corn which averaged at about 90 million acres between 2018-2022 (USDA data).  These figures are based on satellite imagery.  Most corn is grown without irrigation.  If you compare the irrigated acreage for corn of about 12 million acres to that for turf, then you come up with 3-4 times as much lawn as irrigated corn. 

Amount of gas used   Based on EPA figures from 2005, 800 million gallons of gasoline were used to power lawn care equipment each year.  Using this weeks’ national average of $3.72/gal you are talking about $3 billion dollars annually.  On top of that, lawn mowers and other small-engine powered lawn equipment, which have no pollution control devices, are significant contributors to air pollution.  Estimates are that combined landscape care equipment contributes about 5% of the total air pollution, CO, hydrocarbons and NOx .

Amount of water used on residential landscapes   EPA estimates of water use for landscape purposes is 9 billion gals/day (WaterSense 2013).  Most of that is treated potable water that could be used for domestic consumption rather than poured onto the ground.  With the increasing severity of droughts, particularly in areas of the Southwest where population is shifting towards, there are very real problems with providing all the water that is needed. 

So considering that lawns and lawn care have increasing costs and negative effects it is time to ask why and how much lawn can we afford and what are the alternatives.

Trends away from lawns:

No mow May.  Started in England as a push to provide early season pollinators with flowers that are common in English lawns.  Blindly adhering to a no-mow-May program in a country with so many diverse climates and types of lawns as the US is often inappropriate.  To be useful, the lawn or property in question needs to have a population of plants with early blooming flowers that the pollinator population likes.   Depending on the climate the appropriate time for suspending mowing could be as early as February or into the later part of May.  If you have a monoculture of Kentucky blue grass there is little benefit to pollinators in skipping a month of mowing, there is just nothing of benefit there for them.  If you have a diverse ‘lawn’ containing native weeds like violets, self-heal (Prunella vulgaris), fleabanes (Erigeron sp.), spring beauties (Claytonia virginica) and the like, then allowing those to come into bloom would have a positive effect.  If you really need to mow, take the effort to mow around the blooming plants until they are done.  Lawns can also be interplanted with spring bulbs.  While not native, very early bulbs like Crocus, Chionodoxa and Scilla can add interest to an early spring lawn.  These bulbs have usually completed their growth and blooming cycle by the time the need for mowing kicks in.

I have been allowing this patch of Philadelphia fleabane
to develop without mowing.  It reaches peak bloom
in mid-May.  I usually mow it down in early June
after it sets some seed. When not in bloom plants survive
as low-growing rosettes.  

While there is the oft repeated advice to never cut more than one third of the length of the grass blade at a time, I rarely let that force me to cut the lawn before I’m ready.  I can’t say that I have ever noticed a problem by occasionally letting the lawn get too long between cuts.  In those cases when I do the biggest problem is the long clippings left on top.  A mulching mower can help deal with that.  All these problems are magnified on the ‘perfect’ lawn, where any imperfection becomes blaringly obvious.  In a diverse, multispecies lawn imperfections blend into the mosaic of plant colors and textures.

Lose the Lawn  This is a phase that is used by many people when voicing their concern about the amount of resources being pouring into and onto lawns.  You can get excellent advise on this subject for university extension services.  Doing an internet search on ‘lose the lawn’ and your state of region can give you information on lawn alternatives suitable for your area.  For example try this link to the UMD extension for the Mid-Atlantic region.

Climate appropriate landscaping   This is another phrase used when talking about more sustainable landscape practices.  Simply put, it is using plants that grow well with the resources that are naturally available.  Native species appropriate to the local climate require much less water and other inputs than turf or other non-adapted species.  When there are no plants suitable, look to using other materials to achieve the design goals.  It also means avoiding the use of plants and materials that require an extraordinary amount of inputs to maintain them.  

As droughts are becoming more frequent and severe, many municipalities are instituting water restrictions and/or offering enticements for installing water efficient landscaping.

What can one do?

>If you have a lawn, mow and water when lawn needs it, rather than on a preset schedule.  This can be difficult with lawn services since making a flexible schedule with multiple clients can be very difficult.  I did see on the web some services that offer options for having a less frequent mowing schedule.  That may be a move in the right direction.  In general lawns maintained at 3-4" have deeper roots making them less dependent on frequent watering.  Also the taller turf shades the soil which reduces weed seed germination and evaporation or soil moisture.

>Replace high maintenance lawn grasses with climate appropriate turf.  The US is divided into 3 zones for turf grass, cool season, warm season and the transitional zone between them.  A nice overview of turf grass types for the various regions of the United States can be found in this blog post from Landscape America.  While most turf grasses are not native to North America a few are.  Buffalo grass (Bouteloua dactyloides) is a native species found in the plains from Southern Canada to Northern Mexico.  It has been developed as a drought tolerant turf grass.  A native of the Gulf States, St. Augustine grass (Stenotaphrum secundatum) has been cultivated and planted along the east and west coastal areas of the US.  Fine fescues are well adapted to the Pacific Northwest and Northeastern states.  A few subspecies of red fescue (Festuca rubra) are native to North America; however, the blends suited for turf usage contain a variety of fine fescues most of which are not native.  There are at least three blends of these fine fescues that have been selected for use in cool season growing zones that are drought tolerant, need little fertilization.  Look for Eco-Lawn, Eco-grass or No Mow fine fescue blends. 

This patch of lawn is mostly fine fescues that is mown about every two weeks. 
It looks like regular 'grass'.  If I did not mow it it would would develop a
 fine silky, mounded texture that fine fescues are noted for.  

>Develop a tolerance for having mowable green, rather than a perfect cloned lawn.  My lawn, in the Mid-Atlantic region, is a mixture of tall and fine fescues, nimblewill (Muhlenbergia schreberi, a local native species), probably some purple top (Tridens flavus, also native), violets, fleabanes, clover and some less desirable (but tolerable) weedy stuff.  A diverse lawn requires fewer inputs to maintain.

>Consider alternative ground covers.  Regionally native species are preferred because, in addition to requiring little to no mowing, they also support local wildlife.  Some lower growing North American natives that can replace, or be incorporated into a lawn include frog fruit (Phyla sp.); pussy toes (Antennaria sp., for sunny dry conditions), and golden ragwort (Packera aurea, partly sunny, moist conditions).  Moss is perfect for a shady spots. Again, doing a search on ‘lose the lawn’ coupled with your region yields results that offer a list of alternative ground covers.  I recommend focusing on web sites managed by university extension services as providing the most unbiased results.

This patch of golden ragwort bursts into bloom in April. 
It is semi-evergreen and grows to about 6" tall.  It is slowly expanding,
but can be kept under control with mowing.

>Reduce or eliminate fertilization.  In many situations it is a vicious cycle.  Fertilizer is needed to replace the nutrients removed when grass clippings are removed while mowing.  Then, the more fertilizer you add, the more the lawn grows, then the more there is to mow.  By leaving grass clippings in the first place and mowing in the leaves in the fall, you are recycling the nutrients in place and feeding the microbes living in the soil.  Using a mulching mower will reduce the amount of clippings visible on the lawn.

>Reduce area committed to lawn and replace with bedding, meadow-type plantings, successional plantings, or cropping (hay fields).  When reshaping the lawn, go for simple shapes that can be mown efficiently, avoid tight turns and acute angles.  I have one triangular area that requires a lot of backtracking to mow.  A rectangle or oval could be done with less backtracking. 
A successional planting builds on the natural process of succession.  Succession is the natural process where the mix of plants on a site changes over time, and it begins when one stops mowing.  East of the Mississippi River, the sequence is usually bare land becomes grasslands, which in turn becomes shrublands which eventually turns into forests.  This process usually takes many years.  The land owner could  speed up the process by planting desirable shrubs and trees to create an idealized version of the natural landscape.  Intervention by the landowner can also pause succession at various stages such as as a meadow or shrubland.

Here is a possibility of allowing some succession of  local native species
(redbuds, dogwoods, asters, etc.).  Clean edges and sightlines to and
from the dwelling confer intention to the landscape.  This more
diverse landscape offers much more to the local ecology. 

>When creating a new space, clean edges, whether straight or curved, convey a sense of intention in the landscape.  A wilder space surrounded by a clean edge is visually more comforting than a totally wild area.

>Where climate is not suitable for growing plants, use hardscape or inorganic mulches. Hardscape does not have to be impermeable concrete.  Dry laid stones and pavers allow for water infiltration which reduces runoff problems.

>Be creative with the space, put in artwork to fill the space and send a message.  On a recent trip to Sebastapol, CA we visited Florence Ave where many of the residents have sculptures in the front yards by local artist Patrick Amiot. 

This owl sculpture is complemented by a variety of
perennials in this lawn-free front yard.

The minimal landscaping around this catfishing dog works quite well. 
The colors of the spiky New Zealand flax play well with the colors in the statue.

Reducing the area committed to lawn does not have be be done all at once.  It can be done one area at a time, or by expanding planted beds or wilder areas a little bit each year.  I would love to hear about your experiences with reducing resources committed to maintain a lawn.

July 2020 What to do about Japanese Stiltgrass NOW

In late July through early August Japanese stiltgrass, Mircostegium vimineum, puts on a major growth spurt prior to blooming.  This presents an opportunity for removing a large amount of this invasive annual grass before it blooms and begins to set seed for the following years.  There are several methods that can be used now, which is best depends on the particular situation. 

 

Pulling  This is my method of choice in areas of mixed species. In late summer stiltgrass can grow to 3-4 feet tall.  At that height it is above many desirable plants and you don’t need to bend over too far to pull it out.  By using a loose grip and grabbing higher up on the plant mass I can selectively pull out the stiltgass and leave most perennial and more deeply rooted plants in place. By wiggling the grass side to side as I’m pulling the relatively weak roots are broken and the stems remain intact.  

Here stiltgrass and the native grass nimblewill, Muhlenbergia schreberi, are growing together.

Pulling the stiltgrass with a light touch leaves the well rooted nimblewill in place.

I usually leave the piles of stiltgrass to dry out in the sun for a couple of days before disposing of it.  If the grass is not setting seed I’ll put it in a brush pile or in a segregated location where it can break down but will not accidentally be spread elsewhere.  If the grass has bloomed it will need to be bagged or put into an isolated location where the seed cannot escape.  This is the number one reason for pulling before bloom!

This is a woodland area where I have been pulling stiltgrass of 2-3 years. 
Though it looks dense there are not that many individual plants.

 

After 20 minutes of pulling I was able to clear this area of stiltgrass. 
What remains is a ground cover of mostly rosy sedge, Carex rosea.

Low Mowing  Mowing as close to the ground as possible in late summer (just before bloom) is a common recommendation for combating stiltgrass.  This prevents blooming and seed set in the upper stems.  Unfortunately stiltgass will also set seed in the stem at the base of the plant, 1-2 inches above ground level.  These cleistigamous flowers are difficult to remove without cutting really close to the ground.   If you wait too long to mow, after seeds begin to develop, mowing may only serve to spread seed unless you have a well fitting grass catcher on your mower.  ( In that case you should dispose to the clippings in a way that the seed will not escape into the environment.)  These extra flowers make stiltgrass very difficult to remove from turf areas.

Late summer mowing had been used in this area for 2-3 years.  Here it is in 2017. 
There is a lower density of stiltgrass, but still a lot.

I’ve been trying to remove stiltgrass solely by timed mowing in one area but have made only minor progress over 3-4 years.  What I have found to be most effective in lawns is to use a pre-emergent herbicide, marketed for crabgrass, in early spring.

Here is the area in 2020.  In addition to late mowing I treated this area with the
preemergent herbicide Dimension.  Above the line has been treated for
two consecutive years, below the line only once in spring 2020.

 

Weed whacking  Using a weed whacker can be effective where you can selectively cut down to ground level to remove those stem flowers. It can get tedious if you are trying to preserve desirable plants intermixed with stiltgrass.  You can leave the cut stems in place if the grass has not begun to bloom, but if it has you should consider raking out the debris.  (If plants are beginning to set seed weed whacking will likely spread more seed than doing nothing.)

I had good success in a woodland edge area using this method.  Starting out, the area was nearly a monoculture of stiltgrass so I did not have to be too careful.  In the second and third years I also raked out the cut stems.  I have also seeded the area with Virginia wild rye, Elymus virginicus, a shade tolerant native grass.  Now six years later I can manage that area with just a little pulling. 

 

Fire  Because stiltgrass is a weakly rooted annual burning at ground level can be an effective means for killing it.  I have been experimenting with burning stiltgrass at various times during the year.  Burning in early and mid spring reduces the amount of stiltgrass seedlings but does not eliminate its presence.  This is in part due to the extended time over which stiltgrass can germinate in the spring.  Burning in late spring seems to thin out the amount of stiltgrass but can also reduce the amount of desirable vegetation.  In one spot where I did a mid-spring burn the area was overgrown with stiltgrass by the end of July.  On removing that stiltgrass there were very few other plants growing there. 

This is a small area of lawn dense with stiltgrass that I burned with a garden torch
two days ago.  It's not necessary to consume the entire green plant with fire,
just burn the roots at the soil surface.  Perennial grasses should
bounce back in a week or two.

In this area I pulled most of the stiltgrass then used the torch to burn the surface
to kill any remaining vegetation.  I was then able to immediately plant several
plugs of switch grass, Panicum virgatum.

Where burning has proved very effective is in hard to reach areas where clear ground is desired, such as pathways and fencelines.  Burning stiltgrass is particularly effective in late summer. In lawns with cool season grasses you can burn areas infested with stiltgrass with a garden torch.  The cool season grasses are dormant because of the hot weather and dry conditions.  As the weather cools in September the clumps of cool season perennial grasses will resprout, without the presence of stiltgrass.

Here is the garden torch in action, burning the roots of some 3 foot tall stiltgrass. 
I can stick the torch through the openings in the fence the get to hard to reach areas.

It is interesting to note that heat is conducted better in slightly moist soil than in dry. While burning stiltgrass leaves no chemical residues you must use great caution to keep flames under control and not allow any fire to spread out of control.  There may also be local rules to follow.  

Herbicide   While I have had very good results from using preemergent herbicides in early spring to get stiltgrass out of the lawn, I have not had personal experience using postemergence herbicides to control Japanese stiltgrass.  Based on information provided by a number of university agricultural extensions there are several herbicides that can be used in summer time (up to the onset of flowering)  to control stiltgrass.  Low levels of the broad spectrum herbicide glyphosate, about half the normal concentration, are reported to be effective against Japanese stiltgrass.  Glufossinate is another broad spectrum herbicide that is effective against stiltgrass. 

I pulled this from the Rutgers Cooperative Extension (NJ) site:

Glyphosate and Glufossinate (various trade names) can be used to spot treat Japanese stiltgrass in gardens and planting beds. Both are broad spectrum herbicides that should be applied only to the unwanted plants. If applied to the foliage, stems, or woody portions of desirable plants, it could damage them as well.

Sethoxydim (tradename Bonide Grass Beater Over-the-Top Grass Killer®) and Fluazifop-P-Butyl (Ortho Grass B Gon Garden Grass Killer®) are selective herbicides that can be applied to growing stiltgrass in landscape beds. When used according to the label, these herbicides will not damage most non-grass ornamental plants. Be sure to follow the label closely and heed all precautions.

According to the labels on the Bionide and Ortho products these products are not effective on sedges.  That is a good feature for use in woodland edge habitats since native sedges are a major component of the ground covers growing there.  I not sure if that means that those, mostly desirable species would be unharmed, or, just not killed at a high rate.  I noticed that the label on the Bionide product indicated that it could be used safely on lawn with red and Chewings fescue.

Here is another example of the effectiveness of a preemergent herbicide. 
To the left of the line I applied dithiopyr (Dimension) in mid-March,
to the right is untreated.  

Stiltgrass Fall 2019

I'm continuing my multipronged attack on Japanese stiltgrass, Microstegium vineum, that I have been waging for about 5 years now.  Depending on where the stiltgrass is growing different techniques are more effective.

Here are links to some earlier posts on my campaign against stiltgrass: Spring 2019, Spring 2018, Fall 2017, Original Plan 2014, and Use of Pre-emergents.

Woodlands  In the  shady woodland settings pulling the stiltgrass through the summer and especially in late summer just before blooming has been pretty effective.  In several of these shady areas removing the stiltgrass before is sets seed has shown good results after two seasons.  It is important to continue to follow up year after year to prevent a re-infestation.  When I first started do this I used a weed whacker to cut very close to the ground and I left the cut grass in place.  In places where I removed the cut grass progress toward eliminating it seemed to go faster.  Also as other, hopefully native, species begin to fill in, weed whacking risks cutting out those species as well.  Now I've gotten to the point of hand pulling the stiltgrass and piling it up in segregated locations where any seed present will be less likely to spread.

Here are some clumps of Virginia wild rye growing under a young tupelo tree. 
This is a cool season grass, seen here in June.  By the end of summer
 it will be golden brown with arching seed heads.

Bottlebrush grass is also a cool season grass that like partly sunny sites. 
These early season grasses have a chance to shade the ground before
the stiltgrass begins maturing in July

In these locations I have been trying to have more native species fill in, by either encouraging the existing natives of adding new ones.  Virginia wild rye, Elymus virginicus, is a native grass that grows pretty well in the shade, as is bottle brush grass, E. hystrix.  Other species that are filling in on their own are Virginia jumpseed, Persicaria virginiana, and clearweed, Pilea pumila.   A variety of smartweeds are also increasing, but I fear many of those are non-native species.

Clearweed is a native annual that has had a banner year here in 2019. 
It grows well in shady locations.  

Meadows  I've been having more trouble in the open meadow sites.  Some of this is my reluctance to do anything but hand pull.  I am trying not to disturb the more desirable species that co-inhabit the meadows.  In one area that I have been hand pulling for 3-4 years I'm seeing a reduction, but it still has a long way to go.  This past spring I put some pre-emergent  in several meadow areas and saw a further reduction in stiltgrass density, but not an elimination.  I also tried burning a patch of ground in early spring but that had no noticeable effect on the amount of stiltgrass.  (That is consistent with what the Forest Service reports on the use of fire.) 

By virtue of how stiltgrass grows, sending out shallowly rooted runners to fill all available space, by the end of summer you will have a similar density of flowering stalks whether you have 10 or 50 seedlings per square foot.  (These are my impressions, not proven facts).  But having fewer rooted individuals means it gets easier to clear an area by pulling because so many of the stems are interconnected.  I will try the pre-emergent again this spring, but do the application earlier (read on below).  One of my concerns in the meadow is that the pre-emergent will inhibit some native species from growing/reproducing.  I did not go in and inventory what was or was not growing in the treated and untreated areas.  I did see smartweeds and tick trefoils, Desmodium panniculata,  growing in all areas.  Where stiltgrass was growing thickly the ground plane was essentially barren after the grass was removed.

In May stiltgrass seedlings are less than an inch tall.  The right side of the area
was treated with Dimension pre-emergent herbicide in the first week of April. 
The untreated side has a greater density of stiltgrass seedlings.  I expect that
 applying the herbicide earlier in the spring will further reduce the amount
 of sprouted stiltgrass.

This is the same area, photograph from behind.  The treated side (left)
 has a slightly lower density of stilt grass, but still
 most of the available space is filled with stiltgrass stems.

Removing stiltgrass from the lawn.  Pre-emergent herbicide is still showing very good results.  2 years ago I applied herbicide (Dimension^tm) around the 3rd week of March.  While in the spring of 2019 I waited until the first week of April.  Or using the forsythia bloom as an indicator of spring weather, mid-bloom in 2018 and late bloom in 2019.  Despite the presence of the herbicide I did see more stiltgrass seedlings in 2019, so I think applying the pre-emergent earlier may be more effective.  For folks in the Northeast and Mid-West  there is a website that helps with the timing of pre-emergent application based on degree days.   Another problem with getting stiltgrass out of the lawn is that repeated mowing can stimulate earlier formation of flowers lower in the plant.  These are much harder to remove than the terminal flowers that form on undisturbed plants.

Here is some stiltgrass pulled from the lawn after mowing.  You can see
 how low in the plant the stem flowers (cleistogamous) occur. These flowers
 need to be cut off for mowing to be really effective at eliminating stiltgrass.

Some folks have reported success with cutting the lawn really low in August, the beginning of flowering season.   Looking at some of the stiltgrass growing in the lawn, it looks like you would need to cut down to about an inch to reach those lower flowers.  I tried that in one section of my lawn that I have not otherwise treated and is mostly stiltgrass.  Next spring we'll see how that area compares to normally mown areas. 

After you manage to suppress the stiltgrass you need to get something else growing in its place.  The easiest option in the lawn is to overseed with a well adapted turf grass.  In the Mid-Atlantic the commercially available options are tall fescue blends for sun and fine fescues for shade.  In my rural setting I also have many other grasses growing in and around the lawn.  Some of the native species that are mixed in include path rush (Juncus tenuis), purple top (Tridens flavens), nimblewill (Muhlenbergia schreberi) and a variety of sedges.  While I encourage these to grow, they would be much happier if they were not mown on a regular basis.  Nimblewill, though, does seem to tolerate mowing pretty well.  

This is what nimblewill looks like in the lawn.  This warm season grass is
 not as 'pretty' as commercial turf grasses, but is is native and is well adapted to
 the climate here, even in this unseasonable hot and dry year.

I was planning on overseeding a large area in early fall, but here in Maryland it has been unseasonably hot and dry so I have been holding off seeding until the weather cools.  Getting the new seed established in the fall is critical to using most pre-emergents because they will suppress growth of most weeds planted in the spring. 

Another option to turf grasses is to convert from lawn to meadow or other types of plants.  Based on my meadow experience you should get rid of the stiltgrass before just adding other plants.  This can be done chemically, by solarizing (covering with plastic for  enough time to kill the stiltgrass seeds), or covering with cardboard or many layers of paper followed by mulch or clean soil and then planting on top.

In one shady area of lawn I have using timed mowing as the primary means of stiltgrass control.  I leave the area unmown from mid-June until mid-August.  At that time I'll pull out and remove the tallest grass and follow up with a low mowing.  After 3 years of this I am getting less stiltgrass, but it is still pretty thick.  One explanation is that there is a lot of stiltgrass in the surrounding area and the seeds may be coming in from there, either blown in or carried by the rain.  I did put down some pre-emergent in a small section of this area and there was no stiltgrass present there.  Mosses and perennial grasses seemed unaffected. 

The vegetable garden  In the garden one of the places stiltgrass flourishes is along the fence line.  It interlaces with the chicken wire and can be hard to remove completely.  This year I have been using a flame weeder to clear those areas.  This method is more effective early in the season when plants are smaller and more tender.  As weeds mature they have more moisture in their stems and leaves and are more difficult to kill with heat.  One caution with using a garden torch is not to expose soaker hoses or drip irrigation lines to the direct flame.  Unlike some weeds a soaker hose will not recover after being melted. 

Next steps: 

• Overseed with turf grass.  For next season  I am going after a large open area that is mostly mown stiltgrass.  I will use pre-emergent on this area in early spring assuming I can get the new seed established.
• Continue use of pre-emergent in lawn areas where stiltgrass is depleted.  While I have not been targeting it, the amount of hair cress, Cardamine hirsuta, a winter annual weed, seems to be decreasing in the treated areas as well.
• Continue testing pre-emergent in meadow, this time apply earlier in spring
• Expand areas in the woods where stiltgrass has been pulled.  Try and remember that the best strategy for removing invasive species is to clear a small area really well and then expand that area each year.  Also start in a less infested area and then move to higher density areas.