Monday, October 17, 2016

Last Comments on Stiltgrass -- This Year

I've been talking a lot about Japanese stiltgrass control and how I am trying to eliminate it from my property.  One of the really insidious features of stiltgrass is that in addition to its normal seeds produced on tall stalks, it also produces a second set of seeds on flowers enclosed in stems close to the ground.  These are referred to as cleistogamous flowers.

Here in mid-October you can see the height difference
between the regular flowers and cleistogamous ones.
While removal of the upper flowering parts of the plant will help control the spread of stiltgrass and reduce the total number of seeds produced, that second set of seeds keeps the local population going.  These cleistogamous flowers are particularly relevant in mown lawns, where these ground-hugging flowers survive the regular trimming.

An approach that I am expanding on further this year is to use a stiff rake to pull out the stilt grass from the lawn.  This works best when the desired grass is clump forming.  The rake can get locked into the creeping stolons of the stiltgrass, while the clumping grasses are not snagged (too much).  Timing is critical -- wait until late in the season when the expanding lateral growth of the stiltgrass makes it easier to snag, but before the cleistogamous seeds begin to mature.  This year I did a thorough raking at the end of September.  That worked out with the timing for overseeding the lawn with a more desirable grass seed.  When I went out a week later I noticed that some of the stiltgrass in the lawn did have seeds forming in the lower stems.  Next year I will do the raking in early or mid-September to reduce the chance of actually spreading any matured stiltgrass seed while raking.

Here are the piles of stiltgrass and other debris I raked out in preparation for overseeding
the last week of September.  The 4 smaller piles are from an area I overseeded
with tall fescue last year; the larger piles are from a new area I started this year.
After drying for a couple of days these piles were carefully carried away to a segregated brush pile
to avoid spreading stiltgrass seeds.

A general strategy for removing invasive plants is to start with a manageable sized area and clean it up thoroughly.  In subsequent seasons expand the area for cleaning.  This reduces the chance that the previously cleaned areas become reinfested.  Trying to do too much at once risks leaving many seeds or plants behind that will reinfect your 'clean' areas and real progress will difficult.

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.

Sunday, July 31, 2016

Mid-Summer is Coneflower Time

Here's some orange conflower poking through a  mass of vines,
including virgin's bower, Clematis virginiana, and passion vine,
  Passiflora incarnata (the large palmate leaves at the top).

While the black-eyed Susans (Rudbeckia hirta) have been blooming since June its not until mid-summer that other members of the genus Rudbeckia kick into high gear.  Most folks are familiar with orange coneflower, R fulgida, particularly some of the cultivars like 'Goldstrum' and 'Viette's Little Suzy'.  But there are other species in the genus that are worthy additions to the home landscape.

These cutleaf conflowers are 5-6' tall and blooming in open shade.
One relatively new addition to my gardens is cutleaf coneflower, R. laciniata.  This is a tall  perennial that can grow up to 10' in height and can tolerate shade as well as full sun.  The reason I put some in was to add some color to the back of a planting partially shaded by pine trees.  They took 2 years to get established, but this year they are performing beautifully.  It's interesting that in those first years the deer nibbled them back as they got over 2' tall, but this year the plants seemed to be ignored by the deer and now they are standing 6' and in bloom.

Unlike many other Rudbeckias cutleaf coneflower has a green central cone.
These plants prefer moist to wet soils and are not uncommon along river banks and in flood plains.  I've seen some good sized stands of these while walking on the C&O Canal trails along the Potomac River in Maryland.

These plants are growing on the edge of my vegetable garden,
a perfect disturbed habitat.  I will be pulling seedling out next year.

Another species of coneflower that is performing well this year is brown-eyed Susan, R. triloba.  This species has smaller, more rounded flowers than either orange coneflower or black-eyed Susans.  However, it does grow larger, 1.5-4.5', than those two. The Latin name 'triloba' refers to the 3-lobed leaves that tend to occur near the base of the plant (none of these are visible in this photo.)

This is a short-lived perennial that prefers average to dry soils and part to full sunshine.  It is usually found in disturbed habitats, on the edges of fields and paths.  It tends to get shaded out by longer lived perennials in less disturbed habitats.  The deer really ate this species up at first, now they browse on it occasionally.   Still, I need to protect mine in order to get a full set of blooms.

 Note:  all four of these species of Rudbeckia are native to the Chesapeake Bay watershed.

Monday, July 11, 2016

A Native Returns

Back in 2014 I found a small patch of American germander, Teucrium canadense, growing on the edge of a woodland dominated by invasive species like, Japanese stiltgrass, Mircostegium vimineum, and wineberry, Rubus phoenicolasius.  Since then I have been pulling the stiltgrass in late summer and cutting the wineberry to the ground each spring.  This year we have been rewarded with a much larger swath of germander and a correspondingly smaller mass of invasives.

Mid-July and this area is now dominated by American germander, Teucrium canadense, in bloom

My work is not over.  This area still has a lot of stiltgrass and wineberry, as well as garlic mustard, Alliaia petiolata, which gets pulled in spring, but it is encouraging to see that, given a little help the native flora can come back.

Here's a honey bee about to land on some American germander.  The flowers are unusual
in that the stamen project straight out above the lower lip, which serves as the landing pad.

Thursday, June 16, 2016

Finding a mate for my Plants, part 2

One of my goals in creating a more wildlife friendly landscape is to use plants that produce fruits and berries in addition to pollen, nectar and habitat.  While for some plants that is not a big deal.  A single specimen may be self fertile, or there are other nearby plants for cross-pollination.  Where I have been having more trouble is with some of the less common species to my neighborhood.

A good number of fruit bearing trees and shrubs are dioecious, that is, they have male and female flowers on separate plants.  You need one of each in order for the female to bear fruit.  The classic example of this in horticulture is with the hollies (Ilex sp.).  Fortunately, the industry knows that customers expect to see red berries on their winterberry hollies, so they have provided distinctly named male cultivars to interplant with the more attractive females.  Usually one male plant is sufficient to fertilize five females. 

Finding information on the genders of other plant species is more challenging.  Many maples are dioecious, but it is rare to find its gender in the plant description.  Most folks don't care much about the flowers on a maple, they are too far away to see and the foliage is the main feature anyway.  However gender is an issue for many allergy suffers.  Male trees produce loads of pollen and if it's wind borne, that's a lot of pollen in the air.

This Sassafras was blooming at the beginning of April.
Males have showier flowers because of all of the stamen.
The female flowers are more subdued.
My goal is to have mating pairs so that I can get fruit production for the birds and other wildlife.  On my property I have a number single specimens.  In order to find out which genders I have, I need to be out there observing them while in bloom.  I learned that my big sassafras tree is a male since I was out there in early spring while it was blooming.  I didn't see any others in bloom.  I recently purchased a new seed grown sassafras, but it will be maybe 10 years before I learn its gender. 

One approach to getting mates when buying young plants is just to buy a lot of them and then play the odds.  I often buy 3 at a time, but 5 gives you a better shot. This is only certain for seed-grown plants.  Plants propagated from cuttings will have the gender of the 'parent' plant.  Then you need to hope that the propagator started from a mix of plants and not a single cultivar.

This fringe tree is probably 4 years old and
has a few blooms on it.

Another approach is to be at the nursery and find plants in bloom.  I got lucky this year when I found small fringe trees in bloom at my favorite nursery.  I went home and saw that both of mine were also in bloom and they were both females.  I headed back to the nursery and looked though their plants until I found a male and bought it.  Now I'm all set for next year.

This is the female flower, there are two stigma held closely in the center.
The male flowers have two paddle-shaped anthers that protrude from the flower center.

Tupelo, Nyssa sylvatica, is another tree that is dioecious.  I put in two of them in a couple of years ago.  Then I realized it was a big gamble that I would have one of each, so a added a third this year.  These mature into fairly large trees, so I don't want to fill up the yard with a bunch of them.

I have a mature persimmon tree that is female.  The first year we moved here I added 5 more saplings.  Now, 4 seasons later they are about 10 feet tall, but still no sign of blooming.  Maybe next year.

Here's the female persimmon in bloom.  I haven's seen what the male looks like, yet.

The native pussy willow (Salix discolor) also comes as separate male and female plants.  The male is showier with its large fuzzy stamen.  These plants do bloom when they are small, so you might have luck determining which to buy at the nursery.  These bloom in mid-April around here and, unfortunately, many nurseries aren't open for business then.  The one I purchased two years ago was male.  Willows are very easy to propagate by cuttings.  So I was able to quickly grow several new plants, but these will all be male.  I did pick up another this spring, but it was not in bloom.  The vendor said it was seed grown so I'm working blind.

The male flower of this pussy willow is adorned with bright yellow stamen.
The flowers on female plants are green and somewhat scaly in appearance.

I did get a couple of goatsbeard (Aruncus diocus) which turned out to be both male.  This is a case where I am happy not to have a mate.  The male has the showier flower and two plants take up more than enough to space in the garden.
The stamen on these male goatsbeard flowers really catch the light.

Monday, May 9, 2016

Which is the Strawberry?

I am adding a number of Virginia strawberries, Fragaria virginiana, to my gardens this year.  This is part of my plan to incorporate more edible plants, particularly natives, into the landscape.  While I may not get many berries from these little plants this year, I expect to get a harvest next year after the plants have settled in.  One important thing that I will need to learn is how to tell these fruit bearing plants from the insidious mock or Indian strawberry, Duchesnea indica, that is growing just about everywhere on the property.

Here is mock strawberry with its bright yellow flower
and trifoliate leaves.  These leaves are evergreen here in zone 6.

Indian strawberry is an exotic species from southern Asia imported to the US as an ornamental plant and has widely naturalized over the years.  The 'Indian' in the name refers to a region of Asia, not Native Americans.

Both plants have similar trifoliate leaves with bluntly serrated (toothed) edges.  They each form tight clumps of basal leaves, spreading by above ground runners.  Also, they each produce bright red fruits with seeds on the surface.  The most obvious difference is the flower color, Virginia strawberries have white, 5-petaled flowers, while those of mock strawberry are bright yellow.

This newly planted Virginia strawberry has not settled in enough to flower.
The leaves are persistent through the winter, but these will turn red,
adding to winter interest.

Another difference is in the fruit.  The seeds of Virginia strawberry are located in depressions on the surface of the red 'berry'.  Mock strawberry seeds are actually in projections above the fruit's surface.  Also the fruit from mock strawberry is dry and tasteless compared to the sweet, juicy fruit from the Virginia strawberry.

These differences make it easy to tell the two plants apart when they are in bloom or fruit, but what about the rest of the year.  I was looking for a definitive feature to rely on.  Many times botanical descriptions depend on doing a comparison, e.g. more or less hairy, or 'broader' leaf.  I was looking for a yes or no test that I can use quickly while pulling weeds.

Here are both surfaces of the leaves of mock strawberry.
The arrow at left points out the longger terminal tooth.
So while the leaves of mock strawberry are more coarsely serrate and its veins are more divided than those of Virginia strawberry, the more practical method for me is to look at the tip of the leaf.  On nearly every leaflet of mock strawberry the  terminal tooth is longer than the ones on either side.  For Virginia strawberry the terminal tooth is shorter the its neighbors.  Maybe after working with the Virginia strawberries for a season or two I will appreciate the finer differences.  For now the goal is to not pull up any of my new plants.

Here are both leaf surfaces of Virginia strawberry.  Again,
the arrow points to the terminal tooth on the leaf, which is
distinctly smaller than its nearest neighbors.