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Current Conditions With the Philadelphia Flower Show's appearance, Philadelphia knows that spring is not far behind. And, with the time change earlier by three weeks this year, even with cold temperatures, it is hard to ignore the fact that it's still light outside at 7 in the evening.
Early sign of spring – bulb foliage emerges through the snow Of course, a certain indicator of spring's approach is the return of the Mallard ducks to the pond. By early March a male and a female had already staked their claim to the Kaskey Pond. One of the most asked questions we get here in the Kaskey Garden in the winter is, "What do the pond animals do in the cold weather?" This winter it was mild enough that we still had turtles basking on the center island into the late fall, but most winters the temperatures begin to get cold enough for the fish and turtles to hibernate in late October. The ducks leave for more open waters. Once the pond freezes they are vulnerable to dogs and children, since predators can simply walk out onto the ice to get to them. I suspect our Mallards don't go very far; perhaps to Fairmount Park or Tinicum for the winter. When we designed the pond we made certain that there was enough "mud" on the bottom for the fish and the turtles to burrow into so that they would survive. Part of the reason that the pond is usually cloudy is that the animals – the fish, ducks and turtles stir up the bottom and it swirls into the water, giving the pond an opaque appearance. In the coldest part of the winter the pond is often clear because nothing is stirring up the bottom silt. Fish and turtles are cold-blooded and they are able to survive extended periods of freezing weather as long as they have mud to burrow into and a sufficient depth of water overhead. Although they do not actually freeze, they slow their respiration and heart rate and assume a dormant state. In this state they don't require as much oxygen and turtles can remain submerged for months at a time. The depth of the pond, nearly five feet, provides an insulating barrier of cold water which keeps the temperature at the very bottom, if not even, at least not quickly changing with the ups and downs of the air temperature. Visitors may notice during an extended warm spell in the winter, (we had quite a few of those in December and January) the fish are swimming and the turtles are climbing out on their logs, but once the cold returns the animals seem to vanish. If you look carefully, you might see a few unmoving fish resting on the bottom of the pond when it's very cold, not moving. They aren't dead, merely dormant. The turtles, because they are not as brilliantly colored as the Koi and comets, are more difficult to make out. Only when the pond has been still for weeks and none of the bottom mud has been stirred up by the fish and turtles can you make out the dark forms of the larger painted turtles. Our turtles are Red-eared Sliders, a common eastern water turtle. These turtles are the kind that were sold throughout the '60s as pets, few of which survived long enough to outgrow their small tanks. Unfortunately, these cold-hardy turtles look very similar to the "Yellow-eared Sliders", a southern species. If people put the "Yellow-eared Sliders" into the pond they won't survive the winter. We highly discourage people placing animals into the pond, for several reasons. First, animals raised in captivity might not adjust well to the environment in the pond and die. Second, animals that are taken from other ponds could contain diseases and infect our pond critters. And, third, there is a limit as to how many fish and turtles our pond can sustain. We don't want to make the environment inhospitable to the existing animals, so we limit the numbers we keep. If you do have a turtle that needs a home, please contact us at biopond@sas.upenn.edu. If we can't take it, we do know of organizations that will find it a good home, particularly if it was kept indoors previously and therefore might not be a good candidate for release. In order to keep enough oxygen in the water during the winter, one or more of the water features in the pond keep running. In the past, our old pond froze solid during an extended cold spell and all of the fish died from lack of oxygen. In the Kaskey pond, the waterfall, weeping walls, and water jets keep enough water moving that the surface does not entirely freeze over. Even in bitterly cold weather, water is moving and oxygen is plentiful for the denizens of the pond.
The water features keep the pond from freezing solid March is always a juxtaposition of the bleakness of winter and the hopeful little signs of spring. The Cornelian Cherry Dogwood, Cornus mas blooms as early as the first days of March, along with Snowdrops (Galanthus nivalis), Early Crocus (Crocus imperati) and Lenten Rose (Helleborus orientalis).
Cornus mas: An early blooming small tree This winter was one of the warmest I ever remember, continuing until the first week in February when we saw single-digit nights and days in the teens. I saw flowers that we normally don't see until March at the earliest blooming months ahead of schedule. First, one of our recently planted evergreen azaleas, Dawn's Early Light, sported pale yellow blooms at Christmas. The picture below shows the spent blossoms covered with snow.
Dawn's Early Light, which bloomed several months ahead of schedule Bearded Iris, (Iris germanica) looked spectacular in mid-January. Dwarf iris, (Iris reticulata and Iris danfordiae) small, cheerful irises that sometimes bloom along with crocus, I could have understood. But these were the large purple "Flags," the May-flowering iris that should have only recently gone to sleep for the winter back in November. Along the south side of the Leidy Labs building, shortly before the early February single-digit weather, a handful of purple Bearded Iris put on their annual display along with daffodils, which also bloomed around the corner on the east side of the Leidy building. No one warned them that they were months ahead of schedule.
This Bearded Iris shows damaged foliage and spent flower stalk. It will probably not bloom in May as it is supposed to do. It's normal to see foliage from Daffodils or Crocus, even Grape Hyacynth (Muscari armeniacum) emerging throughout the winter. I've seen Daffodil spikes six inches out and not in the least bit unhappy to endure frigid nights. But, once the plants have bloomed, it's a very different matter. Notice in the picture below of the Daffodil foliage, the emerging leaves and the leaves that have fallen over.
Having bloomed a few months too soon, the Daffodil on the right shows freeze damage, while the spikes on the left, partly emerged during our single-digit weather, are in fine shape for spring. Having stored the energy and the flower buds the year before, these spent Daffodils will not bloom again this year. The ones that bided their time and waited, however, will have a chance at seeing a pollinator or two. Although, at the same time these very early Daffodils and Iris bloomed, I do recall seeing a few honeybees out enjoying the mild weather and taking advantage of the warmth to do an early cleaning of the hive. So, perhaps the effort of these very early bloomers was not entirely wasted.
In a few short weeks the Daffodils will be in full bloom As magnificent as the Kaskey Garden looks in the snow, I think that the visitors to this lovely place, people and animals alike, will welcome the warmer weather.
The Garden is beautiful after a late winter snowfall. I know that the ducks are probably even as I write this, plotting their next batch of ducklings. Soon enough visitors will be delighted by the sight and sounds of baby Mallards.
In a few months, ducklings will be swimming in the Kaskey Pond.
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Last Modified August 23 2007 12:47:30 |
