From the Field - Crow's Nest Preserve

Roses

The native swamp rose, Rosa palustris, is now blooming at Crow's Nest. Its pink flowers are larger than the more common (and invasive) multiflora rose's white ones, and for us it blooms a bit later. It also lacks the hairy stipules at the base of each leaf stem, or petiole, that you find on multiflora rose. Swamp rose's hips--the fruit--are also much larger. But even if you didn't know this, you could distinguish swamp rose from multiflora rose by its behavior: multiflora takes over everywhere, and swamp rose is a well-behaved clump at the pond, along the stream, and near a spring.

Multiflora rose (Rosa multiflora) is a plant we love to hate. Imported for soil conservation, wildlife habitat, and as a "living fence" to contain livestock, it has taken over many old fields, hedgerows, and wood lots. I lose a lot of blood to its thorns.

A disease called rose-rosette is moving into our area, and it disfigures the new growth on multiflora rose (and some garden roses). The disease reduces the vigor of the plant. Experts think that this will cause multiflora rose populations to be reduced in a cycle of disease boom and bust. It will never eliminate multiflora rose, but perhaps it will never be as dominant as it is today. See links such as this one for more information: http://www.ext.vt.edu/pubs/plantdiseasefs/450-620/450-620.html.

Vacation!

They let me out of here, sometimes.

Occasionally I am reluctant to go away on vacation, because I want to keep a watchful eye on the preserve, because the preserve is such a beautiful place that I view it as a vacation destination, and because I don't want to miss anything, like blooms.

But there is something restorative about not wearing a watch or shoes for a week. And the only vines I saw at the Outer Banks were native ones: our native honeysuckle (Lonicera sempervirens), trumpet-vine (Campsis radicans) and greenbriar (Smilax sp.). I enjoyed the beach and the good company. Thank you, Laceys, for the invitation!

Travel notes:

We fit four adults, two dogs, and all of our gear in the VW Jetta turbodiesel (we used the roof bag for luggage) and still maintained over 40 mpg. I don't know of any other vehicle that can do that!

When I left, the spiderwort (Tradescantia sp.) was blooming. It still is. The blooms open in the morning and are closed by midday.

Likewise, the goatsbeard (Aruncus dioicus) at the base of the porch has reached full bloom. This plant attracts the most interesting little native bees to pollinate the flowers. I enjoy watching them work while I sit in the rocking chair.

Among the new flowers blooming is butterfly weed (Asclepias tuberosa). If the orange flowers weren't enough, it reliably attracts butterflies.

Thank you to summer intern Sean Quinn, who did such a good job keeping up with the maintenance at the preserve that I feel like I can go away again, and to Steve Holmburg and his family for looking after my pets and houseplants!

A pet peeve: Bug zappers

A neighbor has erected one of those ultraviolet bug zappers in the backyard, where it makes nearly continuous obnoxious zapping noises. No doubt this sends a reassuring message to the people who purchased it. But it is not doing anything good for their well-being or for the environment.

My first reaction, when I happened to drive by and see it erected near the preserve's woods was an indignant, "Hey, they're killing our bugs!" An overwhelming majority of insects are not pests of humans, so many of the bugs being zapped are "innocent," or at least "not bad." Some of them prey on other insects. Notably, mosquitoes are not attracted to ultraviolet light, so probably few of the zaps are killing our least desirable insects. At best the machine is a waste of electricity.

But also I feel that if we are living with nature (which I think we should be) then we should accept that there will be some bugs around us. To do otherwise would be like living on a houseboat and not liking water. Insects play an important role in the food web, pollinating the flowers they evolved with and serving as food for the other species that depend on them.

The best way to reduce the numbers of mosquitoes around our yards is to eliminate places where standing water persists: old tires, buckets, tarps, and bird baths. It doesn't take very much water to grow mosquito larvae. Dump out the water, and change bird bath water frequently.

What is a Weed?

Or, why am I relatively unconcerned about dandelions in my lawn, and yet very upset about invasive species taking over woods and meadows throughout our region?

A weed is simply an undesirable plant: a plant that is growing in the wrong place. Most likely the plant is unwanted because it grows too aggressively, is unattractive, or has some other negative impact on the landscape or ecology.

Dandelions (Taraxacum acaule, above) have beautiful flowers. It's when the stalks going to seed rise above the lawn that the turf looks terrible. Sure, I worry what the neighbors think. But it only looks bad for a week or so. A lawn is not a natural state of vegetation—turfgrass is not native and woods and meadows are our natural flora—and so having weeds in it is purely an aesthetic objection. I can overcome this by learning to live with it. Really, controlling dandelions is not worth the risk and effort of the pesticides that so many people use.

On the other hand, plants that are invasive in natural areas have the capability of changing the kind of world we live in—reducing us from a diverse native forest to one that is degraded and less complex. Invasive species outcompete others; we risk living in a world where only the thugs have survived. That's five-leaf akebia (Akebia quinata) above, reaching into powerlines.

Humans have introduced thousands of species to new habitats, either on purpose or by accident. This rate of introduction is orders of magnitude greater than what would occur naturally. A fraction of these have later been discovered to be invasive in their new habitat.

The introduction of species appears to bring new bounty to our landscape. But as Kim Todd writes in "Tinkering with Eden: A Natural History of Exotics in America" (Norton, 2001) there are unintended consequences. She writes about the introduction of non-native game species as one example: while these stories “. . . appear tales of addition, subtraction is the underlying theme . . . Instead of a world with heath hens and ring-neck pheasants, we have only ring-necked pheasants . . . Instead of a world with passenger pigeons and rock doves, we have only rock doves . . .” (p.252).

If we are successful controlling invasive plants on our preserves, our lands will be merely . . . less invaded. However, they will also be greater reserves of biodiversity. It is thankless work, this controlling invasives plants this summer (and every summer). People don't tend to notice the absence of something like the increasingly ubiquitous mile-a-minute; they don't know whether it hasn't invaded here yet, or that we spend a great deal of effort keeping it from becoming established (the latter is true). But the stakes are high—either do what we can to minimize the impact of invasive species, or we'll pass on to later generations a world that lacks many of the species we enjoy.

Contra dance, potluck, hayride

Our Crow's Nest Preserve open house and contra dance was a success! Thanks to the folks from the Elverson Dance and the staff of Natural Lands Trust for helping plan and prepare for this event. And thanks to everyone who came--the potluck tables were groaning under the weight of lots of good food!

After a short hayride we had dinner in the barnyard, and took time to digest the meal and socialized with friends and neighbors. Then the band and caller started up and the foot-stomping began! Lots of beginners mastered the basics of contra dancing, which is a bit like square dancing but arranged in long lines so that eventually you dance with everyone in the line.

The last guest to leave at the end of the evening (just like last year!) was a red salamander (Pseudotriton ruber). I guess having the barn open at night is an invitation to enter...

Bold colors and tiny flowers

In the garden a planting of the native flame azalea (Rhododendron calendulaceum) contrasts sharply with the dark red of the leaves of coral bells (Heuchera villosa 'Purpurea') balanced by the white flowers of Canadian anemone (Anemone canadensis). The Canadian anemone is a garden thug; don't plant it unless you have room, or be prepared to rip it out by the handful.

The flame azalea is listed in "The Plants of Pennylvania" (Rhoads and Block, 2000) as having been found only in Somerset County, now thought to be extirpated (no longer present). There is always a concern when choosing to garden with a native plant that is rare in the wild, even if you know the plant was nursery propagated, not dug from the wild.

The nursery plant you buy could have been propagated from a population that is genetically distinct from your local wild population, and subsequent interbreeding from cross pollination could "swamp"--replace or change--the wild plants. In this case, the native population was not located nearby, and the local nursery used open-pollinated seed that exhibit some of the variability of a natural population.

At the more subtle end of the plant kingdom are a couple tiny flowers we saw blooming last weekend on a hike that took us through Crow's Nest Preserve and into French Creek State Park. The first is blue-eyed-grass (Sisyrinchium montanum), named with obvious reason for the tiny blue flower atop grass-like leaves.

And finally, the small flower called bluets, or Quaker-ladies, or innocence, or eye-bright (Houstonia caerulea). It often has blue or violet flowers with a yellow center; these were truly white.

There is a beautiful woodland estate called Houstonia, in Nether Providence, Delaware County. The township protected it as a park, and I always admired this place with a beautiful name that is also a dainty flower.

While I was looking up the origin of the common names (which I didn't find, yet) I noticed this blurb in "Wildflowers of the Southern Mountains" (Richard Smith, University of Tennessee Press, 1998): "In Houstonia, it is possible to see dimorphic flowers, in which some have short stamens and a long pistil, and others just the reverse. This arrangement caught the attention of Charles Darwin, who concluded that it has the effect of making self-fertilization virtually impossible." (page 166).

Dimorphic means having two forms. Though some plants do self-fertilization of their flowers (in a pinch, some seed is better than no seed), many have evolved strategies to prevent it so that the plants have the greatest opportunity to incorporate the genetic variation of the species' nearby population, rather than just pass along the genes of a single plant.

A Sunday Walk

If you were walking at the preserve this weekend you would have seen the mountain laurel (Kalmia latifolia) starting to bloom. It's a favorite food of deer, and usually grows in thickets in dry, rocky woods.

This garter snake (Thamnophis sirtalis) was sunning itself beside the trail. It was very cooperative, since these pictures were taken from inches away.

This plant, Indian cucumber-root (Medeola virginiana), I had never seen in bloom before. The leaves are distinctively whorled around the stem, and more easily found than the flowers. Can you guess where the common name came from?

Why must dogs be leashed?

Why do we require that dogs be kept on a leash when visiting Natural Lands Trust Preserves?

Even the most well-behaved dog--like the one pictured here--can chase wildlife when roaming loose. Ground-nesting birds and other wildlife raise vulnerable young here. Off-trail traffic can also damage natural vegetation. Our preserves are used for research, and we don't want loose pets to disrupt ongoing projects. It is also more difficult to pick up after your dog when not leashed. Leashes are the law in Pennsylvania, and for the safety and comfort of all of our visitors we require them. (Thanks for your cooperation!)

Millersville Native Plant Conference

I was fortunate to be able to attend two days of the Millersville Native Plants in the Landscape Conference. Now in its 15th year, I had attended several times in the early 1990's but had not been able to make it in recent years.

The mission of the conference is in part "...to increase the knowledge, propagation, cultivation, and use of native plants in the Mid-Atlantic and New England regions...to promote methods of land management and design that respect "sense of place" by restoring native species and natural processes..." Home gardeners, nursery growers, landscape architects, and people from public gardens and non-profit conservancies all attend, and part of the purpose of the meeting is to build community.

Topics included planning your livable landscape, native trees and shrubs for the shade, growing for hummingbirds, native grouncovers, pruning, creating inspired gardens, and many others. Planting native plants in our yards makes them better habitat for wildlife, sort of a "build it and they will come" scenario.

I've incuded pictures of three of my favorite plants from my yard that were also recommended in the various talks. Above (top) is our native coral honeysuckle (Lonicera sempervirens). It's not at all invasive like the Japanese honeysuckle is, and it attracts hummingbirds, and re-blooms a lot through the summer into fall.

Below that is a fringetree (Chionanthus virginicus) that is covered right now in white, fragrant flowers. This one is a male, which has larger flowers than the female (both are needed for females to set fruit). Many native plants that are propagated from seed express the full variability of the species, so some set more flowers than others--pick yours out when it is in bloom.

And this one I planted right by my front door--Carolina allspice, or strawberry bush (Calycanthus floridus). The flowers are a rich velvety-red and subtly fragrant.

Next year's conference will be held at Millersville University June 1 - 3, 2006. See www.millersvillenativeplants.org.

Farmers Markets

I was invited to share information about Natural Lands Trust on the opening day of the Eagleview Farmers Market (now open for the season, Wednesdays 2 - 6 p.m.) I had a lot of fun talking with people who shared an interest in knowing where their food comes from, preserving local farmland, and making the connection between the two.

Farmers markets, farm stands, and CSA (Community Supported Agriculture) farms are widespread in Chester County, and they have high quality produce that they personally, passionately grew for you. For a listing of local farms and markets, go to www.chesco.org/agriculture/farmmarkets.