Among the Christmas carols I grew up singing was the English song “The Holly and the Ivy,” which begins
The holly and the ivy When they are both full grown Of all the trees that are in the wood The holly bears the crown.
Anyone who has worked at removing invasive non-native species in western Washington is likely to disagree with that sentiment—unless holly wears the “crown” of most prickly and most leathery.
But then that carol dates to no later than 1823 according to Wikipedia. That was a time when botanical explorers were busy moving plants from one continent to another.
Both holly and ivy are thought to have been associated with Druid celebrations of the winter solstice. They were evergreen and able to survive winter blasts. By the fifteenth century, both had been incorporated into Christmas church decorations.
English holly (Ilex aquifolium) is not native to England although English ivy (Hedera helix) may be. The website of the Kew Royal Botanic Gardens indicates that English holly is thought to have originated in the Mediterranean basin (north Africa, Middle East, southern Europe). English ivy is native to western, central, and southern Europe.
In the winter 2013 issue of the Washington Native Plant Society’s journal Douglasia, Al Smith provides a terrific overview of how an intentionally introduced non-native plant can wreak havoc. His piece puts holly in its place (and it isn’t in a crown.)
Al details how one woman (Mrs. Lillian McEwan), with help from her influential friends and countless schoolchildren, planted thousands of English holly seedlings in Seattle parks and elsewhere. She advocated beauty in landscaping and wanted Washington to become “the Holly State.” She may also have been seeking a commercial crop for logged-over lands but that isn’t clear.
I suspect that Mrs. McEwan’s intentions were benign. At the time the holly planting began in 1927, she was president of the Washington State Society for the Conservation of Wildflowers and Tree Planting. When she died at age 80 in 1960 she was remembered for her contributions to (non-native) beautification landscaping at the University of Washington (i.e., Azalea Way) and for memorial highway plantings after World War I.
My mother, a Seattle native, avid gardener, and garden club member, likely crossed paths with Mrs. McEwan. I remember accompanying my mom to flower shows (displays of artfully arranged flowers) at both the Olympic Hotel and the University of Washington’s Hec Edmundson Pavilion.
As a gardener, my mother worked to have plantings with different textures and bloom times. Her “garden bible” was Trees and Shrubs for Pacific Northwest Gardens by John A. and Carol L. Grant. I have my mother’s copy, which was published in Seattle in 1943.
I worry that many of my (and others’) innocent gardening projects may eventually be seen as something akin to Mrs. McEwan’s holly folly (if not on so large a scale). I was curious to see which trees that were recommended for Pacific Northwest gardens 70 years ago have since become pests—or worse.
I printed out weed lists from the Washington State Noxious Weed Control Board’s website and compared those plants with the Grants’ landscape recommendations.
The weed board doesn’t yet consider English holly a weed (after all, we still have a holly industry in the state); however, it is on the monitor list. The monitor list includes 34 other plants, many of which are commonly found in gardens and commercial nurseries, such as English or cherry laurel (Prunus laurocerasus) and European mountain ash (Sorbus aucuparia).
My personal nemesis, English ivy, is a Class C weed, meaning essentially that it is so widespread that there is little we can do about it.
As for the Grants and their landscape recommendations for the Pacific Northwest, even in 1943 they commented that English ivy is too rampant of a grower to be trusted under favorable circumstances (see Botanico-Literary Question Mark II: Ivy on the Islands? for another consideration of ivy in mid-century Washington). Unfortunately, they liked English holly, suggesting it could be usefully grown as a shrub or tree.
They seemed uncertain about English laurel, noting that it was mostly planted to form hedges. But the Grants disdained laurel hedges because of high maintenance costs and considered them a poor background for other plants. They did suggest that individual laurel trees made magnificent specimens if allowed to grow without pruning.
The Grants also liked the European mountain ash, which they said had “become naturalized in North America.”
My take-away from this cursory comparison of past landscape practices and current invasive species is that we should be very careful! Choosing ornamental plants for our yards may have unintended and long-term consequences. Plants may be pretty and appealing when they are in nursery containers but we need to do “due diligence” before we bring anything home.
For the New Year, my gardening resolution is to incorporate more non-invasive plants in my home landscape. Fortunately, I can consult state and county weed board websites for help. And I’ll study up on the excellent western Washington Garden Wise pamphlet that shows plants to avoid along with good alternatives.
There’s an eastern Washington Garden Wise pamphlet too.
As we slip into 2014, I’m looking ahead to continued wrestling with the holly and the ivy in my garden, and to continuing my search for lovely and well-behaved plants—native and non-native—that will thrive there.