Westmount Park’s
Invasive Honeysuckles

Their outward beauty disguises what can be best described as a Trojan Horse

By Michael Walsh

September 5, 2024

Objects in a park suggest static repose rather than any ongoing dialectic. Parks are finished landscapes for finished art.

– Robert Smithson

Have you noticed the lack of shrubs in Westmount Park? The scarce number that exists are either overgrown or, in the case of the beautiful yellow Forsythias, in the process of being removed. One would assume that a large city park would have its walkways and water courses bordered with a variety of indigenous plants, providing a natural environment and food source for local wildlife as well as exposing visitors to the richness of the local biodiversity. Instead, Westmount Park’s concrete pathways are bordered with commercial sod and, where a handful of invasive bushes exist, they form an impenetrable mass of roots and stems.

This, however, was not always the case. Specifically, in 1990, the City received a variety of plants from Macdonald College, the Montreal Botanical Gardens, and Agriculture Canada. More importantly, in the latter case, the City participated in a multi-year study (REPLOQ) that examined the hardiness and propagation of a variety of ornamental shrubs native to Quebec. The results of the study were published in 2002 by Agriculture Canada as a 500-page reference manual geared towards commercial and amateur horticulturalists.

Morrow’s Honeysuckle in Westmount Park

Today, the park’s lack of local biodiversity suggests that the City did not use this opportunity to provide residents with a mosaic of local plant species. Instead, Westmount Park’s Eurasian honeysuckles form an unsightly thicket of hedges bordering the former putting green, and adjacent to the lagoon and wading pool. In some places along the walkways, their growth is so dense that they impede visitor traffic. It is not surprising that they are classified as an invasive species.

At this point, one can only wonder why the City did not propagate and maintain the local plants obtained during their involvement in the Agriculture Canada study. The large question remains: Why is the City cultivating plants deemed invasive, and allowing their seed dispersal? The importance of invasive plants cannot be overstated. They are beyond the “weeds” that take root in one’s garden.

Morrow’s Honeysuckle blossom

Invasive plants, such as honeysuckles, are aggressive invaders of forests throughout the northeast. These bushes grow on the edges of forests, in clear-cut areas, and in the interior of intact forests. Many forests are nearly impenetrable due to the mass of these bushes.

Studies have shown a decline in oak forests, as these bushes compete for soil nutrients and prevent the germination of seedlings, as well as the localized extinction of some species. In addition, their dense growth pattern allows for the transmission of various plant diseases. Other studies demonstrate that the decline of songbirds is related to these bushes. Their low branch structure, and lack of thorns, make nesting birds susceptible to predators. To control plants, many local agencies use aggressive chemical and herbicidal spraying of open areas and destroy forest growth.

To be fair, these plants were transplanted from their native environment – and as such, one should gain a familiarity with their uniqueness. The bushes, growing in a row of clumps along several portions of the park’s lagoon, are Tatarian honeysuckles (Lonicera tatarica). More commonly, they are referred to as Arnold red or Fly honeysuckle. Interestingly, they are a clonal species – each is genetically identical.

‘Invasive plants, such as honeysuckles, are aggressive invaders of forests throughout the northeast. These bushes grow on the edges of forests, in clear-cut areas, and in the interior of intact forests.’

The plant was introduced to North America in 1752, from Turkey and Russia. Initially planted as an ornamental shrub, it quickly escaped cultivation. Its unique ability to produce the volatile compound actinidine, which deters parasitic insects, enabled the plant to spread through the northeast regions of North America.

The most interesting aspect of this plant is its effect on domestic cats. Studies have shown that it releases a variety of lactones (including nepetalactone), causing a euphoric effect, like catnip, in domestic cats.

Fruit of Tatarian Honeysuckle

The park’s much larger growth of honeysuckles is known as Morrow’s honeysuckle (Lonicera morrowii). These can be found as massive hedgerows along the park’s former putting green (today’s Shakespeare in the Park area) and the children’s splash pad. These bushes are native to Japan and were introduced to North America in 1875. During the 1930s they escaped cultivation, finding new habitats in abandoned farmland and, assisted by government agencies, propagating as shelter and food for wildlife.

Interestingly, birds ingesting the plant’s fruit develop an aberrant colouring of their feathers. The ripe fruit contains the deep red carotenoid pigment rhodoxanthin. Birds ingesting this pigment during their pre-basic mold develop uncharacteristic colourings in their feathers. In particular, Cedar Waxwings will lose the characteristic yellow colouring and display a bright orange plumage. (Needless to say, the fruits of both honeysuckles are mildly poisonous to humans and dogs).

In retrospect, I am sure these bushes arrived in Westmount Park with every good intention. In fact, during the park’s major renovation in the 1960s, honeysuckles were regarded as ornamental shrubs and planted in various residential areas. Today, unfortunately, we know that their outward beauty disguises what can be best described as a Trojan Horse.

Feature image: Tatarian Honeysuckle blossom, by 대정 김 – Pexels
Other images: Michael Walsh

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