The scent of pine is one of the hallmarks of this happy time of the year. Perhaps that’s what inspires so many homeowners to plant pine trees in their yards.

“Unfortunately, many of them don’t do very well,” said Sharon Yiesla, plant knowledge specialist in the Plant Clinic at The Morton Arboretum in Lisle. “It’s wonderful to enjoy them indoors for the holidays, but outdoors, the Chicago region just isn’t hospitable to most species of pines.”

Pines, like most evergreens, need very well-drained soil that lets water flow away from their roots — the opposite of the sticky, water-retaining clay found in most of this region. In the Arboretum’s Conifer Collection, many evergreens are planted on sloping sites where water drains away more readily than in a typical flat city or suburban yard.

Pine species that are widely planted around homes, such as Scots pine (Pinus sylvestris), Austrian pine (Pinus nigra), and Japanese red pine (Pinus densiflora), are vulnerable to several nasty diseases and insects. “Plants that are in less than optimal conditions, such as pines in poor soil, are always less able to tolerate pests, diseases and other stresses,” Yiesla said.

Pine wilt is a serious disease caused by microscopic roundworms, or nematodes, that are carried from tree to tree in spring by pine sawyer beetles. A tree infested with pine wilt can die in just a few weeks or months.

Needle cast diseases, caused by fungi, make pine trees lose needles and slowly decline. Diplodia tip blight, another disfiguring and damaging fungal disease, is especially common in Austrian pines.

Fungal diseases spread more readily in wet weather. The Chicago region is seeing more rain as the climate changes. Kris Bachtell, vice president of collections and facilities at the Arboretum, thinks that’s one reason all evergreens, including pines, are struggling.

“We have seen many more evergreens die in the last five or 10 years,” said Bachtell, who is in charge of the Arboretum’s trees and plants. He attributes the change to the region’s increasingly variable weather: more spring rainstorms, more summer heat, and higher atmospheric humidity, because warmer air holds more moisture.

Most pine tree species come from distant places where the soil is acid and rocky or sandy rather than clay. Only Eastern white pine (Pinus strobus) and the scrubby jack pine (Pinus banksiana) are native to a few parts of the Chicago region, although they require very well-drained soil. “White pine really can’t tolerate clay,” Yiesla said.

White pine is better able to resist some diseases than nonnative pines, Bachtell said, but it is vulnerable to another scourge: salt. “The salt we use to melt ice and snow in winter really dries out the foliage and roots of evergreens,” Yiesla said.

The species matures to be a very tall tree, more than 50 feet tall and up to 40 feet wide. It has fine needles and a more open, irregular habit than the neat triangles seen on Christmas cards. “It’s more picturesque,” Bachtell said.

Pines aren’t the only evergreen trees with problems. Other popular species, such as blue spruce (Picea pungens), also struggle with clay soil, diseases and the changing climate in city and suburban settings.

Bachtell said he expects better performance from tough, salt-tolerant junipers, such as Chinese juniper (Juniperus chinensis) and the native Virginia juniper (Juniperus virginiana, also known as eastern red-cedar). There are cultivated varieties of junipers in many shapes and sizes.

He also has hopes for some evergreen tree species that may be more difficult to find in Chicago-area nurseries: Nordmann fir (Abies nordmanniana), Siberian fir (Abies siberica) and Sawara-cypress (Chamaecyparis pisifera).

The Plant Clinic can help you choose an evergreen or other plant that is suited to the conditions and size of your yard. Identify what you want the plant to do, such as create privacy or display holiday lights. “A tree will live a long time, so it’s worth it to invest some time and effort in finding a plant that is likely to succeed,” Yiesla said.

And if you’ve simply been swept up in holiday spirit, perhaps wait a few weeks to see if you’re still feeling strongly about adding an evergreen.

“You may want to take a step back and consider whether your site is really suitable for an evergreen,” Bachtell said. Pines and spruces are beloved guests at holiday celebrations, but for your yard, there may be better alternatives.

For tree and plant advice, contact the Plant Clinic at The Morton Arboretum (630-719-2424, mortonarb.org/plant- clinic, or plantclinic@ mortonarb.org). Beth Botts is a staff writer at the Arboretum.