Blog - Page 11 of 21 - Nature Center at Greenburgh

November 3, 2022January 7, 2025 Cathy Ludden Around the Grounds, Native Plants

Autumn Hy-lights

Everybody loves hydrangeas. But especially at this time of year, it’s the Oakleaf Hydrangea that really steals the show. Just when other hydrangeas start dropping their leaves, Oakleaf Hydrangea (Hydrangea quercifolia) lights up the landscape with colors ranging from hot pink to deep burgundy. The shrub holds its leaves until very late in the fall, and the colors keep changing for weeks — so the show lasts well past Thanksgiving!

**Oakleaf Hydrangeas blaze (no photo filters!)**

Oakleaf Hydrangea is a flowering shrub native to woodlands in the Southeastern US, from Georgia and Tennessee to Florida. It does very well in more northern gardens and is an excellent year-round landscape shrub in Zones 5 to 9, and even in Zone 4 with some protection. It prefers moist soil, but is surprisingly drought tolerant once established, especially with some afternoon shade. The fall color is best with more sun, so a morning sun/afternoon shade situation is ideal. Oakleaf Hydrangea is fast growing and can occupy a space 10-12 feet high and wide in just a few seasons. It is easily pruned for size, but should be pruned just after flowering to avoid cutting off the flower buds that form later in the season.

The scientific name “quercifolia” means “oak-shaped leaves.” The shrub is not related to oaks, but the leaves do resemble very large oak leaves. Interestingly, the leaves of the shrub grow significantly larger in shade than in sun. Deer resistance is questionable. Deer have not bothered the shrubs at the Nature Center, but neighbors report deer browsing, especially on younger plants.

Fall color may be the “hy-light,” but Oakleaf Hydrangea has advantages over non-native hydrangeas in other seasons as well. In spring, Oakleaf Hydrangea leafs out earlier than Asian mop-head hydrangeas (Hydrangea macrophylla) and seems to be less vulnerable to late spring ice storms. While mop-head hydrangeas suffer significant winter die-back, leaving lots of twiggy stems into late spring, Oakleaf Hydrangea fills in attractively and reliably by the end of May.

**Side-by-side comparison in late May of Oakleaf Hydrangea on the left and mop-head hydrangea on the right**

Oakleaf Hydrangea blooms in June with large cone-shaped clusters of white flowers. The 4-petaled outer flowers are sterile, and their only purpose is to attract pollinators to the tiny fertile flowers hiding underneath. A huge variety of bees and other tiny insects feed on the pollen produced by the smaller flowers.

**Large cone-shaped clusters of white flowers in mid-June**

**The outer 4-petaled flowers attract pollinators**

**The tiny inner flowers supply the pollen**

While many gardeners love the big blue and pink flowers of mop-head hydrangeas, those flowers come at a price: they have been manipulated by growers to dramatically increase the number of colorful sterile blossoms, while eliminating entirely the tiny fertile flowers that feed pollinators. Have a closer look at mop-head hydrangeas and you will notice the complete absence of butterflies and bees. There is nothing for pollinators there.

After the fertile inner flowers of the Oakleaf Hydrangea have been pollinated, seeds form inside the flower clusters. At the same time, the sterile outer flowers begin to turn pink. It’s an enchanting sort of garden magic.

**The outer flowers turn pink in July sheltering the seeds produced by pollinated inner flowers**

**By late October, the flowers have turned craft-paper brown and the seeds are available for songbirds**

In November, Oakleaf Hydrangea lights up the late-season landscape as no other hydrangea can. When the leaves finally finish their show, they reluctantly fall, revealing cinnamon-brown bark on stems and twigs. As the shrub ages, the bark peels attractively, adding layers of warm brown color for winter interest, and forming a great shelter for winter birds.

Oakleaf Hydrangea really is a “hy-light” of the landscape all year long.

**Late season landscape composition with Winterberry and Hemlock**

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 27, 2022January 7, 2025 Cathy Ludden 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.

October 20, 2022January 7, 2025 Cathy Ludden Around the Grounds, Native Plants

Seasons in the Meadow

Meadows change. All landscapes change, of course, even the most formal manicured gardens. But native plant meadows are wilder, less predictable. Nature has a freer hand where plants are allowed and expected to reproduce naturally, and where humans impose less control over conditions. In each season since the initial planting of our native Meadow (see last week’s blog post here), we have been surprised, sometimes frustrated, and always fascinated by the changes we see. Our challenge is to accept as many of nature’s changes as we can, while preserving the value of the Meadow for nature itself.

In the Northeastern US, which was once almost entirely forest, naturally-occurring meadows are typically “successional.” They occur when a storm or fire opens a spot in the forest and more sunlight allows grasses and wildflowers to emerge. Eventually, woody shrubs and tree seedlings settle in, grow taller, cast shade, and the forest returns. Unfortunately, in modern times, any newly opened ground is immediately colonized by invasive species, plants from other parts of the world that out-compete native plants because they have no natural insect or animal controls here.

So, maintaining a designed meadow in the Northeastern US requires effort to prevent invasive plants or forest from claiming the space. The incredible value of a native meadow as habitat for insects, birds, reptiles, and mammals makes that effort totally worthwhile.

Guy Pardee of Suburban Natives, LLC mowing the Meadow in early April

We begin each year in the Meadow by mowing to prevent tree seedlings from developing, and to allow sun and water to reach new growth. The timing of mowing is important. We need to wait for over-wintering insects, including native bees and caterpillars, to emerge from their hiding places in leaves and hollow stems, usually in late March or early April. The Meadow is cut to the ground, leaving plant debris in place to add nutrition to the soil and to protect emerging growth from late frosts.

**Seedlings of White Pine, sumac, and birch appear every spring, trying to re-forest our Meadow**

**Plant debris is left on the ground after mowing**

Spring mowing also allows us to check the Butterfly Arbor and the trees in the Oak Circle for any winter damage. And it’s a good time to look for and remove invasive species before they can hide among the native plants.

A few weeks after mowing, when the first spring flowers emerge, we see that the Meadow has changed again. Each year there are surprises, and occasional disappointments, as plants appear and disappear. We are delighted when native plants volunteer in places they were never planted – a true indication of a healthy landscape! And, sometimes, we notice that flowers we love have disappeared as they reach the end of their life expectancies, or lose ground to stronger plants.

**Whorled loosestrife, Wild Sarsaparilla, and Appalachian Sedge are native plants that volunteered at the Meadow edge**

**Prairie Smoke, a spring bloomer, sadly disappeared from the Meadow after a few years**
Photo: Travis Brady

By June, the Meadow is in full bloom. Coreopsis, Penstemon, Baptisia, and many other flowers greet visitors — including butterflies, bees, and countless other pollinators!

Throughout the summer, the Meadow continues to change – not just seasonal changes, but changes in plant populations. Years after the original seeding, plants have appeared and bloomed for the first time as slow-growing seeds finally matured. And the number and location of plants in the Meadow changes every year.

**An uncommon plant, *Castilleja coccinea,* was included in the original seed mix planted in 2014, but only appeared and bloomed for the first time in June 2021**

**Joe Pye Weed was not a big presence in the early years of the Meadow, but after one rainy summer, it became prolific**

Throughout the growing season, some weeding is necessary to keep invasive plants out of the Meadow. Even some native plants are too aggressive to leave uncontrolled, or they would soon dominate. We make careful edits, avoiding use of herbicide, and quickly fill in weeded areas with container-grown native plants.

**Canada goldenrod is a beautiful native plant, but can out-compete everything else, so we cut it back before it goes to seed**

Autumn is the most dramatic season in the Meadow. Late-blooming flowers and grasses change the scene daily with a profusion of color. Seed pods from faded flowers attract songbirds in large numbers, and bees scramble to stock up for winter.

**Milkweed seed pod**
Photo: Travis Brady

**Late October view of the Butterfly Arbor**

Meadow plants are left standing all winter to provide seeds for birds, cover for animals, and winter hiding places for insects. There is a lesson here for all of us as home gardeners: a little mess, a little bit of wild in the landscape, can be as beautiful as it is beneficial for living things.

As the light changes with the seasons, the Meadow changes, too. It really is a different place each time we visit!

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 13, 2022January 7, 2025 Cathy Ludden Around the Grounds, Native Plants

How We Made a Meadow

It was a weed-infested patch of land just steps away from the busiest commercial corridor in Greenburgh. A little less than 2 acres, it had been neglected for decades. But it was flat, sunny, dry, and open. Perfect for a meadow!

After an initial clearing, we got a better look. There were some nice native birch trees, an ancient stand of bayberry, and several old apple trees remaining from what had once been an apple orchard.

We were very lucky to meet a talented landscape architect who offered to donate his design services to the Nature Center. Bill Boyce of Biosphere Landscape Architects brought his expertise in natural landscape restoration to the project. He designed a space that would retain the best features of the site, while adding places for education and contemplation. Our guiding principle was to create and preserve a diverse habitat of native plants for insects, birds, and other animals.

We knew that the most natural look for the meadow would require planting from seed, carefully selected for site conditions, using a large variety of native wildflowers and grasses. For that, we turned to Larry Weaner of Larry Weaner Design, the foremost authority in the Northeastern US on designing and planting native meadows. Larry formulates custom seed mixes using a complex formula based on seed germination rates, aggressiveness of various species, length of time each species takes to germinate and establish roots, and many other factors. Like Bill, Larry was kind enough to contribute his time and expertise for the Nature Center’s meadow project.

**Larry Weaner, expert on meadow design and planting**

In December of 2014, we cleared the site again, much more thoroughly, removing as many roots of the weedy invasive species as possible, but leaving a few valuable native plants. Bill marked off the areas to be seeded, and we carefully hand-cast Larry’s specially-formulated seed mix.

**Final thorough clearing and marked off planting areas**

**Hand casting seed in the new meadow before rolling to press seed into bare soil**

**Bill Boyce, Cathy Ludden, Larry Weaner, and Travis Brady did the final clearing and hand-seeding in December 2014**

Bill’s design included an Oak Circle, which we hoped would become a calm space for meditation, as well as contribute the immense ecological value of native oak trees. Bill also designed a Stone Classroom, where our staff naturalists could work with students on-site in the meadow.

It takes at least 3 years for a seeded meadow to establish. Soon after plants emerge in the first spring, the meadow is mowed to about 6 inches in height. The idea is to cut back returning invasive species, which grow faster, giving the native seeds time to germinate without being overwhelmed. Two additional mowings the first summer, at increasing heights, keep invasive weeds under control as the new native plants develop roots.

**First season meadow is kept short to allow new seeds to germinate, Spring 2015**

In the second season, the meadow is mown once in the spring, and once more in mid-summer. The third year, the meadow is mown only once in the spring, as it will be annually thereafter.

**Baby native plants appear in the meadow**

In the winter of 2016, Bill Boyce constructed our Butterfly Arbor, taking his design inspiration from the wings of a Monarch Butterfly. He allowed native sumac shrubs to remain near the Arbor to soften the edges of the design.

**The new Butterfly Arbor in April 2016**

The Arbor has removable doors and is specially designed to allow netting to be suspended inside for our annual butterfly exhibit

**Preparing for the butterfly exhibit, Spring 2016**

The native plant meadow at the Nature Center is now 8 years old. It has matured, but it still changes each year and in every season. It has become the very special place we hoped it would be. It is filled with life and beauty.

The meadow is a wonderful place for education and contemplation.

The meadow is a joyful place to explore for people of all ages.

Next week in Around the Grounds we will discuss meadow maintenance and how changing seasons affect the 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.

October 6, 2022January 7, 2025 Cathy Ludden Around the Grounds, Native Plants

Good Weed, Dude!

No, not that kind!

The “good weeds” we feature here are special native plants that pop up spontaneously in our gardens, lawns, and roadsides. They may be “weeds,” but they are also beautiful and important to local birds and pollinators. So, before deciding to get rid of them, you might pause, consider them a gift from nature, and allow them a place in your garden. After all, what is the difference between a “weed” and a “wildflower”? If a native wildflower appears in your garden, is it a nuisance or a happy accident?

Native plants (the plants that evolved in a particular ecosystem without human intervention) may — and should — propagate themselves in their natural habitat along with the other plants, insects, and animals that evolved there. When these native plants “volunteer” in our yards, especially in the right spot, simply allowing them to stay may be a good choice. And because they are better adapted to their native area, they may out-perform the plants we buy that need special handling, fertilizer, and extra water.

Jewelweed (Impatiens capensis) is a good example. Native to most of North America, Jewelweed is an annual, but it can return each year because it freely self-sows, dropping seeds that will sprout the next season. It prefers rich, moist soil and part shade, but can appear in sun or shade, in soggy areas, and even in heavy clay. The Latin name Impatiens and “Touch-me-not,” another common name for the plant, both refer to the explosive way its seed capsules burst, throwing seed all around the mature plants.

**You may find Jewelweed seedlings in spring**

**Jewelweed flowers are loaded with nectar**

Jewelweed starts blooming in late summer and continues well into fall. The flower is shaped like a cornucopia, and its nectar provides critical energy for migrating hummingbirds and monarchs, as well as late-season bumblebees. The plants require no care whatsoever, and the bright orange flowers light up the fall landscape.

If Jewelweed appears in your garden where you don’t want it, it is easy to pull. But it makes a great show in spots where you can leave it standing.

**Volunteer Jewelweed along the street**

Another wildflower that frequently volunteers in shady areas is White Wood Aster (Eurybia divaricata). Native to the Eastern US, it blooms earlier than most asters, beginning in late summer. Native bees love it, and birds eat the seeds all winter. It is not an aggressive spreader, so you can relax if it pops up in your yard. It looks beautiful scattered around under trees and shrubs. You can even find White Wood Aster sold in nurseries if you want to plant it, and it is a great choice for dry shady spots – even where there are deer.

**White Wood Aster is usually low-growing with deep green arrow-head shaped leaves**

If you’re lucky, a very similar-looking wildflower may also appear in shady areas in the fall. Common Blue Wood Aster (Symphyotrichum cordifolium) is native to most of Eastern and Central North America and found along forest edges and open areas, as well as in urban and suburban gardens. Its flowers are pale blue and it grows taller than White Wood Aster, typically 2 to 4 feet. We find it along woodland paths and even street-side where deer seem to ignore it, as they do White Wood Aster.

**Common Blue Wood Aster volunteering in a patch of ivy**

**White Wood Aster, Common Blue Aster, Goldenrod, and Sensitive Fern along a wooded path at the Nature Center**

If you live in the Central or Eastern US, you’ve probably seen White Snakeroot (Ageratina altissima) popping up in various places. Blooming in early fall, White Snakeroot attracts a wide range of pollinators to its nectar-rich flowers. Bees, butterflies, moths, and even spiders preying on the nectar-hunters, all visit the clusters of tiny flowers produced by these native plants.

White Snakeroot has an interesting history. At one time, it was believed – erroneously — that the roots could treat snakebite. In fact, the entire plant is toxic to mammals, so deer avoid it entirely. Early American settlers discovered that if cows consume White Snakeroot, their milk becomes poisonous. Abraham Lincoln’s mother is said to have died from “milk poisoning,” as it was called then.

In the landscape, however, White Snakeroot is dazzling. The plants grow up to 3 feet tall, and the flowers are brilliant white against dark green leaves. Snakeroot is spectacular massed in shade where it can be a very effective groundcover. It does well in part sun also, and in either dry or moist soil. It is an aggressive spreader and can be challenging to control in smaller gardens. Its seeds are produced in large numbers and wind born, but it also spreads by rhizomes.

**White Snakeroot claims territory in the shade of an oak tree at the edge of this front yard meadow**

If White Snakeroot appears in an area where there is only ivy or pachysandra, or in dry shade under old trees, or on a tough embankment where other plants struggle, you may just want to leave it alone and let nature take its course!