The Tulip tree
Jessica Quinton
2020-09-15
For anyone who has recently become interested in tree-species identification, you are in luck—this week’s street tree is easy to spot in a crowd (or a tree-lined avenue). Thanks to its distinctively shaped four-lobed leaves, the tulip tree (Liriodendron tulipifera L.) is a species you will never forget. The only potential source of confusion is the one other closely related species, the Chinese tulip tree (Liriodendron chinense L.). While L. tuliperifera is native to eastern North America, L. chinense is native to, well, China. Although geographical context may be useful in differentiating between these two species in some scenarios, it is worth noting that the North American tulip tree has a long history of horticultural use, and the Chinese tulip tree is increasing in popularity for this purpose. This means that you may run into a Chinese tulip tree in an urban setting in North America. There is more information later in this article regarding how to distinguish between the two species, but if you still struggle with the differences, at least you have a 50/50 chance of guessing correctly!
The common name of ‘tulip tree’ comes from the flowers, which resemble perennial tulip flowers. One could also argue that the leaves of the tulip tree (see photo) resemble a tulip flower in profile—or perhaps a cat’s face, depending on who you ask. The tulip tree is also sometimes referred to as a yellow or white or tulip poplar, despite not being closely related to true popular trees (the Populus genus). The species is actually part of the Magnolia (Magnoliaceae) family of flowering plants.
The tulip tree is a deciduous species, with leaves that turn yellow (or sometimes orange) in the autumn before falling to the ground. The flowers bloom from May to June, with greenish-yellow petals and a vibrant orange centre (see photo). The North American tulip tree typically has smaller leaves that are less deeply lobed than the Chinese species. The flowers are also larger and contain that vibrant orange centre, while the Chinese tulip tree does not. The seeds form a cluster that looks similar to a cone, and it remains upright on the tree throughout the summer and into the autumn. This species of tree can grow to over 40 m in height, depending on the location and growing conditions, and is one of the largest tree species native to eastern North America.
The tulip tree is an excellent shade tree, provides benefits to wildlife (particularly to pollinating insects and birds), and is an aesthetically pleasing (and just plain interesting) species. With pretty flowers in the spring, jaunty cones in the summer, and lovely fall foliage, it is far from a one-trick pony. It is also fast-growing, pollution-tolerant, suited to a wide climatic range, and fairly resistant to insects and diseases. These characteristics make it a useful species for urban planting. However, some consideration does need to be given to their planting location as the species does better with large volumes of well-drained soil and limited exposure to salt. The height of the tree and extent of its branches, which both contribute to making it such a good shade tree, means the tulip tree needs a large amount of space to grow.
Although not native to Halifax in particular, the tulip tree is on the city’s approved species planting list due the reasons mentioned previously. You can find some wonderful large specimens, as shown in the accompanying photos, on the University of King’s College campus (south side of the quad), the Halifax Public Gardens (northeast corner, close to the fence), and Chebucto Road (on the north side just east of Dublin St. – this is a private tree). A lovely young tulip tree – also pictured - is located on the north side of Allan St. just west of Chebucto Lane. It was planted in 2004 in a gap left by Hurricane Juan. Finally, you will also be able to find smaller specimens throughout the city in recently planted streetsides.
