31 October 2005

Happy Halloween!

Doll's eyes (Actaea pachypoda {syn. A. alba}) MMMWAH!

Creepy, isn't it? The infructescence of doll's eyes makes an impression on you - wandering in a dark wood in fall, suddenly, it feels as though there are eyes on you. You look down, and it's true!

In late spring, when this member of the buttercup family (Ranunculaceae) is in flower, it would be easy to overlook, with it's small, white, star-like blooms held aloft sharply toothed, compound leaves. At this stage, it closely resembles its congener, red baneberry (Actaea rubra). But the real fun comes later in the season, when stark white berries with dark "eye" spots appear in early fall. (This spot is a persistent stigma from the flower). These berries are collected on a grape-colored stem, which makes quite a striking contrast that lasts over a month. And as tempting as it may be, don't eat them - they are poisonous.

In New York State, doll's eyes is considered "exploitably vulnerable", which means people poach it in the wild. If you come across it, for goodness sakes, don't pick it!

However, it would be easy to enjoy this plant at home - it makes an excellent addition to any garden in partial shade. Growing to 2.5 ft tall, both baneberries are long-lived and willingly germinate from seed.

24 October 2005

I've been knotty



Just in time for the holidays!

The place to buy mugs, clocks, and other gear for your favorite invasive plant hater...is here What stone cold heart can resist a knotweed-hating teddy bear?

19 October 2005

HGG: Witch Hazel


In another installment Home Grown Greenery we take a look at witch hazel (Hamamelis virginiana). Witch-hazel has a number of traits that help it steal the limelight, including smooth grey bark, attractive architecture, and colorful fall foliage. But the real show stopper comes when you least expect it. As November approaches and most respectable plants have dropped their leaves and gone to seed, Hamamelis virginiana bursts forth in floristic splendor. Clusters of small pale yellow blooms, each with four streamer-like petals, hug the twigs. Some flowers may linger on the branches into December.

In the wild, Hamamelis virginiana is a common shrub of North America’s eastern deciduous forest, making it an easy plant to get to know during a casual walk in the woods.

Slow growing and multistemmed, witch-hazel typically reaches heights of 15 to 20 feet. The shrub has a full, rounded crown and an attractive vase-shaped habit. Its bark—thin, smooth, and gray—is quite attractive and adds interest to the winter garden. In the shade of canopy trees, witch-hazel exhibits zigzag branching and may look as though it were roaming for light, which it is. Its branching pattern and its leaves—which are held perpendicular to the sun—make it a good competitor for the limited light found in the understory.

The leaves themselves are decorative. Broadly oval with scalloped edges and inverted V-shaped venation, they grow up to six inches long and mature from deep green to a rich golden color in fall. Scientists have speculated that the leaves are a food source for larvae of an endangered moth, Acronicta hamamelis. One definite leaf eater is the witch-hazel leaf gall (Hormaphis hamamelidis). To house its eggs, this aphid chews through the leaf underside and secretes chemicals that lead to the formation of Hershey kisses-shaped galls.



Each individual witch-hazel blossom is functionally monoecious, meaning that it’s equipped with both sets of reproductive organs but acts as either a male (producing pollen only) or female (producing fruit only). Thus, any chance of self-fertilization is eliminated. Instead, the flowers use their showy petals and faint fragrance to attract pollinators to facilitate cross-fertilization. Small gnats and bees are the main pollinators, and they are rewarded for their labors with sugary nectar and sticky pollen.

Researchers suspect that the plant’s unusually late flowering period induces insects to pay extra special attention to the unique blossoms—after all, the flowers are the only game in town.

After pollination, actual fertilization of the seed is delayed until spring. The fruit develops during the regular growing season and is newly ripened as flowers begin to open in late autumn. The fruits develop into hard, fuzzy, tan-colored capsules, under an inch long, and they carry one or two dark shiny seeds. In fall, the capsules burst and eject their seeds up to 25 feet away, but they persist on the branches for a while, resembling baby birds, beaks agape, expecting a worm. If left undisturbed on the forest floor, the seeds will germinate two years after dispersal. In the interim, they might be eaten by songbirds or small mammals, or even the occasional bear.

The ideal garden setting for witch hazel is part sun to light shade with moist, slightly acidic, organically rich soils. While best flowering occurs in full sun, planting witch-hazel out in the open will subject it to scorching and burning. Balled-and-burlaped or container-grown specimens can be transplanted in spring or fall. As a landscaping element, individual plants are showy enough to stand on their own, but witch-hazel also works well when multiple specimens are grouped together.

More on Hamamelis virginiana

16 October 2005

New Invasive Plant Field Guide

Invasive Plants Field Guide: An ecological perspective of plant invaders of forests & woodlands.

A source for information on key plant invaders in eastern forests. The guide examines 15 main species in four plant categories and presents extensive information about each. There is also a references section. Full color photos appear throughout.

The publication is put out by USDA (#NA-TP-05-04). It can be downloaded here as a pdf.

14 October 2005

Will the real Aralia elata please stand up?

Japanese angelica tree (Aralia elata)??? Nice fall color, which I have never seen on (& reported doesn't exist for) the ubiquitous other Aralia.

Japanese angelica tree (Aralia elata)??? with infructescence

Devil's walking stick (Aralia spinosa)???

Welcome to the world of botanical taxonomy. For your entre, I thought we would go right for the jugular. Devil's walking stick (Aralia spinosa) is native to the U.S. Most literature cites its range as Delaware & south (e.g., Gleason & Cronquist). One (Mitchell & Tucker) says it's native to New York State. So I called our state botanist who assured me that G&C was right, it is not native to NY. In fact, field work has shown that there is no A. spinosa in the state at all. Everything we have been seeing is actually Aralia elata, an exotic invasive. There is a population of Aralia spinosa out on Long Island, but that was shown to have piggybacked in on nursery stock from North Carolina.

So when a colleague of mine called me to say he had found an interesting Aralia, I was excited. To compare, we began with the familiar.

We went to Highbridge Park in northern Manhattan. There was a small cluster of less than 10 shrubs in an opening in the forest canopy, not far off a trail. This is the Aralia shrub that I see all over NYC. It had dark green leaves held at almost a 90 degree angle to the main stem. We were calling this "spinosa" based on the leaves - veination (joined before margin) & finely toothed, no obvious pubescence. The fruit panicles no longer held berries & had already whithered, so we didn't take a sample.

Now, the fun part. Next we went to Fort Washington Park, a subset of Riverside Park in northern Manhattan (around 158 St.). There were maybe 5 shrubs scattered along a stretch between a trail & fencing for the Metro North train line (so not obviously colonial like above). These plants were new to me - I had never seen this species before. We were calling this "elata" based on the leaves - veination (run to margin), broadly toothed & obvious pubescence. Additionally, these leaves were lighter green & held at a more acute angle to the midstem.

So we sent the samples to Brooklyn Botanic Garden - I could barely get to sleep that night, I was so excited to hear back what the new-to-me plant was. Apparently they think they are both the same species...Aralia elata. They said what they really need is the point at which the inflorescence attaches to the main stem - that is the critical piece distinguishing one from the other. Oh. We didn't get that. But still, sometimes I think taxonomists are too by the book. Can't you just tell which is which? If I can ID species with just basal leaves, I expect a little more info when I provide such bounty.

And so the mystery continues..........
OK, OK, I know. Don't go by leaves. Flowers/fruits are more stable, & so the basis of taxonomic determinations. But c'mon - these have to be two different species. (And additionally, if you aren't supposed to look at leaves, then why the difference between Smilax herbacea & S. pulverulenta (NYS rare) - the former has no hair on it's leaves, the latter has hair. Be consistent, people!)

09 October 2005

Invasive willow threatens wetlands, rare plants in East


Egads - another one.

From The Boston Globe

A European invader has been sneaking onto the New England coast, infiltrating and undermining the natives.

The large gray willow, a shrub or small tree that spreads rapidly and closely resembles our native pussy willow, has been flying under the radar for years, colonizing the edges of ponds and crowding out rare plants and animals throughout the eastern United States. It was just identified this spring.

Other countries that have been invaded by the species, Salix cinerea, also called the European gray willow, paint a grim picture. New Zealand considers it a major "pest plant". Australia calls it the worst of the invasive willows and warns it can cross-pollinate with other willows.

There is concern about the threat to coastal plain ponds that are host to a whole complex of rare insects, animals and plants, including the Plymouth gentian, rose coreopsis, hyssop hedge-nettle and slender marsh pink, as well as rare dragonflies and damselflies.

The European willow's presence is confirmed for Cape Cod and Rhode Island. It is expected to show up in coastal areas stretching from Maine to Long Island. The Harvard Herbaria in Cambridge, Mass., has a specimen collected in Old Orchard Beach, Maine, in 1967, so the willow has a lengthy head start on efforts to control it. (Yet ANOTHER reason why herbaria are so important!!)

The full article from The Boston Globe

More on Salix cinerea

07 October 2005

Good Gardening: Medley


Solomon's seal (Polygonatum biflorum)
Solomon's seal, with it's tall, arching stems and showy foliage, is a statuesque addition to any shade garden. Once in the ground, they require very little attention.

Flowering dogwood (Cornus florida)
This is another example of why everyone should have a flowering dogwood...the rich fall foliage.

Evergreen woodfern (Dryopteris intermedia) and Sensitive fern (Onoclea sensibilis)
These ferns are attractive as border plantings in moist locations.

Mist flower (Eupatorium coelestinum)
Beloved by gardeners & butterflies alike, this easy-to-please member of the aster family (Asteraceae) is a rampant spreader, so give it lots of room.