Japanese Stiltgrass Spring 2020. Time to get started!

Woodland edge inundated with Japanese stiltgrass in 2014.  This was my starting point

Japanese Stiltgrass, Microstegium vimineum, is an invasive annual grass that has taken over many natural woodland areas as well as suburban lawns.  Infestations are particularly bad in the Eastern US from Connecticut, south to Florida and Texas.  I have been posting blogs on my progress battling this grass a couple of times a year for the last 7 years.  Now that spring is rolling around it’s time to get into action.  Here a link to my initial post.

Stiltgrass germinates around the time of annual crabgrass and several pre-emergent herbicides used for crabgrass are effective at controlling stiltgrass.  I have been using a product containing Dimension™ (dithiopyr) on my lawn for 3 years now and it has significantly reduced the amount of stiltgrass present.

This is a comparison of treated and untreated areas in 2019 when the
pre-emergent was applied late.  The stiltgrass seedlings are about
an inch tall at this time.

Last year I tested this product in a mowed meadow area, but the application was at the end of the recommended application time (about 2 weeks late).  I saw a slight reduction in stiltgrass.  I was also concerned that the treatment would affect other plants growing in the meadow, but most of them are perennial species and not as strongly affected as annuals.  On casual inspection last year I didn’t see much difference in the types of plants growing in the treated and untreated areas.  This year I expanded the coverage treating both the lawn and the meadow at the same time at the beginning of the recommended treatment window.  (The meadow was mowed several days before treatment so that the treatment could have direct contact with the soil.)

Here's the mowed meadow after the pre-emergent was applied.  Lots of bare soil now. 
Various grass and sedges are starting to grow.  The wingstem, Verbesina alternfolia,
which dominates this area, has not started growing yet.

I use a website called GDD Tracker 4.0 to tell me when to apply the treatment.  It tracks the days that the average temperature is above 32F.  250 degree-days is the trigger for crabgrass pre-emergent treatment.  Here at my home we hit that on March 10 and I applied the treatment March 12.  (Optimum application time is projected to last through at least 3/21 in my zip code.  Watch out, time is running out!)

Wild Bergamot, Monarda fistulosa, that I planted last year is starting
 to sprout in the meadow with its purple-tinged leaves.  

New Additions for 2020

Every spring (and sometimes in the fall) I make plans on what new or additional regionally native plants I want to add to the garden/landscape.  Here's what I am planning for 2020.

I’m trying big leaf aster, Eurybia macrophylla, from home grown seed again this year.  Last year I harvested seed from an isolated plant.  This year I got it from an area that had several distinct individuals.  Many asters are self-incompatable, so the seeds that I am using this year are more likely to be fertile.  (Though tiny, they did seem to be thicker this year).  I’m still waiting for them to germinate; it’s been 14 days, so far.  Over the years I've had a hard time getting good levels of germination from asters and goldenrods.  Fortunately, in nature, they do just fine on their own.  (I’m also comparing unstratified to 30 days cold moist stratification.  We’ll see.)

There bigleaf aster are doing quite well in the dry shade under
the eaves along the foundation of a house.

I’m also stating some more switch grass, Panicum virgatum, from seed that I bought 3 years ago and kept in a refrigerator.  I was pleased to see that they are still viable, germinating beginning in less than a week.  They were planted in seed starting mix, under lights and bottom heat to warm them to 65-72 F (no stratification). I've been planting these out in a meadow area as plugs where I am trying to displace the very invasive Japanese stiltgrass, Microstegium vimineum. 

Here's an American lady butterfly on its host plant, pearly everlasting.

The tiny seeds of pearly everlasting give way to tiny sprouts (little green spots in this photo). 
After 30 days of cold, moist stratification, these germinated on the soil surface after only 3 days.

The bright pink flowers of fireweed should
stand out through mid-summer in the meadow.

Some new seeds that I am starting now are downy wood mint, Blephilia ciliata, pearly everlasting, Anaphalis margaritacea, and fireweed, Chamaenerion  angustifolium (formerly an Epilobium).  In the past I’ve tried the latter two before from seed with little luck.  This time I’m stratifying at lower temperatures, 37 vs 45 F.  Again, we’ll see.  Of these plants, fireweed can be pretty aggressive, once established.  My plan is to put it into a mown meadow that is home to other tough plants like wingstem, Verbesina alternifolia, Panicled tick trefoil, Desmodium paniculatum, and a variety of thistles.

When we first moved here one of my goals was to rip out all the vinca that was growing along our shady driveway and replace it with native species.  Before going whole hog I wanted to test some species to see which ones were strong competitors in this dry, shady location.  Seven years later and I haven’t made a lot of progress.  Plants that are doing well and slowly expanding are Green and Gold, Chrysogonum virginianum, and Pennsylvania sedge, Carex pensylvanica.  Alum root, Heuchera villosa and cultivars, and foamflower, Tiarella cordifolia, are surviving but not expanding rapidly, I have high hopes for the hay scented fern, Dennstaedtia punctiloba, but it has not expanded much in its first 3 years.   This year I decided to get moving again on this project.  I’ve ordered a number of dry shade tolerant plants:  Red columbine, Aquilegia canadense, ivory sedge, Carex erburnea, wild geranium, Geranium maculatum, Zigzag goldenrod, Solidago flexicaulis, and Labrador violet, Viola labradorica.  Also some of my big-leaf aster will go in, if/when they are successful from seed. 

These Green and Gold, are doing well in an area that was covered in vinca. 
They are continuing to spread but they have not out-competed the vinca.

Last year I potted up some of the red maples that were coming from seed.  I have killed a number of invasive Ailanthus that were dominating the canopy in one area of my woods.  I wanted to give the newly opened up woods a jump start with some native trees.  Red maples, being more shade tolerant, seem to be a good choice (and they’re free).  Since we have sugar, red, and silver maples here it is possible that these seedlings could be any of these or even a cross between red and silver, Acer x freemanii.  When they were young they looked like red or sugar maples.  But as they developed it became harder to tell from the leaf shape, they weren’t as deeply divided as a sliver maple, but not all simply 3-lobed like the ideal red maple.  They all seemed to have overwintered successfully under some shrubs along the garage foundation.  Later this spring I will start putting them in.

Here's my collection of maple seedling after I potted them up last spring. 
Most of them had the 3-lobed leaves indicative of red maple.  As they grew on
it became less clear that these were all red maples.