We may or may not have a lot of cold weather left, but the question on everyone’s mind is how all this warm weather is affecting plants and how is it going to affect them when the cold weather comes back.
We have been seeing many perennial flowers/plants and bulbs nosing up out of the ground.
Some plants are beginning to bloom ahead of schedule, mainly those that bloom in mid to late February. Some plants that typically bloom early that might be out or close to coming out are daffodils, paper whites, Japanese Apricot, Okame Cherry, Japanese magnolia, quince, and forsythia. Blooming early will not hurt them but will simply mean that they won’t rebloom later.
I have also heard reports from gardeners that their vegetables are bolting. Bolting is where warm weather causes the cool-season vegetables (lettuce, broccoli, cabbage, etc.) to go to seed. This normally doesn’t happen until late spring.
Fruit trees are also affected. In most cases, too much unusually warm winter weather will cause fruit trees to bloom later than normal. This is because they need a certain number of chill hours (below 45 degrees), and they won’t come out until this requirement is satisfied. This could be a blessing down the road this spring if we have a late frost.
As far as our other landscape plants, they get confused by the on again off again weather. Landscape plants prepare themselves for winter temperatures by growing fuzzy insulating layers for protection. They reduce the amount of water they absorb and create their own antifreeze condition.
When it turns unseasonably warm, plants begin to change from their winter state to their spring state. When winter temperatures rise, plants think spring has arrived. The soil warms and the plants pump water into their roots and tissues.
When the temperature drops again, these plants will be more susceptible to freeze damage because of the changes they’ve made.
There is not really much you can do about all this. You have to let Mother Nature take its course. You can add an extra layer of mulch to help insulate plant roots. For the spring bulbs or perennials that have begun to emerge, cover them with a layer of mulch until freezing passes.
You can protect certain plants by covering them with cloth or plastic at night. If you use plastic and the sun shines on the plant during day, be sure to take it off or you can burn the plant.
You can also cover landscape plants that have started producing buds such as forsythia and azaleas. This is probably not needed unless we drop to around 20 degrees or below.