Nativars?

What are Nativars?

Nativars are the subject of much discussion in the native plant community right now.  The comments I've seen have ranged from mild interest to deep concern.  I originally formed my opinion on these cultivated native plants over ten years ago.  Before writing this post I thought I should do a little refresher on the subject and I learned that the world is a complicated place.

Nativar is not a true botanical term but rather a word coined by Robert Armitage for a cultivar of a native plant.  It’s a combination of native, for native species, and cultivar.   A cultivar is short for cultivated variety and is reproduced by asexual means, not from seed.  Anytime you see a botanical name followed by a capitalized word (or words) in single quotes you are dealing with a cultivar.  Alternatively, cultivars may be call using common names.  For example Jim Dandy Winterberry Holly is the same thing as Ilex verticillata 'Jim Dandy'. 

Here are two inkberry cultivars, Ilex glabra 'Nigra' on the left and 'Shamrock' on the right. 
These have been in the ground here for about 3 years.  'Nigra' has darker green
 leaves and nice branching.  'Shamrock' has narrower bright green leaves and
is also well branched.  'Nigra' should grow to be over 6' tall, 'Shamrock to about 4'.

This is a wild type inkberry.  I don't know how big
 this will get, but it should grow to 6-8' tall.  Unlike the
cultivars this one has few lower branches.

Advantages of Nativars:

• May possess improved traits like disease resistance or improved blooming (size or quantity).  For example, mildew resistance in phlox.
• Predictable performance as design elements for color, shape and size.  Size is particularly important when you are working close to structures.  You can avoid a lot of  maintenance pruning by electing a properly sized cultivar.
• Greater commercial availability as a result large scale, asexual reproduction.
• As a nursery propagated cultivar there is no risk that it was collected illegally from the wild.
• For dioecous species the gender is often known, e.g. male and female hollies.  This is important if fruit production desired.
• Good introduction to native species for the novice.

 

Concerns about Nativars

There is concern that cultivated natives may not be as good of a food source for pollinators and herbivores.  The potential impact is both on pollinator preference and acceptability as host plant.  In some cases plant breeders have gotten creative and, in order to create some very interesting forms, have sacrificed ecological function.  Examples of this include double coneflowers such as Echinacea 'Pink Double Delight' which does not produce significant amounts of nectar, pollen or seeds.  There is also evidence that unusual colored foliage, particularly reddish, is less attractive to larval insects.

This wild-type purple coneflower grew from seed. 
Its parents were about 10' away.  It is 'fully functional'
producing  pollen, nectar and seeds.

 

When you get into the details of a native ecosystems it can get complicated.  Native insects depend on plants, mostly native ones, for food.  This food consists of  not only the pollen and nectar from flowers that everyone loves, but also on the leaves, stems and other plant parts that not our focus when we think of how we want to support our insects.  Insects consuming biomass is a key step in how sunlight is able to nourish all life on earth.  Insects convert plant matter into a higher protein form that that is consumed by retiles, birds and other small predators, particularly those that are feeding their young. These first line predators then supply food energy for larger predators and so on.  If these insects are not able to survive then the food web comes crashing down.

As clones, nativars lack the genetic diversity of wild-type, seed-grown plants.  In sufficient quantity the cloned population may have an adverse effect on the wider eco-system.  This may be from introducing either under or over-performing traits to the population.  This possibility of introducing an overly advantageous trait is an aspect I had not considered, an example of which was brought out in an article found on the University of Maryland Extension website by Dr. Sara Tangren which identifies many of these issues around nativars.  The article cites a case where the stronger growth habit of 'Shelter' switch grass, Panicum virgatum 'Shelter', may allow it to out-compete other meadow species and throw off the ecological balance in that system.

 In most cases there is a lack of science based evidence for actual damage, but there is a strong basis for concern.  The Budburst project is using citizen scientists to collect data on pollinator preference between cultivars and wild-type plants.  In general the more that the cultivar resembles the wild-type plant the more similar the interaction with pollinators. Factors to consider are bloom size, quantity of blooms, seasonal timing, color and the accessibility of pollen and nectar to pollinators.  This addresses one piece of the puzzle.  The effect of the narrower genetic diversity of nativars on the surrounding natural communities will be much harder to establish and I expect it will be different for each cultivar.  

One study out of the University of Delaware has shown clear evidence that as foliage color shifts from green to purple hues (increasing anthocyanin) that feeding by insect herbivores (e.g. caterpillars) decreases.  Other features of cultivars like varigation, fall color, disease resistance, habit  and fruit size did not significantly affect how insects fed with these plants compared with their wild type relatives.  This would be a factor in choosing among the new red-leafed ninebark cultivars.  This study was focused on insect feeding on woody plants and did not get into pollinator behavior.  

A much more positive spin on nativars can be found in this article from Nursery Management Magazine by Jolene Hansen.  It cites the findings in the University of Delaware study.

An article  by Rhonda Burnett and Carol Davit on the Grow Native! website also takes a cautious and critical view of nativars.  But it also offers one of the best, though least satisfying, answers to the use of nativars, from Douglas Tallamy, "It depends."

Problem is when there is an imbalance.  Questions to ask: Will my planting adversely affect the surrounding ecosystem?  Is there a local native population that may be affected.  What is the scale of my installation.  Is it a single clone or is it from open pollinated seeds?  Another quote from Dr. Tallamy (from the GrowNative! article) is the assertion that “It’s not the presence of cultivars, but the absence of natives that’s a problem.”

A major concern with cloned native species is their lack of genetic diversity.  The question is whether a large-scale injection of one set of genes will negatively impact the larger population.  This impact may be seen as a change in the native population or as a loss diversity leading to a decreased ability to adapt to environmental changes.  Plant genetics is complicated.  In many cases observable traits are passed on by the interaction of multiple genes.  

To make this issue even more complicated consider that many nativars and hybrids do not reproduce true to type (if they can reproduce at all).  Anecdotal evidence from my yard is that seedlings from 'October Skies' aromatic aster, Symphyotrichum oblonifolium 'October Skies' have very different forms.  One is gangly and another is nicely rounded but about 50% larger.  To my knowledge there are no other aromatic asters within 200 yards or mine (probably further).  So these are probably the result of self pollination.  So despite this being a cultivar, there is still a lot of variability packed into its genes.  I watched the insects visiting the flowers, there was no obvious preference among the three plants.  One advantage of having both was that the effective bloom time was increased over just having a single plant.

October Skies is a compact, early blooming cultivar of aromatic aster, seen here
in the foreground.  To its right is another aromatic aster that is likely a seedling
from the cultivar.  It bloomed a couple of weeks later, with fewer flowers
and it has a more open habit.

This is the first seedling I got from the original planting
of October Skies.  It is about 25% taller, floppier and
blooms a little later than its parent.  

Reversion of an individual cultivar to the wild form is not uncommon, dwarf Alberta spruce and Henry Lauder walking stick are two examples.  Though when being developed for commercial sale genetic stability is an attribute that is selected for.  An obviously unstable plant will not make it to market (or stay there long).

How and when to use Nativars

For many residential gardeners in urban and suburban developments there may not be much of a remnant ecosystem nearby that would be adversely effected by your plant choice.  Closer to natural areas and especially when doing large scale restoration work, using locally adapted, or even locally sourced plant (local ecotype) material becomes much more critical. There are several companies that can help with suppling large quantities local plants.  For example Ernst Conservation Seeds, Cardno, Carolina Native Plant Nursery, and  Archewild.  When concerned use seed grown native species from local eco-types.  This is easy to say but much harder to do.  

At this time there are many more questions than answers, but studies are underway to begin to answer some of these concerns.  Based on examples of disastrous plant introductions such as kudzu and Japanese knotweed it is understandable to be cautious when introducing new plant materials, especially when we are doing it in quantity and for what we believe is a 'good reason'.

For me, in my rural location I will the following guidelines.

• Within 50' of my house where design aspects such as color, shape and particularly size are important, cultivars are fine to use. 
• As I move outside that designed space I will use mostly wild-type or straight species.  Most, if not all of these are seed grown and are species native to this ecoregion (foothills of the Blue Ridge Mountains).  
• As I get into natural spaces I try to avoid adding any new species not already present in the area.  In many cases I am just managing the native species that are existing on-site (or have blown in) and most of the work involved is the removal of undesired and invasive species.

So I've written a lot of words but I'm afraid the conclusion comes down to the less than satisfying 'it depends'.

 

 

Getting More Fruits

Sassafras blooms in the first part of spring. 
This photo was taken on April 12th.

I have been planting more native trees and shrubs with the goal of increasing the amount of food available for birds.  Particularly fruits that are available in fall and winter.  In many cases these plants are dioecious. That is, an individual plant of the species is either male or female.  To get berries you need at least one male to fertilize the female flowers.  Sometimes getting male and female plants is easier when you are buying cultivars.  It is often documented somewhere (but not always) if a cultivar is male or female.  When buying seed-grown natives it is difficult to tell unless they happen to be in bloom when you are shopping.  If plants are not in bloom the recommended approach is to get 5 random plants so that there will be a good chance that you will get at least one of each.

This year I have spotted some firsts in my campaign to produce more native berries.  The first success that I noted was that my newly planted sassafras tree, Sassafras albidum, was a female [note structure of female flower].  There is a number of wild sassafras in the area, but the flowers are way up in the tree so I have not been able to distinguish their gender.  About a month after blooming I noted that there were a couple of berries forming.  They are green right now, but will turn dark blue when ripe.

Female flowers have 6 sterile stamen (staminodia) surrounding
a central pistil.  Male flowers have 9 stamen.

Here at the beginning of July you can see the green berries.  When ripe these berries
will turn dark blue and the pedicels will turn red.

The second species I spotted with fruit forming was persimmon, Diospyros virginiana.  There has been male tree on the property for some time.  I don’t know if it’s wild or was planted by the previous owners.  When I moved 7 years ago I planted a number of native persimmons all of unknown gender.  To improve the chances that I had at least one female I planted 6 new plants.  Last year one of them bloomed that proved to be a male.  This year two additional trees bloomed, both of which were female.  Shortly after the flower petals fell off I noticed that two of the female flowers had swollen ovaries.  Now I can hope that they survive long enough to ripen.  I may need to build a little fence around them to keep the deer away.  

Female flowers are usually solitary and have 8 sterile anthers around the pistil.
 On male trees flowers are clustered and are typically packed with 16 anthers.

About a month later this persimmon is developing. 
Green now it will turn orange when it ripens in the fall.

Another recently planted native tree that is now showing some berries is fringe tree, Chionanthus virginicus.  Fortunately these bloomed the second year after planting.  The first three of these I planted either appeared to be females or had not bloomed after two years.  The following year in early June I was in a native plant nursery when these were in bloom.   I was able to identify one specimen as a male (paddle-shaped anthers in throat of flower) and bring it home for the girls.  Now 4 years later I’ve spotted the first berries on the fringe trees.  Like with the sassafras these start out green then turn dark blue when ripe. 

This green berry on the fringe tree will turn dark blue when it ripens in early fall.

Two years ago I replaced some invasive leatherleaf mahonia, Mahonia bealii, with some inkberries, Ilex glabra.  I wasn’t able to get a male cultivar locally.  I found a suggestion on the internet that other hollies could fertilize inkberries.  To try this I planted an early blooming winterberry holly, Ilex verticillata ‘Jim Dandy’ nearby.  After planting my collection of inkberries including the ‘Nigra’ and ‘Shamrock’ cultivars I took a close look at the flowers.  While the flowers on ‘Nigra’ were exclusively female, ‘Shamrock’ appeared to have both male and female flowers.  Unfortunately this year I forgot to take a close look at these flowers to confirm my earlier observations.  I can say that this year I am seeing a lot of berries developing on the ‘Nigra’ plants, as well as on a single wild-type plant.  The ‘Shamrock’ cultivars bloomed this year but are lacking berries.  They had a lot of berries in their first year here.  

This female flower has a large central ovary surrounded by six sterile stamen. 
In male flowers these stamen will have yellow pollen on the anthers.

Also on the holly front, this year I added another winterberry holly, ‘Winterred.’  This is a later blooming female.  Its blooming cycle is perfectly timed with the male, ‘Southern Gentleman.’  While it was still in its pot I placed the ‘Winterred’ next to the ‘Southern Gentleman’ until the blooming period was nearly completed.  This should ensure some berries as long as it doesn’t get stressed too much from being planted out in late June.

Some other species that are not dioecious have mechanisms that encourage cross pollination. This ranges from clever flower construction that prevents self-pollination, to offset timing of pollen release and receptivity, to outright rejection of pollen with the same genetic material as the ovary.  To encourage fruit and seed production you should have at least two genetically distinct individuals within pollination range. 

This is what I’m thinking about my single American plum, Prunus americana.   Despite several years of impressive blooming I have not seen any fruits on this tree.  I don’t know how long these need to mature before they are ready to bear fruit.  To help with cross pollination I’ve planted several bare root American plums in the area but I think it will be a few more years before these begin to bloom.

Another fruit-bearing native that has appeared on my property is black raspberry.  I’d like to think that these have been encouraged by the removal/reduction of invasives like Japanese stiltgrass, wineberry and garlic mustard.

Black raspberry has round stems and first year canes are glaucous. 
Flowering occurs in mid-May

The black fruits ripen around the end of June and have a distinctive sweet flavor. 
These ripen a week or two before the wild blackberries, which are much tarter.

New Plants for 2019

Top and left are the female 'Blue Rug' junipers, lower right is the
supposedly male 'Andorra Compacta'.  Normal bloom time
for these is late May to early June.  So I will keep an eye out..

I had an established planting of creeping juniper, Juniperus horizontalis, die back last year.  This may have been due to a number of factors, but I think mostly the very wet weather causing the soil to stay very moist for most of the year.  While many folks poo poo junipers as too common, they have their place.  They are a durable, low-maintenance ground cover for sunny, dryish locations.  This species is native to the northern third of the US and most of Canada.  Their usefulness and adaptability has, however, made them a staple in the landscape trade.  One thing you don't see too often is berries on these plants.  Like other junipers, creeping junipers have separate male and female plants.  Ever since seeing cedar waxwings last year I have been looking to have more bird berries on our property.  To the extent that I could find gender information, it seems that most creeping juniper cultivars are female, such as the very popular 'Blue Rug' cultivar (aka 'Wiltonii').  Digging through the literature I found mention that the cultivars 'Bar Harbor', 'Blue Horizon', 'Plumosa' and 'Andorra Compacta' are male (or at least may be male).  In addition to a bunch of 'Blue Rug' junipers I was able to get an 'Andorra Compacta' to serve as a breeding partner. Now by having both male and female cultivars there is a better probability that berries will be produce to help support the winter bird population. 

These large-flowered bellworts came into bloom
just after our mid-season daffodils.

In an area just outside our kitchen window we have a large, somewhat wild perennial garden backed up by pine trees.  The shadier areas are dominated by several species of lamium and ground ivy.  I have had some success with shade-tolerant goldenrods here, particularly blue-stemmed and zigzag goldenrods.  To introduce some more natives to this area of potentially dry shade (assuming it will stop raining at some point), I ordered a few large-flowered bellwort, Uvularia grandiflora, as bare root plants.  We'll see how well these compete.  They have done well so far, all of them sprouted and bloomed this first year.

They say, planting trees is planning for the future, even one that I am not likely to see.  I have been dismayed that some of the big old trees here are dying.  Don't know if it's just their time or if there is something going on.  Besides the loss of their biological function, many of these trees are on a slope where they are helping to hold the soil.  Emerald Ash Borer is definitely one of the problems, causing a early death of many established ash trees.  But we have lost some big oaks and black cherries as well.  Besides these trees going away I am also actively targeting the invasive Alianthus trees and this is opening up the canopy even more.  While natural succession is kicking in, this is slowed by the number of deer that eat the tree seedlings.  I am more than a little concerned how many of these seedlings will reach maturity.  So I am looking for some shade tolerant trees that I can put in and protect to help nature along. 

I got these bare root American beech in the
ground the day they arrived. 

In the woods right now there are a lot of new beech trees, Fagus grandifolia.  These are quite shade tolerant, and seem to be well adapted to our location.  I found a source of bare root beech trees in southern Virginia, Mid-Atlantic Natives, so I ordered a few to see how that works out.  They were planted in early March and are just leafing out now, a bit behind the established beeches.  Beech are fairly slow growing trees, but will mature to be dominant elements in the canopy. 

These are the maple seedlings I gathered from around the property.  These may include
Red, Sugar, Silver and the hybrid Freeman maples. (Also one tulip tree in the mix.)

Red maples, Acer rubrum, are also quite shade tolerant but are much faster growing.  I am looking to add a few of these to fill in the gaps.  Sugar maples are another possibility.  These are slower growing, but better adapted to the near neutral soil pH we have here. (Based on the natural distribution of trees here (Box elder, Hickories, American hornbeam and Tulip tree) soil pH is probably running 6-7.5.)  My regular source of native trees, Stadler Nursery, is cutting back on its supply of reforestation plants (I don't know why), so I decided to harvest some of my own seedlings and nurse them along a little before planting them out.  I've got several species of maples growing here, so at this point I can't say for sure what each of these seedlings are.  Tulip trees also do well here and I've got lots of these seedlings too, so I could move those to some of the more open areas in the woods.

This Henry's Garnet Virginia sweetspire has flopped a little due to the weight of the rain. 
It is nearly full height, at 4' and should spread to about 6'. 
The racemes of white flowers are about to pop.

Another area that I have been trying to bulk up with native species is a  slope that has been built up with sandy clay and is dominated with Japanese stiltgrass, Japanese honeysuckle and garlic mustard.  I've been putting divisions of wild bergamot, Monarda fistulosa, and they are taking hold. I am focusing on shrubs that are colonizers.  These spread out by underground shoots and should help stabilize the soil to erosion.  This year I'm adding a Henry's Garnet sweetspire, Itea virginica 'Henry's Garnet', gray dogwood, Cornus racemosa, and some bare root smooth sumac, Rhus glabra.  Unfortunately my deer do like to munch on these so I need to stay on top of these with either fencing or repellent sprays until they get established.

Since deer like to browse on my gray dogwood I
put some fencing around this one right away.

You can see that the leaf buds on this smooth sumac
are about to pop.  I should get some fencing around this
one soon (in addition to the repellent spray).

In my battle with Japanese stiltgrass, I am planting native species to help displace that invasive grass.  One grass that does well in shadier locations is bottlebrush grass, Elymus hystrix.  I started some from seed this winter and planted them out in early spring.  These make take a year to get established, but should help fill in areas where the stiltgrass has been (is being) removed. 

I started this bottlebrush grass from seed in February and planted it out in April.
It may not get too big this year, but should form a dense clump next spring.

Last year I put in a Red Sprite winterberry holly along a sloping path.  I already had a mate, the early blooming Jim Dandy cultivar, Ilex verticillata 'Jim Dandy'.  To improve berry availability for winter time birds I added another early blooming female cultivar called Afterglow, Ilex verticillata 'Afterglow'.  This cultivar is also compact, like 'Red Sprite' and is supposed to be very dense with flowers and berries.

Also on the holly front, I put in some inkberries, Ilex glabra, in a shady location, near an English walnut tree, last year.  Of the three cultivars I put in, Shamrock and Nigra did well, but the Densa cultivar died.  I don't know if it was just the amount of shade or sensitivity to the juglone from the walnut.  I replaced it with another Nigra cultivar this spring, so we'll see if that one does better.  

Inkberry berries

This past spring I replaced some non-native Leatherleaf Mahonia, Mahonia bealei, with inkberries, Ilex glabra.  While moderately invasive, the mahonia did produce a decent crop of berries over the winter which was available to the resident bird population.  I wanted to make sure that these inkberries would also produce berries that the bird could use through the winter. Inkberries, like most other hollies, tend to be dioecious, that is have male and female flowers on separate plants.  Most inkberries commercially available are listed as being female.  The only male cultivar I could find listed is 'Nordic', which was selected for is cold hardiness.  Here in the relatively warm Mid-Atlantic, I couldn't find any for sale.  I did find a mention that you could use another species of male holly as long as it blooms at the same time as the inkberry.  Jim Dandy winterberry holly, Ilex verticillata 'Jim Dandy' (blooming in late May-early June), seemed to be a good fit for inkberries which bloom from about mid-May to mid-June.

The selection of native hollies that I put in to replace the leatherleaf mahonia.  Left to right:
Jim Dnady winterberry (male), Nigra inkberry and Shamrock inkberry (both female)

The selection of inkberries I settled on were two Shamrocks and one each of Densa and Nigra.  The Shamrock cultivars a supposed to top out at around 4' while the other two should grow larger to about 6'.  By having a mix of cultivars I hope to add a little extra texture and variation in height to this planting.  Right next to these I put in the Jim Dandy winterberry, to help with fertilization.

Here's the Shamrock inkberry at the end of May.  Looking closely
you can see some of the flowers have anthers with pale yellow pollen. 
Other flowers are lacking stamen, but have a large central ovary.

This Nigra inkberry has only female flowers.  The flowers are
not in dense clusters like many of the male flowers on the Shamrock cultivar.

At the end of May the flowers on this male winterberry are just opening up. 
This timing overlaps with the flowers on the inkberries.

As the inkberries were blooming I paid attention to when the flowers were opening up on each plant.  To my surprise I noted that the Shamrock inkberry seemed to have both male and female flowers on it.  The Nigra and Densa cultivars appeared to have only female flowers.  I would have thought that if the Shamrock cultivar is typically monoecious (have both flower genders on one plant) then that should be called out in the description of the plant as this would be a great benefit to wildlife gardeners. 

Fast forward to mid-fall and there are reasonable numbers of black berries on both the Shamrock and Nigra cultivars.  I can not say unequivocally that the Shamrock did all the pollination work since the male winterberry was right there in the mix, but at least I have been successful in replacing the leatherleaf Mahonia with a native evergreen shrub that provide berries for the resident bird population in the winter.

Got a few berries on this Shamrock inkberry.  It's missing
 quite a few leaves, my guess would be deer browse.

 Unfortunately the Densa cultivar died back by the end of summer.  Two possibilities are that it was in the shadiest spot of all the newly planted hollies, and/or that it is planted at the edge of the drip line of an English walnut, Juglans regia.  While not as potent as the native black walnut, Juglans nigra, the English walnut does produce juglone, a compound the inhibits the growth of a number of plants, including inkberries.  We'll see how the other inkberries overwinter before I find something to replace the Densa cultivar.

This Nigra inkberry also has a few berries, as expected.  It too
has taken some deer damage.  I've since sprayed them with some deer repellent.  

New Plants for 2018

One of my big plans for this year was to replace the non-native, invasive leatherleaf grape holly, Mahonia bealii, with some native shrubs.  Features of the grape holly that I wanted to preserve were flowers and berries for wildlife and some evergreen qualities that help define that space in the winter.  I decided to use inkberry hollies, Ilex glabra, to carry most of the load.  Also in this space I put a 'Snow Queen' oakleaf hydrangea, Hydrangea quercifolia 'Snow Queen' to continue a screening effect started with two older oakleaf hydrangeas nearby.  A few cinnamon ferns, Osmunda cinnomonea, completed the composition.

Shrubs from left to right are Jim Dandy winterberry holly, Nigra inkberry and Shamrock inkberry. 
Also new are the bright green cinnamon ferns toward the front.  The background is dominated
by a Carolina allspice, Calycanthus floridus.

To create some size variation in the evergreen I got a variety of inkberry cultivars.  'Shamrock' being the shortest (3-4') is in the front and behind it are a 'Densa' (8-10') on one side and 'Nigra' (4-6') on the other.  All three of these are listed as female plants.  To get berries a male plant is needed.  Unfortunately I was not able to get hold of a male plant (such as the 'Chamzin' cultivar).  I saw somewhere that any male holly that blooms at the same time is capable of fertilizing a female, so I put in a 'Jim Dandy' winterberry holly, Ilex verticillata 'Jim Dandy' nearby.  This bloomed at about the same time as the three inkberries. 

Since I was watch the flowers rather closely I noticed that while both 'Densa' and 'Nigra' had exclusively female flowers, 'Shamrock' appeared to have both male and female flowers.  I could find no mention of 'Shamrock' bearing both types of flowers.

Also on the holly front I added a 'Southern Gentleman' winterberry near a well established female.  A few years ago I but in an early blooming 'Jim Dandy' as a pollination partner, but berry production did not improve much.  The 'Jim Dandy' is usually finishing up blooming just as the established female is starting to bloom.  This new 'Southern Gentleman' here has started blooming about 2 weeks later than 'Jim Dandy', hopefully in better synch with the female.  Maybe this year we will get a bush full of red berries. 

Here's the slope prior to planting.  The winterberry is at the top left and
the lower growing aromatic sumac cultivars are on either side of the steps.

 In another area of the yard is a slope almost too steep to mow (about 30% grade).  This year I've decided to put in some steps and plant the slope with native shrubs, perennials and grasses so that it can be left alone.  New plants for this area include 'Grow-low' aromatic sumac, Rhus aromatica 'Grow-low', 'Red Sprite' winterberry holly, Ilex verticillata 'Red Sprite', and fireweed, Chamerion angustifolium.  The 'Red Sprite' is a female clone and was put in as a partner for the 'Jim Dandy' that I planted a few years back. 

Tried to grow fireweed from seed last year, but no luck. 
This year I got some as seedlings.

Here are two red oaks that I will be planting in the woods.
These saplings are about 4 years old.

In the woods around our house a number of older trees are dying.  Some of this may just be natural, some may be the work of the emerald ash borer.  I've also been identifying and killing as many tree of heaven, Ailanthus altissima, as I can.  To fill the open spaces I've been planting oak saplings.  This year I am putting in the more shade tolerant oak  species, red and black oaks, Quercus rubra and Q. velutina.  [P] 

We are also seeing a number of our white pines, Pinus strobus, in our wind break coming apart.  These were planted 40-50 years ago and are probably not in their ideal habitat.  To fill in the gaps in this row of evergreens I've planted some seedling of Canadian hemlock, Tsuga canadensis.  I've spaced these out widely so that any future attack by wooly adelgid will be slowed, since the plants won't be in contact with one another.  I've marked the location of each with a pink flag, otherwise these little plants would disappear into the undergrowth.

 

I also got a bunch of bare root wild ginger, Asarum canadense, in early spring.  I would like to use them as aground cover along with some Heuchera and violets.  So far most of these are surviving, but they do need some help by removing some of the competitive plants.  My previous attempt did not go so well as the plants were overwhelmed with vinca  and the leaves of an English walnut. 

Most of the American plums, Prunus americana, that were planted last fall survived winter.  One died rather suddenly this spring when all the leaves wilted.  There was a lot of insect activity near the roots, or it could have been too much shade from a neighboring box elder.

I've always loved the look of blue cohosh, Caulophyllum thalictroides, blanketing a shady hillside.  I've been reluctant to plant it in the past because I haven't seen it growing nearby, even though I seems like the right conditions.  This year I broke down and bought a couple of plants to put in on a shady, moist hillside.  This is an area where I have been removing garlic mustard and Japanese stiltgrass, so it's time to get some more plants in there to take their place. 

Post bloom, this Itea tends to blend in with the surrounding foliage.

A few years back I planted a small Virginia sweetspire, Itea viginica, possibly 'Henry's Garnet' under a tulip tree.  It has never got too tall.  Possibly due to the shade and possibly due to deer browse.  Despite its lack of size, this year it managed a couple of blooms.  Encouraged by this, this year I added a larger specimen to a sunnier location.  'Little Henry', a cultivar growing to about 3', was my choice.  It has a compact habit and large flowers.  While the flower display on this one this spring was impressive, now at the beginning of summer it's hard to recognize.  It should have good fall color, though.

Replacements for Nandina and other learnings

Recently I wrote an article for Houzz on plants to use instead of Nandina domestica, aka Heavenly Bamboo or Sacred Bamboo.  This overused Asian species is adaptable to a wide range of growing conditions in USDA zones 7-9 and has reached invasive status in the Southeastern US.  In Maryland it is listed as a Tier 2 invasive plant meaning that, while it can still be sold in Maryland, it must be accompanied by signage stating that this is problematic species. 

What to Plant Instead of Heavenly Bamboo

In addition to its invasive characteristics, the bright red berries so prominent in winter are actually quite toxic to over-wintering birds.  The cedar waxwing is particularly susceptible due to their feeding behavior.  Blue Jays and Mocking birds are examples of other species that are at risk from this shrub.

You can read more about the toxicity of Nandina berries to birds in this post from Audubon Arkansas. You can mitigate this problem somewhat by planting more plants that bear fruit late in the season, particularly native species; but, you should not consider Nandinas as wildlife-friendly plants. If you want to use Nandinas for aesthetic purposes consider cultivars that do not produce berries such as 'Nana', 'Nana Purpurea', 'Atropurpurea Nana', or 'Gulf Stream.' These non-bearing cultivars are also less likely to spread outside the garden.

One of the species that I recommended in this article is Oregon Grape, Mahonia aquifolium, and other members of the genus.  This broadleaf evergreen shrub is native to the Pacific Northwest, but is also found growing wild in some eastern states, most likely as a garden escapee.  I thought I had some growing in my backyard, too.  While researching this species I discovered that what I had was, in fact, Mahonia bealei, Leatherleaf Mahonia.  This species, originally from western China, is listed as invasive in many of the same states as Nandina.   

Here are two Leathrleaf Mahonia growing in a clump in late January. 
This species of shrub typically grows 4-10' in height,
compared to 3-6' for the Northwest native Oregon grape.

The bright yellow flowers of Leatherleaf Mahonia bloom in late winter to early spring
on clusters of terminal racemes.  This species can be distinguished from Oregon Grape,
M. aquifolium, by the number of leaflets, 9-15 vs. 5-9, for Oregon grape. 
Also the leaf color of leatherleaf mahonia is a dull bluish green compared to
the shinier dark green leaves of Oregon grape.

Learning that what I thought was Oregon Grape was actually a non-native species with invasive tendencies, I've decided to replace it with species native to this area.  Even before this revelation I was considering replacing it with a more appropriate East Coast species.  I would like to have an evergreen shrub that likes moist soils and open shade.  Looking at my list of Nandina replacements for inspiration, I think I will go with Inkberry Holly, Ilex glabra, as the replacement. As with most hollies I will need both a male and a female plant to get berries for the birds.  Fortunately there are both male and female cultivars available in the nursery trade so I will be able to start an inkberry family without too much trouble.  As the male I will go with 'Nordic', a fairly compact species.  There are more choices for the female.  I would like them to grow to about 6 feet, so I have a choice of 'Compacta', 'Densa' or 'Nigra'.

This inkberry is part of a new parking lot planting at a local library
that features mostly native species.  It does well in part to full sunlight. 
My site may be on the shady side, but that may encourage
a more open form that I would like for my particular application.