Paeonia (Suffriticosa Group) ‘Ezra Pound’ – tree peony

A gorgeous white flower dancing along the walkway to the Theresa Lang Garden of Fragrance, Paeonia (Suffriticosa Group) ‘Ezra Pound’ rings in the first, early-blooming tree peonies in the Peony Collection. This cultivar originally comes from William “Bill” Gratwick’s collection at Linwood Gardens in the outskirts of Rochester, NY. The flowers are most notable for their delicate, off-white hue, suffused with light pink that seems to bleed from the dark pink markings within the central, ensconced layer of petals.

Dotted along the sloped terrain, tree peonies have started to bloom in the Peony Collection. Paeonia represents more than 30 species, the majority of which are herbaceous perennials. Tree peonies instead develop woody stems into shrubs. As a result, these plants flower before their herbaceous and Itoh hybrid counterparts. Suffriticosa Group peonies refer to cultivars bred using Chinese Paeonia species from the subsection Vaginatae. More commonly these plants are called Moutan peonies. The flowers they produce easily grow to the size of an adult human hand, and a fully-grown, 5-foot tree peony may develop as many as 100 flowers in a single season.

Wisteria brachybotrys f. plena – silky wisteria

Another white flower currently in bloom gracefully drapes from the overhanging arches of the Theresa Lang Garden of Fragrance. Wisteria brachybotrys f. plena dangles its strings of pearly white flowers over the square lawn in front of the Intercultural Center. The curling vine structure combined with the hanging flowers make for a stunning ornamental plant. Up close, you can also get a whiff of its sweet fragrance as it wafts through the garden. 

Wisteria plants interact with a number of different organisms to succeed. The plant operates as food for some Lepidoptera species larvae, including several kinds of moths. Wisteria falls under the Fabaceae family as a legume along with peas. As a legume, Wisteria have symbiotic relationships with Rhizobia in the soil that fix nitrogen. Growers therefore don’t need to supplement the soil with nitrogen fertilizers, only potassium and phosphorus. Wisteria brachybotrys originates in Japan, and its species name refers to the “small clusters” of flowers. Although the species isn’t native, it’s not as aggressive as the W. floribunda (Japanese wisteria) and W. sinensis (Chinese wisteria) Asiatic species. 

However, there is a native species W. frutescens (American wisteria) that doesn’t take over the local forests. The biggest difference between the plants is that the North American species blooms after the plant has leafed out. Asian Wisteria vines bloom before the foliage opens. W. frutescens can typically be found in the wild along streambanks in the eastern United States. For gardeners, find a space for the plant to either climb or grow into a tree-like form in full-sun with moderate soil conditions. Although W. frutescens doesn’t have the history of cultivation that shaped other Wisteria species for centuries, its lavender-shaded blooms still offer a delightful vining spark to the garden – if you can handle the endless pruning maintenance, that is.

Cornus florida ‘Pluribracteata’ – flowering dogwood

The final white flowering plant of the week isn’t actually a white flower at all. Outside of Parrish Hall, the Cornus florida ‘Pluribracteata’ is in full bloom and covered in creamy white bracts. Unlike flowers and petals, bracts are actually modified leaves. On the flowering dogwoods, these petal-like bracts frame the true yellow inflorescence. The species name florida is also deceptive, meaning “flowery” in Latin. However falsely floriferous these plants are, the white ornamentation on Cornus florida ‘Pluribracteata’ provides a simple elegance to the Parrish Hall walkway. The layers of petal-like bracts gracefully top the leafy branches like sprinkles on a cupcake.

Cornus florida grows best on flatlands or lower on slopes rather than the tops of hills. Their shallow root systems have a difficult time collecting enough water for the plant on these higher, drier locations. Typically Cornus florida can be found in the shaded understory of Pinus taeda (loblolly pine) stands in the South although these trees grow from Ontario to Mexico. They’re an important ecological staple for birds and mammals who feast on the tree’s seeds, fruits, flowers, leaves, and bark. Flowering dogwoods have surprisingly high calcium and fat content. However, their anthropogenic uses tend to lean more towards small wooden tools such as textile shuttles, spools, malletheads, and pulleys. 

The post Plants of the Week: April 30 appeared first on Scott Arboretum & Gardens.

Graduates also receive an Itea virginica ‘Henry’s Garnet’, Virginia sweetspire, as a living memento of their years spent among the gardens of the campus-arboretum. ‘Henry’s Garnet’ was named and introduced by the Scott staff in 1984. It has exceptional fall color lasting from October into December reflecting the Swarthmore College school color of garnet.

It also has long sprays of creamy white, fragrant flowers in the summer, hence the common name of sweetspire. This shrub received the Gold Medal Award from the Pennsylvania Horticultural Society in 1988 for its outstanding qualities.

An adaptable native shrub, sweetspire will grow in full sun or partial shade, although the fall color and flowering will be best in sunny locations. It will thrive in wet sites, but also performs well in fairly dry ones. It is free of serious pests and diseases. At maturity, this shrub will reach 4-6 feet, forming a mound of arching stems.

Because Itea has a growth habit of sending out new shoots throughout its life, graduates can plant this shrub in a family or friend’s garden now (if they don’t have their own garden yet) and in a few years the graduates can transplant it, leaving a piece behind. Itea is hardy in zones 5-9, meaning it will grow from Southern Maine south to Florida and across the Midwest (through the middle of Illinois, Missouri and Ohio) to and through the West Coast states.

We invite you to look at Virginia sweetspire growing in the Terry Shane Teaching Garden behind the Scott office building (Cunningham House) and in the Rose Garden Circle between McCabe Library and Parrish Hall. This plant makes a great addition to any young or mature garden. We hope this plant will be part of each graduate’s garden and will bring back fond memories of Scott Arboretum & Gardens.

We wish all Swarthmore College graduates a bright and green future!

The post Commencement Traditions appeared first on Scott Arboretum & Gardens.

Lagerstroemia ‘Natchez’ – hybrid crapemyrtle

For the brave adventurers who have explored the Scott Arboretum & Gardens in the winter, there’s lots to see. Mainly bark. However this new perspective on plants allows the casual viewer to really develop an appreciation for the distinctions between barks. Lagerstroemia ‘Natchez’ has a particularly unique appearance. The pinks and greens meld and overlap like a springtime camouflage. 

Towards the end of the summer, this plant will produce white panicles of flowers. These blooms earned Lagerstroemia the moniker “Lilac of the South.” Often grown in multi-stemmed clusters, this hybrid crapemyrtle can sometimes sprout as a single-stemmed small tree in warmer climates. Between the bark, flowers, and luscious green leaves, this plant is a year-round spectacle.

Plenty of crapemyrtles have unique bark colors and designs. ‘Natchez’ stood out to me by the stark contrast of these hues. Originally a cross between L. indica and L. fauriei, ‘Natchez’ is one of several mildew-resistant hybrids developed by the National Arboretum. The Arboretum named each hybrid’s cultivar after a Native American tribe. Lagerstroemia ‘Natchez’ produces the best flowers in full sun, planted in acidic loams or slightly clayey soils.

Cornus mas ‘Spring Glow’ – corneliancherry dogwood

This week’s late winter storms featured grey skies and cold winds. This corneliancherry dogwood in front of Bond Hall called to me as a shining beacon against the final dreary weeks of winter. Around the gardens, some flowers have begun to peek their heads up from the newly-mulched beds, but Cornus mas ‘Spring Glow’ stands a head above the rest. Or maybe closer to a couple heads. These bright, puffy, mustard-yellow, pompom-like inflorescences reflect every photon of light that breaks the cloudcover. They also contrast the morose, purple blooms and leaves on the Helleborus x hybridus ‘Black Diamond’ flowers below. The collective image of early spring delight has even encouraged a few cautiously optimistic bees.

Beyond the sunny flowers, this tree also has notable bark. The mottled, dusty browns layer against a rosy undertone, and strips crackle and fray around the bends and corners. In the late summertime, the bright red fruits will speckle the branches in a similarly vibrant fashion. They’re completely edible and definitely worth a try, but maybe have a glass of water on hand.

Depending on the sun and soil quality, Cornus mas ‘Spring Glow’ only maxes out around 25 feet. Find a sunnier spot to promote better blooming, and keep to moist, well-drained soils if possible. This small, flowering tree can withstand a variety of urban conditions, and it’s moderately drought tolerant. With the right garden space, this show-stopping shrub could provide year-round excitement and breathe life into the late winter garden.

Galanthus nivalis – snowdrop

Tis’ the season of the snowdrops. Just as the snow officially melted, these tiny white flowers sprung their own white blanket on the forest floor of the Metasequoia Allée. In the foggy dusk light, these flowers glow eerily like tiny flower ghosts. 

Like many of our bulbs, this flower is native to Europe and southwest Asia, having naturalized in some areas of North America. In some gardens around the Cunningham House, staff on our horticulture teams have had to spend hours digging their fragile stalks out from under piles of leaf debris left over from the previous fall. They’re not accustomed to our teeming oak organic matter. The little white wisps have nonetheless livened the post-snow gardens like tiny harbingers of spring. Whether or not the false spring has fooled them, I’m delighted by this glimpse of the gardens to come.

Galanthus nivalis features six tepals rather than any true petals: three milky white tepals on the outside and three more enclosed within. Monocots like Galanthus nivalis can be identified by their clusters of three flower parts. Dicots, alternatively, have flower parts in groupings of four or five. The leaf blade is thin and narrow with parallel venation and a rounded tip.This particular species of snowdrop prefers moist, humusy soils. In the summertime, horticulturists frequently water the allée to make sure these perennials planted under the Metasequoia glyptostroboides (dawn redwood) don’t dry out in the drought. We’re also at the lower end of their zone range. Galanthus nivalis struggles south of Zone 7.

The post Plants of the Week: March 20 appeared first on Scott Arboretum & Gardens.

Must be the season of the witch because our witchhazels have finally bloomed. Across campus, winter-blooming witchhazels can be spotted by their unique, confetti-like flowers sprouting off the branches like a fungal disease.

Only five species of Hamamelis exist, and we currently have at least one of each on campus: Hamamelis japonica (Japanese witchhazel), H. mollis (Chinese witchhazel), H. ovalis (bigleaf witchhazel), H. vernalis (vernal witchhazel), and H. virginiana (common witchhazel). Only H. virginiana is native to our region of North America. While common witchhazels bloom in late October in the Crum Woods, our other witchhazel species bloom in the winter months. These brightly-colored flowers speckle the landscape with a shock of color and provide a sweet nectar treat to the many flies, wasps, and moths bumbling about outside of the typical growing season. With little else blooming, witchhazels don’t have to compete; they only have to lure in their pollinators.

Despite their vibrant color and bountiful nectar, people once believed that witchhazels were wind-pollinated. Their fragrance is another key indicator that witchhazels rely on insect pollinators to fertilize. Witchhazels have a cloying, sweet scent once described to me by a Swarthmore community member as “floral.” Ideally, prune your witchhazels after they bloom, but a few cut branches can lift a room with their aroma.

Outside of the blooming season, Hamamelis can most easily be identified by its leaves. Each leaf has a wavy, scalloped margin with an uneven base, and oftentimes leaf galls protrude from the tops too. Many of our witchhazels also have an upside-down pyramidal shape. In the woods, this form would be advantageous to maximizing captured light as photons filters through the canopy.

While witchhazel is a fascinating common name, its origin has nothing to do with the cackling, broom-riding characters from fantasy stories. “Witch” likely comes from the old English word wych, meaning “to bend.” Like an old-fashioned dowsing rod, users searched for hidden, underground water deposits with the sticks. The witchhazel branches made ideal dowsing sticks because of their forked, y-shape. Dowsers believed that the branches would bend towards the ground upon discovering water sources although no scientific evidence supports these claims.

People have also used witchhazels for medicinal purposes for centuries. Native Americans used the bark and twigs to treat anything from colds to insect bites. Since the 1850s, several companies have specialized in producing witchhazel extract, which you can find today in numerous lotions, toothpastes, and soaps. Some studies found anti-inflammatory benefits when the witchhazel extract is applied to the skin, with demonstrated effectiveness against some bacteria and fungi.

Witchhazels will continue to bloom for the coming weeks. I’ve highlighted a few of the early-blooming species and cultivars that will soon be past their prime but leave a wondrous fragrance in their wake.

Hamamelis mollis ‘Early Bright’ – Chinese witchhazel

We have a number of ‘Early Bright’ Chinese witchhazels around campus. In the peak of the winter cold, these plants resolutely flowered in all of these nooks and crannies. The spindly flowers are a bright yellow, and they popped out by the end of January even amidst the freezing temperatures and snowfall. Its distinctive sweet scent wafted through the Fragrance Garden where you can spot a unique espaliered version of this tree. Through the stone windows across from the Gender and Sexuality Center, the vibrant petals also catch the sunlight.

Hamamelis x intermedia ‘Jelena’ – hybrid witchhazel

Crosses from H. mollis and H. japonica plants created our Hamamelis x intermedia (hybrid witchhazel) trees. They tend to bloom earliest in the season, signalling the start of the witchhazel bloom period. A number of our cultivars also have gorgeous colors. A bit off the beaten path, this hybrid witchhazel ‘Jelena’ boasts a gorgeous combination of oranges, yellows, and purples in the bed south of the Dining and Community Commons. At this point in the season, the petals have seen better days, but it’s a flower to await next winter.

Hamamelis x intermedia ‘Diane’ – hybrid witchhazel

Another hybrid witchhazel, I checked Hamamelis x intermedia ‘Diane’ every morning on my way into work. Throughout the week, the petals cautiously unfurled, finally settling into their stunning display on the slopes behind the Wister Center. The unusual purples and pinks make this cultivar particularly exciting in the landscape and distinguish itself from most other Hamamelis cultivars that generally fall closer to yellow shades and tones.

The post Plants of the Week: March 2 appeared first on Scott Arboretum & Gardens.

2024 -2025 Public Horticulture Intern Seamus Lewin reviews how to identify and remove invasives plants commonly found in PA woodlands.

Tune into the Gardener’s Almanac to learn what we are doing in the garden at this moment. Learn from Scott Arboretum staff which plants we are pruning, planting, weeding and which pests we are monitoring and removing right now. This virtual almanac is a great reference guide for gardeners.

The post Gardener’s Almanac: Winter Invasive Plant Removal appeared first on Scott Arboretum & Gardens.

Without leaves on the trees, it’s easy to assume our deciduous trees have nothing going on. However, many bare branches hold winter interest. Here are a few plants that may not have leaves on their branches, but they do have something else.

Magnolia x soulangeana ‘André Leroy’ – saucer magnolia

Some magnolias hold onto their leaves throughout the season, but Magnolia x soulangeana ‘André Leroy’ and other saucer magnolias are deciduous. However, their leaflessness adds to their spring charm. This saucer magnolia, along with many other Magnolia species, will be some of the first trees blooming in late March. That early-bird mindset can be partially attributed to their buds. Stark and visible at the tips of the branches, magnolia flower buds are designed for early blooming success. Magnolia x soulangeana flower buds have two thick, hairy scales layered on top of each other. Fuzzy trichomes cover each layer, giving them an extra boost of insulation. Together, these features allow the flower buds to withstand the winter and bloom early in the spring.

However, this early bloom has its risks, too. Early spring frosts can damage the Magnolia x soulangeana flowers so they lose their vibrant, cup-shaped sheen. If possible, avoid planting this tree in a warm, southern spot near a building. The extra warmth that comes from a sunny spot and close proximity to a heated structure can induce early blooming, putting your tree at greater risk of losing flowers to frost. Ideally, this saucer magnolia prefers partial shade with protection from cold, harsh winds. If you’ve got the right spot in the garden, it’s worth the hassle. 

Without having too much spring envy, these trees really excel during the blooming season. Around late March, the cup-shaped pink flowers take over the tree. The ‘André Leroy’ cultivar has a deep magenta to white gradient that perks up the garden at the end of winter. It is also known for having a shorter, bushier habit, which might make this plant more ideal for smaller gardens. Magnolia x soulangeana was originally a hybrid cross between M. denudata (Yulan magnolia) and M. liliiflora (lily magnolia) in 19th Century France. Now, there are a range of saucer magnolia cultivars to choose from, so don’t be afraid to explore the shades and shapes for whatever best suits your garden.

Edgeworthia chrysantha ‘Snow Cream’ – paperbush

I’ll preface this by saying that I swear I’m not exaggerating for once. The Edgeworthia chrysantha ‘Snow Cream’ branches twinkle with dozens of silver-bell-like flower buds. A shock of silver. Eye-catching, even from a distance. Trust me, they pop in the winter landscape.

Paperbush is another plant to keep your eyes out for in the springtime, too. These delightful baubles transform into adorable, little, yellow inflorescences come April. They also continue to dangle like tiny falling stars upon blooming. With the spring blooms comes another treat: the fragrance. These blossoms give off a sweet, lilting scent described as a mix of jasmine and honey. Its entrancing odor beckons visitors through the early spring garden and provides ample excuse to throw open the second-floor Cunningham House windows.

The plant itself is a rotund shrub, no more than eight feet, which keeps it mostly at eye level for year-round enjoyment. This woody perennial does best in partial shade with moist, well-drained soils, but it’s adaptable as long as it avoids hot, afternoon sun. ‘Snow Cream’ tends to be a fast-growing, somewhat hardier specimen if your garden has a cooler microclimate. Beyond that, it’s a critter favorite. Throughout the seasons, sparrows and chipmunks take up temporary residence among the multi-directional branches.

Perhaps the most odd thing about this plant is its weird nomenclature debate. In the 1800s, two separate researchers submitted a species name for this plant around the same time (E. chrysantha and E. papyrifera), leading to some confusion as to which author had penned the name first. Currently, both are listed as a synonym for E. tomentosa, but search results for E. tomentosa redirect to E. chrysantha webpages. At least it’s not just public horticulture interns who struggle to keep up with scientific name changes. The common name “paperbush” refers to this plant’s history as paper bark for creating quality paper and Japanese banknotes.

Liquidambar styraciflua ‘Slender Silhouette’ – American sweetgum

Flower buds aren’t the only thing to spot on a wintering, deciduous tree. These bare Liquidambar styraciflua ‘Slender Silhouette’ branches still bear the identifiable, urchin-like seed pods. Leafless, nothing blocks these uniquely identifiable spiky balls from view. Add the narrow spired shape of this particular cultivar, and the overall look is unexpected and unique.

Liquidambar allegedly gets its genus name from an encounter between Spanish conquistador Hernán Cortés and Aztec emperor Moctezuma II tasting sap from a sweetgum tree. In the account, the recording soldier describes the sap as “liquid amber.” Probably in Spanish, but somehow the Latin name solidified, much like the sap after a week, as Liquidambar. For your own taste of liquid amber, the sap reportedly hardens to a gum if you knock off part of the bark and wait for one week to collect off the wound. This gum, or rosin, has historically been used as chewing gum among indigenous communities. The bark and fruits can also make a palatable tea for experimental tastebuds. 

As a child, I often grouped American sweetgum and maples together because of the star-shaped leaves. Alas, they are not closely related. The Liquidambar styraciflua leaves are alternate instead of the opposite formation among Acer species, and American sweetgum actually falls into the Altingiaceae family where they exist as the sole extant genus. For a while, it was included in the Hamamelidaceae family with witchhazels, but that has since been revised following several molecular phylogenetic studies. A 1935 study published in the Journal of the Arnold Arboretum by Edgar Anderson and Karl Sax identified n = 12 chromosomes in every sub-family of Hamamelidaceae except Liquidambaroideae which was n = 15. The slow march of science took its sweet time from there.

Most plants we grow at the arboretum prefer generous growing conditions – average, well-drained, loamy soils with adequate sunlight. L. styraciflua ‘Slender Silhouette’ is no exception, only you don’t want to provide optimal growing conditions. To slow growth, keeping its habit tall and tidy, grow this tree in poor soils and tough spots in your garden, but still in full sun. During the first few years as the plant establishes, provide ample water without overdoing it. The widest the plant should become is 5 feet.

The post Plants of the Week: January 22 appeared first on Scott Arboretum & Gardens.

Cedrus deodara – Deodar cedar ‘Roman Gold’

What’s left of the Cedrus deodara male cones confetti the grounds and tree rings north of the Dining and Community Commons. As students tromp from lunch to class, their footfalls smoosh the last puff of pollen like a deflated balloon. Bustling through this side of campus, I found the destruction so delightful that I decided to investigate further.

From there, it’s clear to see how this particular tree captured my attention. Cedrus deodara ‘Roman Gold’ is a beautiful tree. There are a number of specimens on this corner of campus to enjoy – with their counter-balanced, swinging branches, whorled with three-inch, lush green needles, balanced into a tall pyramidal shape vaguely resembling a floppy witch’s hat. This ‘Roman Gold’ cultivar carries golden spring leaves, but its graceful, vertical stature is probably its most attractive feature. And then, of course, the last of the fuzzy catkin-like cones clinging to the branches.

Cedrus represents a genus of plants known as true cedars. Unlike other conifers closely associated with boreal forests, Cedrus species actually prefer warmer climates. Here in the Philadelphia area, we’re at the edge of the C. deodara hardiness zone. C. deodara trees originally hail from the western Himalayan region, where the name “deodar” in Sanskrit roughly translates to “timber of the gods.” Local populations greatly value the deodar cedar timber. Stretching across mountainous forests in Pakistan and northern India, C. deodara wood builds furniture, building reinforcements, and other large-scale construction and carpentry projects. The wood is not only sturdy and rot-resistant but also aromatic and red-tinted.

C. deodara thrives in full sun with plenty of room for its roots and well-drained soils. For best results, Deodar cedar needs deep, fertile soils in cooler areas with high humidity. However, the tree is hardy once an adult. Its drought and heat tolerance have made this tree particularly well-suited for western and southwestern United States climates. Some have even dubbed it the California Christmas tree.

Hydrangea anomala – climbing hydrangea

The snow has fallen. Winter is here. Most people aren’t thinking about their deciduous woody vines that aren’t much more than a naked, brown structure on a wall. Just wait until you’ve seen the vibrant pink buds on this Hydrangea anomala.

In fact, this climbing hydrangea displays a lot of surprising winter interest. The mature bark peels and strips in a reddish hue typically hidden by the flowers and foliage. The winding structure also plays off the schist walls and the marbled texture of the pillar on the North side of Kohlberg Hall that it snakes around. Then stay tuned for the spring leaf out and the summer blooms that usher in their own architectural dance.

Hydrangea anomala is the only hydrangea that climbs. And boy, does it climb. Once established, these plants are well-known for their ability to scale a two-story building within only a year or two. Its scruffy aerial roots easily grasp walls, too, without the need for a trellis or other climbing structure. If you want to and let it, this plant could vigorously and happily become your new building facade.

To sign yourself up for summers maintaining its structure on your own garden walls, plant this climber in full shade to partial shade in fertile, moist, well-drained soils. Plants will also do better in cooler microclimates in this region. White or pale green flowers will bloom in the early summer. Flowers bud from the old wood, so it would behoove growers to avoid pruning except for size and shape control. Although fast-growing and hardy, this plant may take a few years to settle and establish in your soils, during which time the plant will not produce any blooms or much growth.

Juniperus rigida – needle juniper

I’ll start by admitting I was first drawn to the bark. After most of the leaves have dropped – I’m not talking about oak leaves – some of the most exciting aspects of the arboretum are the underrated barks often shielded by dense, green foliage. Not the case here. With drooping branches of spiky needles swinging overhead, nothing has changed for Juniperus rigida, but with the allure of bark in the winter season, that’s what I saw first. The overlapping strips of greens and blues and reds and browns bend around branches and knobs like their own wooden river. Patches of lichen and moss highlight these hues like a mottled masterpiece. It’s beautiful and something singular to enjoy.

While not quite the temples where Japanese gardeners typically plant these trees, this needle juniper hugs the corner of western pathways near Wharton Hall. However, situated next to a Juniperus communis ‘Oblonga Pendula’ (common juniper), you can notice some of the distinguishing features between needle juniper and the native counterpart. For one, the needles are closer to the ground. The pokey appendages on the Juniperus rigida hang above and out of the reach of small children.

More often garden retailers will have the ‘Pendula’ cultivar. These branches weep with needles, which can have an interesting effect for smaller gardens in need of winter interest. The trees themselves max out around 20 feet, so it might even perform well closer to a wall. Juniperus rigida prefers average, drier soils in full-sun, and it will handle heat and drought as long as it doesn’t get bogged down in a wet spot. Fruit-like cones on female trees matures from a green to a bluish-black that some birds enjoy in the fall.

The post Plants of the Week: December 22 appeared first on Scott Arboretum & Gardens.

Ampelaster carolinianus – climbing aster

Plenty of plants climb and vine, but how many bloom in fall or late summertime? Garden Supervisor Chuck Hinkle first pointed out this lovely plant in August, promising all I had to do was wait. I circled back to this corner of campus, an unassuming fence behind Beardsley Hall that blocks unappealing equipment and dumpsters. At first, this Ampelaster carolinianus was just a climbing plant. Then, a few weeks later, I saw some early buds. Then, another few weeks later, they finally broke free in late October. With how busy it’s been around the Arboretum, I haven’t been able to give these flowers their flowers.

Asters provide simple sparks of joy. Each little head inflorescence may teem with tiny florets, but from a distance, they’re rather common. For months, different asters have been popping in and out of the wildflower landscape, and amidst that flurry, the purple-flowered, yellow-centered Ampelaster carolinianus might get lost in the mix. This is where the timing is key. Instead, they’re an autumnal surprise, facing otherwise falling leaves and senescence across campus, and finding a pocket of reigning blooms. This late bloomer turns a plebeian flower into a crown jewel.

All exaggerations aside, it’s a cheerful little blossom when the wind is nippy and the sky is gloomy. The flowers coat the skinny-leaved climber in purple delight. You can almost imagine the splendor in a few years when the plant has thoroughly ensconced the wooden slats.

Unfortunately, these sprightly sights have already bowed out. If you’re hoping to catch a whiff of these last-minute superstars, you’ll have to wait your turn for next season. Or grow your own! These crawling perennials could spice up a fence, a wall, a shed, a trellis, or any sturdy frame around your house, promising pops of purple while much else in the garden shifts to bronzes, yellows, and browns. Plant in a garden spot with plenty of good drainage and average water, ideally with more sun to encourage greater flowering. Deadhead the flowers in early winter, but avoid pruning until the new growth is visible in the spring.

Pinus strobus – eastern white pine

Leaves may have fallen from the deciduous angiosperms, but this time of year, needled evergreens are a garden staple. And the cuddliest of them all has got to be Pinus strobus. Eastern white pine’s bundles of quintuplet needles rustle gently in the wind and bend easily to the touch. It’s a forgiving plant where Picea and Abies bristle and poke. 

Back in the early days of North American colonization, eastern white pines were prized for their straight, tall trunks. The wood is easy to work with, and they’ve been frequently used for timber, ship masts, and construction lumber. The Pine Tree Riot of 1772 was actually a result of the King of England claiming the best and tallest of the eastern white pines, and revolutionaries flew the pine tree flag as a symbol opposing tyranny during the American Revolutionary War.

In the wild, these trees can teeter as high as 100 feet. Historical records indicate some eastern white pines were even 200 feet tall. However, many of these giants have fallen victim to white pine blister rust, a fungal infection first spread from Ribes spp. that initially infects the needles, then forms cankers on the branches. Infections that reach the trunk can girdle a tree, cutting off its water and nutrient transport mechanisms beyond that point. Girdled adult eastern white pine trees won’t die, but the infected branches could die, and the tops will become incapable of continued growth. Infected eastern white pine trees won’t reach their maximum height potential.

All white pines are at risk, but the greatest ecological impact concentrates around high elevation trees in the western United States. While our eastern white pine trees are young and spry, it’s important to keep an eye on the branches and scout for potential diseases that could wipe out smaller trees.

And yes, I also adore the dwarf cultivar ‘Nana’ perched on the corner of the Arboretum Entrance Garden. And yes, readers might see that particular specimen pop up in an article a month from now. Sue me; I love a fluffy eastern white pine.

One of the garden beds I love at the Isabelle Cosby Courtyard houses swaths of purples and yellows, and this variegated treat glowed in the afternoon sun. Ilex crenata ‘Drops of Gold’ is one of our few variegated woody plants in the Arboretum collection. These yellow mottled leaves emulate an unfinished paint coat, as if someone had only completed one pass of yellow using a roller paintbrush on the tops of the plants. This splash of color allows the tops of the plants to shine while still providing depth from the dark green beneath. In the winter, the waxy, evergreen leaves make an eye-catching addition to gardens but also wreaths and decor.

Japanese holly is a short but spreading plant, allowing for bulky bed coverage throughout the seasons. As in the Isabelle Cosby Courtyard, perennials easily pop through the branches, allowing for interesting color and pattern combinations. For the most vibrant yellows, be sure to plant this particular cultivar in full sun, but the Ilex crenata ‘Drops of Gold’ otherwise holds up under shadier conditions as well. The plant doesn’t produce much by way of flowers. Similar to the native Ilex glabra, the tiny, white flowers hide amongst the foliage in the spring, and the small, black berries don’t distract from the variegated color display. That being said, ‘Drops of Gold’ is a female clone of a dioecious plant. Ilex crenata won’t produce fruit without both a male and female plant, the male plant providing pollen for the female plant, so it’s possible to miss out on the fruits altogether.

The post Plants of the Week: December 16 appeared first on Scott Arboretum & Gardens.

Rhododendron ‘Milestone’ – rhododendron

The Harry Wood Garden is a cove of striking pinks and deep greens at the moment, and nestled between the dense foliage, the Rhododendron ‘Milestone’ glows. Its delicate pink flowers, one strong puff from disaster, have clung to these branches through willpower and a lightning strike of potentially favorable environments. You might be thinking, Don’t rhododendrons bloom in the spring? And you would be right. This late-blooming, rusty Rhododendron does typically bloom in the spring, from early-May to mid June. ‘Milestone’ is not an exception. However, sometimes rhododendrons will bloom in the fall due to a number of uncontrollable factors: a timely rainstorm after a drought, highly stressful conditions, or in certain areas of the world, La Niña. 

Rhododendrons have long been prized as ornamental shrubs. Dubbed “the tree of roses” in Greek, over 1000 wild species populate the planet with their spring blooms, and hundreds more cultivars occupy gardens around the globe. Most cultivated rhododendrons are hybrids, having cross-pollinated and left their species names behind. Its petals have been used to make tea, its leaves for essential oils, and its fine-grained wood for a number of tools and furniture. Weston Nursery developed Rhododendron ‘Milestone’ to withstand the northeastern climates of Massachusetts, making this cultivar particularly hardy to colder zones.

Lindera angustifolia – willow-leaved spicebush

Perched atop the Biostream, this Lindera angustifolia holds on to its shining fall color like a cozy autumn bonfire. Amidst the rusting reds and souring yellows, these bell pepper orange leaves could truly embody a burning bush. The fall color won’t last much longer as the shades shift to a dusty brown, but the leaves themselves might cling to the branches through the winter months and into the spring. L. angustifolia may change colors, but it doesn’t quite lose its coat. The leaves themselves are year-round fun, with their oblong, lanceolate shape and their glossy, vibrant texture. Place this plant in a spot of your garden that could use a little autumnal pop of color.

If you’re looking to plant your own L. angustifolia, this plant has a multi-stemmed, bushy habit with plenty of texture and an aroma in the summer spiced just enough to deter deer predation. L. angustifolia can also scale fellow trees and buildings, which could add some character to your garden. This plant is adaptable to most gardens but prefers sandy, moist spots in the sun. The North American native Lindera benzoin doesn’t have quite the shock of showy color or leaf shape of its Asiatic counterpart, but it does have delightful flowers decorating its early spring branches that resemble Hamamelis blooms. 

Hamamelis virginiana ‘Harvest Moon’ – common witchhazel

We may have passed the Harvest Moon (October 6, 2025), but it’s never too late to celebrate the Hamamelis virginiana ‘Harvest Moon’. This common witchhazel gets its cultivar name from its late-blooming flowers, showing off its spooky splendor when little else is blooming this close to winter. Hamamelis virginiana consistently takes the prize as one of the last native plants to flower in the northeastern United States.

The genus name Hamamelis refers to the flowers and fruit appearing on the tree at the same time (Hama meaning “same” and melon coming from the Greek word for fruit), which is especially true for fall-blooming Hamamelis species. The life-cycle of these fruits are quite unique. The pollinated ovary enters a resting state during the winter and only begins fertilization in the spring, five to seven months after pollination. The fruit reaches maturity over the course of the summer into small green capsule dries and splits, rocketing the seeds like a cannon in late October. Just in time for the new flowers to appear! The seeds then lay dormant for two winters before sprouting.

One fall semester of college, I took a field biology class which involved tree identification. By the time we were quizzed on any of the plants, we all had to get really good at bark identification except when it came to common witchhazel. In the spring and summer months, this understory tree is delightful if unassuming, but its bizarre flowers have always been an autumnal, woodland gift. Older botanical references claim this tree is wind pollinated, but in actuality, these flowers are siren songs for moths, bees, flies, beetles, parasitic wasps, leafhoppers, and a number of other desperate critters looking for a late-season snack. In particular, you can find winter moths like witchhazel dagger moths (Acronicta hamamelis) and their larvae are known to feast on the sap and seeds. Its primary pollinators, though, consist mainly of flies and wasps.

‘Harvest Moon’ occupies a hidden pocket near the Glade, pinned between the Whittier Place backroad and the Science Center. While Hamamelis virginiana tolerates a range of shady conditions, the plant flowers best and grows larger in sunnier locations. Soils should be moist and well-drained, especially when establishing the young tree, preferably with slightly acidic and organically rich characteristics. This plant makes a great addition to a naturalized garden, winter garden, or rain garden, especially with a woodland focus. 

The post Plants of the Week: November 19 appeared first on Scott Arboretum & Gardens.

Salix ‘Swizzlestick’ – corkscrew willow

There are plenty of ways to enjoy fall color at this time of year, but if you’re looking for a unique twist to yellow right now, Salix ‘Swizzlestick’ delivers. The last of the thin, rough leaves cling to the ends of the branches, but the leaves are merely the curling, green, serrated icing on the metaphorical cake. At this time of year, the branches themselves really pop. Ranging from highlighter yellow to pumpkin orange, the vibrant bark holds a 2b curl with ease, bending in a slight corkscrew, spiralling upwards like a ballerina in a music box. It’s unusual and, in its oddity, exciting. At the moment, this tree makes quite the statement framed by conifers in the John W. Nason Garden.

Salix has an estimated 350 species, most native to the cooler climates of North America and Eurasia. Although its origin is unclear, Salix ‘Swizzlestick’ heartily handles winters in Zones 5-8. There’s plenty of winter garden potential for mid-Atlantic green spaces, but for maximum swizzle branching, make a hard cut back in late winter every few years as the plant gets larger to encourage new growth. ‘Swizzlestick’ enjoys sunny, well-watered sites but is otherwise not too picky. It will happily tolerate high salt concentrations, moist environments, and low soil quality. Salix species are great for erosion control, and they’re often found in the wild along banks and water edges. 

The original swizzlestick tree is Quararibea turbinata, a Caribbean understory tree growing up to 18 feet tall. These plants also have a slight bend to some of their branches, but the real swizzling comes from its nodes – points on the stems where multiple branches shoot outwards like wheel spokes. These spoked sticks have allegedly been used for rum cocktails to mix ingredients.

Rhus aromatica‘ Fine Textured Compact Select A’ – Lacette™ fragrant sumac

In terms of eye-catching color, Rhus aromatica ‘Fine Textured Compact Select A’ might not be your first thought, but as the leaves have slowly eked gradients of copper reds, the shrub looks magical right now. The leaves have a fun, pastel sheen to them as the greens, rusty purples, and brick reds mottle together. This Lacette™ fragrant sumac blesses its browning bed at Dan West House. The dark, reddish-brown bark compliments the speckled leaf senescence slowly creeping up each branch, dripping scarlets and plums up the dying greens.

This Rhus aromatica also easily tolerates our environment and all its conditions. ‘Fine Textured Compact Select A’ enjoys anything from full sun to partial shade. Although usually grown on the drier side of soils, it doesn’t mind a little rain. The main issue is poor drainage where Rhus aromatica doesn’t like to soak for too long. The ‘Fine Textured Compact Select A’ is particularly noted for its drought tolerance, so definitely lean into the absence of water when established for best results. This shrub works excellently as a collection, stabilizing sloped conditions and forming a delightful, colorful mass. Its species name highlights the light, lemony scent the leaves emit when crushed, but the plant isn’t otherwise too scent-forward. 

Salvia glabrescens ‘Shi-Ho’ – Japanese woodland sage

In autumn, we’ve got colorful branches, colorful leaves, and – would you believe it? – colorful flowers, too! Salvia glabrescens ‘Shi-Ho’ fills that gap. These initially unassuming plants nestled along the shaded walkways by the northern corner of Trotter Hall are speckles of violet sprinkled amidst the green foliage. The late-blooming flowers beckon the last of the bees and butterflies with very little competition. This Salvia hails from the Japanese island of Honshu and survives over winter as a perennial in the Philadelphia region. Despite its common name Japanese woodland sage and its membership in the Lamiaceae family, the plant doesn’t have much of a scent compared to its fun-smelling brethren. True to its name however, ‘Shi-Ho’ perfectly dots woodland environments in partial shade and moderate soil conditions. 

The post Plants of the Week: November 3 appeared first on Scott Arboretum & Gardens.