The tulip tree (Liriodendron tulipfera), also known as the tulip poplar and yellow poplar, is one of the tallest trees in the forests of the Eastern United States. The tulip tree, named for its large, yellow, tulip-shaped flowers, often reaches heights of 100 feet or more. Thomas Jefferson once described it as, ''the Juno of our Groves.'' This fast-growing tree, hardy in U.S. Department of Agriculture Plant Hardiness Zones 5 through 9, also has a deep root system.
The tulip tree's large size and narrowly oval shape above ground is mirrored by its root system underground. For example, the crown of a mature tulip tree can be about 100 feet tall and 30 feet wide. The root system would also be 100 feet deep and 30 feet wide, according to the Miami University Department of Botany. For this reason, Ohio State University recommends planting this tree away from house foundations and power lines. It is a tree more suited to parks, forests and open spaces.
If the leaves of your tulip tree suddenly wilt, it may be a victim of verticillium wilt. Tulip trees are susceptible to this soil-borne fungus that attacks the roots, according to the University of Kentucky. At the first sign, trim out dead twigs and branches and spray foliage with a powdered nitrogen fertilizer diluted in water or in liquid form. Severely infected trees cannot be saved and should be cut down. Destroy the wood and as many roots as possible. Do not compost or recycle the debris.
In the wild, the tulip tree grows near rivers and streams. It prefers moist soil and may become stressed by drought, according the University of Connecticut. For this reason, avoid planting tulip trees in hot, dry sites. Leaves yellowing and dropping in summer is a sign that roots are not getting enough water.