BOZEMAN - My thumb may be far from green, but for many Bozeman gardeners, that’s not the case. Still, with this unusual winter, some might start to worry.
Jerry Cashman knows gardening well — he’s been in the nursery business off Springhill Road for more than 51 years, helping locals plant trees, grow perennials and tend their gardens. “We’ve been at this location for 51 years, and we’ve seen a lot of winters come and go,” Cashman said.
Given his experience, I asked Cashman if this year’s winter weather was abnormal. He said it was — but it’s not the first time. “The winter of 1986 was the one I remember when Bridger Bowl didn’t open until about the 25th of January. There was no snow at all,” he said.
Walking through his nursery, Cashman explained how mild winters can hurt plants. “Well, the negative effects include the freezing and thawing of the bark,” he said.
Particularly at risk, he noted, are deciduous trees — those that shed their leaves seasonally — such as maple, birch, chokecherry and lilac.
WATCH: tips for keeping plants and trees healthy during warm winter
“It causes the bark to expand in the daytime as it warms up, and then freeze, and expand and freeze again. They crack and split,” Cashman said, adding that the damage can eventually kill the top of a tree.
To prevent this, he recommends using white sleeves or tree protectors to help regulate temperatures during the tree’s first four to five years.
Another concern during warm winters is moisture. “Deciduous trees I don’t worry about. It’s the evergreen trees,” Cashman said.
Because evergreens keep their needles year-round, they constantly respire — in other words, they release water. With last week’s temperatures hitting 60 degrees in Bozeman, Cashman worries the root systems could dry out. “If they give off water, they can’t replace it because the root system starts to dry out. So what you want to do with evergreen trees at this time of the year is water them,” he said.
The conversation turned to perennials. “Some of the perennials planted, particularly along the south side of a house that warms up quickly — those could be in a bit of jeopardy because they could start to come up fast,” Cashman said.
His recommendation? Mulching, to keep soil cool and moist through the warm spells. But if the mild temperatures continue into next month, the risk increases.
“If we continue to have a mild February and the plants start to advance a little more, then we get a real cold spell following that — that’s when the damage will occur,” Cashman said.
For now, Cashman hopes Mother Nature returns to her regular rhythm. “You learn by experience. There’s nothing like many years of seeing plants grow and maybe sometimes struggle and have problems,” he said. “But you learn from those problems and try to solve them. That’s key to growing success.”
If you want to learn more about some warm winter affects, such as early season budding, visit the Cashman's website here: https://cashmannursery.com/gardening-tips/
