native plants Archives - Page 8 of 14 - Nature Center at Greenburgh

July 15, 2022February 13, 2025 Cathy Ludden Around the Grounds, Native Plants

Summer Buzzin’

Have you ever heard a plant hum?

On a sunny summer day, you can actually hear Shrubby St. John’s Wort humming. It’s not the plant itself, of course, but the sound of extremely happy bumblebees buzzing as they collect pollen from countless bright yellow pom-pom flowers.

“St. John’s wort” is the common name for a family of almost 500 plant species worldwide. The name refers to its time of bloom – around St. John’s Day on the Christian calendar, or June 24. “Wort” is the old English word for “plant,” especially plants known for their medicinal value. Perhaps you’ve heard St. John’s wort recommended as an herbal remedy for mild depression? That particular St. John’s wort is Hypericum perforatum, a weedy perennial native to Europe and now considered invasive in parts of North America.

**Shrubby St. John’s Wort in front of the Manor House**

The “humming” plant we love is Hypericum prolificum, or Shrubby St. John’s Wort. It is a beautiful shrub, native to the US from New York west to Minnesota and south to Louisiana and Georgia. It does indeed start blooming at the end of June, and continues to dazzle for weeks into the summer. The scientific name “prolificum” refers to the enormous number of flowers the shrub produces. The shrub itself forms a rounded mound 3 to 4 feet tall and wide with small blue-green leaves.

**Shrubby St. John’s Wort loaded with flowers**

If you go shopping for Shrubby St. John’s Wort, you will likely see Hypericum frondosum, a very similar shrub with a cultivar called “Sunburst” that has slightly larger flowers. Its original native range is further south, in Tennessee and Kentucky, but it does perfectly well in southern New York gardens and throughout Zones 5 to 8. Another species, Hypericum kalmianum, is native to the Great Lakes region and hardy to Zone 4. While botanists can tell these three shrubs apart, most gardeners consider them virtually interchangeable. And all of them have year-round value as landscape plants.

Shrubby St. John’s Wort is essentially carefree, and makes an attractive foundation plant or hedge in full sun. It doesn’t need pruning, but you can shape it to suit your site. The leaves produce a substance that is mildly toxic to deer, so deer avoid it. In autumn, the shrub holds onto its leaves until late in the season, and it has great fall color. And in winter, interesting seed capsules remain on branches that have attractive grey-brown bark.

**Fall color is a mix of red, yellow, and orange**

There is no nectar in the flowers of St. John’s Wort, so it’s not a stopping place for butterflies. However, caterpillars of several moth and butterfly species, including the lovely gray hairstreak butterfly, do use the leaves as a host plant. Pollen is the big attraction. The flowers have a huge number of stamens, all loaded with pollen, so bees of every size and description come to the party.

**How many bumbles can you find on just 3 flowers?** **(Hint: there are 5!)**

We never get tired of watching the action, and we can observe up close because the bees won’t spare a second even to notice nearby humans. They are fixated on pollen collection, as you can see in this slow-motion video:

Pollen collection

And what about that summer buzzin’? Turn your sound up and, technology permitting, you may hear the sound of a plant humming!

Summer buzzin’

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 30, 2022February 13, 2025 Cathy Ludden Around the Grounds, Native Plants

How Sweet It Is!

Itea virginica is one of our most beautiful and versatile native shrubs. Its romantic common name, “Virginia Sweetspire,” is a good one, because this shrub is a sweet addition to the landscape year-round.

*Itea virginica* or “Virginia Sweetspire” shrub

Itea (pronounced eye-tee-uh) grows in a loose mounding form, reaching 4-5 feet tall and wide in a few years, with gently arching branches. In mid-June, after most trees and shrubs have finished blooming, Itea is just starting its summer show. Spikes of white flowers 4 to 6 inches long cover the shrub, arching away from the deep-green leaves on long stems.

The star-shaped flowers begin opening from the stem to the tip, and last several weeks. And they are sweet! The elegant fragrance is not over-powering, but definitely carries in sultry June air. The flowers are loaded with nectar and butterflies flock to them. When the flowers fade, birds will feast on the seeds that remain all winter.

**Itea’s fragrant flowers justify the name “Sweetspire”**

Itea is native to swampy meadows and wet woodlands from New Jersey to Florida, and west as far as southern Illinois, but it does very well in more northern gardens. It can thrive in full sun or part shade, and is surprisingly drought tolerant given its swampy origins. It is winter hardy in Zones 5-9, and is not attractive to deer or rabbits.

Throughout the summer, the foliage remains fresh and glossy, so Itea looks great in full sun as a hedge or foundation plant. But because of its shade tolerance, it can even replace pachysandra, vinca, or ivy under trees.

**Itea is part of our full-sun foundation planting at the Nature Center’s Manor House**

**Itea in part shade under a Redbud tree at the Nature Center**

And have we mentioned fall color? Itea is known for its gorgeous fall foliage, turning various shades of red, orange, and purple while holding onto its leaves until snowfall. Cultivars called “Henry’s Garnet” and “Merlot” are specifically marketed for their brilliance in the fall landscape. Fall color is best in full sun, but it’s still impressive in part shade. We frequently recommend Itea as a native alternative to invasive burning bush.

**The same Itea planting in mid-November**

So, Itea is carefree, a hedge or foundation plant, an under-tree plant, has showy and fragrant flowers, offers nectar for butterflies and seeds for birds, grows in sun or shade, and has fabulous fall color – we think that’s pretty sweet!

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 23, 2022February 13, 2025 Cathy Ludden Around the Grounds, Native Plants

Billy Goat or Nanny Goat?

“Goat’s Beard” is the common name of Aruncus dioicus, a gorgeous native plant that is perfect for shade gardens. It is spectacular toward the back of a mixed border, along a fence, or at the edge of a woods. Blooming from late spring through mid-summer, Aruncus (pronounced “ah-runk-us”) grows 4 to 6 feet tall with very large, fluffy white flowers. Many different pollinators are attracted to its flowers, which makes Aruncus especially valuable in shade where great pollinator plants are more difficult to find.

**Bumblebee collecting pollen on Aruncus**

Sometimes confused with Asian astilbe, Aruncus blooms only in white, is much taller, and has bigger flowers. Common names can add to the confusion – we have seen Asian astilbe sold in nurseries as “false Goat’s Beard,” and we’ve seen Aruncus labelled as “false astilbe” or “false spirea,” so it’s always important to check the Latin or scientific name on plant labels.

**Asian astilbe is shorter and has smaller flowers**

And, as is often the case, the scientific name is very interesting! Aruncus dioicus refers to the fact that Aruncus is “dioecious,” meaning the plants are either male or female. The word “dioicus” in its name comes from Greek meaning “two households.” While dioecious plants are fairly common among trees and shrubs, they are rather unusual in garden perennials.

The flowers on male Aruncus plants have many pollen-bearing stamens, while the flowers on the female plants have only 3 pistils and, of course, no pollen. Bees are drawn to both types of flowers by nectar, and transfer pollen from the male to the female flowers.

**Male flowers have many stamens loaded with pollen**

**Female flowers have 3 pistils and nectar to attract bees**

The male flowers are somewhat showier because the stamens give them a fluffy appearance, but the plants are not typically labelled separately for sale. You’ll have to look closely to see whether your Goat’s Beard is a Billy goat or a Nanny goat! Both make excellent garden plants, and look fabulous massed in the shade.

**Female Goat’s Beard blooming in the shade**

**Tiny pollinator on male Goat’s Beard**

Aruncus is native to the US from Pennsylvania to North Carolina and west from Indiana to Arkansas. Although it is not native to New York, it does very well in northern gardens and is hardy through Zone 4 in rich, moist soil, and part sun to full shade. It is not generally attractive to deer or rabbits, and it is the larval host plant for the Dusky Azure butterfly.

As pollinators face increasing stress, providing native plant sources of nectar and pollen is more critical than ever. Goat’s Beard does that while adding light and beauty to your shade garden.

**Bumblebee with a paste of pollen and nectar packed into her pollen basket (corbicula) for transport**

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 16, 2022February 13, 2025 Cathy Ludden Around the Grounds, Pollinators

Happy Pollinator Month!

June is here — the bees are buzzing, the butterflies are fluttering, and everybody is excited about summer flowers. It’s National Pollinator Month!

At the Nature Center, we are also celebrating the first anniversary of our newest Pollinator Garden. It is astonishing to see how lush, diverse, and colorful our garden has grown in just one year!

Want to know how we did it?

Right next to our big open lawn, in a very visible spot near the beehives, there was a messy patch of weeds. The soil was poor and dry, and there was very little shade. So…the perfect spot for a pollinator garden! The first task, done by Guy Pardee of Suburban Natives LLC, was to clear the area, getting rid of all the weedy invasive plants. Then, the ground was covered with leaves and left for the winter.

The following spring, we cleared it again and prepared to plant.

A good friend to the Nature Center, Bill Boyce of Biosphere Landscape Architects, came up with a great idea for the garden. We would make a literal “pollinator pathway” wandering through the blooming flowers, with signs along the way identifying pollinators. Bill did a “back-of-the-envelope” concept sketch for us on site.

We roughed out the lines in the dirt, and then defined the path with mulch.

Then it was time to plant. We chose tough native plants — species that evolved in our region growing in open dry meadows, able to survive without fertilizer, pesticide, or supplemental water. And though we planned to water and weed the garden for a season or two until the plants were established, we wanted a garden that eventually would need little maintenance. We also needed plants that would not be attractive to deer, rabbits, or woodchucks. We made a plant list, scoured the nurseries, and bought about 450 plants in containers (with funds contributed by multiple donors).

If you would like to know which plants we selected, click on the link below.

Plants-in-the-Pollinator-Garden-at-the-Greenburgh-Nature-Center Download

We started in the middle, planting the “spine” of the garden with tall, deep-rooted Switch Grasses that would support the tallest flowers in the center of the garden.

**The center “spine” of the Pollinator Garden**

We then worked outward, planting clusters of flowering species arranged in descending height. Shorter native grasses and ground covers were added along the edges to fill in and provide texture. We planted densely, aiming to have the plants grow together to occupy all soil areas within 2 seasons, thereby reducing available space for weeds.

**Plants are spaced 12 – 18 inches apart**

We decided not to mulch after planting, for a few reasons. Some of the invasive plants removed from the area were deep-rooted and would re-appear soon, with or without mulch. Weeds would be easier to see and remove promptly if we did not mulch. We also hoped our new plants would quickly grow together, expanding to occupy the entire ground space, and reseed themselves freely in the garden. Mulch would inhibit those natural growth processes. Finally, mulch would prevent the pollinators we are trying to attract from nesting in the ground, as many of them want to do. We want to support pollinators through their entire life-cycles.

We finished planting the Pollinator Garden on June 2, 2021. By August 2, it was in full bloom and alive with pollinators.

**Two months after planting, August 2021**

As we had hoped, this spring the garden came back full and lush. Weeding is ongoing, but not as difficult as we had anticipated.

**The Pollinator Garden this week, June 2022**
Photo: Nick Macaluso

So, please come celebrate Pollinator Month with a walk on our new pathway, and let the pollinators give you a tour!

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, 2022February 13, 2025 Cathy Ludden 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!