Saturday, March 31, 2012

Shrubs bursting

What: Leaves on Red elderberry (Sambucus racemosa), Tartarian honeysuckle (Lonicera tartarica), and Black cherry (Prunus serotina), respectively, bursting.

Ecological notes: Trees in the understory are often the first to leaf out. They risk hard frosts (like that 19 degree night we had the other day) in order to photosynthesize before the canopy trees leaf out. As a generalization, larger trees can store more energy relative to body size so they have a little more of a buffer on how long they can overwinter, plus they're in prime real estate during the summer to make for lost time photosynthesizing.

Where: All over Burlington the green is starting to return. First in the grasses and celandine poppies, then in the shrubs. By now the ostrich fern is starting to pop up as are the wild leeks.

Other notes: Already I've seen blossoms on red elderberries (at Red Rocks in South Burlington). My ornamental elderberries (Sambucus canadensis) haven't put out flowers yet and the emerging leaves do not have the same reddish tinge to them as the wild ones do. The red is caused by the same pigments that make the leaves red in the fall (non-photosynthetic vacuolar pigments called anthocyanins). It's possible that these require little energy investment chlorophyll takes lots of energy to produce) and the plant can produce the structural part of leaves initially and then chlorophyll once the fear of frost is reduced.

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