From the soaring Norway spruce at New York City’s Rockefeller Center to the concolor fir displayed inside the White House, there is no single exemplary Christmas tree. Historically, the requirement has been a conifer that looks nice come winter.

Before World War II, most families brought home a pine, spruce or maybe a Douglas fir. After the war, the housing boom drove demand for lumber, which led to the practice of tree farming and sparked interest in growing Christmas trees on farms. By the 1990s, firs — valued for the aroma, longevity and needle retention — had earned a national following, even in regions that traditionally favored pine, cypress or spruce, as advancements in harvesting and distribution meant growers could ship trees across the country.

“I wouldn’t call it homogenization of Christmas, but there’s this myth that people hike out into the woods and chop down trees from the wilds, and therefore, they would have a tree that was from the local region,” said Trent Preszler, the author of “Evergreen: The Trees that Shaped America.” “But Christmas trees are grown on farms just like corn or soybeans.”

But with more than 20 tree types marketed as Christmas trees, knowing what kind of tree you’re getting is helpful. Whether you pick a locally grown tree from a choose-and-cut farm or browse the aisles of a retail lot, shopping by type helps ensure you get the fragrance you want (or none at all). The right pick can spare you from excessive needle drop, droopy branches or sticky sap. You might even land a tree that won’t give up on you if you miss a day of watering.

Here’s what you should know about 12 common varieties you’re likely to see while shopping this year, organized by the regions in which they’re most often grown.

Trees from the North

Balsam fir

This classic fir is especially popular in the Northeast, with soft, dark-green needles on sturdy horizontal branches arranged in tiered layers to support heavy ornaments. Balsam is one of the most fragrant firs, with a spicy, sweet, piney scent that might be delayed if you’re tree shopping in cooler temperatures. Eric North, the urban forestry program manager at the Arbor Day Foundation, said the essential oils responsible for a fir’s fragrance are sensitive to heat, so the aroma intensifies once the tree is indoors around room temperature.

Eastern white pine

Before Christmas trees were farmed, Eastern white pine was a popular wild-harvested option. Budget-friendly and native from the northern United States down to Georgia, its soft, bluish-green to silvery-green needles — up to 5 inches long and clustered — give the tree a feathery, almost fluffy appearance that traditionalists love. Needle retention is good, scent is mild, and lighter branches suit ribbon, tinsel and lights rather than heavy ornaments.

Scotch (Scots) pine

Native to Europe and Asia, Scotch pine is one of the most popular Christmas trees because of its strong, woodsy scent. Its dense form features stout branches that support heavy ornaments and strands of lights. Short, stiff needles range in color from medium green to blue-green, with white undersides that lend a subtle, shimmering look. Scotch pine retains its needles well, even if you go a few days without watering.

Norway spruce

The fast-growing Norway spruce, native to Europe and widely planted in the Northeast, has drooping branches and dark green foliage that form a classic, conical Christmas tree shape. In the wild, it can reach 150 feet tall, which is likely why Rockefeller Center has used a Norway spruce since the early 1980s. Valued for its color, classic scent, and sturdy branches, the spruce’s needle retention is short, and a cut tree typically lasts about three weeks with proper watering.

Trees from the South

Fraser fir

The Fraser fir addresses a common real-tree complaint: shedding. “It’s called the perfect Christmas tree because it has that combination of aroma, branch strength, the needles are soft, and it has elite needle retention,” said Justin Whitehill, of the Whitehill lab Christmas tree genetics program at North Carolina State University. Native to a small swath of southwest Virginia to western North Carolina, the Fraser, like other firs, has dark green needles that curl slightly, revealing silvery undersides that lend a frosted look. Its moderate scent is a blend of pine and citrus.

Canaan fir

The Canaan fir, which appeared on farms in the early 1990s, is relatively new to the market. Native to Canaan Valley in West Virginia, the tree is still primarily grown from the Midwest to the Northeast. Canaan fir is similar to balsam, with excellent needle retention, but its slightly upward-arching branches give the tree a lighter, airier appearance. The foliage is deep, dark green with striking silvery undersides, and the scent is a mild blend of classic pine with a hint of citrus.

Virginia pine

In the pine family, Virginia is the “Goldilocks” choice for fragrance — more aromatic than Eastern white, but milder than Scotch pine. Originally native from Pennsylvania to Georgia, it now thrives across the South. Its sturdy branches can support heavier ornaments, and its short, stiff needles range from dark green to yellow-green, often with a slightly twisted shape. With a dense, full form, Virginia pine delivers what many consider the classic, traditional Christmas tree look.

Arizona cypress

Native to the Southwest and western Texas, the Arizona cypress is popular in the South for its silvery-blue to gray-green, scale-like foliage. Upright, sturdy branches form a dense, steeple shape. Mildly to very aromatic, with a sweet to citrus-mint scent, this tree offers excellent needle retention and can last up to four weeks with proper watering.

Trees from the West

Douglas fir

While technically not a true fir, the Douglas fir has been a popular choice in the Pacific Northwest since the 1920s. Its soft, dark green to blue-green needles radiate in all directions, giving the tree a bushier appearance. The scent is mild, with hints of citrus and a sweet, forest-like aroma. Though classic, the Douglas fir’s main drawbacks are its indoor longevity — typically around 21 days with proper watering — and branches that may not support the heaviest glass or ceramic ornaments.

Noble fir

Found from Washington to Northern California, the noble fir is the West Coast’s answer to the Fraser. Stiff branches capable of holding heavy ornaments provide a symmetrical shape, which is filled with bluish-green needles that twist upward, revealing silvery undersides. The scent is mild, sweet, and slightly woody, and the tree is robust enough to last well into the New Year. “If you take a noble fir and display it without water, it’ll last 21 days,” said Gary Chastagner, professor emeritus of plant pathology at Washington State University. “Display in water, it will last six to eight weeks.”

Concolor (white) fir

The citrusy aroma — somewhere between lemon and grapefruit — is concolor’s love-it-or-hate-it trait. Native to the West, it grows from the Rockies in Colorado south into New Mexico and west toward Oregon and California; today, it’s also farmed in the northeast. Typically wider than other firs, it’s filled with soft, unusually long needles — up to 2 inches — that can be silvery-green to blue. The branches are strong but less sturdy than a Fraser or noble, with a less saturated green color.

Colorado blue spruce

If young children are helping decorate, the prickly Colorado blue spruce might not be ideal. “As a kid I remember hating the spruces,” Mr. North said. “They tend to have sharp needles and especially for a kid, you’re trying to hang ornaments or sneak under the tree to look at presents and you’re getting poked.” Native in the mountain West, the Colorado blue spruce has stiff, striking blue-gray to silvery needles on sturdy, symmetrical branches that grip onto ornaments. Its resinous scent — citrusy to camphor-like — is released when the needles are crushed, so you have a little more control over the smell.