Plants With Vertical Roots

Toxic Weeds

• Some vertically rooted plants are noxious weeds. Whitetop or hoary cress (Cardaria draba) has vertical roots that grow up to 15 feet deep. This perennial weed grows up to two feet tall and prefers sites with moist soil, such as swales, riparian regions and irrigated landscapes. Whitetop reproduces through roots and seeds. Its long vertical root system allows it to withstand severe drought conditions. Whitetop is mildly toxic to livestock.

  Leafy spurge (Euphorbia esula) grows from two to three feet tall and produces tiny green blossoms inside yellow bracts. This weed grows in grasslands, pastures, tilled fields and woodlands. Its vertical roots can reach lengths to 20 feet and are dark-brown with pink buds. This perennial stores a two- to three-year supply of food in its long roots and reproduces through root buds and seeds. It has poisonous, milky sap.

Nontoxic Weeds

• Other long-rooted weeds are nontoxic, but their long, vertical roots make them difficult to eradicate. Canada thistle (Circium arvense) is an invasive weed that grows in disturbed sites, such as cropland, pastures, tilled fields or roadsides. This perennial plant develops vertical roots that grow from 6 to 15 feet deep, as well as horizontal roots that spread up to 15 feet wide. Canada thistle reproduces through its root system as well as through seed, making it a difficult weed to eradicate. Canada thistle grows best in cool, moist soils and tolerates full sun to partial shade. It has spiny leaves and produces fragrant, insect-attracting flowers.

  Dalamtian toadflax (Linaria dalmatica) was once grown as an ornamental plant, but now grows wild in unused lots and fields. This perennial, a member of the snapdragon family, produces yellow and orange flowers, has heart-shaped foliage, and grows from two to four feet tall. It has six-foot-long vertical roots and horizontal roots that spread up to 10 feet wide.

Vines

• Some climbing vines have vertical root systems. Field bindweed (Convovulus arvensis) grows a taproot that extends for nine feet or longer into the ground. This perennial vine climbs by twining and grows wild in disturbed sites, lawns, gardens and pastures. It is native to Europe and Asia and is considered a weed in 33 countries. Field bindweed grows to nine feet long, has blue-green, arrowhead-shaped foliage, and produces white-to-pink, funnel-shaped flowers.

  Bigroot morning glory (Ipomoea pandurata) is native to North America. This twining vine has a thick taproot that grows up to seven feet deep. Bigroot morning glory grows as a weed and has large, heart-shaped foliage and three-inch-wide, white-and-pink-striped flowers.

Trees

• Several trees produce vertical roots or taproots. These include the Brazilian rubber tree (Hevea brasiliensis), a South American native used to make rubber. This tropical tree grows to 130 feet tall and has a long, well-developed taproot. It grows best in moist, acidic soils but tolerates wet to dry sites.

  The sugar pine (Pinus lambertiana) develops a long taproot. This coniferous evergreen grows up to 200 feet tall and can live up to 500 years. Sugar pines tolerate a range of site conditions, but grow best in acidic, well-drained soils. Their native range extends from northern Oregon to Mexico's Baja Peninsula.