Even with this week’s freezing temperatures, the winter jasmine has been coaxed into full bloom by another mild winter. (Adrian Higgins/THE WASHINGTON POST)
Gardening columnist

This is the time of year when gardeners are supposed to take up basket-weaving or wood-turning to stave off thoughts of frozen soil, but this winter has been another so mild that folks are joyed and unsettled at the same time.

Yes, it has turned a wee bit more wintry of late, but contrast Monday’s inauguration parade with the one 28 years earlier for Ronald Reagan, when there wasn’t one because it was so cold — around zero degrees — that it was deemed too dangerous to endure.

Horticultural maniacs such as myself greet this newfound warmth — a paradise shift? — with ambivalence.

To see the carnival of pansies, lenten roses and Japanese apricots is a delight, but there are technical worries: Will there be more ticks or stink bugs this year? Will this week’s freeze, or a deeper one in February, wreck the camellias now in full flush? How can you dormant-prune roses that aren’t dormant? Fruit trees need the cold for flower buds to form and then to open late, after frost season. As Robert Frost wrote: “No orchard’s the worse for the wintriest storm; But one thing about it, it mustn’t get warm.”

Well, it has gotten warm, and the darker shadow, of course, is that this is all tied up with climate change of our making. You will remember last summer, a steamy stinker, and the recent news that in the continental United States, 2012 was the warmest year on record.

I have a friend in Arlington who has the pain and pleasure of helping a hummingbird through the winter. She has put out hummingbird feeders to supplement the poor creature’s reliance on mahonia blooms, themselves a month or two early.

But back to the parade: not down Pennsylvania Avenue, but the one in our back yards. Pansies and their prettier kid sisters, the violas, have been full, perky and a delight since I planted them in October. I wish I had put them in garden beds rather than just in pots, and chosen more of the pastel bicolors.

In a warm winter such as this one, the garden-variety lenten rose or hellebore keeps its old leaves aloft in a nice leafy mound (they flatten in a freeze) and from beneath this protective canopy grows this year’s show, stems with baby leaves and the first of many white, cream, lime and purple nodding blooms.

In cutting back this perennial, a job I’d leave for another month, you have to be careful to remove last year’s leaves without cutting the new growth. The warmth has also coaxed some lovely hellebore hybrids into flower, including a delightful variety named Pink Frost. I bought a glazed frost-proof pot for it, though this year, so far, a clay pot would have survived intact. I’ve had two small bearded irises bloom since December, a new experience.

It’s worth repeating that the forsythia you see flowering isn’t a forsythia but a winter jasmine and that the cherry blossoms that have now erupted and will surely ruin the annual spring visit by Aunt Edie and Uncle Fred aren’t the cherry blossoms after all. They belong, probably, to the Japanese apricot, or the autumn-flowering cherry, which blooms sporadically from November to March depending on weather.

The hardy banana is supposed to die back to its roots but this year is still in leaf in some sheltered locations. Maybe this week’s cold will alter that. The fragrant winter daphne is about to bloom along with the pungent sweetbox.

Let me tell you about my lemon tree. Over the years, it became large but not particularly handsome, and it was a spiny devil to bring indoors in October each year. This year, I left it out to die by cold; it was like tying a kid goat to a stake and waiting for a tiger to show up. Except the beast has stayed away. The lemon tree not only has shrugged off the odd night of light frost but looks far healthier out on the patio than it ever did in its dark winter quarters. I now don’t have the heart to let it freeze and brought it indoors this week.

My view is that our gardens, especially inside the Beltway, are now essentially well in the South, in the floral equivalent of Richmond or even Raleigh, N.C.

What must that mean for Raleigh? North Carolina State University’s J.C. Raulston Arboretum is named for a plant scientist who once traveled to Korea to collect plants to breed hardier camellias. Today, the arboretum doesn’t hibernate much, with sweetbox currently perfuming the air. The horticulturists are growing Chinese podocarpus, a tender evergreen great for hedging in dry conditions but previously considered marginal north of Spanish moss country. The arboretum also has hybrid grapefruit trees that are 12 feet tall along with amaryllis that grows outdoors unmolested. No one bothers to lift and store canna or dahlia tubers.

Mark Weathington, the arboretum’s assistant director, said that in five years, “I haven’t really seen any cold winters.”

He suggests people enjoy a precocious flower now because “there are a lot of other blooms in the spring.”

But there are practical problems associated with mild winters that lull people into thinking that it is spring. For all the mildness, it’s a safe bet that a good freeze or two stands between us and early April.

Weathington makes the cogent point that gardening nuts who like to push boundaries to try neat plants know the risks of loss. The unsuspecting homeowner has different expectations. Weathington rails against the practice of mass merchandisers selling material that is pretty much doomed if grown outdoors in the long term. The list includes certain palms, oleander and a plant called sea grape, a tropical shrub grown on the Gulf Coast.

Consumers plant it, kill it and then tell themselves, “ ‘I’m not a good gardener,’ and they give up,” he said. “That’s my biggest fear.”

The other problem with retailers appealing to spring fever is in selling tender annuals in late winter that no one should buy until April or May, things like sweet basil, pepper plants and, most of all, tomato transplants.

“I know nurseries that last year sold tomato plants to the same people three times,” he said. “It warmed up pretty early and then it got cold again.”

More vexing to me is the idea that plants that need chilling won’t get it. Most spring bulbs need that cold for the flower embryo to develop. At the Raulston Aboretum, Weathington has seen this phenomenon in the way that species tulips don’t hold their blooms aloft, as they should, but close to the ground. You can buy pre-cooled bulbs — this is how folks in the Deep South, for example, enjoy certain daffodils or crocuses — the difficulty is that 60-degree temperatures in the middle of winter will coax them into bloom.

If there comes a winter when Washington gardeners need pre-cooled bulbs, I think I’ll head north in search of Frost — Robert and Jack.

@adrian_higgins on Twitter

Read past columns by Higgins.