The Lungs of the City

Frederick Law Olmsted

The urban parks designed and built by Frederick Law Olmsted and his firm were described as the “lungs of the city” and as “public pleasure grounds.” Olmsted completed Central Park, his first project, in 1873, having begun it in 1857. One of his last park designs was Jackson Park in Chicago, which was constructed in 1893 for the Columbian Exposition. Although he began his landscape design career in the Victorian Era, he prefigured the Progressive Era through his concern for the welfare of the common man.


Because public transportation to rural areas was limited and because American cities of the increasingly industrial 19th century were dirty and crowded, it was difficult for urban dwellers to get to the countryside and experience the recuperative effects of being in the natural landscape. So Olmsted simulated natural landscapes in the city.

Olmsted’s first design, Central Park, is a mixture of formal and natural landscapes. Through his career Olmsted used fewer and fewer built structures in his designs and fewer formal features of any kind. In the latter part of this career he was essentially re-creating a pastoral landscape, a sort of Romantic vision of the countryside rather than an actual copy of Nature.


His trees were carefully spaced and his vistas carefully aimed. Each bend in a walking path or a road was intentional placed to created a series of new views for the pedestrian or carriage rider.

Olmsted used a mixture of native and exotic species to vegetate his landscapes. Some areas, like the Ramble in Central Park, are nearly all native species, but if he wished to get a particular effect with foliage color or texture, Olmsted would plant non-native species.

In the selection of plants … Olmsted generally called for “American trees of the stateliest character” and a liberal use of native shrubs. An examination of the lists he compiled for the [Central Park] commissioners, however, demonstrates a willingness to use whatever plant he thought would achieve a particular effect rather than plants suited to particular soil conditions or found together in natural associations. (Robert E. Grese, Jens Jensen: Maker of Natural Parks and Gardens, Baltimore: Johns Hopkins UP, 1992.)

Jensen was a popularizer of the so-called “prairie school” of landscape design, which was developed by O.C. Simonds in response to Frank Lloyd Wright’s invention of that school in architecture.

But his chief inspiration came from Frederick Law Olmsted, who with Calvert Vaux imported the English meadow garden style to New York in the 1850’s, creating Central Park, the first of the great urban natural areas.” (“Native Grounds,” Jim Robbins, New York Times, May 16, 2004).

While Olmsted, as he traveled more widely and experienced more ecosystems, incorporated more exotic plants into his designs as his career progressed, Jensen became increasing devoted to the use of native plants to the point where it began to cross over into a nativist ideology that was unpleasantly chauvinistic.

Designed pastoral landscape

Olmsted, however, held to his original intention of broadening the lives of urban dwellers of modest means through the experience of landscape. In addition to being places to recreate and convalesce, Olmsted landscapes were places where the common man could appreciate the beauty, variety and even the majesty of plant life.

For generations of children right up to the present day Olmsted parks are their first experience of something like a natural setting. A century and a half after construction of Central Park began, it is still providing a place for New Yorkers to encounter life forms other than their own species and the odd pet. The urban forest of Central Park is home to over 200 species of birds (both resident and migratory) and a surprising number of mammals, including a couple of coyotes.


Diet of Flowers

Flowers are not just for looking at, or even just for smelling. You can eat them too. Culinary use of flowers experiences periodic revivals, but has been know since ancient times. The last surge in flower-as-ingredient was probably in the 1980s with the rise of nouvelle cuisine. At that time they were also used extensively as a garnish.

Japanese food

One of the more lampooned features of nouvelle cuisine during its initial phase was the enormous size of the plates and the relatively small portions. There were huge expanses of plates that positively cried out for decoration, at least to some. That period actually saw the bridging of two arts: flower arranging and cooking. The flowers were in the food and next to it too.

Before bringing flowers into the kitchen, though, some reading, even research is in order. There are many caveats to including flowers in cooking. One, flowers may include pollen (if they are male or “perfect” flowers) and many people are allergic to pollen. For example, ragweed is hay-fever-inducing whether it is eaten or inhaled.

If you consider yourself to be an allergy-prone person, then eating flowers may not be for you at all. A safe course for anyone may be to remove the anthers and other parts of the plant that may be heavily coated with pollen grains.

Two, some flowers are poisonous. These include some very attractive and very common flowers like those of rhododendrons, azaleas, daffodils, crocuses, foxglove, cardinal flower and clematis. There are lists of poisonous flowers all over the Web. In some cases – rose, tulip, yucca and lavender – only the petals are edible.


One writer, Ann Lovejoy of the Seattle Post-Intelligencer, was startled to look through cooking magazines and see very toxic flowers placed as ornamentation on various dishes. These included Datura stramonium (devil’s trumpet), which is wildly hallucinogenic and will stop your heart if a sufficient quantity is consumed. The active ingredient is strychnine.

Three, some flowers are poisonous because they have been sprayed with herbicides or pesticides. Do not eat flowers purchased at florists or collected along the roadside. The decay periods for chemicals sprayed onto crops are well studied. Those for chemicals sprayed onto plants not usually thought of as food are not, so it isn’t safe to eat this vegetation regardless of how long ago it was sprayed.

The safest course of action is to grow your own flowers to eat. Sherry Rindels at the Department of Horticulture at Iowa State University recommends picking only fully open flowers, not those either still partially closed or past their prime and wilting. Also, she commends picking them during a cooler part of the day.

“After harvest, place long-stemmed flowers in water and then in a cool location,” counsels Rindels. “Short stemmed flowers should be placed between layers of damp paper toweling or in a plastic bag in the refrigerator. Immediately before using, gently wash the flowers to remove dirt and check for insects.”

Harvesting flowers

People around the world have been eating flowers for centuries. One of the more detailed articles about the historical dimension of the topic is by Lynn Smythe at Associated Content. In short it is one of those things that the Chinese and the Romans both did, introducing the idea to various other cultures during imperialist expansions.

According to Smythe, flowers were a popular addition to salads during the Victorian Era, but they were also pickled so that they could be used during the months when no flowers were available for harvest.

There are a number of sites with lists of edible plants, but all of them suggest that you learn your plants really well before including them in your diet.

Some sites with lengthy lists of edible (and inedible) plants:

What’s Cooking America

Colorado State University Extension

National Sustainable Agriculture Information Service

The Garden Helper

And for recipes that use flowers: The Seeds of Knowledge

Beautiful and Invasive

If you have ever stopped to pick flowers along the roadside, taken them home, put them in a vase and when they died, thrown them out, then you might be helping to spread invasive species.

Roadsides are disturbed and stressed environments, the ideal spot for non-native species to take hold. Natives, coping as they are with the challenges of the many predators – macroscopic and microscopic – that impeded their growth and reproduction, are at a competitive disadvantage against introduced species. They have been placed in a new ecosystem where nothing recognizes them as food. If they can cope with the stresses of the physical environment, then they are off and running.

Purple loosestrife

A very beautiful, pervasive and noxious example of an invasive plant is the purple loosestrife (Lythrum salicaria). Purple loosestrife is native from Great Britain to Japan and south to northern India. It was introduced to the United States in the 19th century. It is still sold in many states as an ornamental, but Wisconsin, Minnesota, Illinois have prohibited its sale. It is found in every state except Florida.

The earliest introductions may have been through seeds in ships’ ballast and caught up in imported wool. It was noted in estuaries and canals of northeastern United States in the early 19th century, but was much written about in horticultural texts as a popular addition to ornamental gardens in both Europe and the United States.

Once it had a foothold along the east coast it penetrated inland along the canals that were being built during first half of the 19th century and also it followed the westward advance of the clearing that accompanied agriculture and European settlement.

In the early 20th century it was imported for use by beekeepers; it flowers profusely between June and September and is an excellent source of nectar.

Efforts to physically remove purple loosestrife have been largely unsuccessful. In some wildlife refuges where it has come to form monotypic stands, crowding out native species and providing substandard browse to herbivorous animals, volunteers efforts have been organized to physically remove the plants by simply digging them up or carting them away. It is, though, something like bailing out the ocean.

Cornell University is looking for natural predators to introduce that reduce the density of the species if not eradicate it. Bernd Blossey has found that the Galerucella beetle feeds on purple loosestrife foliage. It was introduced to rangeland in Washington state in 1995 and three years later had made serious inroads to the loosestrife population. It would take several years, however, to eradicate the plants because they are able to store energy in their roots and grow back through several years of defoliation.

Galerucella calmariensis and G. pusilla are native to Europe, where they feed only on purple loosestrife. They show no interest whatsoever in native loosestrife species and, when their introduction to North America is complete, are expected to reduced purple loosestrife by 90 percent over 90 percent of its range.

Lesser celandine

The lesser celandine (Ranunculus ficaria) is another introduced plant that becomes invasive. At present there are no biological controls available to limit its numbers. Like purple loosestrife, it is attractive. Its chief detrimental effect is to prevent native spring wildflowers from emerging; it forms such an extensive and dense mat of vegetation that it actually blocks other plants from poking through.

This introduced plant forms a lush green mat of vegetation as early as March in the northeastern states. It flowers through late March and April. By May the foliage has died back, leaving large bare areas in lawns that it has invaded. It spreads vegetatively; just beneath the soil surface is a dense network of tubers. All of these must be removed in order to rid an area of the plant.

Lesser celandine was introduced as an ornamental and is still commercially available.

Many invasive plants are as attractive as purple loosestrife and lesser celandine and may prove tempting to add to a garden. Many non-native thistles are invasive, as are orange daylilies. And it is not only herbaceous plants that can be invasive; aquatic plants, vines, shrubs and even trees can move in and take over acreage.

Consult the following websites (and more) before bringing any species into your yard:

National Arboretum

USDA National Invasive Species Information Center

Center for Invasive Plant Management

Insectivorous Plants

Pitcher plant

Carnivorous plants seem to attract their own breed of plant lover. Browsing through the many Web sites posted on this subject one is struck by the difference in tone between a site dedicated plants that eat insects versus, say, one devoted to roses. People devoted to roses emphasize their pedigree and elegance while those interested in carnivorous plants focus on their exotic behavior and the apparent ingeniousness of the insect-snaring mechanisms.

Although there seem to be many outlets for the sale of carnivorous plants, there are fewer sites that go into any detail about how to care for them. A sort of central clearinghouse for this kind of information is to be found at the site of the International Carnivorous Plant Society. One of the more detailed sites to be found is that of Michael Zenner, although it has not been updated since 1998.

One of the more complete references for carnivorous plant systematics can be found at the Web site of the Botanical Society of America. The strategy of carnivory (more strictly, insectivory) has evolved independently and differently in several phyletic groups (five different orders are listed here) within the kingdom Plantae.

Pitcher plant

The insectivorous plants are frequently divided into active and passive eaters. Members of the latter group simply have architecture that traps hapless trespassing insects, while members of the former group have moving parts that close on insects that trip triggers (usually hairs) on the plant.

Classic examples of the passive type are the “pitcher plants,” which also illustrate the polyphyletic development of similar forms. The pitchers of the eastern United States are members of the genus Sarracenia in the family Sarraceniaceae. Those of the western United States are members of the genus Darlingtonia in the same family. In the tropics the family Nepenthaceae includes the genus Nepenthes. All of these plants have reservoirs lined with downward pointing hairs that allow insects to crawl in, but not out. The insects are attracted by an odor and when unable to get out, slip into a pool of digestive enzymes at the base of the reservoir.

Venus fly-trap

The best-known active insect eater is the Venus’ flytrap (Dionaea muscipula) a member of the family Droseraceae, which include the passive-strategy member, the sundew. The Venus’ flytrap has a series of sensitive hairs that must be either tripped successively or triggered more than once in order for the plant to react. The trap portion of the plant consists of semi-circular plates lined with tooth-like structures that are held open until triggered, whereupon the close with surprising rapidity. The mechanism is still not completely understood. The flytrap makes an airtight seal around its prey and secretes digestive enzymes. It takes five to 12 days to digest an insect.

All of the carnivorous plants have developed their insect “hunting” abilities in order to supplement a nitrogen-poor environment. Many live in bog environments, which are highly acidic. The acidity is due to the accumulation of minerals in the ambient water, which is a result of water leaving the ecosystem only by evaporation rather than run-off. Reactions necessary for nitrification – conversion of ammonia into nitrites and nitrates, nitrogen compounds usable by plants – do not go forward in low pH conditions. It is therefore necessary for the plants to harvest the nitrites and nitrates directly from the insect’s bodies. Because they are adapted to somewhat extreme, marginal environments, these plants are often restricted to such places.

Wild pitchers

Unfortunately wetlands have been traditionally viewed with distaste. In the pre-“germ theory” era it was thought that the “vapors” rising out of wetlands brought sickness and they were filled or drained in the interest of public health. Because they are mosquito breeding grounds, even in the germ theory era they are viewed as sources of pestilence.

The eastern pitcher plants (Sarracenia purpurea et al.) are broadly distributed – found across Canada from the Rockies to the Maritime provinces and down the East Coast – but still largely confined to bogs and other marginal environments. By contrast, the natural habitat of the (much cultivated) Venus’ flytrap is a small region of coastal North and South Carolina.

Pet Banes

Since we are usually not inclined to start nibbling on the flowers – cut or potted – that we bring into our homes, we might not stop to consider the danger to pets from poisonous plants.

A bad combination

Some plants, like poinsettias, have been rumored to be dangerous, but have actually been shown to be more irritating than deadly. That is, your cat will throw up, but is not likely to die.

But there are long lists of plants that, if your cat or dog gets into them, will require an immediate trip to the veterinarian. A few of these plants are named in a helpful manner, such as “dogbane,” “wolfbane” (and even “henbane”), but mostly you would never know a plant was going to kill your pet until it was too late.

One of the groups to look out for is the lilies. These plants are abundantly available as either cut flowers (Asian varieties) or as potted plants (Easter lilies). The Cat Fanciers’ Web site is quite blunt about this:

Unfortunately, all parts of the lily plant are considered toxic to cats and consuming even small amounts can be life threatening. Within only a few hours of ingestion of the lily plant, a cat may vomit, become lethargic or develop a lack of appetite. These signs continue and worsen as kidney damage progresses. Without prompt and proper treatment by a veterinarian, the cat may develop kidney failure in 36 to 72 hours.

They suggest cat owners purchase “Easter cactus,” “Easter orchids,” or other “Easter” flowers rather than lilies.

However, another organization called Paws & Purrs lists cactuses in general as toxic to pets, so it is probably best to cross reference several different lists.

Attractive nuisance

Bulbs are another class of dangerous vegetation. House pets will be exposed to them if you are forcing them in the late winter and they are just sitting out on beds of gravel in shallow containers. Amaryllis, daffodils, crocuses, hyacinths and tulips are all toxic to animals. Usually all parts of the plant – not just the bulbs – are poisonous.

As a counterpoint to these spring plants, some people might keep chrysanthemums inside during the fall months. It would probably be a better idea to leave on the front steps.

Some of the most ubiquitous houseplants turn out to be not the greatest idea to have around. Philodendron, that trusty die-hard for dwellers in light-deprived apartments, is poisonous. Ficus trees are another no-no. This is especially troubling because it seems like every time you move a ficus they shed leaves in protest. All ferns are bad for your cat to eat too, but not deadly.

Aromatic poison

Even dried arrangements can get you in trouble: all eucalyptuses are toxic, which, given their oily odor, isn’t that surprising.

Keep your cats and dogs out of the kitchen when you are cooking too. This is not just for hygienic reasons, but because if drop some things on the floor during your preparations, there might be a problem. All of the members of the Solanaceae – tomatoes, eggplant and potatoes – are toxic to pets. This isn’t too surprising since other members of the family – nightshade and jimsonweed, for example – are toxic to humans. Rhubarb is also poisonous to cats and dogs.

The mention of jimsonweed (Datura stramonium) brings up the subject of recreational drugs. Simply put, they are all going to kill your pets. Marijuana, mescal (peyote) and even tobacco should not be left around if you want to keep body and soul together in your pet population.

The list of dangerous plants is rather long, but obviously not all plants are dangerous. The aforementioned Paws & Purrs site conveniently lists non-toxic plants instead of completely depressing you, which is what most other Web sites do.

A Green and Pleasant Place

As a child I was taken to Planting Fields, an arboretum that is now a state park, in Oyster Bay on Long Island. As an undergraduate I visited the Royal Botanic Gardens in Edinburgh, Scotland and as a graduate student I found myself wandering into the Rhododendron Gardens in Bremen, Germany during some free time in between shifts at the deep-sea core repository.

Planting Fields, Long Island

Planting Fields was perhaps a refuge for my mother, a place where she could take her three small children, and both they and she could enjoy themselves. The botanical gardens of European cities are inexpensive places for traveling students to spend time; they provide a green and quiet respite from days and hours of train rides, cheap hotels, and crowded cafés.

Botanic (or botanical) gardens tend to include greenhouses and more exotic plants, while arboreta may include exotic plants, but generally from the same climate. “Public gardens” are likely to be the most of-the-place oases in the sense that more (although almost certainly not all) of the plants, shrubs and trees present will be either native or at least from the same continent.

Because they are, in all cases, planted, and because they are often rife with exotic species, botanical gardens, arboreta and public gardens are excellent places to meet new species. The plants there have the added advantage of being labeled. If you wanted to add a specimen to your own landscape, buy a potted plant for your sun room or even add some interest to the next bouquet you purchase from the florist, these plant menageries are the right places to broaden your botanical palette.

Early British botanical garden

The Royal Botanic Garden in Edinburgh began its life as a “physic garden,” which is to say one devoted to growing medicinal plant. It was founded in 1670 and is the second oldest botanic garden in Britain. It moved to its present location in Inverleith in 1820, in order to escape the growing pollution that the Industrial Revolution brought to Edinburgh.

Many botanical gardens in the US and the UK are non-profit organizations, whether or not they are allied with a university. The Royal Botanic Garden has a full research staff, an education department that offers botanical instruction to the general public and is simply a public institution for its city, staging community events, art exhibits and other cultural undertakings.

Across the pond in the Bronx, Americans will find the New York Botanical Garden. Established in 1891, it is much less boastful about its venerable history than its Edinburgh counterpart. In fact, the NYBG’s Web site states that the founders, Columbia University botanist Nathan Lord Britton and his wife Elizabeth, were inspired by a visit to the Royal Botanic Gardens at Kew. They purchased the Bronx acreage from the Lorillard family, who were tobacco merchants. Its financiers were the usual gang of Gilded Age despots.

Thuja Gardens

The NYBG’s public offerings are remarkably similar to those offered in Edinburgh: a mixture of educational and cultural programming for all ages. And like the Royal Botanic Garden, there is an extensive research staff. Both institutions are overtly devoted to plant conservation around the world.

Most major (and many minor) cities in the developed world have some form of botanical garden or public garden somewhere in their confines. Some of the ones that I have visited are listed here in no particular order:
Chicago Botanic Garden
San Francisco Botanical Garden
Brooklyn Botanic Garden
Botanical Haven and Museum of the University of Copenhagen
Villa Borghese, Rome
Villa d’Esta (Tivoli Gardens), Rome
Thuja Garden, Northeast Harbor, Maine
Abby Aldrich Rockefeller Garden, Seal Harbor, Maine
Dundee Botanic Garden, University of Dundee, Scotland
Rhododendron Park and Botanic Garden of Bremen, Germany
Buffalo and Erie County Botanical Gardens
Lamberton Conservatory in Highland Park, Rochester, New York
George Eastman House, Rochester, New York
Cornell Plantations
Planting Fields, Oyster Bay, New York
Arnold Arboretum, Boston, Massachusetts

That’s a haphazard list of the ones that I can think of off the top of my head, but you get the picture: they are pretty much anywhere you go. When you need a break during a journey, a conference or a family visit, find a botanical garden.

A professional organization dedicated to public gardens, in general is the American Public Garden Association (formerly known as the American Association of Botanical Gardens and Arboreta).