PHOTO: ADOBE STOCK

We’ve all suffered through one of the longest stretches of miserable, bone-chilling subzero temperatures in years in the Pittsburgh area. Surely that means we won’t have to suffer through a miserable summer of tick and spotted lanternfly infestations, right?

Unfortunately, yes we will. Here in Pennsylvania we have black-legged ticks, also known as deer ticks, that live for two years. To complete their life cycle, they have to be able to survive winter, says Emily Struckhoff, vector-borne disease specialist with Penn State Extension.

“How they do this is they become less active and sort of bury themselves in the soil and the leaf litter, under the snow. It helps insulate them a little bit from these really frigid temperatures,” she says.

While she acknowledged that it may be hard to predict the outcome, “we don’t expect a cold winter or a cold snap in the middle of winter to have a huge effect on their population,” she says. “I wish I had the opposite answer.”

Tick populations are of concern in Pennsylvania because approximately 30% of them that are active in the spring and summer carry lyme disease; the state has one of the highest rates of lyme disease cases in the United States. In 2024, there were more than 11,000 cases reported of the bacterial infection that can spread to the nervous system and lead to other complications.

As far as the spotted lanternfly, the adults die off during the first hard frost of winter but the egg masses survive the cold temperatures, Stuckhoff says. “Those egg masses will hatch in the late spring/early summer.”

Will this stretch of cold harm our spring plants and landscaping?

Sandy Feather, horticulture extension educator for the extension service, said perennials should be fine because the steady coatings of snow we’ve had acts as an insulator.

What is a concern is the growing popularity in the Pittsburgh area of trees and shrubs better suited for southern climates like crape myrtle. “They could take a hit because they’re not going to be reliably hardy for this subzero stuff.”

Broad-leaf evergreens like rhododendrons, mountain laurel and boxwoods also could take a hit, she says. Trees that lose their leaves in the winter like maples, oaks and magnolias are able to seal off their water loss during the winter.

For evergreens with huge leaf surfaces, the cold wind is able to suck out moisture from the leaves because they contain microscopic pores called stomata. “So a lot of time you see a lot of winter burn on those types of plants.”

Subshrubs such as lavender and butterfly bushes (popular in yards because they’re deer resistant) also might be threatened, she says. Because of milder temperatures last fall (this region didn’t hit 32 degrees at night until Nov. 13, she says) the plants didn’t have a good opportunity to “harden off” to be resilient against the colder temperatures. “There could be some damage from that. The thing with winter injury, you’re not really going to notice it until the plants start to put on new growth in the spring and then die.”

She urges homeowners not to trim back these subshrubs — which have a woody base and herbaceous growth on top — until after the risk of any frost in the spring or they could die.

Homeowners and landscapers also may see some damage in the spring from all the de-icing salts being used this winter. Those made up of calcium chloride or magnesium chloride are not as damaging. “Most plants don’t like heavy doses of salt,” she says.