Invasives Archives - Greenburgh Nature Center

October 27, 2022October 27, 2022 greenburghnaturecenter Around the Grounds, Invasives

Boo!

Ghosts, skeletons, and zombies! It’s Halloween, and our neighborhood is overrun by scary creatures playing trick-or-treat.

But look carefully. The most terrifying monsters in our neighborhood are the ones strangling our trees! Invasive vines are real-life ‘serial killers’ — stealing food, water, and light from trees, and leaving ghosts, skeletons, and zombies behind.

You’ve seen these vines doing their evil deeds. Our roadsides are infested with them. Our woods are being devoured by them. They cause trees to fall onto roads and buildings, costing taxpayers, utilities, highway departments, parks, and private property owners billions of dollars in property damage, clean-up, and removal. Even worse, in forests, meadows, and wetlands, these vines are replacing the native plants essential to maintaining biodiversity –the insects, birds, and animals in our ecosystem.

Three of the most destructive vines in our region are Oriental Bittersweet, Porcelain Berry, and the ever-popular English Ivy.

**Oriental Bittersweet (*Celastrus orbiculatus*)**

**Porcelain Berry (*Ampelopsis glanduosa*)**

**English, Irish, or Persian Ivy (*Hedera spp.*)**

All of these vines belong on other continents. They are invasive here because they have no natural controls in North America and, therefore, are able to aggressively out-compete our native plants.

So, how did they get here?

Gardeners! All of these killer vines were imported and planted here intentionally because gardeners found them attractive. European colonists introduced English Ivy as early as 1727. Oriental Bittersweet was introduced as a garden plant in the 1860’s, and Porcelain Berry was brought to the US from East Asia as an ornamental ground cover in the 1870’s. These plants had no commercial use or food value for humans or animals — they were planted solely for decoration. To be fair, gardeners back then had no idea what horror they were unleashing on the Eastern US. But we can learn from their mistakes.

Oriental Bittersweet is invasive from Maine to North Carolina and west to Wisconsin and Missouri. It is fast-growing and easily overwhelms native vegetation, both on the ground and in the tree canopy. Its enormous vines, up to 4 inches in diameter, can strangle, and even uproot, mature trees and shrubs.

**Oriental Bittersweet vine choking a tree**

Porcelain Berry is invasive from New England to Virginia and west to Wisconsin and Iowa. It is extremely aggressive on roadsides and other disturbed areas, as well as along forest edges. It runs along power lines, and often brings them down in storms. Porcelain Berry kills by completely enclosing shrubs and trees, stealing all available light, until the smothered plant dies.

**A young spruce tree struggles under a mound of Porcelain Berry**

**It’s too late to save these trees and shrubs from Porcelain Berry**

Ivy is a serious problem for us at the Nature Center, and we have warned about its dangers in earlier posts. See Evil Ivy Over Everything here. Where Ivy has escaped gardens in the US, it has destroyed vast areas of woodlands, reducing vibrant and diverse local ecologies to monocultures with no value at all for birds, insects, or forest animals. In suburban landscapes, Ivy causes enormous damage to trees, fences, and wood siding.

So, what have we learned from these gardening mistakes? According to the National Park Service, of the 1200 invasive plant species currently documented in natural areas, almost two-thirds were intentionally imported and planted as ornamental plants. Until recently, all three of these killer vines were still being sold and planted in gardens. In 2015, Oriental Bittersweet and Porcelain Berry finally were recognized as threats to the environment, and legally prohibited for sale and distribution in New York and a number of other states. English Ivy, however, has somehow been given a pass, and is still legally sold in every state except Oregon. Unfortunately, hundreds of other ornamental plant species, already known to be invasive, are still being sold and planted by gardeners all over the US. Legal regulation of invasive plants lags way behind the science.

So, what can we do to help? First, remove and destroy these three killer vines wherever you can, and be sure that the vines and berries go into the trash – not into brush piles or compost where they can easily spread further.

Next, before buying or planting any ornamental plant, do a quick investigation. It’s easy! Enter the name of the plant you’re considering into Google, or another search engine, along with the word “native” to quickly find out where the species originated. Plants native to your region are safe and beneficial to the ecology.

If the plant you are considering is not native to your region, do the search again, adding the word “invasive” along with the plant name. Websites devoted to preventing the spread of invasive plants will come up in your search and warn you if a plant is a known threat to our environment. Here is a sample search for the common landscape plant, Burning Bush.

Collectively, home gardeners have a huge impact on the environment. The most obvious example of their power – for good and for ill – is the horror of almost 1000 invasive ornamental species damaging our ecosystem. Our gardening forebearers made some terrible mistakes and unleashed these scary monsters on us. We can do better.

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

August 4, 2022August 4, 2022 greenburghnaturecenter Around the Grounds, Invasives

For the Birds

Pokeweed. You’ve probably seen this plant on roadsides, vacant lots, along hiking trails, and maybe even pulled it out of your own yard. It’s definitely a weed, and either a curse or a curiosity depending on your point of view. Considered a dangerous and poisonous plant by some, and a nutritious and delicious plant by others, we think of it as a valuable food source for over 30 species of native birds.

Phytolacca americana is commonly known as Pokeweed, Polk weed, Pokeberry, Poke root, Virginia poke, Poke sallit, Poke salad, Redweed, Redberry, Pigeonberry, Pocan bush, Red ink plant, and at least a dozen other names. As is often the case, the number of common names for a plant indicates the variety and duration of human experience with it. Pokeweed has a long and complicated relationship with humans.

Pokeweed is native to most of the US and is found now in all but a few states. It can reach 6 to 10 feet tall, spreads both by seed and rhizomes, and has a very deep tap root. It is a perennial that can live in a wide variety of conditions, which makes it a rather successful weed.

**Pokeweed stands tall among other roadside weeds**

Indigenous peoples used Pokeweed for medicinal purposes and as a dye, especially for painting their horses. The name “poke” may come from the Algonquian word “pocan,” meaning red dye. American colonists fermented the deep magenta juice of the berries to make ink. There are preserved letters from Civil War soldiers written in Pokeberry ink, which was much more available to them than imported ink.

**Pokeweed berries yield a staining red juice**

There is common agreement that all parts of the plant, if eaten raw, are toxic to humans and livestock, but agreement ends there. Some writers claim that Pokeweed is so poisonous it should not even be touched without gloves. Yet in most of the Southern US, Pokeweed has been hand-harvested as a staple of the local diet for generations. Some authorities say the root is the most poisonous part of the plant, and the berries are the least so. Other authorities say the berries are the most toxic part of the plant and eating even a few may be lethal. Many articles claim that Pokeweed poisoning can cause death, but after surveying historical records, a recent report found only 2 deaths from Pokeweed over a couple hundred years, and noted that one of those deaths was more likely caused by the medical treatment of the time, blood-letting.

**Tiny pokeweed flowers open throughout the growing season**

**Pokeweed flowers attract pollinators, including hummingbirds**

The role of Pokeweed as part of Southern US culture is memorialized in the song “Polk Salad Annie” written in 1968 by Tony Joe White and made popular by Elvis Presley.

“Everyday before supper time, she’d go down by the truck patch
And pick her a mess of Polk salad, and carry it home in a tow sack
Polk salad Annie….”
Tony Joe White

Recognizing that Pokeweed is indeed toxic if eaten raw, recipes for polk salad, or poke sallit, require boiling the tender young leaves at least twice, and with two or three changes of water. The boiled greens are then sauteed in bacon fat and eaten like spinach or collard greens. Poke sallit festivals are still part of local traditions in the South every spring. But other than those circumstances, we do not recommend eating any part of Pokeweed, and children should be warned away from the berries.

We do suggest letting the plant live if you find it in an out-of-the-way spot in the garden. Pokeweed provides a real service to our native songbirds. Migrating birds store energy from eating ripening Pokeberries as they begin their journeys, and winter birds will eat the dried berries for as long as they last. Cardinals, mockingbirds, blue jays, robins, catbirds, bluebirds, mourning doves, and over 20 other species of native birds love Pokeberries. Squirrels, chipmunks, and other small mammals do, too.

**Pollinated flowers develop interesting berries**

**As the berries ripen, the stems change color!**

Pokeweed is interesting to watch, and it will definitely attract songbirds. So, if there is a spot near you where Pokeweed appears, we hope you can allow it to live its weedy, but useful, life.

For the birds.

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

June 9, 2022June 9, 2022 greenburghnaturecenter Around the Grounds, Invasives, Pollinators

The Trouble With Double

One beautiful spring morning, we stood under our Kwanzan cherry tree and noticed that something was missing: pollinators! Not one bee or butterfly was visiting the tree, even though it was loaded with flowers. Not far away, a blooming crabapple tree was literally humming with pollinators! What accounted for the difference?

We realized that the cherry tree has “double blossoms.” Its flowers have been modified by humans to replace all of its pollen-bearing stamens with flower petals. The flowers are beautiful – but only to people. There is no pollen or nectar for bees or butterflies. The flowers of the crabapple, on the other hand, were loaded with pollen and nectar. And the pollinators were all there for breakfast!

**The stamens are missing completely in these sterile double blossoms**

**The stamens in these flowers are ready for pollinators**

Flowers are the reproductive organs of plants. Pollen contains the genetic material that must be transferred from the (male) stamens to the (female) pistil for pollination (fertilization) to occur. In most flowers, the petals form an outer ring and the stamens are just inside, forming a second ring around the pistil. The flower’s colorful petals, its fragrance, and the sweet juice called nectar all are designed to attract pollinators. As pollinators sip the nectar located at the base of stamens, and collect pollen to feed their offspring, they “accidentally” transfer pollen from flower to flower and deposit it on the pistil where pollination happens. Successful pollination results in seeds, which then grow to produce more plants.

But sometimes nature makes little mistakes. Sometimes a plant will develop extra flower petals where the stamens should be. This is not a good thing for the flower, because with fewer stamens there is less pollen, which reduces the chances of pollination and, therefore, reproduction. In nature, plants that continue to develop too many petals instead of stamens eventually would fail to reproduce.

For hundreds of years, however, horticulturists have been fascinated by this “mistake” of nature. Humans enjoy flowers, and we tend to think bigger and fuller flowers are better. So, when horticulturists discover a flower that has extra petals where stamens should be, they can select that plant for special treatment. They can propagate the plants with extra petals and, eventually, even develop plants with so many extra petals they have no stamens (or pollen) at all! Without stamens, of course, those plants are sterile. They cannot develop fruit or seeds or reproduce themselves.

Roses are a good example. Natural roses have 5 petals surrounding a circle of many stamens carrying pollen.

**A simple rose with 5 petals, stamens with pollen, and pistil in the center**

Roses frequently make the “mistake” of trading stamens for extra petals.

**Note the under-developed petals in the ring of stamens**

Over centuries, horticulturists have selected these “mistakes” for intentional manipulation to create roses that are more interesting to people.

**In fully double roses, extra petals replace virtually all of the flower’s stamens and pollen is scarce or non-existant**

Today we have thousands of flowering trees, shrubs, perennials, and annuals that are popular specifically because they have double blossoms. But this comes with a cost to pollinators. Butterflies need nectar. Bees need nectar and pollen to feed their offspring. Butterfly and bee populations are declining under pressure from loss of habitat, pesticide, and limited food sources. We can help with our garden choices.

**Double peony with no stamens, pollen, or nectar**

**Double trillium with no stamens or available pollen**

**Double sunflower – native, but not useful for pollinators**

**Single peony with stamens and pollinator**

We humans love our double blossoms, but if you’re making a choice, think about providing a big variety of native single-blossom flowers for our pollinator friends!

**A buffet for pollinators in the Nature Center’s meadow**

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

April 7, 2022May 23, 2022 greenburghnaturecenter Around the Grounds, Invasives

Let’s “Switch Grass”

On this week of Around the Grounds we learn about Switch Grass, a native plant that can replace invasive ornamental grasses.

Do you have this ornamental grass in your yard? If so, it may be time to switch grass!

Miscanthus sinensis, or Chinese silver grass, is a too-popular ornamental grass so problematic that New York State has regulated it as an invasive species. Switch Grass (Panicum virgatum), on the other hand, is a native ornamental grass that is a perfect substitute. Maybe it’s time to switch?

Ornamental grasses have become increasingly popular as modern tastes have shifted to more naturalistic garden designs. Grasses bring year-round interest, movement, structure, and seasonal changes of palette that enhance every garden. Unfortunately, at least this one non-native grass has created an ecological problem.

**Invasive *Miscanthus sinensis* offered for sale on line**

Sold under the names Chinese silver grass, zebra grass, maiden grass, and porcupine grass, Miscanthus also has many cultivars, including “Morning Light,” “Flamingo,” “Ghana,” “Adagio,” and over 100 others. Despite being identified as invasive by New York and other states, it is still being sold, and is still spreading itself everywhere. It is invading natural areas because it has no biological controls on this continent.

Switch Grass is just as attractive as Miscanthus, just as easy to grow, and just as diverse. An original denizen of America’s prairies and meadows, it has deep roots and is both drought tolerant and deer resistant. It is increasingly available in a huge variety of sizes, shapes, and colors. And Switch Grass is the host plant for very cute native butterflies called, “skippers.”

**Skipper butterflies lay their eggs on Switch Grass**
Photo: Pixabay

**Switch Grass is a beautiful native plant**

Switch Grass is gorgeous through all four seasons, and its versatility is on full display at the Greenburgh Nature Center. The cultivar “Heavy Metal” is steel blue in summer and grows up to 5 feet tall. It is equally impressive in winter when it provides texture, movement, and contrast to evergreen shrubs.

*Panicum virgatum* ‘Heavy Metal’ frames our patio in summer

**The golden tones of ‘Heavy Metal’ contrast with Inkberry and Red Twig Dogwood in winter**

Another Switch Grass cultivar, ‘Shenandoah,’ is 3 to 4 feet tall and has a graceful vase shape that complements both shrubs and perennials. Because it hosts skipper butterflies, it is a great addition to pollinator gardens. Like all Switch Grasses, it enjoys full sun and tolerates poor soil. No supplemental water, no fertilizer, no worries.

***Panicum virgatum*** **‘Shenandoah’ in the Pollinator Garden at the Nature Center**

When we planted the Gerrie Shapiro Memorial Pollinator Garden at the Nature Center last June, we started with tall Switch Grasses as the center “spine” of the garden. Along with ‘Heavy Metal,’ we planted ‘Northwind,’ a Switch Grass cultivar that stays tall, narrow, and straight all season long. These two native grasses support tall flowers that would otherwise flop over when in full bloom. Switch Grass evolved supporting tall wildflower companions in American meadows and prairies, so it’s perfect for that job.

**Tall Switch Grasses define the structure of the new garden**

**A month later, ‘Northwind’ Switch Grass supports tall flowers**

One of our favorite smaller Switch Grasses is ‘Ruby Ribbons.’ At only 3 feet tall, it’s a good choice for smaller gardens. It has multi-colored leaves in shades of red and purple all summer long, and just gets prettier in the fall. Even smaller is ‘Cape Breeze.’ At less than 2 feet, it makes a great edger along the garden path.

And if you want to see what Switch Grass looks like in its natural habitat (almost) come visit our Meadow! After spring mowing, Switch Grasses start showing new growth. By late June, they fill out the Meadow terrain. And in the fall, clouds of tiny seeds hover above the Switch Grass stalks, feeding flocks of birds then and all winter long.