Early spring, maybe not quite so early!

TPP is in St. Louis for a society meeting, the business end of botany.  Spring here is about 2 full weeks ahead of us 150 miles further north, and the star and tulip-flowered magnolias are in bloom here. But a huge front is pushing in from the north west, and lows are expected here in the low 20s (remember 32 is freezing in the crazy F temp scale).  In our area probably even a few degrees lower. Any plant with flowers out will likely get toasted. This is the problem with early springs in the great Midwest.  Our weather patterns are so big and so variable that late and even not so late freezes are more than likely, they are virtually certain.  Stoopid plants just don't know to wait.  TPP's stoopidist plant is certainly our star magnolia, so ours is planted in a cool, slightly shady location, and it flowers a week later than most others, and it this case this just might be enough to save its floral display from frost damage, or maybe not.  It's a wait and see game.  Been too busy to peek at the Missouri Botanical Gardens to see how advance their gardens are.  Even this morning while picking the newspaper up off the front stoop, TPP noticed that the potted pansies were pretty stiff, but they are quite tough plants and once you're frozen, you're frozen.  So we'll see.  Nothing much to worry about in any case, but magnolias are another matter entirely.

Sudden Ginkgo leaf fall

A number of people noticed this year that the leaves of ginkgo trees turned bright yellow, as usual, and then suddenly dropped all their leaves literally overnight leaving a golden carpet of leaves around the trees. This is actually pretty normal too, but usually it happens along with a lot of other trees dropping leaves, so fewer people notice.  2016 has been a long warmish fall with no good hard frosts before there was a very cold overnight freeze.  What happens is this. The shorter, cooler days stops the production of chlorophyll that ordinarily masks the yellow pigments (carotenoids, xanthophylls) and the leaves turn yellow. This is pretty common for lots of trees. At the base of the leaf stalk deciduous trees form a week place called an abscission zone, and in most trees a bit of back and forth bending in the wind causes the leaf to fall.  Gingko makes such a zone, but some of the vascular tissue remains connected and it takes a freeze, forming some ice crystals, to break the residual vascular connection, so after such a freeze, the leaves all fall at once. One day ginkgo trees have yellow leaves, the next day the trees are bare and the ground carpeted with ginkgo leaves.