Spikes are sharp, thornlike appendages that grow on plants. Many species of trees develop spikes as a defence against animals and other ecological threats. Some homeowners plant trees with spikes in front of windows or along property lines to discourage burglars. Trees with spikes along the bark of their trunk or branches come in evergreen and deciduous varieties.
Deciduous trees have foliage that turns colours in the fall before dying come winter. Honey locust (Gleditsia triacanthos) is a species from the Fabaceae family. This eastern United States native is a deciduous tree with a rapid growth rate. Reaching heights of 66 to 100 feet, this large tree develops red spikes along its branches. Mesquite (Prosopis glandulosa var. glandulosa) is a small to medium-size deciduous tree that grows to 30 feet in height with a spread of 40 feet. This drought-tolerant plant forms 2-inch long spikes on any new growth.
Evergreen trees keep their leaves year round. Jerusalem thorn (Parkinsonia aculeata) is a fast-growing 30-foot-tall drought-tolerant evergreen tree. The bark of this Fabaceae member has a green tone with sharp spikes. Jerusalem thorn has fragrant five-petaled yellow flowers that grow in sprays. Roemer's acacia (Acacia roemeriana) is a small tree that is 15 feet tall. The branches form sharp spikes along the twigs. Roemer's acacia produces cream to green-tinted aromatic flowers.
Flowering tree species blossom with large showy or numerous blooms. Fever tree (Acacia xanthophloea) is an indigenous tree to Africa spanning regions from Kenya to South Africa. This flowering tree grows to heights of 80 feet with blossoms that form in clusters of yellow spheres during March until April. White spikes develop at the base of the leaves on the woody twigs of the fever tree. "Monsa" floss-silk tree (Chorisia speciosa) is a member of the Bombacaceae family that thrives in tropical to semi-tropical climates. This fast-growing 35- to 50-foot-tall tree has a spread of 40 to 55 feet with an irregular vaselike formation. "Monsa" floss-silk has a trunk covered in pointy projections, evergreen oval-shaped leaves and large showy pink flowers with five petals.
Lemon tree (Citrus limon) is a 10- to 20-foot-tall tree with evergreen foliage and sharp spikes along the plant's woody twigs. The leaves of the lemon tree start out a reddish colour and change to green with age. Lemon trees produce acidic, sour fruits in multiple shades of yellow. Wild plum (Prunus Americana) is a member of the Rosaceae family endemic to the United States and Canada. This flowering ornamental tree grows white blossoms and produces large red plums during the fall. Wild plum has large brown thorny spikes along the woody branches of the tree.
- Lady Bird Johnson Wildflower Center: Roemer's Acacia
- Lady Bird Johnson Wildflower Center: Jerusalem Thorn
- University of Minnesota Extension; Trees, Vine and Shrubs for Minnesota Landscapes---Trees; 1997
- Texas A&M University Extension: Mesquite
- Purdue University Extension: Lemon
- University of Florida Extension: Monsa Floss-Silk Tree; Edward F. Gilman and Dennis G. Watson