Crossing the Line: When Plants Become Invasive

Athyrium nipponicum ‘Pictum’ grows with English ivy. Ivy is considered a highly invasive plant.

There is a long history of botanists and horticulturalists traveling around the world in search of new, beautiful and useful species of plants.  It is an essential part of our nation’s history to both send native American species to Europe, and to seek out and grow imported species here. 

You’ll hear wonderful stories of early colonists risking their lives and freedom to bring back some rice, or a tea shrub, or some other potentially productive and lucrative plant encountered on their travels, to put into production here in the ‘New World.’  Tony Avent of Plant Delights near Raleigh is one of many contemporary horticulturalists still importing new plants from elsewhere.

One of the trees imported from Asia was the white mulberry tree, Morus alba.  They were supposed to form the beginnings of a silk industry here in Virginia.  Sadly, the silkworm industry never took off in Virginia.  Worse, the white mulberry became an invasive species, even hybridizing with our native red mulberry.  But who knew that would happen in the Eighteenth Century?

Another Asian tree imported during the Colonial era, to potentially support silkworms, is the paper mulberry, Broussonetia papyrifera, formerly known as Morus papyrifera.  You may have noticed these odd-looking trees lining Francis Street near the Colonial Capitol building.  They are not considered invasive, but the silkworms didn’t care for them.  In China, they were used in the production of early paper products.

It may take only a few decades for a wonderful new plant introduction to cause enough problems in its new environment to find itself reclassified as an invasive nuisance plant. The very qualities that make a new introduction exciting and marketable may also make it harmful to its new ecosystem.

Read more and see more photos of Virginia’s invasive plants on Our Forest Garden. All new posts now go to the new website. Have you followed it, yet?

See Virginia’s Invasive Plant List

Six on Saturday: With Patience and Flexibility….

Turneric in bloom with elephant ears

It’s finally raining. Cool, soft rain has been falling for several hours now with more on the way. It is such a relief, because I’ve been pulling hoses and carrying full buckets of water nearly every day for the past several weeks to keep the pots and certain parts of the gardens watered. It has been hot and muggy, which has encouraged all of the flowers and elephant ears to push out new flowers and growth and stay beautiful longer than usual; so long as they can stay hydrated. Otherwise, we have drooping stems and crispy leaves.

I’ve been doing July chores in October.  And even as we admire the lushness, my thoughts have already turned to changing out plants for the winter, planting bulbs and cutting back. 

I dug out the first Caladiums and Callas this week, laying the bulbs in a cardboard flat to dry.  I replaced the Caladiums with soft pink snapdragons to bloom on into the winter and again in earliest spring.  Trays of ferns and herbs are marshalled, ready to begin new lives in pots as soon as I lift out the summer tenants.

And here into the second week of October I’m still waiting to find that particular variety of Panola that blends pink and burgundy and softest yellow in each ruffled blossom.   My planting visions are filled with this warm palette of color to brighten winter pots. 

Climate confusion affects us all.  Butterflies linger a bit longer.  Trees remain green well into ‘autumn.’ It is still too warm to plant most of the winter ornamentals that usually fill nurseries and garden centers in October.  Gardening trains us in patience and flexibility.  And appreciation for even the smallest bit of beauty.

Read more and see four more photos on my newer website, Our Forest Garden

Four Season Container Gardens

This ‘Four-Season’ container garden grows at the Williamsburg Botanical Garden. It is lush with ferns and Caladiums in late September 2021.

Do you have pots that stand empty for weeks out of the year?  In northern climates, gardeners often empty and clean their pots in winter.  Since unglazed ceramic pots absorb water and sometimes crack in freezing temperatures, this makes sense.  But how empty things must look once summer’s beautiful pots go into storage.

Fourth Dimensional Gardening

Gardeners work in four dimensions. Of course we consider how tall a plant will grow and how deep its roots will go. Every plant grows to a certain width and depth to fill the space around it. But we also work in a fourth dimension: time. Each plant appears, grows, and fades according to its own schedule. We can use this to our advantage, planning for various plants to appear in their season, dovetailing to create a series of beautiful compositions during each gardening year.

Our coastal Virginia remains mild enough to enjoy our pots throughout the year.  With a little planning, a gardener can have a beautiful display, and maybe even something in bloom, every week of the year.  Once you have the right sort of pot positioned in a sheltered spot, your horticultural imagination is free to experiment with a range of beautiful plants.

Read more of this post on Our Forest Garden, which is my new website. Please follow me there to see all new posts.

Six on Saturday: Gifts

These windmill palms made it from California to Virginia in perfect shape, thanks to Tony Tomeo.

Gifts are always fun.  Gardening gifts are the best, and gifts of plants always warm my heart.  A living plant is a gift from the heart, and it creates a special bond between giver and receiver as the plant grows on and develops into its potential.

That said, sometimes those gifted plant can get too enthusiastic and create work down the road.  But when that happens, I try to dig up those I can’t use and share them with someone else.  I love trying new plants I’ve not grown before.   Most gardeners I know love expanding their gardening experience by growing out new types of plants.

When California Horticulturalist, Tony Tomeo, who I’ve been corresponding with for the last several years through our respective blogs, offered to send me some windmill palms, Trachycarpus fortunei, I immediately accepted his kind offer.  He told me these were babies, and he assured me that they should grow OK here in coastal Virginia. 

I’ve not grown palms before.  What a wonderful opportunity to learn something new!  I know that they will do well on my sheltered front patio.  Since these are slow growing, I can keep them in pots on the patio for the time being, to watch them grow.  Once they settle in and grow more roots, I expect to transplant two of these beautiful palms into large pots on either side of my front porch.

Read more on Our Forest Garden

Six on Saturday:  For the Birds

Our upper garden at the end of September is a haven for wildlife

A cold front this week blessed us with cooler temperatures and lower humidity.  The oppressive summer air was blown out to sea, and what followed feels crisp and clean.  I can see a few scarlet leaves and scarlet dogwood berries in the trees near my window, a sure sign that the season has turned, and the equinox is behind us now.

Each day will be minutes shorter now.  Mornings come later, but the cool comfortable hours for gardening last deep into the afternoon.  I’m drawn out again and again to tweak this or that and to capture a few photos.  Colors have grown bright and intense after days of rain and real relief from summer’s heat.

Even as the wheel of the year turns towards winter, we enjoy the culmination of a fruitful summer.  Beautyberries glow purple, inviting the many birds filling our garden to feast on them and spread their seeds.  Goldfinches fly up from stands of Rudbeckia to safer perches in the trees at our approach.  We find partially eaten hickory nuts and exploded beech nut hulls on the driveway, dropped by birds and squirrels.

It is a season of abundance for all the wild creatures our garden supports.  Nectar rich flowers open daily, pushing against one another in their expansive growth.  It is hard to walk through the upper garden now.  The paths have filled with fallen stems, and I rarely cut back some faded something to make the way easier for our passage.

Read more, here…. on my new website, Our Forest Garden, which is a continuation of A Forest Garden. I hope you will follow the new site so you don’t miss any new posts.

Six on Saturday: Early Autumn Beauty

Dark form female Eastern Tiger Swallowtail butterfly nectars on butterfly bush

… While the calendar may promise cooling temperatures, we continue baking in the late summer heat and high humidity here in coastal Virginia.   The plants are tired.  We find freshly fallen leaves each day now, and the dogwood trees have already begun to turn towards their scarlet finale.    Spiderwebs shimmer across pathways and openings as the zipper spiders grow fat and shiny.  There are plenty of smaller prey for them to feast on, still.

So many leaves on trees and perennials grow ratty in September as insects eat holes in them and dry days leave them with crispy edges.  Perhaps that is why the elephant ears stand out so beautifully in these closing weeks of the growing season…

See today’s photos and read more on Our Forest Garden, which is a continuation of A Forest Garden. I hope you will follow the new site so you don’t miss any new posts.

Unraveling the Mystery of Growing Ferns from Spore

Baby ferns, growing from spores, have begun to colonize this pot.

Fern reproduction remains a bit of a mystery to me.  A mystery that borders on the ‘magical’ when tiny ferns appear growing out of the mosses along the paths of our back garden.  This two-step sexual reproduction appeared on Earth untold millions of years ago, allowing the first plants to recombine their genetic materials to produce new generations of some algae, mosses, liverworts, and finally ferns, the earliest vascular plants.

Most of our familiar plants produce seeds after fertilization of their flowers or cones with pollen.  The pollen may be carried from one plant to another by a pollinating insect or other animal, or by the wind.  Ferns, and other simple plants, don’t produce seeds.  The microscopic activities of their spores are all but invisible to our eye.  So, I am curious, and am studying others’ successes with fern propagation so I might learn to propagate my favorite ferns, too.

I have been studying the Hardy Fern Foundations Spring 1998 Special Publication on Fern Propagation where a dozen experienced growers describe their methods for propagating ferns.  Their essays explain reproduction from spore, and they also describe their own methods for collecting and sowing spore to successfully raise a crop of ferns.

Ferns have successfully propagated themselves in nature, with no human assistance, for millennia.  So it shouldn’t be too complicated, right?  These very knowledgeable writers describe strategies that lead to success, and also explain how inattention to detail can lead to failure.

My first successes in growing baby ferns from spore were entirely accidental.  Spore from potted ferns on my deck fell onto potting soil that I sealed up in a zip-lock bag for the winter while I waited for some seeds I’d sown in that shallow container of potting soil to germinate.  At first, I thought a nice crop of moss was growing on the soil.  As I kept checking the container every few weeks this spring, I was amazed and delighted to recognize tiny ferns growing from the green structures on the soil I had thought would become mosses.

Read more here on my new website, Our Forest Garden, which is a continuation of A Forest Garden. I hope you will follow the new site so you don’t miss any new posts.

Six on Saturday: Companions

Ferns grow with Ajuga reptans ‘Black Scallop,’ Vinca, Arum and Hellebores

Have you ever noticed how some gardeners want to show off their mulch? Every plant or species group is carefully set far enough apart from the next to grow neatly, like little islands, in a sea of brown mulch. These curated clumps of vegetation may be arranged into an arc or grid or another clever scheme.

If shrubs, they are neatly sheared often enough to keep them in their intended shape. And the whole scene is surrounded by a sharp bordered sea of fresh mulch to demarcate the planting space.

I see these neatly manicured beds at the entrances to shopping centers and upscale neighborhoods, always anchored by a few rounded, evergreen shrubs.  The color plants usually get switched out seasonally, with a few dozen little Begonias planted in April or May, replacing the ornamental cabbages and pansies planted last October.  Once the cabbages flower, they look weedy, and are goners. 

Of course, one must weed to keep it in shape.   Seeds blow in from everywhere, so one must weed by hand, or spray periodically with an herbicide, to keep things neat. And often the answer is simply piling on more shredded bark mulch over the old, hiding what has faded. Mulch piles creep up the trunks of any larger trees like little brown mountains, beneath their leafy canopies.

This Aristotelian garden style asks us to make a lot of choices.  First, and most importantly, what is a desirable plant, and what is a weed?  What makes one plant desirable, and another not?  The gardener always gets to choose.

Read more at Our Forest Garden

Six on Saturday: Spring in Our ‘Novel’ Garden

When we first moved to this garden nearly 12 years ago, we were delighted to find daffodils blooming our first spring, in a lush mass across a bank in the front yard.  We watched in wonder as their buds opened, revealing their varied forms and colors. 

Our next door neighbors, an English couple, also love daffies and plant a fresh lot of bulbs each fall to add to their springtime display.  Daffodils are heirloom plants, blooming for many decades after they are planted.  They divide each summer and sometimes their seeds are spread around, allowing for natural hybrids and unpredictable spread. Their bright yellows, whites and golds light up our woodlands before the first buds of Forsythia or wild deerberries begin their bloom.

Read more and see more garden photos

Have you visited my new website, Our Forest Garden?

This is a continuation of A Forest Garden, with additional storage space for fresh photos. You’ll also find a library of directories that make it easy for you to find information published here over the past 7 years.

Directories to previous posts on the site include:

On Gardening

Trees and Shrubs

Ferns and Mosses

Green Thumb Tips

Choosing Native Plants

Good Garden Books

Begonias

Caladiums and other Aroids

Herbs

The new site is still a work in progress, and I hope you will visit and have a look at the new format. Please bookmark or follow Our Forest Garden to continue to receive notice of new posts as they are published.

-WG March 2021

Fresh Start 2021: Carbon Garden

October blooming Camellia sasanqua

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Only recently have I come across the term ‘Carbon Garden’ in the current issue of Horticulture Magazine.  You may be ahead of me on this one, but the picture that came to mind when I first saw the term wasn’t very pretty.  The reality of it is much more attractive, and this garden style proves easier to maintain than many other garden styles.

Like other elements, carbon is an atom that can manifest as a solid, in a liquid, or as a gas.  Carbon dioxide (CO2) and carbon monoxide (CO) remain in the news because they contribute so much to our warming environment.  Gasses like carbon dioxide and methane (CH4) trap heat from the sun near the surface of the earth, causing warmer weather and heavier rainfalls.  Conversations around reversing the current warming trends usually focus on reducing carbon emissions and finding ways to scrub carbon out of the air.

Magically, we have living tools for removing carbon from the air right outside our windows.  You see, every green plant cell uses carbon dioxide in its daily efforts to feed itself and sustain the entire plant.  In the presence of sunlight, carbon dioxide and water transform into glucose, used to power plant growth, and the waste product oxygen, which of course we need in every breath.

When you contemplate a leafy tree, imagine each leaf inhaling polluted air and transforming that air into pure food and oxygen.

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Japanese Maple

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Glucose is further transformed into cellulose, which structures the cell wall of every plant cell.  Now, imagine a tree’s roots growing deeper and wider into the earth with each passing year.  What are those roots made from?  Cellulose:  largely, carbon.

A tree, and most any other plant, can stash carbon deep underground where it will remain for many years in solid form.  Many plants also store nitrogen, filtered out of the air, on their roots.  In fact, any plant in the pea family stores little nodules of solid nitrogen along their roots.  Knowing that nitrogen is a major component of fertilizers, you understand how this stored nitrogen increases the fertility of the soil in the area where these plants grow.

Plant leaves are also made primarily of carbon.  When the leaves fall each autumn, they hold stored, solid carbon.  If returned to the soil as compost or mulch, the carbon remains stored, or sequestered, in solid form in the soil.  This is how ordinary garden soil may be transformed into a ‘carbon sink.’

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Turkey tail mushrooms help decompose the stump of a fallen peach tree. Leaving the stump in place and allowing vegetation to cover it conserves its carbon in the soil.

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A log is made largely of stored carbon.  When you burn it in the fireplace, those chemical bonds break down, and much of the carbon rises back into the air as smoke.  If the same log is made into a cutting board or other wooden object, then the carbon remains in sold form.

Just as burning can break chemical bonds to release carbon back into the air, so will decomposition.  We’ve come to understand that bare dirt, including tilled fields and gardens, releases carbon back into the air.  But ground covered by mulch or living plants doesn’t allow that carbon to move back into the air.

All of this helps explain the science behind the principles of Carbon Gardening, whose goal is to scrub as much carbon as possible out of the air and sequester it in the earth.  Forests have done this very efficiently for untold ages.

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Only in recent times, with so much natural forest cleared and land exposed, has our planet begun its dramatic warming.  Think of all the carbon stored over the centuries as coal, petroleum, peat, and held close under a forest canopy that has been released into our atmosphere over the past century.

So, the point of Carbon Gardening is to use one’s own garden to sequester as much carbon as possible, using gardening methods that hold the carbon in the soil, without burning or releasing any more carbon than possible in the process.

Every breath we exhale contains carbon dioxide.  Our cells produce it as they produce energy.  We live in harmony with the plants we grow, taking in the oxygen they exhale while giving them back our own carbon rich breath.  That said, please don’t try to hold your breath as you make your Carbon Garden.

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Camellia sasanqua

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Here are a few principles of Carbon Gardening that may help point you in the right direction. 

The Audubon Society has a series of articles that go into far more detail.

  1. Plant intensely in layers:  The more plants in growth the more carbon will be scrubbed from the air each day.  Trees are most efficient because they support a huge volume of leaves.  Include evergreen trees that continue respiration through the winter months, and plant a shrub layer, perennial layer, and ground covers under the trees to maximize the amount of carbon absorbed by your garden.  Evergreen perennials and ground covers continue absorbing and storing carbon through the winter months.

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  1. Feed carbon (and nitrogen) back into your soil with plant materials. Use wood chips, bark, and shredded leaves as mulch to minimize bare ground.  Remember that roots sequester a large amount of carbon and nitrogen, so leave those roots in the ground.  Cut weeds or spent annuals at ground level instead of pulling them up.  Compost trimmings and leaves, kitchen waste, and unneeded cardboard, newsprint or brown paper.

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This is a very thin layer of compost covering collected branches, bark and leaves from our fallen tree.  We added additional layers of organic material to build the new planting bed.

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  1. Instead of tilling soil and exposing stored carbon, sheet compost in the winter to prepare for spring planting. Cover the garden area with cardboard or paper to protect the soil and smother any weeds.  Build up layers of composable materials, or even bagged municipal compost, and allow it to decompose in place so that planting seeds or transplants in the spring is possible without tilling or excessive digging.  Coffee grounds, tea bags, rinsed eggshells and other kitchen scraps can be ‘buried’ in the layers of a sheet compost pile, but be careful not to discard of seeds in this way unless you want them to sprout in the spring.

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Paper grocery bags covered with several inches of compost smother weeds and soften the ground for this new planting bed, eliminating the need to dig the area up first.  Pea gravel helps hold this area, which is on a slope.

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  1. Remain mindful of garden ‘inputs’ that burn carbon. This includes garden equipment that burns gas, commercial fertilizers, and maybe even those fun trips to the garden center….?

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This bin of new Caladium bulbs was ready to be planted out in mid-May.  Ordering bare root perennials, bulbs, tubers and seeds and starting them at home reduces the carbon footprint of a garden.  The red leaf is C. ‘Burning Heart,’ a 2015 introduction from Classic Caladiums in Avon Park, FL.

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  1. If you normally buy flats of annual plants each spring for pots or borders, consider how to plant those areas more sustainably. Consider all of the carbon releasing ‘inputs’ required to produce those plants, including the plastic containers they are grown in, the transportation to move them, and the chemical fertilizers and peat based potting soil used in growing them.  While all plants sequester carbon from the air, commercial nursery production of short-lived plants releases carbon into the atmosphere throughout the process and should be considered by conscientious gardeners.  What can you raise from seeds, cuttings or divisions, or obtain through trade with gardening friends?

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Saxifraga stolonifera is an evergreen ground cover that is easy to divide and share.  It grows here with Ajuga ‘Black Scallop,’ Hellebores and ferns.

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  1. Choose native perennials or ones that will naturalize in your climate, so your plants spread and reproduce, reducing the number of plants you need to buy each year to fill your garden. Design a sustainable garden that grows lushly with minimal ‘inputs’ and intervention from the gardener.  Native and naturalizing perennials won’t need much watering during dry spells, will make do with nutrients in the soil, and will expand and self-seed.

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  1. Woody plants sequester carbon in their roots and branches and live for many years. These are the most efficient Carbon Garden plants.   A garden made mostly from trees, shrubs, perennial ferns and groundcovers, will work most efficiently.  Some more arid areas have great success with long-lived succulents.  Consider replacing turf grass with plants that don’t require such intense maintenance.

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Mountain Laurel blooms each May, is native to our region and forms dense clumps over time.

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  1. Use the I-Tree Tool to educate yourself about the power of trees in your landscape to sequester and store carbon, reduce run-off and scrub other pollutants out of the air. Use this tool when selecting new trees to plant in your own yard.

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From left: new leaves emerge red on this hybrid crape myrtle, small Acer palmatum leaves emerge red and hold their color into summer, red buckeye, Aesculus pavia is naturalized in our area and volunteers in unlikely places, blooming scarlet each spring. In the distance, dogwood blooms in clouds of white.

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‘Carbon Gardening’ can make a significant contribution to scrubbing carbon out of the atmosphere and sequestering it in the earth, and the total contribution multiplies as the plants grow and the garden develops year to year.  A fully grown native tree can removed fifty or more pounds of carbon from the air annually.  While the amount varies by tree species and size, every year of growth increases the tree’s effectiveness.

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Each gardener who adopts sustainable practices makes a sizeable contribution to off-set and mitigate carbon production in their area.  Planting more plants and allowing them to grow densely also helps manage rainfall so it is stored onsite, rather than running off so rapidly.  The plants sustain wildlife and build a richly integrated ecosystem.

We reduce our own annual costs for new plants, fertilizers, other chemicals and fuel, while also reducing our time invested in garden maintenance.  It is a good approach for any of us who enjoy watching nature weave her tapestry each year, sustainably, while knowing that our gardens are part of the solution to climate warming and climate change.

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Woodland Gnome 2021

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Please visit my other site, Illuminations, for a daily photo of something beautiful and a positive thought.

Our Forest Garden- The Journey Continues

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A new site allows me to continue posting new content since after more than 1700 posts there is no more room on this site.  -WG

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