Firs are handsome, erect, symmetrical trees with branches in regularly spaced whorls. Needles are short (mostly in the 1- to 2-in. range) and closely set along the branches; they're often banded white on the undersides. Attractive cones of most types grow 25 in. long.
Many people confuse firs with spruces (Picea), but the two are easily distinguished. Fir needles are typically soft and pull cleanly from the stem; spruce needles have sharp points and pull off with a piece of stalk. Also, fir cones stand upright, while spruce cones hang down.
With the exception of the Appalachian region, the South is generally a difficult environment for firs. They dislike summer heat and drought and heavy, poorly drained soils. Success depends on having rich, deep, well-drained soil, providing light shade in the afternoon, and replenishing mulch regularly to keep roots moist and cool. Firs are popular Christmas trees, both live and cut.
A. balsamea balsamea. BALSAM FIR. Zone US; USDA 6. Native to Northeast. Pyramidal tree to 50 ft. tall and 20 ft. wide; 12- to 1-in.-long, dark green needles. Legendary fragrance makes it a favorite for Christmas trees, wreaths. Use dwarf 'Nana' in rock gardens, containers.
A. balsamea phanerolepis. CANAAN FIR. Zone US; USDA 6. Native to the mountains of Virginia and West Virginia. Medium-size, growing 4055 ft. tall and 2025 ft. wide with dark to blue-green foliage, owing to silver line on the - to 1-in.-long needles. Desirable for its adaptability to seasonally wet soil, but it thrives where soil is moist year-round. Grown for Christmas trees but deserves a place in the garden.
A. concolor. WHITE FIR. Zones US, MS; USDA 6-7. Native to mountain regions of West and Southwest but tolerates hot, humid summers better than most firs. Grows 5070 ft. tall and 15 ft. wide in gardens. Bluish green, 1- to 2-in.-long needles. 'Candicans' is bluish white.
A. firma. JAPANESE FIR, MOMI FIR. Zones US, MS, LS, CS; USDA 6-9. Native to Japan. Broadly pyramidal to 4050 ft. tall and about half as wide, with branches held slightly above horizontal. Needles are 11 in. long, dark green above, lighter beneath; unlike needles of other firs, they are very sharp at the tips. Can tolerate hot, moist climates.
A. fraseri. FRASER FIR, SOUTHERN FIR. Zone US; USDA 6. Native to higher, cooler elevations of the Appalachian Mountains. Attractive pyramidal tree resembling A. balsamea in both looks and fragrance. Widely grown as a Christmas tree where summers are not too hot.
A. homolepis. NIKKO FIR. Zones US, MS; USDA 6-7. Native to Japan. Broad, dense, rather formal-looking fir to 80 ft. tall and 20 ft. wide. Dark green, 12- to 1-in. needles are densely arranged and point toward ends of branches. Adapted to warm, moist regions. 'Prostrata' is a low, spreading form that reaches 510 ft. tall and wide in 10 years.