Winter to Spring Transition Brings Challenges

With the spring equinox upon us — Friday March 20 at 10:46 AM Eastern Time in the Northern Hemisphere — Mother Nature recently served up a harsh reminder that spring time weather can bring challenges for gardeners.

Just before sunrise on the morning of March 17, temperatures dropped into the upper 20s F in north Atlanta. When I heard the forecast a few days earlier, I thought about my garden and what plants I needed to protect from the cold and possibly frost. I wondered how, realistically, I was going to do that.

It's almost been like early summer recently. Local high temperatures have reached a record-setting 83 F. The warmth and lengthening daylight hours prompted the garden to do what gardens are supposed to do under those conditions. The plants woke up from their winter slumber, rejoiced and pushed out fresh green growth — make that tender green growth. I rounded up large pots and lawn bags as I prepared to cover what I could. On March 16, the front that was bringing in the drop in temperatures also brought rain that turned to snow flurries blown sideways by gusting winds. The wintry scene continued into the evening as dusk started enveloping the garden. "Guys," I said to the plants, "I'm sorry. But you're on your own."

I turned on the fire in the library and decided to check my email. A message from Journey North served as a quick and unsettling reminder that it's not just gardeners and their plants that face challenges in rapidly changing spring weather. So do early arriving migratory visitors. The email linked to a map with reports of Ruby-throated Hummingbird sightings as they move north through the US. The most northern migrating Ruby-throated Hummingbird at that time that had been reported to Journey North was a male in the east Atlanta suburb of Conyers.

Conyers is about 25 miles from downtown Atlanta and straddles Interstate 20. While I was enjoying the warmth of the fire, this early arriving Ruby-throated Hummingbird was about to experience a very cold night. I imagined him shivering and probably wondering, "What was I thinking in leaving a shaded streamside coffee farm on the edge of a tropical forest in Central America for this?"

I am hoping he made it through the night. If he did he can thank Isabel Wagner. Wagner had posted the sighting of the ruby-throated, and I sent her an email asking about him. I was curious because I didn't think hummers arrived in our area in mid-March.

"I typically use March 15 as a date to hang my feeders, but given the warm up we have had and other sightings in the Carolinas, I have had it up since March 7," Wagner told me in an email response to my question. "I am a master gardener and master naturalist, and with so many things blooming on my one acre garden I was expecting them early." She said she's had the feeder up for 10 years, and "this is the earliest I have ever seen one."

I've always wondered when was the earliest time to hang my hummingbird feeders. Isabel has helped me understand I have been waiting too late — generally about the first of April. Her comments and a reach out to the American Bird Conservancy show that having feeders up for early bird migrating hummers can be important to their survival in the face of sudden temperature drops.

"In spring cold spells ... hummingbirds have a defense mechanism," a conservancy spokesperson wrote in an email. "They are known to enter a state of torpor to conserve energy and stay tolerant of the cold. This means they can drop their internal temperature and their metabolism and heart rate, so that their bodies require less energy and food in order to survive frigid temperatures. They may appear dead, sleeping, or shivering but they are conserving energy. They are small yet very tough and resilient. There are over 360 hummingbird species overall with over a dozen found in the U.S., so torpor and killing temperatures depend on the species, though it is possible the one recorded in Conyers could have survived freezing temperatures."

Let's hope so.

For the record, male Ruby-throated Hummingbirds tend to migrate before females and juveniles, according to the conservancy. The first of my three hummingbird feeders is now up in my garden. I'll start looking for that tell-tale ruby patch amongst the emerald green feathers. And I'll hope we're past these weird temperature swings. That, of course, may not necessarily be the case. March, as the saying goes, still has time to roar like a lion before the calendar turns to April and March departs, with any luck, like a lamb.

In the meantime, fresh growth and blooms in the garden and woodland ravine behind the garden seem to have weathered three nights of below-freezing temperatures just fine. I never worry about the natives, which I try to emphasize in my garden. Nature made them to withstand weather shifts and extremes just fine. The Carolina Silverbell is opening up in glorious bloom in the woodland above the tiny creek at the bottom of the ravine. The yellow witch hazel has been in bloom for several weeks. The viburnums are in massive bloom and flowers are opening on the native azaleas, the fothergilla and the high bush blueberries. The hydrangea Annabelles and oak leafs are leafing out, as have the Clethras — tomentosa and Ruby Spice. The Mayapple that grows naturally on the woodland edge not only has shrugged off the cold but the colony is spreading.

On the non-native front, the recently added David Austin roses that I am hoping will enhance my cottage garden effect all seem to be doing just fine. The epimediums I divided and added to a recently installed sweep of Nikko Blue Hydrangeas not only are surviving with new growth but in one case has produced flowers. Camellias are finishing their annual show and are still putting on a glorious display, even when their flowers fall to a grade path.

The cold-hardy plants, of course, basked in the sub-freezing temperatures. I'm thinking of the peonies, the palms, especially the Trachycarpus fortunei that has produced massive flower spikes, the Edgeworthia chrysantha paper bush and the St. John's wort.

Happily, this morning was our last week of sub-freezing temperatures, at least according to local forecasts. I'll take that and be prepared to welcome spring when it officially arrives. The forecast is for sunny skies and a high of 72 F, which I am sure will make the plants happy. Not to mention the butterflies that are already appearing and a certain hummingbird.