Tulips on Trees

Bloom time is almost over for the tulip poplar tree (Liriodendron tulipifera L.), but look up in the tree canopy of an Eastern forest in late April early May and you'll see pops of bright yellow flowers. These very showy, tulip shaped flowers support a wide number of pollinators and birds, making it an important tree in our habitat garden.

The orange markings on the bottom of the petals help guide bees to the flower's abundant nectar. According to Joan Maloof in her book 'Teaching the Trees: Lessons from the Forest', one flower can produce up to a tablespoon of honey, making these blooms very significant to honey beekeepers. Because each blossom contains so much nectar, honeybees do not have to visit as many flowers before heading back to their hive. The nectar from the tulip poplar flowers contributes to the strong flavor of many wildflower honeys.

Interestingly, the sugar content of the blossom's nectar increases as the flower ages. In addition to bees, hummingbirds and orioles love to sip nectar from these blooms. Hummingbirds will also pluck the small insects that are buzzing around the flowers, an important source of protein for hummers.

It takes twenty years of growth before these trees begin to flower, but once they do they will flower for another 100 years! (another fun fact from Teaching the Trees: Lessons from the Forest) After pollination, seeds form and support many songbirds including the Northern Cardinal, American Goldfinch, Tufted Titmouse, and Black-capped chickadee. Northern Cardinals in particular will gather under tulip poplar trees to sort through the leaf litter to find the seeds.

The yellow-bellied sapsucker, a woodpecker that overwinters in our area, is particularly fond of tulip poplars because of their high sap content. This is often why one sees those perfectly spaced rows of holes around the trunks of these trees. Squirrels also partake in this feast. They will chomp on the flowers and slurp the nectar from the petals, contributing to chewed petals on the ground below the trees.

This tree also serves as the larval host of the Eastern Tiger Swallowtail butterfly. One is not likely to find the caterpillars unless one has young trees or low branches. I've never found a caterpillar but we see lots of the butterflies every year.

The botanical name, Liriodendron, means lily tree (Leirion meaning Lily and dendron is a tree). However, this tree is actually a member of the magnolia family, making the common name 'poplar' misleading. That part of the common name comes from the leaves, which are attached to the branches by long petioles, allowing them to flutter in the wind much like an aspen tree (Populus).

Liriodendron tulipifera is one of the tallest trees in the Eastern forest, growing 80 to more than 150 feet tall. There are records of trees reaching 190 feet! Historically, the wood was used by Native Americans to create dugout canoes and by European settlers to build cabins. Massive logging of this tree occurred after the Civil War when the railroad was built through the Appalachian region. The wood is also used for building furniture, flooring, plywood and paper pulp. Apparently this wood is more resistant to terminate damage than other tree species.

The tulip poplar is environmentally sensitive and a good indicator of conditions. They are susceptible to late spring freezes and severe summer drought. We've often experienced early leaf drop due to drought conditions in late summer, missing out on their fall color. We are fortunate to have a 4 acre wood on our property with many native hardwood trees, including the tulip poplar. It may not be an ideal home landscape tree for many neighborhoods, but if you have the space, this is a great shade tree that will support wildlife and provide tulip blooms in the spring.