Plants of the Week by Kaiden Lytle, Summer Education Intern

If you’ve ever wished you could add plants to your garden that make it look like alien life has taken hold, then stay tuned for this week’s ‘Plants of the Week’ selections!

Allium ‘Millenium’ – ornamental onion

First off is a spiky, globular, blooming perennial that will make passersby stop and marvel at its unique shape. I am talking about Allium ‘Millenium’, otherwise known as ornamental onion. This plant is often used in garden borders as the purple color and planetary shape is eye-catching. Each bloom is large and packed with little star-shaped florets, and in a drift or group can look akin to floral fireworks.

Easy to establish in your garden and drought tolerant, this plant grows best in well-drained soil and full sun, where it will naturalize readily and return year after year as a hardy bulbous perennial. Gardeners also favor Allium ‘Millenium’ as a temporal gap-filler: it will bloom to fill the season between spring bulbs and early summer perennials. Within the Scott Arboretum & Gardens, you can currently find this plant in the Dean Bond Rose Garden, Cut-Flower Display Garden, gravel culture beds, John W. Nason Garden, and around the entrance of the McCabe Library. 

Cynara cardunculus ‘Florist Cardy’ – cardoon 

For those gardeners that prefer varied textures in their garden, you might be excited by the next featured plant this week: Cynara cardunculus ‘Florist Cardy’, commonly known as cardoon or artichoke thistle. Closely related to globe artichokes, and similarly edible, this is an extremely fun plant all around. Unlike the artichoke, however, it is not the fruit or flowers that are edible but rather the blanched leaf stalks! When established in your garden, Cynara cardunculus ‘Florist Cardy’ presents as thick stalks with silvery foliage, and in the summer season, this plant boasts dramatic spiky blooms in varying shades of violet.

This perennial is native to the Mediterranean region, and thrives in warm, sunny, dry conditions, but can still grow in colder regions as an annual or less-hardy perennial. Within the Scott Arboretum & Gardens, you can currently find Cynara cardunculus ‘Florist Cardy’ within the Entrance Garden, outside of the Cunningham Building. 

Colocasia esculenta ‘Illustris’ – elephant ear

Unlike the other two showcased flowering plants, this last featured plant is not planted for its blooms, but rather the striking foliage. I am talking about Colocasia esculenta ‘Illustris’, of course, commonly known as elephant ear or taro. While it can bloom briefly in summer, producing small yellow flowers, the blooms are infrequent and sparse, even in the best of conditions. The real show-stopper, the leaves, are huge and heart shaped (up to 3 ft. long), drooping artfully from the long petioles. The leaves are dark purple to almost black, with electric green coursing through each vein. This plant is a head-turner!

As a tropical perennial, it will thrive in sunny to part-shade areas with rich, moist soils. Be careful of planting too far away from other plants, as the leaves are sensitive to wind gusts, and can break easily without nearby shelter. Regarding height and cohesiveness in your garden, the above-mentioned plants are quite tall, and add a lot of vertical texture and color to the top layers of your garden. If you feel you need a nice medium-height addition, Colocasia esculenta ‘Illustris’ will help to add some balance within the mid layers of your garden. Within the Scott Arboretum & Gardens, you can currently find this plant interspersed within the Terry Shane Teaching Garden.

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Plants of the Week by Natalie Ipock, Summer Horticulture Intern

Lilium ‘Montreux’ – Asiatic lily

Lilium ‘Montreux’ is a stunning lily that can be found in the Tree Peony Collection outside the Hormel-Nguyen Intercultural Center. This lily’s flowers are pink in color with brown dots towards the center, along with brown anthers protruding from the center. As is the case for many Asiatic hybrid lilies, this plant is winter hardy, not fragrant, and readily reproducing. Although on the taller end for Asiatic hybrids, ‘Montreux’ still requires minimal overall maintenance.

Lilium ‘Montreux’ is a perennial that can reach about 3 feet tall and blooms in May through June. When considering a location to plant these lilies, make sure they are in full sun to partial shade and the soil can drain excess water. Lilium ‘Montreux’ could be just the pop of color your mid-summer garden needs. 

Heliopsis helianthoides var. scabra ‘Bleeding Hearts’ – false sunflower 

Heliopsis helianthoides var. scabra ‘Bleeding Hearts’ is native to North America and can be found in the Harry Wood Garden entrance. This perennial’s blooms last throughout the entire summer in ideal conditions, from late June to the first frost. False sunflower forms in clumps and is drought tolerant. With such vibrant colors, bees and butterflies love to swoop by and pollinate these magnificent plants. 

What I find most fascinating about Heliopsis helianthoides is what sets it apart from true sunflowers. These false sunflowers are composed of ray and disc florets, with both flower parts able to seed. However in a true sunflower, the ray florets  – the distinct yellow “petals” – are unable to seed. Beyond its physiological features, the striking orange-red color of the Heliopsis helianthoides var. scabra ‘Bleeding Hearts’ is sure to catch your eye. 

Hydrangea arborescens ‘Abetwo’ – Incrediball™ smooth hydrangea 

Another plant currently attracting pollinators is the deciduous shrub Hydrangea arborescens ‘Abetwo’. The height and spread of this impressive plant can reach about 4-5 feet, and it blooms throughout the whole summer. This Hydrangea can be found in the Hydrangea Collection outside Whittier Hall.

This smooth hydrangea was bred to fix the weak stem of Hydrangea arborescens ‘Annabelle’, previously featured in last week’s Plants of the Week article. Not only does Hydrangea arborescens ‘Abetwo’ have thicker stems holding up the blooms, but its blooms are slightly bigger as well.

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Plants of the Week by Caelon Shugrue, Public Horticulture Intern

Echinacea ‘Cheyenne Spirit’ – coneflower

Blooming in a variety of colors, Echinacea ‘Cheyenne Spirit’ flower can be purple, pink, red, orange, yellow, cream, or white. This specific cluster at the entrance of the Pollinator Garden – found between Cornell Library of Science & Engineering and Martin Hall – attracted me due to its wide range of hues from dusty orange to bright purple. The dried cones can remain into the winter and are often visited by birds such as goldfinches that feed on the seeds. In addition to birds, deer have also been known to snack on the new growth. 

Echinacea ‘Cheyenne Spirit’ is relatively easy to grow, enjoying full to partial shade and dry to medium moisture. As herbaceous perennials, it is tolerant of drought, heat, humidity, and poor soil conditions. These Echinacea can be planted in rock gardens, perennial borders, or almost any garden with sun. They are quite attractive when planted in groups; however, they can reseed themselves and often become overcrowded.

Hydrangea arborescens ‘Annabelle’ – smooth hydrangea

Walking through campus, Hydrangea arborescens ‘Annabelle’ immediately caught my eye due to its huge, round, stark-white blooms. These flower structures (called corymbs) can bloom for up to two months in the summer, sometimes featuring a repeat bloom in the fall. The ‘Annabelle’ cultivar is characterized by having larger flowers than the straight species. This cultivar is a naturally occurring cultivar that was discovered in the wild near the town of Anna, Illinois.

Hydrangea arborescens ‘Annabelle’ grows best in partial shade with medium moisture, and while it tolerates full sun it would require constant moisture. These specimens are located between Parish Hall and the Lang Performing Arts Center and bask in the shade of the dawn redwoods. Flowers bloom on new wood, so to promote an ideal form plants can be pruned back almost to the ground in late winter. Hydrangea arborescens ‘Annabelle’ looks best in mass or group plantings making up a shrub border or as a background for a perennial border.

Hypericum × inodorum ‘Allgrandeur’ – Miracle^® Grandeur St. John’s wort

The deciduous shrub Hypericum × inodorum ‘Allgrandeur’ struck my fancy due to the vibrant yellow flowers and bright red berries that stick out against its dark green foliage. Planted at the entrance of the Harry Wood Garden, the mass of foliage, bright yellow flowers, and glowing berries draw visitors into the garden. While this plant is very attractive for birds and butterflies, it does not attract deer, who have no interest in the plant.

Hypericum × inodorum ‘Allgrandeur’ grows in full to partial shade and does best in dry to average moisture. It is drought tolerant and will die in standing water. Hypericum × inodorum ‘Allgrandeur’ is also tolerant of most soil pH levels and is tolerant of pollution, allowing it to thrive in city landscapes. It can get quite tall (over two feet) and therefore it is best used in mass plantings, as hedges, or in containers. If growing Hypericum × inodorum ‘Allgrandeur’ in a container, it may require more frequent watering.

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Plants of the Week by Kaiden Lytle, Summer Education Intern

Clematis (Early, large-flowered Group) ‘Jerzy Popiełuszko’ – clematis

Popular for its large white blooms (13-15 cm diameter), this clematis adds a bit of elegance to any garden. This variety is fond of climbing and will climb both living and non-living structures nearby (trellises, fences, shrubs, etc). The leaves of this plant are large as well and are tripartite and heart-shaped. In regard to care, ‘Jerzy Popiełuszko’ prefers sunny sites in USDA Zones 4-9, with well-drained, fertile soils. In these conditions, it will bloom happily from May through October. 

This clematis cultivar was originally bred in Poland by Dr. Szczepan Marczyński, and released to the public in 2004. Notably, the following year, it won a gold medal at the 2005 Plantarium arboriculture trade fair, and again in the Gardenia 2011 exhibition in Poznań. The variety name bears reference to the historic Polish-Catholic priest, Father Jerzy Popiełuszko (1947–1984).

On the grounds of the Scott Arboretum & Gardens and Swarthmore campus, one can find Clematis ‘Jerzy Popiełuszko’ on the west side of the historic Dean Bond Rose Garden, or within the Isabelle Cosby Courtyard. 

Asclepias tuberosa – butterfly weed 

One might be more familiar with these bright orange clusters of flowers (and their usual winged clientele). Asclepias tuberosa, more commonly known as butterfly weed, frequents many a home garden, adding texture, color, and a hardy native nectar source for pollinators. 

Native to the lower 48 states and parts of Canada, this bushy perennial boasts flat-topped pops of showy bright orange flowers that are sure to add vibrant color to any garden it’s planted in. Once established, expect this plant to grow up to 1.5-2 ft. tall, with stiff, dark green stems and alternate, pointed leaves. 

This plant will help entice native pollinator species to one’s garden, boosting plant fertilization and improving native species biodiversity. Not only utilized by butterflies and bees, this Asclepias species is used by goldfinches and other songbirds as well, who will use the plant’s seed pod fibers as a food source and as nesting material.

Asclepias tuberosa can be found across Scott Arboretum & Gardens, including in the Entrance Garden, the Pollinator Garden, outside of Singer Hall and Whittier Hall (around the meadows), and the Harry Wood Garden. 

Astilbe ‘Straussenfeder’ (or ‘Ostrich Plume’) – astilbe

Lastly, but certainly not least, is Astilbe ‘Straussenfeder’, also commonly referred to as false spirea. First cultivated in 1952, and notable for its tall plumes of light pink flower panicles, this herbaceous perennial is also referred to interchangeably as Astilbe ‘Ostrich Plume’. (It’s worth noting that the German word ‘Straussenfeder’ translates to ostrich feather in English!) The Astilbe genus, however, is native to eastern Asia and eastern North America, with the ‘Straussenfeder’ cultivar being of Japanese origin. 

Great for any gardener looking to add a bit of light spring-ish color or depth to their garden, this Astilbe variety grows in fern-like clumps (up to 20 in. in height) and produces erect and arching stems that can reach up to 2.5-3 ft. tall. Blooms are light pink, loose-packed, and often trailing or otherwise flowy, and many gardeners favor this plant by a water feature for this reason. Within the Scott Arboretum & Gardens, Astilbe ‘Straussenfeder’ can be found in the Terry Shane Teaching Garden in a sole planter next to the fish pool.

Blooms occur in late spring and into early summer and leave dried seed heads on the ends of the stalks. These seed heads are often favored decoratively by gardeners and left throughout the summer to add ornamental interest to one’s garden. The blooms are also attractive to pollinators, and one might consider this variety for pollinator gardens! 

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Plants of the Week by Natalie Ipock, Summer Horticulture Intern

Spigelia marilandica ‘Little Redhead’ – Indian pink

Found at the western entrance to the Glade Garden, Spigelia marilandica ‘Little Redhead’ is a gorgeous flower you should make sure to check out on your visit to Scott Arboretum & Gardens. Blooming May through July, it is a perennial that prefers moister environments, such as a stream bank.

Spigelia marilandica ‘Little Redhead’ is native to the southeastern US and naturally forms in clumps. It is best grown in full sun to partial shade. Indian pink’s flower has a beautiful red base with a five-point yellow star of petals protruding from it. When in bloom, hummingbirds love to stop by and pollinate this magnificent plant.

Geranium ‘Azure Rush’ – cranesbill 

With striking patches of lavender flowers, Geranium ‘Azure Rush’ is sure to catch your eye throughout the entire summer. It has a floral scent and attracts many pollinators to its countless flowers. When considering a location to plant, cranesbill prefers full sun to partial shade.

This perennial blooms from late spring to early fall making it an ideal summer ground cover. It grows about 1-1.5 feet high and has a spread of about 2-2.5 feet. Not to mention, Geranium ‘Azure Rush’ is cold-hardy, deer resistant, and requires low maintenance. Make sure to check out this beautiful plant on the north side of Kohlberg Hall.

Clematis (Integrifolia Group) ‘Rooguchi’ – clematis 

Another perennial that attracts many pollinators is Clematis (Integrifolia Group) ‘Rooguchi’. A cross between Clematis integrifolia and Clematis × durandii, it inherits cute indigo bell-shaped flowers that dangle from its stem. With vine-like tendencies, it needs the support of another plant or a trellis to help it reach 6-8 feet tall.

Clematis prefers to be in locations with full sun to partial shade, and does not like damp environments. Found outside the Science Center, this Clematis (Integrifolia Group) ‘Rooguchi’ provides a nice pop of color to the area.

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Plants of the Week by Caelon Shugrue, Public Horticulture Intern

Aesculus chinensis var. wilsonii – Wilson’s horsechestnut

Native to northern China, Aesculus chinensis var. wilsonii has stunning branched clusters (also known as panicles) of white, slightly aromatic flowers. Wilson’s horsechestnut is mostly grown ornamentally. In fact, its seeds were collected and distributed due to these showy blooms. They first arrived in the United States when British botanist William Purdom sent saplings to the Arnold Arboretum in Boston from seeds collected in Beijing.

After the panicles of flowers –which can be as large as 16 inches long– bloom from May to June, dry dehiscent fruits form. At maturity, the husks of these fruits open (or dehisce) in early fall to release 1-inch nuts. Beware, these nuts are slightly poisonous due to the abundance of saponins, which can be successfully leached out through a rigorous process of cooking or washing. These nuts have historically been used in traditional Chinese medicine to treat shortness of breath and abdominal pain.

In China, Aesculus chinensis var. wilsonii grows in forests, thickets, slopes, ravines and roadsides. Thus, this tree is planted in places where it enjoys full sun to partial shade and well-draining soils. It can be used as a shade tree in many gardens or a street tree, but cleaning up after its nuts may seem tedious. This specific specimen is planted on the quad between Sharples Commons and Clothier Hall, where it basks in partial shade. Its eye-catching flowers and nuts add an interesting texture and feel to the landscape.

Deutzia x hybrida ‘Magicien’ – hybrid deutzia

Also with large clusters of flowers, this hybrid deutzia produces showy pink and white flowers from late spring to early summer. Adored by Scott Arboretum & Gardens horticulturists, visitors, and bees alike, this beautiful Deutzia has gorgeous, star-shaped flowers. It caught my eye because around this time of year it seems as though the Deutzia has more flowers than leaves. 

This hybrid is a cross between two Asian species of Deutzia: D. longifolia and D. discolor. Rapidly growing and with beautiful, showy flowers and bright, green foliage, this plant is ideal for planting along shrub borders or mass plantings. This specimen is found on the edge of the path by the Cunningham House – calling visitors to the entrance garden or perhaps wishing them farewell. 

Most flowers are produced when the plant is in full sun to partial shade with nutrient rich, moist soils. This shrub typically grows as tall as four to six feet with a similar spread, but regular prunings are recommended to keep it from looking unkempt. The hanging clusters of flowers are eye-catching in bloom, and the fall foliage is a pleasant red. Perfect for a shrub border or a hedge, this Deutzia is sure to spruce up any garden.

Kalmia latifolia – mountain-laurel

The state flower of Pennsylvania and Connecticut, the mountain-laurel blooms in late spring to early summer with striking geometric flowers. With many cultivars available, its flowers can range from pink to white to red or all three! The anthers in the flowers have an interesting pollen dispersal adaptation – when touched by a bee, the anthers spring out of their pockets in the petals and fling dustings of pollen on the pollinator.

As a member of the Ericaceae family, Kalmia latifolia is best grown in acidic soils. Native to eastern North America, this plant is found in a variety of landscapes such as rocky or sandy woods, meadows, and mountain slopes. In planted landscapes, this shrub is often used in shrub borders as it can spread vigorously. Its flowers are quite showy, and as an evergreen shrub, it has excellent year round foliage. Eaten in abundance, the leaves are poisonous but that doesn’t stop deer from enjoying a bite or two.

Kalmia latifolia has dramatic, gnarly branches adding an interesting dimension to any landscape. One of its common names “spoonwood” is a reference to the fact that woodworkers today and in the past have used this wood to make spoons or bowls. Often identified by its branches, Kalmia latifolia bark is rigid with pieces plaited and often hanging or peeling off.

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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. 

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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.

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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.

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