From Tree Hugger to Bug Hugger

Is your sleep disturbed by worries about disappearing spotted owls and snail darters? Maybe the objects of your concern are too grand. What you should really be worrying about is bugs: native bugs and the native plants that sustain them. That is the argument advanced by professor of entomology Douglas Tallamy in his recent book, Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens.(1) He says that we are starving our insects by replacing the native plants that they eat with exotic plants that they can't even recognize as food.

Native sweetbay magnolia. Native insect? Click to enlarge.

Starving the bugs sounds like a great idea, right? Maybe not. Tallamy presents insects as unloved heroes that transform the stored energy in plants into food (themselves) for the next level up in the food chain. In order to transform themselves into bird food, for example, insects must have food of their own to eat. But we are depriving them of food by replacing the native landscape with foreign plants. The vast majority of our insects are dietary specialists; the only foods they are capable of eating are members of the native plant community with which they have co-evolved over millions of years. Those are the foods to which their anatomy and physiology are adapted. They have as much success eating foreign plants as we would have if we tried to adopt the koala bear's diet of eucalyptus leaves. Without native plants, the insects have nothing they can eat, and they perish. With the insects gone, all of the food chain above insects will collapse.

American elm 1267 Park Avenue

The differences between the numbers of insects that can eat native versus foreign plants can be startling. Native oaks can provide food for over 500 different native insect species. Eucalyptus, an exotic, is eaten by only one native insect species. Native plants in Pennsylvania were found to support 35 times more caterpillar biomass, the preferred source of protein for most bird nestlings, than alien plants supported.

Native northern red oak, New Jersey state tree, West 8th St

How big a problem can this insect starvation be? Biodiversity depends on space. The more space, the larger the number of species that can be supported. The relationship is linear.(2) Only 3-5% of the lower 48 states remains undisturbed habitat for plants and animals. The rest has been paved, farmed, taken over by noxious foreign weeds like kudzu and Japanese honeysuckle, or transformed into suburban gardens dominated by exotic shrubs and vast lawns of non-native grasses. Tallamy points out that suburban lawns cover about 62,000 square miles of this country, an area more than eight times the size of New Jersey that is devoted to alien grasses.(3) Worse, 43,000 square miles of blacktop has been spread over the landscape, equal to five and a half New Jerseys. If we have eliminated much of the native vegetation from 95-97% of the American landscape, we can expect to lose 95-97% per cent of our native flora and fauna over time, as extinction adjusts the number of species to the land area that remains. Tallamy cites the toll of habitat destruction on Delaware, where he teaches. As of 2002, Delaware had lost 78% of its freshwater mussel species, 34% of its dragonflies, 20% of its fish species, and 31% of its reptiles and amphibians. Forty per cent of all native plant species in Delaware are threatened or already lost.

American holly East 9th Street

At this dismal point in his book Tallamy offers a ray of hope: suburban gardeners to the rescue! If suburbanites, who control a large swath of the landscape, were to plant native plants on their properties, the countryside could still support a diverse flora and fauna. Mix some American elms in with all those Zelkovas. Make your lawn smaller, and plant a meadow. Tear out some of your English ivy and Japanese pachysandra and plant mayapples. I repent ever having written that foreign, kousa dogwoods have the advantage of not being attacked by the borers that plague native flowering dogwoods (a good example of just what Tallamy is talking about). How petty of me ever to have planted exotic hollies instead of American hollies because of the Americans' problems with leaf miners! I'm going to be beating myself up for years over this. But as part of my rehabilitation program, I will spread the word about Tallamy's book, essential reading for anyone who plants.

Native black walnut leaf nibbled by, no doubt, native insects

(1) Tallamy, DW. Bringing Nature Home: How Native Plants Sustain Wildlife in Our Gardens. Timber Press, 2007.

(2) Tallamy cites the work of Michael Rosenzweig at the University of Arizona to support his claim that species diversity decreases in proportion to the loss of available space. His very cursory discussion of this important underpinning for his argument is, for me, the weakest part of his book. I would like to have seen Rosenzweig's data and analysis described in detail.

(3) If you would object that Kentucky bluegrass is a native, you would be mistaken. Its seeds were imported by European settlers in the digestive tracts and droppings of cattle.

Copyright Gregory Palermo

Black walnut

What do walnuts, Wales, Walloon, Welsh, Walsh, Wallace, and Cornwall have in common? The words all indicate foreignness.

Walnuts are foreign nuts, and the "wal-" in their name indicates that fact. Foreign to whom? To the English. The American Heritage Dictionary explains the history nicely: "Although Celtic-speaking peoples were living in Britain before the arrival of the invaders...whose languages would eventually develop into English, it was the Celts and not the invaders who came to be called 'strangers' in English. Our words for one of the descendants of the Celtish peoples, Welsh, and for their homeland, Wales, come from the Old English word wealh, meaning 'stranger'.... Old English...walhhnutu [exists] in a document from around 1050.... This eventually became walnut in English...literally the 'foreign nut.' The nut was 'foreign' because it was native to Roman Gaul and Italy."(1)

Black walnut (Juglans nigra) is an American native closely related to the Persian walnut (Juglans regia) of Europe and Asia. It grows wild in the eastern United States except for parts of New York and New England.(2) The tree is highly valued for its wood and for its nuts. The wood is so valuable that black walnuts are at risk of being felled and stolen by "walnut rustlers." For that reason, I won't specify the locations of the pictured Plainfield trees. Walnuts have been prized since ancient times. The Romans esteemed them highly enough to call them Jupiter's nut (Jovis glans) from which the scientific name Juglans derives.(3)

Walnuts have pinnately compound leaves (with leaflets arranged like a feather), each leaf a foot or two in length and made up of as many as 23 leaflets. The leaflets are serrated, and the leaflet at the tip of the leaf is often undersized or missing, a useful feature in identification. The leaves emit a spicy odor when crushed. They turn yellow in the autumn and are among the earliest leaves to fall.

The bark is dark gray-brown and deeply furrowed, forming diamond shapes.

The nuts fall around the same time as the leaves and are covered by a fleshy green hull that will stain your hands black if you try to remove it. Breeders have produced over 500 varieties of black walnut, trying to create nuts with a thinner shell and a less convoluted inner structure so that the kernel is easier to extract.

Almost as well-known as its delicious nuts and its beautiful wood is walnut's toxic effect on neighboring plants. This effect has been known for millennia. Pliny the Elder wrote in the first century AD that, "the shadow of walnut trees is poison to all plants within its compass." Juglone, the toxin that the tree produces to keep the rest of the natural world at bay, is present in leaves, branches, bark, roots, and nuts. The chemical is toxic to a variety of other plants. Don't, for example, plant tomatoes near a walnut tree. The toxin's victims are not limited to plants. Bruised walnut leaves and branches have been put into water by fishermen to stun fishes.

(1) The American Heritage Dictionary of the English Language, Houghton Mifflin Company 2000. See the entry for Wales.

(2) Edward Goodell, Walnuts for the Northeast, Arnoldia 44: 1-19, 1984.

(3) The Romans' walnut was Juglans regia, Persian walnut. It is also called English walnut. But, as discussed above, there really is no such thing as an English walnut.

Copyright Gregory Palermo

Sweetbay magnolia

I have fragrant roses in my garden, but I can never detect their scent unless I put my nose right down into a bloom. The difficulty isn't an insensitive sense of smell. It is, rather, that I have a sweetbay magnolia in bloom at the same time. The fragrance of the magnolia is so potent that it overwhelms the scent of the roses.

Sweetbay magnolia (Magnolia virginiana) blooms over about six weeks from May into early July. Its flowers are small and never make a big visual impact. They bloom a few at a time, each flower lasting only a few days. Their fragrance is huge. To my nose their scent is rose-like, but much more intense.

There is a very handsome sweetbay magnolia in front of 500 Stelle Avenue.

The flowers are followed by shiny, bright red, clustered fruits(1) that ripen in August and September. The fruit is a favorite food of catbirds and mockingbirds. The photograph below shows unripe fruits on July 1.

Sweetbay magnolias are closely enough related to southern magnolias to have been hybridized with them. Unlike southern magnolias, sweetbays are mostly deciduous in this climate. Sweetbay flowers are much smaller and much more fragrant than southern magnolia flowers. Sweetbay leaves are duller and have a silvery gray underside that displays itself very attractively in a breeze.

Another feature that helps with identification is the rather smooth, light gray bark.

Sweetbays grow into large trees in the southern United States. In New Jersey a height of 25 to 30 feet is typical.

I have grown one of the hybrids of sweetbay and southern magnolias, 'Timeless Beauty'. The flowers of the hybrid resembled southern magnolia flowers. The foliage was less attractive than that of either southern or sweetbay magnolia. Worse, the hybrid's foliage suffered winter burn in winters that left pure southern magnolias unscathed. All in all, a disappointing plant.

Sweetbay magnolias are underutilized. Any garden can benefit from having their fragrance for six weeks in late spring and early summer. Very adaptable plants, they are tolerant of both wet soil and shade. A peculiarity of sweetbay magnolias is that they make a dense network of roots just beneath the soil surface. Mulch your beds heavily and the roots will grow right into the mulch. When the mulch dwindles with time, you are left with "aerial" roots. A drawback to this beautiful New Jersey native is that deer eat the leaves and stems.

Sweetbays were the first magnolias imported into Europe from the Americas. The genus was named by Linnaeus after Pierre Magnol, pioneering botanist and physician to the court of Louis XIV.

(1) The fruits are aggregates of follicles.

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Copyright Gregory Palermo

Fringetrees

Native American fringetrees are little-known and neglected beauties. They're hard to find. Fringetrees are so few and far between in Plainfield that the poor, solitary things can't even reproduce. Female fringetrees produce a crop of beautiful blue berries in the fall, but to do that they need a male close enough to provide pollen. I have never seen a single berry on a Plainfield fringetree.

The trees produce a magnificent floral display, which has just finished in Plainfield. The fringetree pictured below is between 1745 and 1751 Watchung Avenue.

The native fringetree below, which was also pictured in my June 2 posting, is at 653 Ravine Road.

The Ravine Road fringetree used to be the focus of an annual spring celebration complete with poetry recitations until it broke off at the ground about ten years ago. Its owners, Jean Mattson and the late Norman (Moose) Mattson, brought it back from a hollow stump by cutting away all but a few of the hundreds of sprouts that grew up from the wreckage over the space of a few years. The sprouts that were allowed to grow reconstituted an attractive multistemmed tree. I wish it a long (second) life.

How do I know that these two fringetrees are the native species, Chionanthus virginicus, rather than the beautiful Chinese import, Chionanthus retusus? I happened to be at the Polly Hill Arboretum on Martha's Vineyard for a lecture last weekend when both species of fringetree were in bloom there. I was able to take photographs permitting a comparison. The most easily recognizable difference is in the bark. The Chinese tree's bark, pictured below, is deeply furrowed, while the American's is relatively smooth.

The flowers have easily recognizable differences too. The Chinese species' blooms, shown below, are not as thread-like as the American's, shown at the top of the page.

I have not seen any Chinese fringetrees in Plainfield. Clearly there is a niche available here for both of these species of Chionanthus.

(1) The rarity of fringetrees can inspire deviant behavior in susceptible subjects. Plainfield tree lady Barbara Sandford took me trespassing into the backyard of a house on Sleepy Hollow Lane to see one in bloom a few weeks back. (I place the blame for this transgression entirely on her.)

Copyright Gregory Palermo

Flowering dogwoods

Can there be a more beautiful tree? I don't think so, but I have never been tempted to plant one. Flowering dogwoods, Cornus florida, are so beset with pests and diseases that I have refrained from planting any for fear of losing the fruits of my labor. I prefer to enjoy other people's dogwoods. A very handsome example is across the street from the Plainfield Public Library at the corner of Park and Crescent Avenues.

Flowering dogwood is a tree of four-season beauty. Its spectacular spring floral display is followed by handsome red berries and rich maroon fall foliage. The tree's persimmon-like bark provides visual interest even in winter. A dogwood in fall foliage at 1340 Watchung Avenue is pictured below.

Dogwoods are prey to borers and a number of diseases. The most serious threat to dogwoods is dogwood anthracnose. This fungal disease was first recognized in the United States in the 1970s. By the 1980s, garden writers were lamenting the rapid disappearance of flowering dogwoods, which are native to the eastern United States.

An anthracnose-resistant substitute for the native Cornus florida is an Asian dogwood, Cornus kousa. Kousa dogwoods are in bloom now. Unlike native dogwoods, which bloom on naked stems, kousa dogwoods bloom after their leaves have formed. A native dogwood in flower often gives the impression that an artist has arranged the placement of each flowering branch for maximum charm. With kousa dogwoods the impression is rather of robust and dense bushiness.

There are outstanding kousa dogwoods at 960 Glenwood Avenue, one of which is pictured below.

Another handsome kousa dogwood is at the rear of 975 Hillside Avenue, pictured below.

There is a fine kousa dogwood between 980 and 996 Hillside Avenue, pictured below.

The flowers(1) of some kousa varieties last for much of the summer.

Professor Elwin Orton of Rutgers hybridized native dogwoods with kousa dogwoods in an attempt to blend the look of the natives with the borer-resistance of the kousas. His family of hybrids, called the Stellar series, is also resistant to anthracnose. I have seen them for sale locally, but I don't know of any planted in Plainfield. I would be grateful to hear of any Stellar hybrids that can be seen from the street.

Other trees in flower in Plainfield now include fringetree, Chionanthus virginicus. The tree pictured below is at 653 Ravine Road.

Also flowering now (but I know of none visible from the street) are Japanese styrax, Styrax japonica, pictured below, and

American yellowwood, Cladrastis kentukea, pictured below.

(1) Not really flowers, but bracts. Dogwood bracts are the bud scales that enlarge and take on color after they open. The actual flowers are tiny and are clustered together in the center of what we think of as the bloom.

Copyright Gregory Palermo

Horse chestnuts

Don't eat them. They're poisonous. Horses should abstain as well. But horse chestnuts do have their uses. The British government paid schoolchildren to collect them during World War I. Horse chestnuts even had a role to play in the creation of the state of Israel. See below.

Horse chestnuts, Aesculus hippocastanum, make a spectacular display of huge, white flowers at this time of year. The large horse chestnut pictured in flower above is on the front lawn at 1127 Watchung Avenue. Another handsome example is at 621 Berkeley Avenue, shown below.

The attractive leaves are palmately compound, their leaflets arranged like a seven-fingered hand.

Beautiful as these trees are, they have an Achilles' heel: drought and fungal leaf blotch reliably disfigure the foliage by midsummer. I daily pass by a row of horse chestnuts used as street trees at the corner of Hillside and Evergreen Avenues. In July I look for early signs of damage. By August I avert my eyes; the sight is painful. The photographs below were taken in September of 2007.

The hybrid red horse chestnut, Aesculus x carnea, is less troubled by leaf problems. Red horse chestnuts are uncommon in Plainfield. Two were planted in front of City Hall two or three years ago. There is a wonderful red horse chestnut that can be glimpsed from the street in the rear garden at 429 Stelle Avenue. This beautiful tree was recognized by the City of Plainfield as a specimen tree of special note at the Arbor Day observance in 2006. Its age is estimated at 120 years.

Uses of horse chestnuts:

Nutritional: Although horses shouldn't eat horse chestnuts, the nuts do provide nourishment to public enemies number 1 and number 2: deer and squirrels.

Medicinal: Horse chestnut extracts are used as herbal medicines.

Recreational: Horse chestnuts are the "conkers" used in the game of conkers played in the British Isles.

Military?: Indeed. Back to the creation of Israel: Chaim Weizmann, Zionist and first president of Israel, began his career as a chemist. Professor Weizmann of Manchester University refined a method of producing acetone by bacterial fermentation of starches in various foodstuffs just before World War I. Acetone was crucial to production of cordite, smokeless gunpowder. The Weizmann process was used to make acetone for the war effort. When war made corn and other starches scarce in Britain, Weizmann adapted his fermentation process to use horse chestnuts in place of corn. Schoolchildren were enlisted in the war effort to gather horse chestnuts to produce munitions. Minister of Munitions David Lloyd George, who had worked with Weizmann, became prime minister. Lloyd George's gratitude for Professor Weizmann's war contributions was such that it led to the 1917 Balfour Declaration, which stated Britain's support for "a national home for the Jewish people" in Palestine.(1)

(1) For more detail on the role horse chestnuts played in the creation of Israel, see

http://www.bbc.co.uk/dna/h2g2/A6958812

and

http://everything2.com/index.pl?node_id=1530046&displaytype=printable&lastnode_id=0

Copyright Gregory Palermo

Street cherries

One thinks of Japanese cherries as delicate beings whose ethereal beauty is to be contemplated in the setting of a quiet garden. But at least one species of Japanese cherry can be used on the streets. Prunus serrulata, most commonly known in its variety 'Kwanzan', has a vase-like shape that permits it to fit nicely between street and sidewalk. A group of Kwanzan cherries was planted just last week on West Third Street at Muhlenberg Place as part of Plainfield's Arbor Day observance.(1) Kwanzan cherries also line both sides of Randolph Road near Muhlenberg Hospital. A young Kwanzan cherry in front of the early 18th Century FitzRandolph farmhouse at 1366 Randolph Road is pictured below.

Neither the longest-lived nor the most trouble-free of street trees, Kwanzan cherries are nonetheless outstandingly beautiful in flower. The tree pictured below is at 1115 Prospect Avenue.

Plainfield residents look forward to the annual display of Kwanzan cherry blossoms at the public library, one of the glories of spring in central New Jersey.

Another small tree with showy flowers that has recently been used as a street tree in Plainfield is the eastern redbud, Cercis canadensis. Several were planted on East Ninth Street two years ago. The tree pictured below is at 127 East Ninth Street.

A redbud at 1441 Evergreen Avenue shows how magnificent these trees can be at maturity.

Redbud varieties are available in various shades of pink and magenta. There are even white redbuds for seekers after novelty. The most unusual redbuds I have seen are on Grove Avenue in Edison at the corner of Adams Street. The residents there are apparently redbud fanatics; they have 8 redbuds on their small suburban lot. Two of the 8 are weeping redbuds, pictured below. I have read about weeping redbuds, but those two in Edison are the only weeping redbuds I have ever seen in the flesh.

(1) Planting design by April Stefel, CLA. Quite handsome and worth a visit.

Copyright Gregory Palermo