native gardening Archives - Page 5 of 5 - Nature Center at Greenburgh

December 16, 2021February 14, 2025 Cathy Ludden Around the Grounds, Pollinators

How Can We Help?

News of threats to butterflies, bees, and song-birds is everywhere. We hear that pesticides, climate change, and habitat loss are contributing to shocking declines in bird and insect populations, especially bees needed to fertilize food crops. Scientists report that insects are disappearing. We notice that moths don’t hang around our porch lights anymore, and bugs don’t splatter our car windshields as they once did. We may notice that bird species we often saw as kids are no longer around. We worry about what is happening, but we assume the solutions are beyond our individual control.

“The Insect Apocalypse”
New York Times Magazine, December 2, 2018

The good news is we can make a big difference right in our own back yards! Simple changes in the way we maintain our property – especially in the fall – can have an amazing benefit to birds, butterflies, and bees. We just have to understand what they need and make it available. Birds and insects need food and shelter all year long. Too many of our yards offer neither.

Many of us enjoy seeing winter visitors at our bird-feeders. But birds are vulnerable if they don’t have nearby places to hide. Planting densely with native trees and shrubs, and letting them take their natural shapes, provides shelter and much safer habitat than trimming too tightly to make trees and shrubs artificially neat. Birds need insects they find in holes and crevices in the bark of trees and shrubs, even in winter. So we need to have lots of trees and shrubs all around us, not just up against the house.

Birds need places to hide from weather and predators

Our flower beds and pollinator gardens can be valuable all winter long, too. There are more nutritious seed varieties in native flowers and grasses than in commercial bird seed mixes, so we should leave flower beds uncut until spring.

Most of our native bees over-winter in the ground. Shredded bark mulch prevents burrowing bees from finding the safety they need. Other bee species nest in hollow plant stems. By leaving flower stalks standing through the winter, we can provide habitat for many bee species. At the Nature Center, we have a “bee hotel” to demonstrate that nesting behavior. But it’s easier and far more effective just to leave the stalks of flowers and grasses up all winter long for nest sites.

Artificial native bee winter habitat – note occupied rooms!

Natural winter habitat – uncut flower beds!

Beetles make holes in old tree stumps or fallen logs that are later used by cavity-nesting bees for winter. Brush piles provide winter cover for birds as well as nest sites for bees, butterfly larvae, firefly larvae, and loads of beneficial insects.

Find an out-of-the-way place and stack a winter brush pile

It’s actually easier to create essential habitat for birds and beneficial insects than to strip your yard of all the good stuff in the fall. So, don’t remove your leaves. Don’t over-prune your shrubs. Don’t cut back your flowers and grasses. Don’t bundle up your twigs and branches and put them at the curb. Relax a little instead! There will be time in the spring, after everybody has left their winter beds, to tidy up for the new season. Let’s move toward a more natural look for our winter landscapes and a better environment for the creatures sharing it with us.

We really believe that’s beautiful.

For more information on the value of keeping fall leaves on your property, see our December 2 post here.

This blog is authored weekly by Cathy Ludden, local expert and advocate for native plants; and Board Member, Greenburgh Nature Center. Follow Cathy on Instagram for more photos and gardening tips @cathyludden.

December 9, 2021February 14, 2025 Cathy Ludden Around the Grounds, Native Plants

Season of the Witch-hazel

We were very excited at the Nature Center last week to discover a beautiful Witch-hazel (Hamemelis virginiana) — in full bloom!

It was “discovered” when Guy Pardee of Suburban Natives, LLC freed it from a thicket of invasive shrubs and vines that had hidden it from view. Guy has been working for the past few years removing invasive plants on our grounds. Since restoring native plant life on our 33-acre preserve is one of our top priorities, it is especially gratifying to find a wonderful native tree right at its peak.

Witch-hazel is a fascinating plant. It’s a multi-trunked shrub or small tree that evolved as an understory plant in the forests of the Northeast. You might not notice it at all in the spring or summer when it modestly sits under bigger trees in part shade. But in early winter, when all the leaves are down and most plants are going to sleep, Witch-hazel starts blooming. Its flowers are fragrant, and bright yellow with tiny streamers reaching out in all directions.

The leaves, bark, and twigs of Witch-hazel contain tannins and flavonoids that Native Americans used for centuries to treat skin ailments. European colonists soon adopted the practice, and today Witch-hazel is one of the few plants the Food and Drug Administration has approved for use in over-the-counter products. Many cosmetics companies use Witch-hazel in toners, diaper rash remedies, acne treatments, pore reducers, and after-shaves.

Blooming Witch-hazel stands out against an evergreen background

A more questionable early use of Witch-hazel was the practice of using forked branches as dowsing or divining rods to search for underground water. A “water witch” would hold the forked end of a Witch-hazel branch and walk until the flexible tip supposedly dipped when underground water was detected. Dowsing with Witch-hazel branches for well-digging was a common practice right into the 20^th century.

The real mystery of this plant still isn’t settled. Why does Witch-hazel start blooming in winter when pollinators are already hibernating? And what insect does pollinate the flowers? Some researchers have pointed to a moth species that survives freezing temperatures by shivering so hard that its body warms above surrounding air temperature. Others have suggested that a small and very late-acting bee is the pollinator. Still others have theorized that swarms of tiny gnats do the job. More research is required.

But the coolest thing about this fascinating plant? Because of its strangely late pollination, there isn’t time for the fruit to ripen in the same year the flowers open. It takes the whole next summer for the seeds to slowly ripen in their pod. Then, just as the flowers start blooming in the freezing cold, the pod explodes throwing the ripe seeds 10 to 20 feet away, where hopefully they will rest until spring weather is warm enough for germination.

Lately, we’ve seen nurseries offering non-native hybrids of Witch-hazel for sale. These varieties with orange or red flowers are recent introductions of hybridized Asian species, so their value to our native wildlife and potential for invasiveness are unknown. Our view is that it’s always safer to go with species that evolved in our region.

Hamemelis virginiana, our native Witch-hazel, is a garden-worthy plant that brings late-season interest to suburban landscapes. Try it against a background of evergreens in a partly shaded area. On a cold winter’s day, you won’t be sorry.

Native Witch hazel brings winter interest to the garden

December 1, 2021February 14, 2025 Cathy Ludden Around the Grounds, Invasives

Turning Over an Old Leaf

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

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!

November 11, 2021February 14, 2025 Cathy Ludden Around the Grounds, Native Plants

A Tale of Two Dogwoods

In front of the Manor House at the Nature Center, there are two species of dogwood trees. One is the native Flowering Dogwood (Cornus florida), and the other is the non-native Korean or Japanese dogwood (Cornus kousa). Particularly at this time of year, the critical benefits of the native tree become obvious.

Native Flowering Dogwood at the Nature Center

Non-native Kousa dogwood on the Great Lawn

Plant species evolved together with animal species living in the same habitat. Flowering Dogwood evolved here, in Eastern North America, along with the insects, birds, and mammals native to our forests. Kousa dogwood evolved in Asia with the animals native there – very different animals.

Both species of dogwood have beautiful spring flowers, but the native Flowering Dogwood blooms weeks earlier – just as local pollinators emerge looking for nectar and pollen. Kousa dogwood blooms much later in the spring. By then, lots of other flowers have emerged and the need for early-season nectar and pollen is less crucial.

By the end of the season, the timing of these two species is reversed. Kousa dogwood produces its showy red berries early — in August. The berries of the Flowering Dogwood, on the other hand, start to ripen in October — just as songbirds need them to fuel their migration.

In Asia, Kousa berries are eaten by monkeys and other indigenous wildlife. Here, those berries are largely ignored. The berries are too big for songbirds. Squirrels and chipmunks aren’t interested either. Instead, Kousa berries end up where they fall, mashed by foot traffic and lawnmowers.

Kousa berries are not useful to wildlife and make a mess

The berries of the Flowering Dogwood are an essential food source for migrating songbirds because they are full of nutritious fats and proteins. We have seen flocks of migrating birds descend on a Flowering Dogwood and clean it out of berries in a few days. Any berries that do hit the ground are quickly carried off by squirrels and chipmunks.

Native Flowering Dogwood berries in October

Berry buffet for birds at the Nature Center

Nurseries and garden magazines may tell you that Kousa dogwood is a better choice for home landscapes than native dogwood because the Asian variety is more resistant to disease. The disease in question is anthracnose, a fungus that first appeared in the US in the 1970’s and quickly became lethal to native dogwoods. Research strongly suggests that the fungus actually was introduced to the US by importation of the Asian dogwood. Kousa dogwoods are more resistant to the fungus because they co-evolved with it and developed resistance over time. American dogwoods did not have that opportunity. The arrival of the fungus here was a near-disaster for this iconic American tree.

Fortunately, growers immediately began developing resistant varieties of Flowering Dogwood. “Appalachian Spring” was one of the first varieties to successfully fend off the disease. Other disease-resistant varieties are readily available now. “Cherokee Brave” and “Cherokee Chief” have pink flowers, while “Cherokee Princess” blooms in white. These trees do very well in our area. They prefer sun or part shade in well-drained soil, and benefit from organic fertilizer or compost. In periods of drought, they will need supplemental water. They never get too tall, and they make spectacular lawn trees.

“Cherokee Brave” flowering in Greenburgh in the spring

If you’re looking for an ornamental tree with gorgeous spring flowers, great fall color, and an important role to play in the local ecology, skip the non-natives. You really can’t do better than Cornus florida, our own Flowering Dogwood.

This blog is authored weekly by Cathy Ludden, local expert and advocate for native plants and Board Member, Greenburgh Nature Center.

November 3, 2021February 14, 2025 Cathy Ludden Around the Grounds, Native Plants

Be Still, My Bleeding Heart!

We have a new love at the Nature Center.

Dicentra eximia, a native plant commonly called Fringed Bleeding Heart, started blooming here in May and continued blooming right through Halloween! It has lacy, soft green foliage that stays fresh from early spring through pumpkin time. Its flowers are little red and pink hearts with a “droplet” at the tip. Bees love them, and now, so do we.

Fringed Bleeding Heart (foreground) blooming in May with Prairie Smoke

Still fresh in October, as autumn leaves start to turn

We planted Fringed Bleeding Heart two years ago in front of the Manor House, mostly to fill in until our new shrubs got big enough to occupy the space. The soil there is not rich at all, and the building faces west. Though the overhanging eves protect the flower bed from full sun at mid-day, it is definitely not a shady area. You could think this was a questionable planting decision, since most sources say that Dicentra eximia needs rich, moist, fertile soil, and part or full shade.

We are starting to suspect that this advice comes from gardeners more familiar with the non-native bleeding heart (Laprocapnos or Dicentra spectabilis), an old garden favorite that originated in Asia. That plant definitely wants rich soil, steady moisture, and shade. It has lovely flowers, but it also goes dormant after blooming and disappears completely by late spring.

Fringed Bleeding Heart, on the other hand, originated in the Appalachian Mountains where the soil is often rocky and dries out between rainfalls. Though it can be found on shady forest floors where the soil is rich and moist, it also grows on rocky ledges with thin soil and more sun. We are starting to think this plant is tougher than most gardeners believe.

We are testing that theory by including a big patch of Dicentra eximia in the new Pollinator Garden we planted last June. Most of the other plants in that garden are tough, sun-loving, drought-tolerant perennials and grasses. But right there, in the slim shadow of a small Redbud tree, we included Fringed Bleeding Heart. The soil is poor and dry, for the most part – exactly what the other pollinator-friendly plants prefer. The Fringed Bleeding Heart gets a bit of shade from the tree, but is otherwise exposed.

And this is how it’s done so far:

Fringed Bleeding Heart in the Pollinator Garden in July with Anise Hyssop

Fringed Bleeding Heart still blooming in October!

A native plant that literally blooms its little hearts out for you all season long?
Oh yes, we’re definitely in love!

This blog is authored weekly by Cathy Ludden, local expert and advocate for native plants and Board Member, Greenburgh Nature Center. Follow Cathy on Instagram for more photos and gardening tips.