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Dogwood Lane
The Quarterly Journal of the Mary May Binney Wakefield Arboretum ___________________________________
Volume Six Issue 2 - Winter 2024
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Winter Beauty at the Mary May Binney Wakefield Arboretum | |
The Mary May Binney Wakefield Arboretum woody plant collection puts on a lovely show in winter. The dormancy of winter removes the distractions of lush growth, color and flowers and simplifies our garden views. The broad landscape view of blended canopy transforms into a sculpture of trunks and arching branches against the winter sky, allowing the individuality of deciduous trees and shrubs to be appreciated in a new way. Evergreens soften the view and offer a landing place for snowfall to envelop an area. Moving in for a close-up view of the landscape, plants show off interesting seasonal phenomenon such as leaves that curl to protect against weather, colored and textured bark that stand out in the low light, bright fruit that attracts chattering birds, brave winter-blooming flowers, wildlife tracks in the snowy garden paths, and next season’s slowly growing buds – all highlighted by the simplicity of winter. This edition of the Dogwood Lane Quarterly focuses on some of the plants in the collection that shine in the winter season. | |
Ilex verticillata berries remain on the shrub late into the winter providing food for over-wintering birds. | |
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Winterberry, Ilex verticillata
Many recognize the Ilex verticillata either by the stems covered with bright red fruits that are often used in Christmas decorations or by the fact that they stand out on the edges of wetlands in the winter months after leaves have fallen. There is a mass planting of winterberry in the Brook Garden at the Wakefield Arboretum which is a relatively wet area of the garden. This year the berries on the plant were spectacular, creating a great display of color as a mass planting. Combined with a variety of native magnolias this grouping creates a lovely addition to the landscape. Ilex is latin for plants that are evergreen; while verticillata acknowledges the structure of the fruits that appear to be whorled around the branches. (1)
| Winterberry is a member of the Aquifoliaceae (holly) family and is native to Eastern North America. Like most hollies, it is dioecious meaning there are distinct male and female plants; the proximity of at least one male plant is required to pollinate the females to bear fruit. "Dioecious" comes from the Latin for the term "two households." Male plants bear staminate flowers while female plants bear pistillate flowers. Wakefield’s male ilex known as Ilex verticillata 'Jim Dandy' has flourished in the shrub garden but is less noticed as it does not bear the showy fruit. It is important to select male and female plants of the same flowering period for proper pollination by bees and butterflies. Botanists recommend locating a male plant within 40 feet of a female plant for pollination. Given the abundance of berries on the female ilex plants about 30 feet away in the Brook Garden, the distance seems just right. |  | Winterberry is unique in that the fruits do not drop to the ground after they become ripe, instead they hang on to the stem and persist for weeks to months. Even under freeze and thaw cycles, they remain, which is why they are called "persistent" fruits. Other shrubs with winter-persistent fruits include viburnum, crabapples, chokecherry, hawthorns, and sumac. Because they stay on the plant into January and February, they are an important food source for overwintering birds such as robins, eastern bluebirds, cedar waxwings, woodpeckers, wood thrushes, and gray catbirds. Winterberry is also a larval host to 39 species of Lepidoptera, including the Henry’s elfin butterfly, the pawpaw sphinx butterfly, and the black-dotted ruddy moth. The flowers attract bumble bees, mining bees, sweat bees, small carpenter bees, and plasterer bees. Rabbits and deer browse on the bark and buds of young winterberry. |  | Several cultivars of winterberry have been recently added to the collection including Ilex verticillata 'Little Goblin' and 'Winter Gold', both bearing orange fruit adding beautiful color to the garden while supporting native species. 'Winter Gold’ is a late-blooming, female plant. One male winterberry, such as the late-blooming cultivar ‘Southern Gentleman’, is necessary for every 6 to 10 female plants. |  | |
Carolina allspice, Calycanthus floridus
The Wakefield Arboretum is home to a wonderful shrub, the Carolina allspice or Calycanthus floridus. Because of its fragrance, this shrub is referenced by so many names mentioning fragrance, such as "Carolina allspice," "sweet bubby," "sweet Betsy," "strawberry bush," and "hairy allspice." Beginning in April, a sweet perfume with hints of fruit permeates the air as the urn-shaped flowers open before the leaves have emerged. Although each flower loses its fruity scent within a day or two, other flowers continue to bloom with their bursts of fragrance. Once the leaves emerge, the flowers are often hard to see, but they continue to bloom and release their scent through May and occasionally throughout the summer. By early fall, they give way to drooping, fig-shaped seed pods that provide winter interest to the plant especially when coated in ice and snow. The bark and roots emit a juniper-like scent when rubbed or crushed. The overall intensity and quality of fragrance can vary from plant to plant.
Carolina allspice is native to the southeastern United States. The genus name comes from the Greek words kalyx, meaning “calyx,” and anthos, meaning “flower.” The specific epithet means “of Florida.” This shrub is largely maintenance-free and grows in sun and shade. They are also easy to transplant, ideally after the leaves have dropped in fall or winter. Rooted suckers may be detached from the main plant and replanted. (2)
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Calycanthus is pollinated by beetles in a process known as cantharophily. According to the University of California Agriculture and Natural Resources web page: “Flowers that are pollinated by beetles are referred to as cantharophilous, from the Greek kántharos (beetle) and philos (loving). Cantharophilous plants, or those primarily pollinated by beetles, have flowers that share common characteristics, such as: a bowl shape with exposed sexual organs, no distinction between the petals and sepals, a large and solitary form with radial symmetry, and a strong fruity odor. Researchers believe that the flowers’ oils mimic the odor produced by a fungi that attracts beetles. The Calycanthus flowers are shaped to allow beetles easy entrance. Once inside, it’s difficult for the beetles to escape without transferring pollen. After the beetles consume the pollen, they defecate in the center of the flower and then roll around in the mix, coating their bodies in rich deposits of both pollen and waste. Scientists theorize that because beetles lack the fuzziness of bees and flies, the mixture of waste and pollen has better adherence to their bodies and can, therefore, be more easily transported to other flowers. The mixture also serves to coat the beetle in the scent of the flowers they pollinate, further protecting them from predation.” (3) When the flower has been pollinated, the petals draw back and up, allowing the beetles to exit. | |
Calycanthus being pollinated by beetles in image b. Image published in Flora - Morphology, Distribution, Functional Ecology of Plants | Beetles not only represent the greatest diversity of pollinators, they also carry the honor of being the oldest pollinators on the planet. True beetles were already on the planet during the era of the supercontinent Pangaea, 230 million years ago. Archeological studies have found fossilized beetles in amber covered in water lily pollen dating back 100-150 million years. This pre-dates bees by about 30-80 million years! (4) | |
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Tupelo, Nyssa sylvatica
In order to control the flow of water in her dogwood nurseries, Polly Wakefield created a large swale, which is a shallow, broad and vegetated channel designed to store and/or convey runoff and remove pollutants. This large swale captures overflow from the south end of the property. A vegetated swale is even more effective at trapping, filtering and absorbing water and in this case resulted in a thriving wetland habitat. Polly planted the edges with water- loving, native species including highbush blueberry Vaccinium corymbosum, red twig dogwood Cornus sericia, and the magnificent Tupelo, Nyssa sylvatica. Nyssa sylvatica's genus name, Nyssa, refers to a Greek water nymph; the specific epithet sylvatica refers to its woodland habitat.
This tree also has a catchy colloquial name used only on Martha's Vineyard where Nyssa sylvatica trees are called Beetlebungs. This Island nomenclature is said to reference a local use of wood from this tree that was so hard and rot resistant that it was used to make both the wooden mallet (beetle) and plug (bung) for the barrels used to store oil on whaleships. (5)
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The Nyssa at Wakefield have reached a stately height of 50 feet and create a wonderful display of fall color. Of the Nyssaceae family, only the genus Nyssa is native to North America. Fossils of Nyssa's characteristic ribbed seed reveal the presence of these trees in former geological periods and throughout Europe, Asia and North America. This species has two common names: black gum, referring to the dark leaves; while tupelo is derived from the Creek Indian name for the tree (ito opilwa), which means "swamp tree". (6) | Developing tupelo flower, image by Greg Palermo | Between April and June, greenish-white flowers bearing copious amounts of nectar attract numerous types of pollinators. Flowers are followed by dark blue drupes that lure flocks of birds in fall. Fruit production depends on the amount of male, female, or perfect flowers on each tree. The trees are polygamodioecious, meaning some trees have mostly male flowers while others have mostly female flowers. Perfect flowers, which have both male and female structures, may also appear. Only the female and perfect flowers produce fruit. Black gum hosts 26 species of lepidoptera, including Hebrew moth and false underwing moth. (7) | |
Tupelo fruit usually vanishes early as it's a preferred food source for birds. Image Credit: Johnsons Nursery | |
Black Gum is the longest-living non-clonal flowering plant in Eastern North America, capable of obtaining ages of over 650 years. Nyssa are distinctive in their branching habit. Limbs jut out from the main truck at 90-degree angles making them easy to identify in the forest. The bark is dark gray and flaky when young, becoming furrowed with age, resembling alligator hide on the very old stems. Twigs of this tree are reddish-brown, usually hidden by a greyish skin. Deer are extremely fond of the leaves on seedlings and saplings, to the point where large deer populations can prohibit establishment of the tree. Mature trees are largely left alone. Dying trees have been known to provide a substantial hollow trunk for nesting or denning opportunities for bees and mammals. (8) | |
Persian Parrotia, Parrotia Persica | |
Polly Wakefield planted several Persian ironwood trees in her gardens. One tree in the lattice garden bears a tag clarifying its origin as seeds from the Arnold Arboretum. It is possible that the seeds were harvested from the ancestral specimen tree #2230, but the exact accession number is not recorded. The other Persian ironwood trees at the Arboretum, a row that borders the lower edge of the dogwood allee and two specimens alongside the steps from the mansion lawn into the lower wooded garden are very likely from the same source given Polly’s strong relationships. | |
A hardy and durable plant, the ironwood really starts to shine after 10 years. As the tree ages, the smooth gray bark develops more interest as it begins shedding. The exfoliation reveals a camouflage mosaic of green, white or tan in the underlying layer of bark, offering a striking contrast against a snowy backdrop. One of the mature trees at the Wakefield Arboretum often sheds bark forms reminiscent of the cut-outs used by the artist Henri Matisse. | |
In late winter or early spring, delicate flowers emerge before the leaves appear. The flowers lack petals and are comprised of dense, red stamens surrounded by brown bracts. While the flowers don’t put on a big show, they present a bright pop of color against cool wintry skies and offer interest when most plants are dormant. These flowers morph into brown, velvety inconspicuous seed pods. The seed pods offer a quick show with its seed dispersal method if one should be lucky enough to observe the moment: the seed pod exterior dries and shrinks, building pressure inside the pod which results in forceful ejection of the seed. |  | Foliage emerges reddish-purple in spring and grows into scallop-shaped, dark glossy leaves in summer. The leaves are oval to ovate-oblong with wavy margins, resembling fothergilla or witch-hazel. An outstanding feature of this tree, and one of the main ornamental reasons it is planted, is the blaze of foliage color combinations of golden-yellow, orange, red and purple offered in one tree in the fall season. | |
A Parrotia persica at the Cambridge University Botanic Garden in the UK demonstrates the self-grafting tendencies and fused branches. Image credit: Cambridge University Botanic Garden | |
Once ironwood sheds its leaves, the attractive growth patterns of the sinewy branches offer an interesting silhouette. Growing vertical in early years, the crown relaxes into a dome shape, extending more horizontally as it ages. The canopy of this tree can develop into an intricate lattice of limbs, made more complex due to the tendency for self-grafting. Tree limbs that have grown to touch one another can experience abrasion of the bark which exposes cambium (the cell layer that is the growing part of the trunk.) If the abraded sections of each limb are in direct and prolonged contact under pressure, have sufficient moisture to not dry out, and protection from elements, insects and pathogens, with the cambial cells aligned correctly, the limbs can join and create a graft union. (9) Mature specimen trees planted in the 1880’s at the Cambridge University Botanic Garden exhibit the serpentine network of limbs that can result from this self-grafting. | |
In addition to the ornamental features that span across all seasons, the Persian ironwood is extremely resilient, pest and disease free and requires little pruning. The tree prefers moist, well-drained soil in full sun; however, it is adaptable to numerous growing conditions and once established it is extremely drought tolerant. The hardy nature of this tree along with the beauty it provides ensure this tree will continue to be a sought after specimen in many gardens. | |
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Sawara cypress, Sawara false-cypress, Chamaecyparis pisifera
When snow piles up on the finely dissected foliage of Chamaecyparis pisifera, the wintry scene is picture perfect. Commonly known as the Sawara cypress, or Sawara false-cypress, the large evergreen conifer native to Japan can grow 70 to 100 ft in height with a trunk reaching 3 to 5 ft in diameter in its native habitat. The form is pyramidal, but develops a loose, open habit with age. While it is multi-branched, the lower branches may die with age. The bark is dark reddish-brown, rough or smooth, with fibrous, peeling thin strips. Foliage and bark can be aromatic with a woody, lemony scent.
Thread-leaf foliage appears to be weeping or draping over the entire plant, lending a softness to the tree’s appearance. The foliage is scale-like, glossy green above with small white markings underneath, and somewhat flattened. The species is monoecious, meaning separate male and female cones are present on the same plant. Male cones are very small, 1/8 inch, and elongated. ‘Pisifera’ means bearing pea-like seeds and refers to the female cones, which are somewhat larger, clustered, small, globose, about 6 mm wide, green or brown, with 8-12 scales. The Sawara cypress prefers temperate climates, with moist but not soggy soil, and does not perform well in hot, dry, or windy conditions.
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Examples of bark variations. | |
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The straight species is not as typical as a landscape plant due to its size. However, a wide variety of garden cultivars have been bred for their smaller stature. These varieties are versatile in the landscape, lending color, texture, and structure to beds, borders, containers, and mass plantings. Varieties come in different forms, sizes, and foliage colors, including green, blue-green, gold, chartreuse, and purple.
Numerous garden forms of C. pisifera are more common in cultivation and have been further classified into three sub-divisions of the species, "filifera," "plumosa," and "squarrosa". Cultivars bear normal foliage but differ in leaf color or in habit. Common examples are ‘Aurea’ or ‘Nana.’ In the Filifera group, often called Threadleaf False-cypress, the lateral branching is reduced, resulting in drooping, whip or cord-like branchlets mostly covered with scale-like adult leaves. ‘Filifera Nana’ is a dwarf version in this group. The Plumosa group, called Plume False-cypress, exhibit feathery branchlets of awl-shaped, part-adult and part-juvenile leaves in opposite pairs. ‘Plumosa Aurea’ is common in cultivation and exhibits yellow growths. Squarrosa are Moss False-cypress, growing branchlets with soft, needle-like juvenile leaves and more branching than the plumosa group. The typical form is a dense bushy branching of uniform silvery, dull blue hue. (10)
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Extensive cultivation has led to a wide variety in the foliage. 'Curly Tops' foliage in the image on the right is accentuated with the frost. | |
There are several examples of large tree form of Chamaecyparis pisifera at the Wakefield Arboretum throughout the formal garden area. Visitors can view a mature tree form and a dwarf version, ‘Curly Tops’ from the path between the Wakefield Arboretum’s Dwarf Conifer Reference Garden and the Lattice Gardens to appreciate the contrast. ‘Curly Tops’ is a globose semi-dwarf form of C. pisifera. It grows very slowly reaching 2 × 2 ft in 10 years, and eventually a mature height of approximately 4-5 ft. This plant never fails to attract interest with its a lovely texture and metallic blue foliage with twisted and curled branch tips. | |
We want to hear from you! We appreciate your feedback about our quarterly. Please let us know what research and articles you have found most interesting. | |
Articles written by Debbie Merriam and Bridget Gaffney and edited by Susan Hein. | |
For a printable copy of this or any prior issue of Dogwood Lane, click here or visit the news tab on our website.
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Mary May Binney Wakefield Arboretum | 617-333-0924
1465 Brush Hill Road, Milton, MA 02186 | www.wakefieldtrust.org
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