Saturday, August 27, 2016

An August Drive: Skyline Drive and the Blue Ridge Parkway

August isn't only for pulling stilt grass.  If you don't take some time off to enjoy nature, it could drive you crazy.  With that in mind, we took some time off and headed south to Asheville, NC for a couple of days via Skyline Drive and the Blue Ridge Parkway.  These were beautiful drives with terrific overlooks, lots of green and many plants in bloom.  Not surprising, but these are not great roads if you are try to get somewhere by a given time, so we did have to bail out by mid-afternoon each day.  Here are some of the natural highlights we saw travelling the backbone of the Blue Ridge Mountains.

Thunder storm moving up the Shenandoah Valley south of Luray, VA. 
Mounds of blooming virgin's bower were a common
sight along the route.  This particular photo was
taken near Cherokee, NC.

We started at the northern end of skyline Drive in Front Royal, VA.  All along the way we saw numerous wildflowers in bloom.  Plants we could ID at 35 mph were eastern Joe Pye weed (Eutrochium dubium), several species of sunflowers (Helianthus sp.), wild bergamont (Monarda fistulosa), threadleaf coreopsis (Coreopsis verticillata) and tons of virgin's bower (Clematis virginiana).  We did manage to finish Skyline Drive then jump out to I-81 to get down to Marion, VA so that we would have an easy drive into Asheville the next day.


Later on in the trip we drove the southern end of the Blue Ridge Parkway near Cherokee, NC.  Here we saw similar plants in bloom but maybe different species from further north.  A couple that I feel pretty sure about here was spotted Joe Pye weed (E. maculatum) and thin-leaved sunflower (Helianthus decapetalus).


This spotted Joe Pye weed was growing on a steep slope next to
the Blue Ridge parkway.  The leaf shape and the purple stem are
clues that this is, in fact, E. maculatum.
While I didn't ID this sunflower on-site, I think it is thin-leaved
sunflower (H. decapetalus).  Some clues are the large teeth
on the serrated leaf, the long bracts under the flower head
and the purplish stem.

View to the northwest from near the Craggy Gardens visitor center.
One of the last botanical stops on the trip was at Craggy Gardens, near Mount Mitchell, the highest peak east of the Mississippi.  Among the plants noted there was Mountain ash (Sorbus americana) with its long pinnate leaves and large clusters of orange berries.  The plant that impressed me the most here was hairy alum root (Heuchera villosa).  The bloom period for it is mid-August into early fall.  This is a species that I have been growing for a while at home, but this was the first time I have seen large quantities growing in the wild.

These Alum Root were growing out of a north-facing rock wall
at the Craggy Gardens visitor center. 
This thistle patch was popular with the butterflies.
Here's one of the few Monarchs we encountered.


In addition to the plants, we did come across some interesting animals.  We had a small bear cross the road in front of us on Skyline Drive (no chance to take a photo).  We saw a lot of eastern swallowtails (Papilio glaucus), but only a couple of Monarchs.

The craziest insect we saw was a fast moving caterpillar which I believe to be of a pipevine swallow tail (Battus philenor).  I'm not sure where it was headed, I didn't notice any pipevine nearby, but it could have been in the undergrowth.


This pipevine swallowtail caterpillar was racing across a retaining wall at a scenic outlook
on I-81 from TN to NC.  It's fleshy antennae were waving around wildly.

Tuesday, August 9, 2016

August - Prime time for battling Japanese Stiltgrass

Japanese Stiltgrass, Microstegium vimineum, is a major invasive grass species in the Mid-Atlantic and encroaching on New England.  It forms a dense layer of vegetation that shades out native plants and other desirable species.  In late July and through the rest of summer it puts on a growth spurt jumping from 6 inches to over 3 feet tall.  This is the prime time to take action to reduce its numbers for next year.  As an annual grass the main goal is to keep it from setting seed and, eventually, the seed bank will be depleted.  Unfortunately that can take 5 to 7 years, but if you don't start doing something today, waiting longer will just make it that much harder.

I've published posts in 2014 and 2015 on my approach to dealing with stiltgrass, and I've had to go back several times to remind myself of what to do and when.  So here goes...

Freshly pulled Japanese stiltgrass.  There is a lot of leafy growth
for the relatively small root system.

Letting the pulled stiltgrass sit in the sun for a day or two helps to kill it
and it reduces the weight of the debris.  Before pulling,
 the stiltgrass in the bed was about 3 feet tall.
In planting beds where the grass has gotten several feet high pull it out by hand at the end of July or early August.  Its shallowly rooted and easy to pull, especially after a little rain.  Perennials are more deeply rooted and are harder to pull.  I've found that by loosening my grip a little I can leave perennials like New England Aster in place, while pulling out the grass.  Also at this time the stiltgrass is taller than many of the desirable plants so by grabbing the tops I can leave the lower growing plants undisturbed.  One of the reasons for pull now is to let some light reach the soil and induce more stiltgrass to germinate.  This late germinating grass won't have time to mature and will be killed off when the temperature drops.




In areas to large for pulling I usually wait until blooming is just starting (end of August-early September) and then weed whack it close to the ground.  The idea here is to prevent another season of seed from maturing.  Unfortunately stiltgrass is very slow to decompose and can form a mat layer that also shades out the native seed bank.  Where the cut grass is particularly thick I try to rake it together in piles in the shade where any viable seed is less likely to germinate.


This is an area of lawn that has been seeded twice with a low-mow  blend of fine fescues.
It has not been mown for at least 4 weeks.  There is much less stiltgrass than in  unseeded area to the upper right.
I'll wait until the end of August (ca. 2 weeks) to mow this lawn (I've already pulled out the stiltgrass from the bed).

For lawns that are full of stiltgrass the recommendation that I'm am trying to follow is to leave it unmown from late July to late August.  Then, just as the flowers begin to form, cut the lawn at a lower level.  The idea here is that constant mowing encourages the stiltgrass to form cleistogamus flowers low on the plant.  These flowers self pollinate and are difficult to remove.  While I'm not sure if it's true, it seems that letting the plant put its energy into upper open flowers will reduce the number of these lower flowers.  These upper flowers can then be sheared off and the plants may not have time to recover with a second bloom.

The final stage for the lawn is to rake out the remaining stiltgrass in mid-September and overseed with a desirable cool season turf grass.  The cool season grasses will germinate in the fall and fill the gaps previously inhabited by the stiltgrass.

This shady area was solid stilt grass 4 years ago.  Now, after 3 years of annual weed whacking
and some pulling there is more diversity.  The tall grass here is Virginia wild rye, Elymus virginicus,
which is now going into bloom

I am happy to report that following these practices is showing promise.  In the lawn overseeding with a low-mow blend and 'deferred' mowing has reduced the density of the stiltgrass.  Also in some of the natural areas I am seeing less stiltgrass and more diversity.  One species that is doing well in the shade is Virginia Wild Rye, that I seeded in two years ago.