Archive for category Invasive Exotic Species

Ashes, ashes, all fall down

Top of a canopy Green Ash on my floodplain

Top of a canopy Green Ash on my floodplain

This past weekend, I walked the floodplain portion of my yard to count the number of Green Ash (Fraxinus pennsylvanica) trees growing on it. Thirty-seven trees – 17 females, 20 males – most between 50 to 70 feet tall are the dominant canopy species in this part of our property, about an acre and a half. My adjacent neighbors’ properties also include floodplain areas that are dominated by Green Ash trees.

I was devastated when I realized how completely Green Ashes dominate the canopy layer of the healthy wetland that I live beside, because in less than ten years – more likely less than five, it is a near certainty that they will all be dead – felled by a tiny green insect from Asia that no one has been able to stop: the Emerald Ash Borer.

Trunk of a canopy Green Ash

Trunk of a canopy Green Ash

The insect has already killed “tens of millions of ash trees in southeastern Michigan alone, with tens of millions more lost in Arkansas, Colorado, Connecticut, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Massachusetts, Maryland, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina. Ohio, Ontario, Pennsylvania, Tennessee, Quebec, Virginia, West Virginia, and Wisconsin”. Here’s a link to a current map of infected states that is maintained by the Emerald Ash Borer Clearinghouse (Click on the down arrow to move through time to 2015 and watch how many states become infected). The insect is expected to continue spreading until it has killed every ash tree species in North America.

Southeastern US Ash Species

In the southeastern piedmont region of the US where I live, four species of ash are native. Three are wetland species: Green Ash (Fraxinus pennsylvanica), Carolina Ash (F. caroliniana), and Pumpkin Ash (F. profunda). As is evident on my floodplain, these three are important species in wetlands, and when they are felled by the Emerald Ash Borer, the transformation such areas undergo will be profound. White Ash (F. americana) prefers deep, well-drained soils. Its wood has been used for centuries to make fine furniture, baseball bats, and any other wooden item that needs to be strong and lasting. It has been used extensively as a landscape tree.

Ashes have compound, opposite leaves, which help create shady moist woodlands beneath their canopies.

Ashes have compound, opposite leaves, which help create shady moist woodlands beneath their canopies.

Animals that rely on ash trees

Humans aren’t the only living creatures who have relied on ash trees for centuries. According to Dr. Douglas W. Tallamy in his book Bringing Nature Home, ash trees support at least 150 species of moths and butterflies – more than hazelnut, walnut, beech, or chestnut. Moths whose caterpillars rely on ash trees include the Promethea Moth, Apple Sphinx Moth, Fawn Sphinx Moth, Great Ash Sphinx, and Banded Tussock Moth. Butterflies whose caterpillars rely on it include Eastern Tiger Swallowtail, Hickory Hairstreak, Mourning Cloak, Red-spotted Purple, Giant Sulphur, and Orange Sulphur.

Caterpillars of Eastern Tiger Swallowtails rely on ash trees for food.

Caterpillars of Eastern Tiger Swallowtails rely on ash trees for food.

White ash is an important source of browse and cover for deer. Its seeds are consumed by wood ducks, northern bobwhites, purple finches, pine grosbeaks, fox squirrels, mice, and many other birds and small mammals. The bark of young trees is occasionally eaten by beavers, porcupines, and rabbits. Because of its tendency to form trunk cavities if its top is broken, mature white ashes are highly valued as nesting sites by cavity nesters such as red-headed and pileated woodpeckers, and then secondary nesters such as wood ducks, owls, nuthatches, and gray squirrels.

The same species also utilize green ashes, and game birds such as wood ducks, grouse, northern bobwhites, and wild turkeys use green ash habitats heavily. Green ash woodlands often shelter the highest numbers of bark-foraging and ground-nesting bird species.

Eastern Cottontails enjoy the seeds of ash trees.

Eastern Cottontails enjoy the seeds of ash trees.

What will all these creatures do for food and shelter when every ash tree in North America is dead? No one can predict the future with certainty, but we can look at what has happened in southeastern Michigan, where this has already happened. Massive gaps in forest cover have favored the invasion of non-native invasive plant species. Japanese honeysuckle, for example, is starting to look like kudzu looks in the Southeast. Soil chemistries are changing, as are water cycling patterns, making it more difficult for remaining native species to maintain themselves. All the dead trees initially favored cavity-nesting birds. So the first few years after the ashes died, woodpeckers and other cavity nesters were more abundant. But the profound disruption in the ash-dominant ecosystems soon led to drastic reductions in the insect species the cavity nesters feed on. No insects means no birds. It’s Rachel Carson’s Silent Spring all over again – only this time the culprit is not DDT, but a non-native invasive insect that cannot be stopped.

What is being done?

Ash species in China – the home of the Emerald Ash Borer – appear to be resistant to this insect. Scientists are trying to figure out how to incorporate that genetic resistance into North American ash species. To that end, they are frantically saving as much ash seed as they can, in the hopes that, someday, they can re-introduce the species with genetic modifications that incorporate Asian resistance to Emerald Ash Borer.

Like charms on a bracelet, female ash trees (the species is dioecious) dangle seed clusters from slender branches.

Like charms on a bracelet, female ash trees (the species is dioecious) dangle seed clusters from slender branches.

That’s the dream. They aren’t there yet. And no one knows how long all the animals that need ash trees can survive without them. No one knows how ecosystems in which ash trees have been essential components for thousands upon thousands of years will handle such a massive disruption – the extinction of a key ecosystem component.

What can we do?

In the face of the inevitable destruction of all our ash trees, what should we do? Information is always our ally, so stay current on developments regarding the Emerald Ash Borer and any potentially resistant North American ash species. At the end of this post, you’ll find a list of links to get you started.

Typical branching structure of a canopy Green Ash

Typical branching structure of a canopy Green Ash

What am I doing?

As for my Green ash-dominated 1.5-acre floodplain, I’m going to start planting other tree species that I know are adapted to similar growing conditions, starting with the species that are already there, and adding more of some additional species that I have already added that appear to be doing well.

But note, this is a total Hail Mary on my part. The trees I’ll be adding will be young. I’ll be long gone before they can attain canopy height. Thirty-seven canopy-sized (50-70-feet tall) ash trees are way too many trees for me to remove as they die. This means dead ash trees will be dropping pieces of themselves all over the place, most likely including on top of other species growing beneath them.

Right now, wildflowers like this Monkeyflower thrive beneath the canopy of Green Ashes on my floodplain. Will they remain when the ashes are gone?

Right now, wildflowers like this Monkeyflower thrive beneath the canopy of Green Ashes on my floodplain. Will they remain when the ashes are gone?

Additionally, I can’t predict what changes in soil chemistry and water and nutrient cycling will occur. My new additions may not be able to handle these changes.

And the pressure from invasive exotic plant species is already enormous on my property. I spend more time and money on their removal than any other landscaping aspect by far. I may not have the resources to prevent invasive plant species from outcompeting remaining species and my new additions.

Will Japanese honeysuckle take over when the ashes are gone?

Will Japanese honeysuckle take over when the ashes are gone?

But the alternative is to do nothing, to throw up my hands and walk away, and I can’t do that. The green world is what keeps me going – physically, emotionally, and spiritually. I will fight for its survival until I can fight no longer.

You suburban and urban gardeners with no ash trees on your properties may think you’ve dodged a bullet this time, but in fact, you only perhaps have a bit more time to prepare for other battles before us. Already in areas where ash trees are gone, another tree in the same plant family is being attacked: White Fringtree (Chionanthus virginicus).

Will our spring-blooming native White Fringetrees be victims of the Emerald Ash Borer too?

Will our spring-blooming native White Fringetrees be victims of the Emerald Ash Borer too?

A new gardening paradigm may be our best hope

Your best weapon will be vibrantly healthy home ecosystems. That is why my proposal for 21st-century gardens across the United States is so critical. Every patch of green will be essential to the survival of native animals and plants. Sterile, chemically controlled fescue lawns won’t help them. Healthy, vibrant, beautiful native landscapes might just save them.

The Emerald Ash Borer is now in the county adjacent to mine. It won’t be long before it finds my beautiful ash-shaded wetland. If you live in the southeastern piedmont in areas with ash trees, I encourage you to take your children, your grandchildren – or any child for that matter – to visit healthy ash trees now. Go appreciate the beauty of their dangling seeds, their compound opposite leaves, their gray furrowed trunks. Lock these images into your memories now, for soon they will be all you have left.

Appreciate the furrowed bark of ash trees while you can.

Appreciate the furrowed bark of ash trees while you can.

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Hope = Hydrilla Guerrillas

hydrilla bumper sticker This is a bumper sticker that a great bunch of students from John A. Holmes High School in Edenton, North Carolina created to help get the message out about a non-native aquatic invasive weed called Hydrilla (Hydrilla  verticillata) that is endangering their local river, the Chowan, and many other lakes, ponds, and slow-moving rivers throughout the southeastern US.

These kids and their Earth Science teacher, Stephen Karl, gave an excellent presentation at the joint annual meeting and symposium of the Southeast Exotic Pest Plant Council and the NC Invasive Plant Council that was held at the NC Botanical Garden on May 26-28. I’ll be writing more about the many great presentations I heard over the coming weeks. However, because the topic of non-native invasive species in the southeastern US is not a happy one, I feel obliged to intersperse what I learned with more upbeat posts about my garden.

The objective of this high school project was “to raise awareness by posting videos, posters, brochures, and digital boat ramp signs. ” They are also placing compost barrels at boat ramps along with rakes they’ve re-shaped to fit easily around boat propellers. Their aim is to persuade boaters to rake out the hydrilla from the bottom of their boats when they take them out of the water, and compost the hydrilla in the barrels provided. Hydrilla is mostly spread by boats when they move from contaminated waters to uncontaminated ones.

These are good, relatively simple ideas, and the project made them a finalist in the 2015 Emerging Issues High School Prize for Innovation sponsored by NC State University’s Institute for Emerging Issues. The bumper sticker they printed sports the name they gave themselves: Hydrilla Guerrillas — such a great name!

Theirs was not the smoothest presentation I saw that week. Many of the kids were visibly terrified, even though they had rehearsed their talk. Every student got a chance to speak. At first, they were pretty wooden, standing stiffly at the front of the room, but as they got into their talk, their enthusiasm for the project overpowered their shyness. These kids were passionate about stopping the invader in their home river.

I confess I actually felt hope for the future when these kids started talking about their project. I still am hopeful, mostly, but that hope is tempered by the conclusions of the students themselves. First, they were disheartened to discover that almost no boaters or other local adults they talked to had heard of hydrilla or knew it was a problem.

Second, they’re not confident that their message will have any lasting impact, although I think they certainly tried everything they could think of that was within their budgetary constraints. Third, they’re not convinced that people will change their behaviors. Cleaning boats of hydrilla when they are removed from the water takes time; most folks don’t want to spend that time on something high school kids are telling them about. In fact, the kids expect the special rakes they’ve created to be stolen from the boat ramps. Despite their evident teenage passion, their faith in their ability to change adult behavior is not strong. Frankly, I don’t blame them.

Even so, my take-home feeling for this presentation was one of hope. Mr. Karl, the Earth Science teacher, got his kids energized and focused on a critical problem that will adversely impact their future and the future of their children. I’m hopeful that they will hold on to their enthusiasm and concern as they become adults, so they can teach their children and grandchildren to be better caretakers of Planet Earth than the adults whose behavior they are trying to change.

In their matching T-shirts, the Hydrilla Guerrillas pose for a shot on the grounds of the NC Botanical Garden.

In their matching T-shirts, the Hydrilla Guerrillas pose for a shot on the grounds of the NC Botanical Garden (photo by NCBG staff).

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Need help getting rid of invasive plants in your yard?

Do you hate seeing this:

2-wisteria forest

and this:

English Ivy strangling a Dogwood

and this:

Japanese Honeysuckle thicket in a woodland

and this:

Dead during winter months, Microstegium vimineum (Japanese Stiltgrass) still overpowers a native holly along a creek

as much as I do? Experts battling these and other non-native invasive plants meet once a year in North Carolina to share information on the most effective eradication and management techniques. They are a good bunch of folks — native-loving plant nerds, if you will — who are passionately working to preserve the health of our dwindling native ecosystems by eliminating/controlling non-native invasive plants.

This year, the North Carolina Invasive Plant Council (NC-IPC) is hosting the annual regional meeting of its parent organization, the Southeast Exotic Pest Plant Council (SE-EPPC) at the North Carolina Botanical Garden in Chapel Hill on May 26-28. Interested citizens are encouraged to attend — no degrees in botany required!

I’m looking forward to a number of presentations, especially including one from Edenton (NC) High School students and their teacher on their study of Hydrilla in their area. This highly invasive non-native plant is rapidly choking our streams, ponds, and lakes to the point of making them unnavigable by boats, and unhealthy for the natives that live in those waters. It lifts my heart to know that young people care about the future of their backyards — and their planet!

Early registration ends this Friday, May 15, so visit this page to register today if you’re interested.

I hope I’ll see you there!

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For Arbor Day: Plant the Right Tree

Northern Red Oak Tree Top

Northern Red Oak Tree Top

I’ve never paid much attention to Arbor Day until this year. I knew it was a day to celebrate trees and to encourage people to plant them. I knew I routinely get mail from the Arbor Day Foundation offering me “ten free trees” as a reward for becoming a member. And that was all I knew. So I did a little research.

Chionanthus virginicus

Fringe tree: Chionanthus virginicus

Most states observe Arbor Day on the last Friday in April. Some southern states designate their celebration in January or February — better times to plant trees in the deep South. Some more northern states observe the holiday in late May for the same reason. In the United States, Arbor Day started with an early settler of the Nebraska Territory, J. Sterling Morton.  In 1872, when he created Arbor Day, Nebraska’s lands were being transformed from healthy prairies to farmlands. Native prairie ecosystems are relatively dry, soils are rich, and naturally occurring fires maintain the balance of species that comprise healthy prairie.

Purple Coneflowers are native to prairie habitats.

Purple Coneflowers are native to prairie habitats.

But when you plow up prairie to create farmland, soil erosion becomes a big problem. Those wide open spaces make it easy for strong winds to pick up huge masses of soil and blow them far away. Hard rains exacerbate erosion. Mr. Morton’s solution was to plant trees around fields to serve as wind breaks. He planted more trees to provide building materials and fuel, and to create shady spots during hot Nebraska summers. Morton grew into a prominent citizen over the years. He persuaded a lot of people to plant a lot of trees. Here’s a fact I didn’t know until yesterday: the Nebraska National Forest — all 141,864 acres of it — was entirely and deliberately planted by citizens of Nebraska. If you ever doubted that humankind can transform the Earth’s ecosystems, look no farther than the Nebraska National Forest — once prairie, now trees.

Native fall color left to right: American Beech, Musclewood, and Sourwood

Native fall color left to right: American Beech, Musclewood, and Sourwood

I spent several hours on the Web site of the Arbor Day Foundation. This nonprofit sponsors a number of great programs. They help cities and college campuses promote and grow trees in their locations, they help people all over the world plant trees to improve their lives, they sponsor nature camps for children who otherwise see very little of the natural world, and they help replant our national forests after forest fires. In these cases, they appear to partner with local experts, for example, the National Forest Service partnered with them to replant fire-devastated forests.

Native Flowering Dogwood (Cornus florida)

Native Flowering Dogwood (Cornus florida)

But when the Arbor Day Foundation (ADF) sells trees to US citizens via their Web site, I think they are creating more problems than they are solving. Why? Because from what I saw — and I looked pretty thoroughly — the ADF makes no distinction between native and non-native trees in their offerings. Further, the “Tree Wizard” tool they provide to help folks figure out what kind of tree they should buy is inadequate. And finally, they do not reveal where they get the enormously diverse array of trees —  many not native to North America — that they offer for sale. This last bit is important, because the same species grown in a nursery in Wisconsin is much less likely to thrive in South Carolina. Even within a species, genetic diversity exists, and the genes selected for in a Wisconsin-grown tree are almost certainly not optimal for South Carolina growing conditions.

Where your Redbud was selected and propagated affects how it fare in your yard.

Where your Redbud was selected and propagated affects how it fares in your yard.

I worked through the Tree Wizard to see what trees it would recommend for my area. After it determines your hardiness zone, it asks what sort of tree you want. Your choices are: evergreen shrubs, flowering trees, ornamental trees, shade trees, evergreens, fruit trees, nut trees, and shrubs. Note that selecting only native plants is not offered as an option. I selected flowering, shade, and nut trees. Under “growing conditions,” the tool gives the following soil type options: all types, acidic, alkaline, drought tolerant, loamy, moist, rich, sandy, silty loam, well drained, wet, wide range, and clay. If you know anything about soil science, you know that not all of those choices are standard soil type options. What the heck is a drought-tolerant soil, for example? You can only pick one type here; I picked loamy. “Sun exposure” choices were all, full sun, partial shade, and full shade. Of course, any gardener with experience knows that in the southeastern US at least, the direction from which the sun exposure comes can be more important than the amount of sun. Some delicate understory native trees prefer morning sun and afternoon shade, for example. I picked full sun. The Tree Wizard next asks you to specify how tall and wide a tree you want, and what rate of growth you want. I picked all heights and all spreads, and all growth rates.

Southern Magnolia

Southern Magnolia

The Tree Wizard displayed 11 pages of results. Its top choices based on my input were: White, Pink, or Red Dogwood, Redbud, Washington Hawthorn, Japanese Flowering Cherry, Kousa Dogwood, Saucer Magnolia, and Southern Magnolia. Most of these are actually native to North America, but the Tree Wizard doesn’t tell you that. Additionally, if you want a dogwood or a redbud to thrive in my region, you should never plant it where it receives full sun all day.

A thirty-foot tall kousa dogwood thrives in the shelter of our backyard, where the house shades it from searing afternoon summer sun.

A thirty-foot tall kousa dogwood thrives in the shelter of our backyard, where the house shades it from searing afternoon summer sun.

Species names of the tree options are provided, which is interesting in itself. For example, both the Pink and Red Dogwood options are listed as Cornus florida var. rubra. I guess we’re just supposed to trust them regarding which color they send us. They appear to offer only species, no cultivars. For example, the Southern Magnolia they offer is described as likely to mature to between 60-80 feet, which is what the species does in its native environment. Spicebush ST on milkweed Frankly, I am disappointed in the Arbor Day Foundation. Clearly, they do a lot of good things, but when they aren’t partnering with local experts, they appear to blindly follow standard horticulture industry practices for selecting plants. Given the critical issues our native forests face, this is not good enough, especially for an organization that promotes itself as environmentally friendly. As it stands now, this organization — along with most of the horticulture industry in the United States — is actively encouraging plant blindness. They want you to believe that a tree is a tree is a tree. This is dangerously wrong. But the horticulture industry will not change unless its customers demand it from them. This is what I ask all of you who care about the future of our native ecosystems to do when you visit your local nursery, garden department, mail-order nursery, etc.:

  • If the plant’s description does not tell you it is native to your region, ask the sellers its origin and why that information is not on the label. If they don’t know, tell them you’re not buying the plant — at least until you’ve had time to research it yourself. I’m not saying you must only buy native plants, but you do need to know an unfamiliar plant’s origins before you consider adding it to your landscape.
A non-native annual zinnia attracts pollinators without adversely impacting the health of your yard's ecosystem.

A non-native annual zinnia attracts pollinators without adversely impacting the health of your yard’s ecosystem.

  • Know which species are considered to be invasive non-natives in your region. When you see them offered in your local nursery (and you will), ask the sellers why they offer plants known to be damaging to the local environment. Tell them you won’t ever buy such plants, and that you’ll be patronizing establishments that don’t sell such plants.
Native Joe Pye Weed attracts more diverse pollinators in my yard.

Native Joe Pye Weed attracts more diverse pollinators in my yard.

  • If sellers cannot tell you more than what the label on the plant says, find another nursery where the staff is more knowledgeable. Unless the horticulture industry loses sales from promoting the notion that plants are interchangeable regardless of origin, they will not change.
  • Work with plant sellers who grasp the concept of your yard as an ecosystem. If they can tell you which plants will work together to look beautiful and support native wildlife, patronize their businesses. Your yard is not your living room. Don’t pick plants as you might accessorize a room. Every plant in your yard is a vital, dynamic life form that interacts with every other life form on your property. Make your choices based on how the seasonal dance of life and color will look over time, not on the color of a flower today.
Native Plumleaf azalea blooms in mid-summer, providing a native source of food for local hummingbirds.

Native Plumleaf azalea blooms in mid-summer, providing a native source of food for local hummingbirds.

  • Stop subscribing to gardening magazines that promote plant blindness and tell them why you’re stopping. “Gardens as rooms” is a decorator’s notion, and not relevant to the construction of vibrant ecosystems that we need to be creating to protect our planet’s future. Beauty can also be healthy, but health cannot be achieved via plant-blind choices.

I am happy to acknowledge that the Arbor Day Foundation is doing much good for the environment. Their failing is the failing of much of the horticulture industry. Its promotion of plant blindness — plants as completely interchangeable entities — must be stopped. Only we gardeners — this industry’s target market — can effect this change by directing our dollars to those businesses that  promote awareness of this increasingly critical issue. In my area, I can think of several wonderful locally owned plant nurseries that actively promote native plant gardening and ecosystem-appropriate designs. I can also think of several with inventories full of fancy non-native plants with unknown invasive potential, plants that must be coddled to thrive here, plants that don’t belong here.

Food gardens are easily integrated into a healthy small landscape.

Food gardens are easily integrated into a healthy landscape.

When you visit local nurseries, ask the hard questions. If you don’t get the right answers, tell them why you won’t be patronizing their establishments again. If we walk the talk, the horticulture industry will follow. Let’s get moving! Happy Arbor Day, ya’ll. And I promise to write about my gardens for the foreseeable future. 🙂

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Dear Santa

magnolia cones

It’s been quite a while since I’ve written, and I know that you’re already busy flying around the world spreading your Christmas cheer, but I’m hoping because you’re omniscient and omnipresent that you might still consider my requests.

I’m not asking for any traditional gifts. I’m blessed with all that I really need. And, as I grow older, I’m finding more and more that the acquisition of additional things is just not what I care about.

 

As you know, since you know everything, I love the natural world. I’m sure that you and Mother Earth converse, but perhaps she hasn’t shared with you how challenging humans are making her job. While most every human knows about you and what you stand for, a depressing number – to me, anyway – of humans have forgotten all about Mother Earth.

This looks "normal" to the Plant Blind.

This looks “normal” to the Plant Blind.

In the US, where I live, a disturbing number of humans have developed Plant Blindness. They are no longer able to see plants as individual entities and species; it’s all just an interchangeable green blur to them, irrelevant – they think – to their lives. I’m hoping – if you’ve got any extra Christmas mojo at all – that you will consider zapping the Plant Blind with so much Christmas light that they’ll start appreciating the natural world surrounding them. And please do it today, before the native landscape becomes irretrievable. I know that’s a mighty big request, but I’m very worried, Santa. I’d be grateful for anything you can do.

CORA garden and Carol

While I’ve got your ear, I’ve a couple more favors to ask. I’m also worried about the hungry, Santa. Here in the US, we’re not doing a good job of feeding them. They especially need fresh fruits and vegetables, and community gardens are springing up around the country with the goal of providing these critical foods to hungry folks. But those gardens could use your help. Could you perhaps drop off some supplies – seeds, fertilizers, mulch, tools – anything like that lingering down in the bottom of that big sack you carry? And elves. Those gardens can use all the elves you can spare. It might be nice to send them to warmer climes for a bit, where they can help cultivate and nurture these critical food gardens.

Florida Flame Azalea at the NC Botanical Garden in Chapel Hill

Florida Flame Azalea at the NC Botanical Garden in Chapel Hill

All the wonderful nonprofit organizations dedicated to helping Mother Earth are also hurting these days, Santa. Humans aren’t donating to these essential groups the way they once did. Please consider using your Christmas mojo to direct critical grant funds to their budgets, and maybe if you can help the Plant Blind see, they’ll open their wallets to help out too.

Thanks, Santa.

Thanks, Santa.

I know, Santa, that as you fly around the world today and tonight, you are seeing great need everywhere. The pleas for help, I’m sure, are deafening. But somehow through the noise, I know you hear every request, so I’m hoping you’ll hear this one.

Thanks for listening, Santa.

Merry Christmas. And to all — Happy Gardening!

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In the blink of an eye…

One minute, summer sun kisses green leaves, flowers abound, birds sing. Then you blink, and color happens.

Cornus florida displays peak autumn color.

Cornus florida displays peak autumn color.

For some plants, color comes in patches at first.

Like this native Spicebush, Lindera benzoin.

Like this native Spicebush, Lindera benzoin.

Or this ornamental spirea:

Spirea 'Magic Carpet'

Spirea ‘Magic Carpet’

Fall fruits droop heavy on branches, then tumble to earth.

Chinese dogwood (Cornus kousa) fruits make it impossible to walk without squishing them.

Chinese dogwood (Cornus kousa) fruits make it impossible to walk without squishing them.

Deciduous hollies haven't released their leaves yet, so bright berries look like Christmas balls among the greenery.

Deciduous hollies haven’t released their leaves yet, so bright berries look like Christmas balls among the greenery.

Native Redbud (Cercis canadensis) seed pods rattle in autumn winds.

Native Redbud (Cercis canadensis) seed pods rattle in autumn winds.

Red Buckeye (Aesculus pavia) seed pods  crack open and release shiny fruits.

Red Buckeye (Aesculus pavia) seed pods crack open and release shiny fruits.

The native Black Walnut (Juglans nigra) has finally dropped all its nuts. For a few weeks, walking beneath it required a hard hat.

Now the walnuts are a hazard to unwary walkers.

Now the walnuts are a hazard to unwary walkers.

This past Tuesday, a strong cold front approached. Thick clouds darkened the sky, winds blew in gusts, twirling falling leaves into eddies of gold and red. Later that day, the rains came — almost two inches.  The trees that always abandon their leaves first took the winds, rain, and ensuing cold air as their cue.

The first native trees to bare their branches for winter in my yard are always the Ashes. Ash trees dominate the active portion of our floodplain — about an acre or so. I think they’re probably Green Ashes (Fraxinus pennsylvanica), but local experts tell me this species often interbreeds with other native Ash species, so I’m not certain.

Their fall color is subtle, but they do cast a distinctive yellow-green glow over the canopy just before they discard their summer clothes.

A floodplain Ash before the rains stripped it of color.

A floodplain Ash before the rains stripped it of color.

Ashes are not the first trees most folks notice when walking through their native moist habitats, but they are key components. Their numerous seeds are devoured by many bird species, including Wood Ducks.  The larvae of several of our more colorful southeastern US butterflies eat Ash leaves, including the Eastern Tiger Swallowtail, Orange Sulfur, and one of my favorites, Mourning Cloak. This beauty has dark wings edged in deep gold; I count myself lucky when I spot one or two floating through my floodplain, usually on warm late-winter days, when the over-wintered adults begin seeking mates.

Ashes are easy to identify. They have compound leaves. Botanists define a compound leaf as consisting of a set of leaflets. For example, Poison Ivy has a compound leaf. Those “leaves of three” we all look for actually comprise one leaf. Look for a longer leaf stem (a petiole) that attaches the multi-leaflet leaf to a branch.

Click on this image to clearly see these Ash leaves comprised of leaflets.

Click on this image to clearly see these Ash leaves comprised of leaflets.

A casual observer might confuse the compound leaves of Ash trees with those of another Piedmont forest regular — Hickory, but a closer look is all you need to tell the difference. Ash leaves are attached to branches directly opposite each other. This opposite-leaved arrangement is less common in our native trees and shrubs. A single-leaved tree with opposite leaves that we all know is our native Dogwood. Hickory leaves alternate on the branch, plus most have fewer leaflets per leaf than Ash leaves.

After the rains blasted through, the next day, most of the Ashes on my floodplain were bare. In the blink of an eye, their subtle color was gone.

Bare Ash branches contrast with the remaining still mostly green canopy of other species.

Bare Ash branches contrast with the remaining still mostly green canopy of other species.

This year as the Ashes performed their vanishing act, I got a knot in my stomach. I couldn’t help but wonder if this will be the last year I am able to enjoy their subtle drama. Why?

The Emerald Ash Borer, a non-native, devastating tiny insect, has a confirmed presence in a few NC Piedmont counties just north of mine. This insect has already killed every native Ash tree in many of our northern states. Every single one. They do it in one year. Experts have no idea how to stop them. Here’s the latest information from the NC Forest Service on this Ash-killing bug. Follow the links on that site to learn more.

A key take-away message about preventing the spread of Emerald Ash Borer and several other devastating non-native insects is about firewood. It is critical that any firewood you buy be from local, uninfected trees. Unfortunately, the firewood industry is not closely regulated. Recently dead trees look like a prime source of money to firewood purveyors. More than half the states in the US, including all of the Southeast, have imposed some firewood movement restrictions. Click on your state on this map to see what restrictions apply for you.

Ignorance is our greatest enemy in the fight to save our Ash trees. If you buy firewood, I urge you to learn what counties in your state are still considered safe sources of uncontaminated firewood. Be wary of pre-packaged firewood sitting outside grocery and hardware stores. Odds are it was shipped in from somewhere else. Ask the store manager where the firewood came from, and if he or she doesn’t know, tell them why you won’t be buying from them.

In my area during every impending cold spell, I’ll see folks selling pick-up trucks full of firewood in parking lots. Firewood sales are a supplemental source of income for most of these folks; many of them probably have no knowledge of the restrictions on where they should be collecting their firewood. In North Carolina, no one should be buying or selling firewood from Granville, Vance, or Person counties outside the boundaries of these counties. They are quarantined due to the confirmed presence of the Emerald Ash Borer. Here are the areas in the US with currently imposed Emerald Ash Borer quarantines.

Unless the experts devise a way to kill this insect in the next few months, it is just a matter of a year, perhaps two, before every Ash tree on my property — about a dozen 75-foot trees — will be dead. Their absence in the landscape will be visible to even the most casual observer. What will be less obvious is the disruption in the Piedmont ecosystem where these trees occur. Birds and insects that evolved to rely on Ash trees as a food source will go hungry. If they cannot adapt to other food sources, they will die trying to find Ash trees elsewhere.

No one knows how many components of an ecosystem can disappear before the viability of the entire ecosystem is destroyed, so that the remaining components die. Think of it as an ecosystem-scale game of Jenga. Sooner or later, the wrong piece is removed, and the entire structure fails.

In the blink of an eye, our native Ashes may disappear. How many more blinks before our native forests are gone too?

 

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Forest Envy

A native Wax Myrtle pruned into tree form.

A native Wax Myrtle pruned into tree form at my friend’s new home.

A good friend of mine and her significant other recently purchased and moved into a lovely new home in an adjacent county. They invited me out earlier this week to help them understand what’s growing on their 3-acre patch of Piedmont. I confess, I was a bit envious.

Their home backs onto state park land that protects a scenic river. This land has been covered in Piedmont forest for probably about 100 years now. Most likely before that it was farms and forests, and the forests were certainly regularly logged. That’s pretty much the story of land use for all of the southeastern Piedmont.

Unlike my home, which is on an increasingly busy road (a country by-way when we first moved here), theirs is quite a ways from the nearest main thoroughfare, accessed via a maze of well-established roads filled with nothing but mostly older houses. Frequent speed bumps likely discourage any non-residents from using these roads.

The result? My friend’s new home environment is noticeably quieter than mine. And the vegetation growing on her land and the adjoining protected forest made me long for my childhood days, when all the forests around here looked like that one — mostly anyway.

Her home sits atop a Piedmont ridge. Steep slopes on two sides fall down toward intermittent drainage ways that feed the river below. Large white oaks dominate the landscape; this year’s crop of acorns littered the ground. Mixed among the oaks were tulip poplars, red maples, sweet gums, sourwoods, dogwoods, redbuds, elms, viburnums, and a few mature loblolly pines — in short, all the native species I expect in such an environment.

But in addition to this mix of obviously healthy native plants, what struck me most was what wasn’t there: invasive non-native plants. I only saw two species, and both are likely still controllable if my friends take aggressive action immediately: Japanese Stiltgrass, and Privet.

Evergreen invading privet is easy to spot in the winter landscape.

Evergreen invading privet is easy to spot in the winter landscape.

Just for comparison, in my five-acre yard, I’m fighting those two species and:

We started battling a new invader this year: Oriental Bittersweet. As is true of most of our most pernicious invaders, this non-native vine was planted in the southeastern US for the ornamental value of its abundant, colorful berries. Alas, these berries are beloved by birds. They have “deposited” the seeds all over our southeastern forests. I was horrified when I visited the North Carolina mountains a year or so ago and discovered this invasive vine was snarling vast acreages of once lovely mountain forest.

Elaeagnus flowers will soon morph into berries beloved by birds.

Elaeagnus flowers will soon morph into berries beloved by birds.

This evil vine established a beachhead on my property beneath a native dogwood adjacent to my busy road. This mature dogwood produces abundant crimson berries every autumn, and I am certain that birds dining on the dogwood berries excreted the Oriental Bittersweet seeds that took root beneath the tree. It disguised itself among a bed of poison ivy that I was ignoring, which is how it became well-established.  Wonder Spouse sprayed it with herbicide last spring, which knocked it back considerably. But it’s still there, biding its time until I forget about it. But I am determined that this latest invader will not gain permanent residence on our land.

English Ivy Overpowering a Dogwood

English Ivy Overpowering a Dogwood

I’m also watching for what is likely the inevitable incursion of kudzu. It dominates the property directly across the street from me. It would have crossed the road to my land years ago if the state didn’t mow it off the road every growing season. I can feel it plotting its invasion, perhaps via the drainage pipes beneath the bridge on my road that permits access for the creek that adjoins our  property.

I know I’m not the only Piedmont homeowner battling invasive non-native plants. My blog has recently been visited by a number of viewers searching for information on controlling invasive plants. I have reluctantly concluded that unless your invader is just establishing itself in your yard, trying to pull it up manually will not control it. Herbicides seem to be the only option that will work in most cases. In my yard, deer will nibble on English Ivy in the dead of winter, but they never touch the Japanese Stiltgrass. I’ve read that even goats — known for happily devouring ivy, kudzu, and most any other plant in their paths — will not eat Japanese Stiltgrass.

Japanese Stiltgrass is creeping up the slopes of my friend’s new yard, working its way up from the intermittent drainage way below. That’s its favorite mode of transportation — water, which is why my floodplain is so plagued by it. I’ve resisted herbicides for fear of what they will do to my abundant frogs and salamanders, and the few fish still inhabiting my creek. But the literature states that the key is to use herbicides that do not contain an ingredient called a surfactant, because this is what causes the poison to stick to wildlife and hurt it. This link suggests herbicides that will kill this grass and are supposed to be safe in wetlands.

Wonder Spouse and I are planning on trying this weapon against our increasing infestation of Japanese Stiltgrass. I felt better about trying this weapon after talking with the curator of the Habitat Gardens at the NC Botanical Garden. She told me that she’s using it in her yard to battle this invader. She said the secret is to apply the herbicide consistently for five years — the amount of time the seeds of this grass remain viable in the soil.

I hate using herbicides, but there is no way Wonder Spouse and I can manually remove the invaders fast enough to prevent their spread on my land. I’m going to encourage my friend to begin using them now to prevent her from having my kind of problems. Right now, her land — the property that afflicted me with temporary forest envy — is about 20 years behind mine in invasive plant incursions. It’s been protected by the large stretch of contiguous forest it adjoins and its distance from major roads. But they must remove all the privet hedges planted by the previous owner immediately. And they must start applying wetland-safe herbicides to their Japanese Stiltgrass now — before their yard starts looking like mine.

For those of you wondering why I am so passionate on this issue, I refer you to my previous posts on this topic here and here and here. I truly believe that this is a battle we cannot afford to lose, folks.

Winter-killed Japanese Stiltgrass smothering a native holly along my creek.

Winter-killed Japanese Stiltgrass smothering a native holly along my creek.

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