The trails which run through the Acton Arboretum (Acton, Massachusetts) are home to many native wildflowers, some planted, some naturally occurring. As a long-time gardener of native New England wildflowers, I have been given charge of enhancing and maintaining the naturalistic gardens along this Arboretum's Wildflower Trail, and I have posted this picture-article to call attention to some of the woodland species that can be seen growing along this forest floor habitat, and to suggest some of these species as workable additions to gardens. All of the species depicted or mentioned on this page are native to the forests of eastern, temperate North America, and with few exceptions their natural ranges extend into at least one of the New England states. These particular species were selected for use in this project because of their combinations of attractiveness, relative ease of propagation, and in some cases, a considerable need for conservation by means of cultivation.

Many native species spread prolifically and deserve our attention as possible additions to gardens, while others are best admired in their natural habitats and left alone. Species whose populations are fragile or slow to reproduce are especially in need of protection from human interference. Orchids, trilliums, and gentians tend to be particulary vulnerable, as even the picking of their flowers can interfere with their natural reproduction and can decimate populations. In fact, the collection of native plants from their natural habitats is often against the law, in addition to being unethical and damaging to the environment. Most of the native plants featured in the naturalistic gardens at the Acton Arboretum were purchased originally from suppliers who propagate their own stock, most prominently the New England Wild Flower Society.

The following video, which I created in 2007, shows a selection of spring-flowering woodland natives at their flowering height. To play this movie, turn on your speakers, click the screen below to activate it, and then click the play button.

Some species of lady's-slipper (genus Cypripedium) can be cultivated easily enough, but these plants are fragile and should not be collected from wild populations unless there is an immediate need to rescue them from “development.” In the case of the pink lady's-slipper (C. acaule), digging the plant almost always kills it within a few years, because it is utterly dependent on the presence of healthy colonies of soil fungi for its absorption of nutrients. If it is unavoidably necessary to rescue plants of this species, it is prudent to unearth as wide a rootball as possible with each plant, and to replant in locations where other pink lady's-slipper plants already are growing naturally, so that the transplanted individuals may have a chance of surviving for more than a year or two.

Other lady's-slipper species are not dependent on soil fungi (at least at maturity) and are thus easier to maintain. My efforts to cultivate the large yellow lady's-slipper (C. pubescens) have been marginally successful on a small scale. Professional seed propagation of lady's-slipper species is a complicated practice that is barely out of its infancy, but a few sources are successfully propagating and selling seedlings of a number of lady's-slipper species, including those which occur naturally in New England. The large yellow (C. pubescens), the small yellow (C. parviflorum), the showy or queen's (C. reginae), the small white or prairie (C. candidum), and the ram's-head (C. arietinum) lady's-slippers are rare and imperiled throughout their natural ranges in eastern North America, so any successful, large-scale propagation of these species for cultivation may be their ultimate salvation. Interested individuals can look to such sources as Spangle Creek Labs, Cyp. Haven, Raising Rarities, and Vermont Ladyslipper Company for seedlings of these species. The Gardens at Post Hill provides links to a number of additional suppliers of these and other terrestrial orchids native to temperate North America.

The various species planted along the Acton Arboretum's Wildflower Trail reach their flowering height in April or May, with only a few exceptions which flower during the summer. Many of these plantings are on the left as you walk along the boardwalk away from the twin ponds. This hillside area represents the original wildflower collection that was created by a local volunteer in approximately 1993. (I was put in charge of this garden shortly afterward, when she moved to Kansas.) Since that time, additional populations have been introduced further along the trail, in some cases simply by broadcasting seeds collected from mature plants, and these new populations are becoming increasingly conspicuous with each passing year - some of them on a rather large scale. Anyone in need of a map of the Arboretum can view my home-prepared version, a modified adaptation of a publicly available sketch.

A patch of bloodroot (Sanguinaria canadensis)

As the spring season gets under way, the first flower one may notice is likely to be bloodroot, a native poppy which flowers briefly in the early spring - usually in April, although the exact days of its flowering in any given year always depend on the timing of warm weather. Indeed, many of the species featured in these gardens are spring ephemerals, so called because they flower briefly in the spring to take advantage of the brief period of full sun which occurs in woodlands before the overhanging trees leaf out for the season. Few flowers are more ephemeral than those of bloodroot, which provide an attractive show for a few days at most before they disappear for the season; however, bloodroot makes up for the brevity of its flowering by its showiness and extraordinarily prolific habit. This species is so easy to propagate by seed - or by division of its root stock - that it is becoming an increasingly prominent presence along the Wildflower Trail each year. Most of the bloodroot now occurring along this trail was established simply by scattering its seeds along the forest floor in suitable areas. Such naturally occurring annual and biennial species as jewelweed, cleavers, and the non-native celandine appear to be reliable indicators of suitable soil for this purpose.

Although bloodroot occurs naturally throughout this part of the world, it is not nearly as common as it had been in the primieval forests of the region. When the original forests were cleared in the 1600's, many native populations suffered severe setbacks, and while some species recovered fairly rapidly when the clearings eventually were allowed to revert back to forest, others had greater difficulty. The greatest challenge for bloodroot seems to have been related to its dependence on ants for the natural distribution of its seeds. Each seed presents an edible attachment which an ant drags underground and consumes, leaving the seed in an ideal position to germinate; however, ants have greater difficulty than birds when it comes to transporting seeds across distances or areas paved by human beings. Because of widespread human disturbance of natural areas, this once-common plant has tended in recent years to become locally isolated and generally restricted to areas which have not been cleared.

Squirrel-corn (Dicentra canadensis)

Toward the end of April, assuming that the unpredictable warmth of the early spring has been occurring at more or less the usual times, we can expect to see the ephemeral flowers of the earliest species. Besides bloodroot, these species include Dutchman's-breeches and its close relative, squirrel-corn (Dicentra canadensis), both members of the bleeding-heart family. Dutchman's-breeches is so named because its flowers resemble sets of trousers hanging on a line. Squirrel-corn is similar, except that its flowers are shaped more like those of the related bleeding-heart. Both Dutchman's-breeches and squirrel-corn can be seen in flower along the Wildflower Trail in late April and early May, when the difference between their flowers may be noticed by a sharp eye. Shortly afterward, both species go dormant for the year, and even their leaves cease to be visible above the ground, true to the ephemeral nature of these plants. Both species are fairly easy to cultivate and to propagate, once established; in fact, unusually among wildflowers, both can be propagated by separating the many tiny cormlets apart from the naturally crumbly corms, and scattering them like seeds on suitable sites. In this way, many more plants of flowering size can be generated within a few short years. It is my hope and belief that these two species, like bloodroot, will be among the more prominent features along the Wildflower Trail in the fairly near future, as a direct result of this ease of propagation.

Trilliums are among the more famed and showy of native wildflowers, and the white and red species each tend to flower in April and early May. Both are featured in fair quantity along the boardwalk, where they thrive and flower each year. A single clump of each species had been rescued from a site undergoing “development” during the 1990s, and these two original clumps subsequently were propagated by division into a moderate number of plants which can be seen here. Additional trilliums of various species were planted further along the trail in 2007. Although trilliums can be propagated successfully either by seed or by division, these plants are extremely slow-growing and slow to propagate, making them generally expensive and difficult to find in the nurseries. Some nurseries propagate their own trilliums for sale; however, because of the inevitable temptation of expediting sales by collecting trilliums from native populations where the plants are not in need of being rescued, prospective buyers should make sure that their trilliums are purchased only from suppliers who propagate their own stock. In addition, trillium plants are extraordinarily sensitive to being damaged or set back in their growth by careless treading or picking. Because of these issues, trilliums should not be picked or dug from native populations, except where there is a need to rescue them from inevitable destruction by a bulldozer.

Wood poppy (Stylophorum diphyllum)

The bright yellow wood poppy, a native of the upper midwest, also begins to flower around the end of April or the beginning of May, when it becomes conspicuous in large numbers along the Wildflower Trail. Some people have remarked admiringly on the unusual “yellow buttercups” which they encounter here. Although the flowers of this plant do resemble large buttercups, they are in fact members of the poppy family. Like bloodroot and other members of this family, the wood poppy is showy when in flower, extrordinarily prolific, and full of a brightly colored, toxic sap that protects it from predation. Also typical of the poppy family, it has that same natural adaptation for seed distribution by ants, as described above in connection with bloodroot. As with bloodroot, the wood poppy can be grown in phenomenal quatities by broadcasting its seeds over a moist, exposed forest floor, as one might do with grass seed to create a lawn. Those at the Arboretum were established in exactly that manner; in fact I have ceased efforts to increase this species here, as it seems prudent to keep its aggressive presence reasonably moderate. On this scale, it forms an attractive and welcome addition to the Arboretum's collection of native wildflowers.

Virginia bluebells is another of the most showy native wildflowers, and it is one of the most workable companions for the wood poppy, as it produces brightly colored flowers at the same time of year. In contrast to the fleeting blooms of the earlier ephemerals, the flowers of these two species last for a few weeks during April and May. Shortly afterward, the shoot system of Virginia bluebells wilts for the season, and the entire plant goes dormant, so in this sense the species qualifies as ephemeral. Although Virginia bluebells can be propagated by seed, I have had much better success in propagating it by dividing its root stock in the early spring, before the shoots of the plant become too prominent above the ground. At the Arboretum, several plants of this species are on display in the original wildflower collection area along the boardwalk, and they are conveniently identified with a professional label.

In the middle of May, when the wood poppies and Virginia bluebells are just past their flowering height, and after the earliest flowers have faded, the wild columbine and foamflower begin to reach their flowering height, marking what is probably the showiest period for the majority of woodland wildflower species in the region. Wild columbine produces one of New England's most unusually shaped and intriguing flowers, which are bright red and tube-shaped for the purpose of attracting a specific pollinator, the ruby-throated hummingbird, with which it had evolved symbiotically. Fortunately for this plant, insects also pollinate its flowers, thus compensating for an absence of hummingbirds at any given time. The wild columbine has a relatively short life span and depends heavily on its ability to reproduce in quantity by its seeds, but it will spread prolifically when planted in suitable sites, which generally entail loamy or limy soils and lots of direct sun. This species is most likely to occur naturally on open ledges or on slopes that are rich in limestone, so a generous amount of lime worked into the soil will encourage this species to thrive, assuming that it also has enough direct sunlight. The soil and light conditions along the Wildflower Trail at the Arboretum may not be ideal for this species, but I have been able to establish it here on a small scale, making it at least a welcome presence in the collection.

Foamflower is a prolific, ground-covering species which spreads by creeping runners to cover large areas. Its spikes of tiny white flowers resemble sea foam and add a delicate touch when mixed with other species. The roots of this species tend to be rather shallow, making the plants potentially susceptible to drought; consequently, cultivated patches of it may require regular watering during dry periods in the summer. This species can be propagated easily by seeds sown in a flat, but unlike bloodroot and wood poppy, it is not easy to establish on site by broadcasting seeds along the ground. At the Arboretum, I have been able to establish patches of foamflower by dividing small plants apart from larger colonies and transplanting them. In this way, hopefully, the species will become more of a presence along the Wildflower Trail as time goes by. I also have been able to establish patches of native wild ginger (Asarum canadense) and May-apple (Podophyllum peltatum) along the trail in this way.

Yellow violet (Viola pensylvanica)

Also during May, we can observe several types of violets growing along the Wildflower Trail. Violets are familiar emblems of spring, and they need not be considered weeds, even though some violet species can be aggressive. In addition to the familiar blue species, violets come in yellow-flowering, branching forms, such as the species depicted above. These yellow violets are nearly as prolific from seed as their blue relatives, but unlike the blue violets, they do not crowd out or threaten other plants in any way. They simply add another interesting dimension to native wildflower gardens. The yellow violets at the Arboretum can be expected to spread prolifically in the foreseeable future, thus enhancing the trailsides considerably.

Wood phlox (Phlox divaricata)

Many garden varieties of phlox have been derived from species which occur natively in eastern North America, such as the blue wood phlox which is featured prominently in the Wildflower Trail. This species occurs naturally in an assortment of flower colors or shades, and it reaches its flowering height in the middle of May, coinciding with the flowers of wild columbine, foamflower, and yellow violet, and thus contributing to a colorful, seasonal show. This wild blue phlox is well adapted to the soil conditions of the New England forest floor, and it propagates more readily by stem cuttings or divisions than by seeds. As with foamflower, I have been able to establish patches of this species at the Arboretum by dividing larger patches of it and transplanting the divided sections to suitable sites, where hopefully they will expand, allowing the species to become a more prominent presence along the Wildflower Trail in the fairly near future.

White baneberry (Actaea pachypoda)

The white baneberry, or doll's eyes, and the closely related red baneberry (A. rubra), also can be observed flowering or fruiting along the Wildflower Trail. Both species produce attractive clusters of white flowers in May. The red baneberry produces its bright red berries in the late spring, and it also comes in a white-fruited form which produces pure white berries at the same time. Its relative, the white baneberry or doll's eyes (not to be confused with the white-fruited red baneberry), fruits much later, in August. Interestingly, the white baneberry also comes in a form which bears magenta-colored berries. Both of these species are moderately present at the Arboretum, and it is my hope that they can be made to increase somewhat over the years, both by seed and by division.

Wild geranium (Geranium maculatum)

The wild geranium occurs naturally in open meadows and clearings at the Arboretum and elsewhere, yet it also is adaptable to woodlands and is found occasionally in shady conditions. A few natural patches of it can be observed flowering in late spring in several spots along the Wildflower Trail. Rather than qualifying as a threat to other woodland plants, this prolific, native species seems like an enhancing presence for the trail. Although the invasive European celandine and garlic mustard are probably best removed from the trailsides, it is my preference to leave the native geraniums intact, allowing them to contribute to the collection.

Black cohosh (Actaea racemosa)

Returning to the Wildflower Trail in July, long after the vast majority of woodland flowers have faded for the season, we may observe tall stands of black cohosh in flower. This species is relatively unique among woodland wildflowers in that it produces showy flowers and effectively lights up the woods at a time when the flowers of nearly all other woodland species are gone for the season. The flower stalks commonly reach five feet above the ground and can reach six feet or higher in some instances. The flowers produce the pungent fragrance of carrion, quite unlike the sweet scent of other flowers, and bees and other insects revel in it and pollinate the flowers in the process. Natural populations of this species are rare throughout the northeast and in danger of extirpation in Massachusetts, yet this plant is easy to grow and is commonly grown commercially for use in herbal medicine. Because this species propagates easily both by seed and by division, it seems likely that we will see more of it in the woodlands of the Arboretum as the years go by.

Ferns add a distinctly naturalistic character to gardens when planted alongside flowering plants, and a number of native fern species may be of particular interest for use in this manner. Along the Wildflower Trail at the Arboretum, I have planted many ferns, emphasizing the marginal, male, and Goldie's woodferns (Dryopteris marginalis, D. filix-mas, and D. goldiana, respectively), the Christmas fern (Polystichum acrostichoides), the Braun's holly fern (P. braunii), the maidenhair fern (Adiantum pedatum), and the ostrich fern (Matteuccia struthiopteris). Many of the more common fern species are suitable for cultivation as well. Although some ferns can be propagated easily by division, most can be propagated in quantity by dusting their spores on the surface of a flat of soil and leaving the flat in a bright location for a few months, checking it regularly to maintain moisture and to control mosses and fungi. I have had remarkable success with this practice on a number of fern species, including the Braun's holly fern, an attractive native species that never has been common within its natural range. In Massachusetts, native populations of this fern are found only on the slopes of Mount Greylock, where they are considered endangered. In 1990, I collected a fertile leaf from a plant growing at the New England Wild Flower Society, and I was then able to propagate this species easily from its spores and to establish a number of plants of it along the Wildflower Trail, where they often remain dark green and shapely well into the fall. Anyone with a particular interest in native ferns perhaps will want to explore this section of the trail for the relatively unusual species which have been planted here.

Gems of Streamside Habitat

Although this writing focuses primarily on native plants of forest floor habitat that are being grown along the Arboretum's Wildflower Trail, a few summer-flowering species of particular merit deserve mention as well, even though they prefer the swampy soils alongside streams and in shaded wetlands. This type of habitat is not especially prevalent along the Wildflower Trail, but it has been relatively easy to establish some of these species in their preferred habitats on conservation lands elsewhere in town, simply by broadcasting their seeds in quantity near a flowing brook and allowing the water to do the rest. These species also have proven fairly adaptable to cultivation in home gardens, provided that the soil is kept moist at all times and is never allowed to dry out.

Cardinal flower (Lobelia cardinalis)

The bright red cardinal flower grows naturally along semi-shaded streamsides and pond shores, and it flowers in August. It is becoming less common in many parts of its range, perhaps largely because of overpicking, on top of its dependence in large measure on hummingbird pollination; however, the ease with which this strikingly attractive, native lobelia can be propagated and maintained in gardens would seem to merit its greater use in cultivation. A shortage of suitable habitat at the Acton Arboretum may or may not preclude the establishment of this species here; but once established in suitable habitat, this species can self-seed prolifically, and its bold flowers may catch one's eye along streams at Nashoba Brook and other conservation lands in Acton. Its close relative, the great blue lobelia (L. siphilitica), is also easy to cultivate and to propagate in the same way.

Closed gentian (Gentiana andrewsii)

The closed gentians, including the species depicted above and its close relative, G. clausa, occur naturally along shady streams and in moist thickets, as with cardinal flower, and they flower in September. These plants, too, are becoming less common in their natural habitats, possibly in part because of overpicking. Gentians produce extremely small seeds on which they depend heavily for their proliferation, so they should not be picked. Their unusually colored, deeply indigo flowers do not open on their own, yet worker bees have no trouble in forcing their way inside to collect nectar and to transport pollen. Gentians tend to be challenging to grow, though the closed gentians probably represent the least difficult members of this family to cultivate. They require moist to damp, moderately limy soil in at least partial shade, and they can be propagated with moderate difficulty by division or by seed. The tiny seeds, scattered on the surface of a flat in the fall and left outdoors during the winter, will sprout uniformly in the following spring, and they will require an entire growing season in constantly moist soil to become firmly established as seedlings. Then they can be separated into clusters of small plants and transplanted to suitable locations, where eventually they may need to be thinned. Establishing healthy patches of closed gentian at the Acton Arboretum may or may not prove possible, but hopefully, scattering quantities of closed gentian seeds at the same sites that have proven suitable for cardinal flower will bear fruit over time.

Of all my activities with native plants, the most important to me is the special project through which I am propagating and raising disease-resistant, purely American elm trees for distribution to local conservation areas and sale to organizations and residences. Please visit my article, Saving the American Elm, which features more quality photographs as well as links to sources of trees and information, including an Elm Sapling Gallery showing many of the elm saplings which I have planted in Acton.

Please also visit my article, New Hope for the American Chestnut, which presents valuable information on a highly promising effort to restore this ecological keystone to the forest canopy through breeding for blight resistance.

The photographs on this page were taken at various times by my father, Gilbert Carley. They may be distributed freely or republished for wholesome purposes; in return, a credit link (“courtesy elmpost.org”) is always appreciated.