10/14/2026
Boston Ivy
The story of Boston ivy is well known in horticultural circles. Parthenocissus tricuspidata, as it’s known to science, is a member of the grape family (Vitaceae) and shares with that group a distinctive morphology, which is to have leaves that are opposite its tendrils on the stems. Tendrils (which are not exclusive to Vitaceae), are modified branches that aid in climbing, but in the case of Parthenocissus, the tendril branches not only have the ability to grasp, but are endowed with specialized pads on their tips, allowing them to stick to almost any surface. The English naturalist and father of evolutionary theory, Charles Darwin, once measured the adhesive strength of the tendril pads, writing in 1875 that a 10-year-old branchlet with only one remaining adhesive disc attached to a wall could support a weight of 2 lb without the disc detaching. As an adaptation, “self-sticking” (as it’s known) is just one of several successful ways for plants to climb.
Parthenocissus tricuspidata is native to Asia and was imported to Massachusetts from Japan in 1861. It was found to be a particularly attractive way to clothe stone buildings—especially so in autumn, when the three-pointed-lobed leaves (tricuspidata means “with 3 teeth”) turn spectacular orange, red and deep purple. The species became so popular in Boston that it was soon dubbed “Boston ivy.” Note that some of those New England buildings included the halls and residences of the eight famous private research universities (Harvard, Yale, Princeton, etc.). This is why they are called the “ivy league.”
For my money, I prefer the look of P. tricuspidata growing up trees. Like on the 50-m-tall Douglas fir (Pseudotsuga menziesii) at the corner of Wharton and Henry Trails. The fiery colours of the turning leaves are best viewed from some ways away (and better when the sun is low), looking west from Upper Asian Way. Even there, you have to look up (waaay up) to see the leafy branches hanging stalactite-like from the Douglas fir’s sturdy branches. A more conventional treatment is on the Arbour above the Food Garden. Either way, this would be the time to admire its technicolor glory.
