Around the Grounds Archives - Page 6 of 22 - Nature Center at Greenburgh

November 2, 2023February 12, 2025 Cathy Ludden Around the Grounds

Autumn Wonderland

The Northeastern United States is famous for fall foliage. “Leaf peepers” come from all over the world to see our native plants in their dramatic fall colors.

Why, then, should a walk around suburban neighborhoods, in the same region during the same season, be so disappointing? Where are the colors?

The plants that thrill “leaf peepers” grew in abundance before the suburbs were developed, and they would still thrive here – if only they were planted! It seems that every suburban yard uses the same non-native “foundation plants” — boxwood, pachysandra, ivy, and hedges of yew or privet or even bamboo! – all completely devoid of our famous fall colors!

C’mon people! We can do so much better than this! Why not plant our yards with the same trees, shrubs, and perennials that make this region a tourist attraction in the fall? Let’s add some color, life, and seasonal interest beyond pumpkins! There are so many great choices with our incredible abundance of Northeastern native plants.

Red maple (*Acer rubrum*)
Photo: Michael Martini

The undisputed rock-stars of fall color are our native Maples, and Oak trees are a close second. If you have a lawn, you probably have room for a Maple or a native Oak. Oaks have enormous value for wildlife — and for homeowners! [See this blog post] Both Maples and Oaks are beautiful year-round, but autumn is their glory season.

Our native flowering trees are also brilliant in the fall. Nothing beats the American Dogwood (Cornus florida) with its intense maroon foliage and vivid scarlet berries. Crabapples (Malus spp.) also produce colorful fruit, and American Witch Hazel (Hamamelis virginiana) starts blooming in October!

The Northeast is also blessed with native shrubs that produce kaleidoscopic colors in the fall. While evergreen foundation shrubs are useful, why not add some of the flowering and fruiting native shrubs that bring color and interest in both spring and fall? Here are some easy choices to add to your yard. All of the shrubs pictured below are locally available, easy to grow, valuable to wildlife, have beautiful flowers, and are spectacular in the fall.

Oakleaf Hydrangea (*Hydrangea quercifolia*)

Possumhaw Viburum (*Viburnum nudum*) pictured with
American Witch Hazel

Low Bush Blueberry (*Vaccinium angustifolium*)

American Cranberrybush (*Viburnum trilobum*)

And don’t forget fall flowers and grasses in gorgeous colors!

Aromatic Aster (*Symphyotrichum oblongifolium* ‘Raydon’s Favorite’)

Switch Grass (*Panicum virgatum* ‘Cheyenne Sky’) shown with Ironweed (*Vernonia lettermanii* ‘Iron Butterfly’)

Not only are these plants beautiful, they are incredibly valuable to the ecosystem of the Northeastern US. So many suburban landscapes use non-native plants that offer nothing to birds, butterflies, bees and other insects, and many are destructively invasive as well. If your only fall color is coming from burning bush or Japanese maple, you may want to consider native alternatives for those reasons. Privet, bamboo, ivy, vinca, and pachysandra are all known to be invasive plants and can be replaced easily with native plants that are beautiful in the fall, and year-round.

And wouldn’t you enjoy an autumn view like this?

Willow leaf oak (*Quercus phellos*), American dogwood,
and Pin Oaks

And this?

Oaks, Inkberry (Ilex glabra), Blue Star (Amsonia tabernaemontana and A. hubrichtii), High Bush Blueberry(Vaccinium corymbosum), Common juniper, and Possumhaw Viburnum

The fall glory of native plants lies within your reach!

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.

October 26, 2023February 14, 2025 Cathy Ludden Around the Grounds, Invasives

Halloween Horrors!

Scary Invasive Vines

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.

October 3, 2023February 14, 2025 Cathy Ludden Around the Grounds, Native Plants

Turning Over an Old Leaf

As fall approaches, we want to remind everyone that leaf litter is critical for many pollinators and other beneficial insects. This post about fall clean-up is worth revisiting…

As we learn more about the critical relationships between plants, insects, and birds, the best advice we are getting about fall leaf clean-up is … don’t!

In the old days, suburbanites taking care of their lawns raked (yes, raked!) fall leaves into giant piles to be burned. The familiar scent of burning leaves was everywhere – and we released tons of carbon sequestered in those leaves into the atmosphere.

So anti-burning ordinances were passed, and we started using gas leaf blowers to form the leaf piles, or bagging leaves for municipal workers to collect – all at taxpayer expense. Municipalities started spending millions to ship leaves out of the county. Enterprising souls then turned our leaves into compost to sell back to us. Not a good deal for us.

**Bagged leaves to be collected at taxpayer expense**

**Leaves at the curb clog storm drains, a municipal headache**

Since that routine makes neither economic nor ecological sense, we started hearing campaigns urging us to use mulching mowers. The idea was to chop leaves into tiny pieces and leave them on the lawn to enrich the soil. That method is a big improvement, and it definitely works — it’s great for lawn health and municipal budgets.

But we have learned that chopping up leaves has an unanticipated cost. Native bees burrow into the ground under leaf litter to survive the winter. Eggs and larvae of butterflies, moths, fireflies, and many other insects hang on to leaves, or hide under them, until warm weather returns. If we chop up or remove leaves to clear the ground in our yards, we are unintentionally destroying insects that baby birds need for food in the spring, as well as insects we need and enjoy.

**Many insects need fall leaf litter to survive winter**

**Mourning cloak butterfly emerging in March at the Nature Center**

**Who is hiding in there for the winter?**

The best use of fall leaves – and the best place for them – is under the trees that dropped them. Trees and all other forest plants evolved growing with a thick layer of leaves in the winter. Dead leaves nourish the soil and everything that lives in it. Leaf litter on your shrub and flower beds protects the roots of your plants and protects early buds from freezing and loss of moisture.

Of course, you’ll want to blow (or better, rake!) leaves off of driveways and paths, and either mulch or clear leaves that fall on lawn. But the best place to put them is in your shrub and flower beds and under your trees. A loose, 6-inch deep layer of leaves will not hurt your shrubs and perennials – quite the opposite. If there are still too many leaves, create a leaf pile in an out-of-the-way area, or add leaves to a compost bin. In spring, once the weather is warm and insects have had a chance to emerge, you can mulch the remaining leaves and return them to the lawn or flower beds, or even put them out for removal with spring clean-up.

**Use your leaves to protect trees, shrubs, and perennials**

Pro tip: Less lawn and more garden makes leaf clean-up a cinch! If your trees are surrounded by garden beds rather than lawn, nature does the work for you!

**Healthy yard maintenance is less work!**

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.

September 18, 2023February 12, 2025 Cathy Ludden Around the Grounds, Native Plants

Here, There, and Everywhere

Great Blue Lobelia (Lobelia siphilitica) is a quirky plant.

It is undeniably beautiful, with spikes of blue-violet flowers, 2 to 3 feet tall, blooming at summer’s end. It is adored by bumblebees, host to several species of butterflies and moths, and frequently visited by hummingbirds.

But you never know where it’s going to pop up!

**Great Blue Lobelia in its “happy place”**

Great Blue Lobelia is native to wet meadows in the Eastern half of the US from Maine to Georgia and west to Colorado and Texas. It is not truly perennial since the flowering stem and its roots die off after forming seeds. But in a favorable location, Lobelia seeds itself around — enthusiastically! — to maintain a perennial-like presence.

Lobelia seeds are tiny, like brown dust, which accounts for their easy dispersal. Whether they are carried by wind, water, animals, or even human footsteps is not entirely certain, but they seem to need open soil, moisture, and sunlight to develop into flowering plants.

Each plant begins as a semi-evergreen rosette, a circular cluster of leaves close to the ground. You may not even notice it until it begins to send up stalks in mid-summer with 2 to 3-inch-long pointed leaves. Then, in late August, the flowers begin to open sequentially from bottom to top. In a wooded area, the effect of the blue flowers is cool and soothing. In full sun, the display is a show-stopper!

A patch of Great Blue Lobelia in full sun
*Photo: Cary Maish Brodie*

Like its sister plant Lobelia cardinalis, Great Blue Lobelia needs moisture. In a wet summer, Lobelias can surprise gardeners by appearing in large numbers where they were not intentionally planted and never appeared before! (See “How Did That Get Here?” about the red Lobelia, Cardinal Flower). The plants do well in sun or part shade in Zones 3 to 9 in average soil. They are perfect along streams and ponds, and can even survive occasional standing water, but not drought.

**Two or three Great Blue Lobelias planted from nursery containers a few years ago have filled this woodland garden with offspring**

A friend in Ohio reports that Great Blue Lobelia in her sunny garden went from “oh, good!” to “oh, God!” in no time!
*Photo: Cary Maish Brodie*

But most of us are happy to see Lobelia pop up wherever it chooses. As summer fades to fall, the flowers are more than welcome and pollinators are happy to have nourishment before the weather turns.

The odd history of Great Blue Lobelia adds to its eccentricity. As the scientific name Lobelia siphilitica suggests, the plant was once thought to be a cure for syphilis. Native Americans used the plant’s roots and leaves to treat coughs, nosebleeds, headaches, and colds. If they used it at all to treat syphilis, it was mixed with a complex concoction of multiple herbs. Nevertheless, Europeans began using it as a syphilis remedy in the mid-1700’s when Sir William Johnson, Britain’s appointed Indian agent, bought it from enterprising local herbalists and sent it back to England as the natives’ “secret” cure. Sadly, in 1818, William Barton’ s book, Vegetable Materia Medica of the United States, concluded that despite trying the treatment in every favorable circumstance, “physicians of eminence” had found it to be ineffective against syphilis. Today, we know that Lobelia siphilitica contains a variety of toxic alkaloids similar to nicotine that can cause vomiting and other adverse reactions.

While Great Blue Lobelia may not be a cure for its Latin namesake disease, it is very effective for brightening our late summer landscapes and supporting native wildlife.

So, we still prescribe it!

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 24, 2023February 12, 2025 Cathy Ludden Around the Grounds, Native Plants

A Rare Azalea

Have you ever seen an azalea blooming in August? It is a rare sight, indeed!

Plumleaf Azalea (Rhododendron prunifolium) is the latest-blooming of all North American azaleas. It starts blooming in late July or August, months after other azaleas have finished, and it has been reported still blooming in October!

It is also the rarest of North American azaleas, native to only two states in the US. In the wild, a few small populations grow in forested sandy ravines along streams that drain into the Chattahoochee River, on the border between Georgia and Alabama. Sadly, even those few existing wild populations are threatened by development and careless logging practices, so the only native habitat of this amazing shrub is rapidly disappearing. Rhododendron prunifolium is under consideration for Endangered Species classification, but is not yet on the official list.

Plumleaf Azalea is strikingly beautiful. Its flowers are a deep red-orange with extra-long stamens that curl outward like exaggerated false eyelashes. The flowers are not particularly fragrant, but bees do visit them.

**Long red pistil and stamens protrude from the blossom**

**Shiny, dark green leaves show off each cluster of flowers**

Despite its very limited native range, the shrub does very well in gardens throughout the Eastern US in Zones 5 to 7. It prefers rich, acidic soil, even moisture, and dappled sun. It has a rounded, fairly compact shape, and will reach 5 to 8 feet tall and 3 to 4 feet wide. It is an absolute show-stopper in a shady garden when nothing else is in flower.

**Plumleaf Azalea in a woodland garden**

A plant as rare as Plumleaf Azalea poses a challenging question for ecology-minded gardeners. If it is native only to a limited area in Alabama and Georgia, should we be planting it in Northeastern gardens? There are several considerations:

We know that plants introduced into areas where they are not native can become invasive and cause ecological harm. (See our blog posts on very aggressive invasive plants introduced from other continents: Nip ‘Em in the Bud!, Evil Ivy Over Everything, and Boo!) While there are some native US plants that have become a nuisance when introduced outside their native range to other parts of the US, the danger is far less than with plants introduced from other continents. Plumleaf Azalea does not spread itself by the roots, and is not easily spread by seed, so it is not likely to move into areas where it is not intentionally planted.

But we also know that the value of any given plant to an ecosystem is greatest within its native range because it will have co-evolved with the other plants and animals in that ecosystem. A Colorado Blue Spruce, for example, supports insects native to the Rocky Mountains, but is of little use to most insects in the Mid-Atlantic region. Similarly, we can imagine that insects native to the Northeast may have no use for a plant from Alabama, though insects that evolved along the Chattahoochee River may depend upon that plant for survival. It is not known whether Plumleaf Azalea is a host plant for insects outside its native range, or whether it is useful to pollinators in the Northeast, but we do know that plants native to the Northeast are more valuable to local insects.

For these reasons, the best ecological choice is to plant species native to your specific region. But what if a plant is endangered in its own native region?

Michael S. Dosmann, writing for the Arnold Arboretum at Harvard University in 2022, noted that shortly after the founding of the Center for Plant Conservation in 1984, the Arnold Arboretum began collecting seed from disappearing populations of Plumleaf Azalea in three counties in Georgia. The goal was to prevent the extinction of the species. As of last year, the Arboretum was growing 34 Plumleaf Azalea shrubs – in Massachusetts. He said “preserving wild populations remains the highest priority, but it is important to have a back-up…”. He also observed that Plumleaf Azalea looks great in the garden, and for endangered species, “being charismatic and attracting attention is a gateway to its security (just look at the giant panda)!” Does planting Plumleaf Azalea in our gardens provide additional “back-up” for conservation of an endangered species? Maybe…