The Tidal Basin cherry trees still had their brown scales on March 8 of last year. This year they’d already moved onto their green stage by the last week in February. (Bill O’Leary/The Washington Post)

The National Park Service is expected to announce Wednesday when Washington’s cherry blossoms might hit peak flower. Countless folks far and wide are counting on having a date — tourists who need to know when to arrive for the spectacle, and locals, for whom it marks the psychological arrival of spring.

This winter (we use the word loosely), making such predictions has to be one of the hardest and most thankless jobs in town. Gardeners in the Mid-Atlantic have seen mild spells in winter before, but a prolonged balminess since the New Year and the downright warm days of February have simply kick-started the growing season at least three weeks early.

(Claritza Jimenez/The Washington Post)

Temperatures in the 70s have also induced a synchronicity of flowering that brings an overwhelming sense, even for people with the faces stuck in screens, that the season has shifted.

This happened — as far as I can tell — on Saturday afternoon, when the saucer magnolia in my garden, whose buds opened in the morning, burst fully open amid a garden full of the first daffodils, crocuses, hellebores and bulbous irises. Oh, and dandelions.

A saucer magnolia in the author's Alexandria garden on Feb. 25. (Adrian Higgins/The Washington Post)

But buds don’t just open at once: If you look closely at a cherry tree you will see that first the bud swells, then the brown scales that wrap and protect it fall off. Then you see the buds as green orbs before they finally show color. With the cherry tree, this sequence occurs at the same time the flower stalk begins to grow. Last year’s peak bloom came March 25.

As of Monday, the Yoshino cherry on my street was in full green haze, and it’s fully reasonable to think we are going to have one of the earliest appearances in history of the Tidal Basin cherry blossoms, most of which are those blushed, single blossoms of Yoshino. The thicker, magenta blooms of the Kwanzan come about a week or 10 days later.

The inevitable wrinkle with a precocious spring is that you get the dying dragon of winter swinging his tail back at you. This weekend looks like we may see a frost, though I believe the Yoshino and Kwanzan cherry trees are sufficiently budded that any freeze might slow their development but not, at this stage, damage the blooms.

The same cannot be said for things already in full bloom. To the saucer magnolia, I would add the white star magnolia. Take pictures of them now, and here’s another tip: Get ready to cover those hydrangeas, which have broken into growth.

The challenge for horticulturists is to explain to non-gardeners there is no one Japanese cherry tree. Other varieties have already begun to flower. The winter-flowering cherry (Prunus subhirtella Autumnalis) has been blooming sporadically since December, but the showier early ones arrived last week, conspicuously the Okame cherry. The related Japanese apricot has been in flower for much of February, unassailed by usual second-month freezes.

Some flowers in my garden are going over, including the snowdrops, the winter jasmine and even the little irises.

Cyclamineus daffodil in the author's garden on Feb. 26. (Adrian Higgins/The Washington Post)

So if Aunt Lizzie wants to know when to come to town, mid-March might be a good bet, but be ready for gales or wet-snow storms that might make the inherently fleeting blossoms even briefer. Moral: Nature, not the National Park Service, is running the show. And never believe a groundhog.

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