Relatively fast growing if soil is humus-rich and moist, the tulip poplar (Liriodendron tulipifera) is a noble woodland tree that is great for casting shade. Also called tulip tree, yellow poplar or whitewood, this deciduous plant is a member of the magnolia family, Magnoliaceae. The wide-spreading shallow roots can make gardening under this tree challenging. Grow tulip poplars in U.S. Department of Agriculture winter hardiness zones 4b though 9, including southern California.
Tulip poplars are native to the eastern United States. The natural range of this species extends from the southern Great Lakes to the Gulf Coast and no further west than the Mississippi River.
When the tree is young, the tulip poplar is pyramid-like in shape. With age this outline becomes significantly more oval-rounded with several large, outward-reaching branches radiating from a tall and long trunk. When the leaves are present, this tree almost always looks lush and dense, although summer drought finds leaves prematurely yellowing and dropping as a result. Mature tulip poplars reach 70 to 90 feet tall and 35 to 50 feet wide but a tree 150 feet tall isn't unusual, according to the University of Connecticut.
The 3 to 8-inch sized leaves are glossy bright green and broadly oval with four distinctive pointy teeth. In autumn they turn alluring shades of yellow and gold. In mid to late spring after the leaves are present, the tulip-shaped flowers appear in the upper branches. Each blossom is 2 to 3 inches in size and yellow-green with a base of orange. Many golden-yellow stamens fill the floral cup. The golden-brown fruits that ensue look like upright pine cones and persist on the tree across winter, allowing this tree to be readily identified when leaves are absent. The cultivar "Aureo-marginatum" bears leaves that are a pale yellow-green, with blotches of dark-green in their centers.
Since this is such a massive tree, plant tulip poplars in a fertile soil that is rich in organic matter and is always moist but well drained. Irrigate trees during droughts to prevent stunted growth and drop of interior foliage. Soils should be acidic (pH below 7.0). It attains a full canopy if planted in full sun locations with ample space to grow, but as a woodland tree it also grows well in partially sunny areas in unison with other trees. Trees native to the coastal areas of the extreme southeastern United States may grow with reddish-green foliage and can tolerate seasonally flooding soils according to the U.S. Forest Service.
Other than being an impressive shade tree for parks, large gardens and golf courses, honeybees create a distinctively tasting honey from tulip poplar flowers. The wood of the tree is heavily used for furniture as well as structural fiber components of veneer, plywood and for pulp, according the the U.S. Forest Service. Wildlife doesn't rely heavily on this tree for food, but quail, mice, squirrels, rabbits and purple finches will eat seeds.