Spring in the Blue Ridge 2020

As I write this in late April we have just recently migrated from FL to NC. So we find ourselves in our summer home in Boone, NC, which is at an altitude of 3400 feet. You can see from the photo that dogwoods, azaleas and viburnums are bursting into blossom. We have planted these on our two mountain-side acres with various perennials, shrubs and trees that benefit wildlife. We were also fortunate to inherit some older well grown plants which attract animals from the former owners. For example the dogwood flowers are pretty but their wildlife value mainly lies with the fruits which are avidly consumed in the fall by migrating Swainson’s thrushes and tanagers. The striking azaleas attract many bumblebees for the nectar.

We are close to the Blue Ridge Parkway and thus to the escarpment that drops down as much as 2000 feet to the Piedmont. My photo shows a view of this drop-off from the parking lot of the Cascades Trail. When that was taken April 22 the nearby trees were leafless, yet you can see the trees down below in a warmer micro-climate are green and leafed out. This geological feature is due in large part to the collision of proto-Africa (Gondwana) and N America (Laurentia) about 330 million years ago and their separation 220 million years ago. The originally high peaks of the Appalachians (more than 20,000 ft) have now been worn down to their rounded current elevations.

The forests are famous for the communities of wildflowers that bloom and thrive in the ephemeral burst of light delivered to the ground before the trees leaf out. Here are a couple of examples from a hike along the Blue Ridge Parkway. The plant commonly referred to as “Jack in the Pulpit” should also be termed “Jill in the Pulpit” since the plants are either male or female. But they can switch sexes dependent on the resources available for growth and reproduction from the previous year. High resources support a female with consequent high demands for production of seeds, whereas low resources lead to males (pollen is cheap to make).

Trilliums can be abundant in some areas with suitable growth conditions and protection from serious deer herbivory. In this area steep slopes seem to discourage deer to some degree. It is interesting to consider what might pollinate these large flowers so early in the season when flying insects are not common. The red Wake Robin flower stinks and attracts flies as pollinators. The large flowered white trillium is odorless and is likely pollinated mainly by bumblebees which are warm blooded and can fly in cool spring weather. The seeds are dispersed mainly by ants.

Bluebirds are a conspicuous bird in early spring and begin to breed early and continue to breed several times. This male was sitting on a fence post near its nest box supplied by a local bird club. Hole nesting species such as bluebirds and tree swallows compete vigorously for the few natural nest cavities so we can help them out with boxes. The spectacular blue color of the male is not due to a pigment but to structural arrangement of keratin molecules and tiny air pockets in the feathers.

So wherever you are during Spring you can enjoy the biological changes that occur during this transitional period between winter and summer. The further north you go the more distinct these changes are but they occur even in southern areas. There is probably greater human enjoyment of spring in the north simply because winter can be so harsh, but spring flowers and a study of their pollinators is fun in any location.