Common Holly, Ilex aquafolium, growing wild in a greenspace. (Image: Brendan McGarry)
I know for certain that at some point in my past, my ancestors revered holly.
Ilex aquafolium, known variously as Common Holly or English Holly, is a plant of significance wherever it grows.
Holly was the plant of the Roman holiday Saturnalia and later picked up by the traditions of Christmas which borrowed from the latter traditions. This plant has variously protected people from evil, represented good fortune, and gave hope for the greener pastures that came with fairer weather on the darkest of solstice days. I am honestly somewhat flabbergasted that this spiky, persistent plant has held on so long in our imaginations.
It must have been powerful stuff in the eyes of my European ancestors.
Today the significance of holly in the Pacific Northwest is largely problematic.
For me, I think it all started when my mother asked me to dig up a medium-sized holly in our backyard. If I had to guess I was maybe 16 and well versed in the removal of small trees and shrubs from growing up helping in the large garden she always tended. My mom goes HAM. But neither of us had ever seen the taproot of a more than modest holly tree. I recall blood, sweat, and tears. In the end I crawled into the hole I had excavated around the root and cut it as low as I could with a reciprocating saw, backfilled the hole, and hoped for the best. Surprisingly it worked even if the robins visiting our neighbor’s holly tree regularly planted them all over the garden.
Common Holly is ubiquitous on the Hill. Whether planted intentionally or spread by seed, there are few blocks on the Hill where you can’t find one. With spikey evergreen leaves and red fruit (on female plants only, holly are dioecious), they are easy to spot when mature and easy to ignore when they sneak in on the margins, seeded by rodents or birds. If I needed a hedge impenetrable by light or the zombie apocalypse I might choose to plant a row of hollies. But please, don’t.
One of the main aesthetic draws of holly – red berries. (Image: Brendan McGarry)
Holly is listed as Class C by the Washington State Noxious Weed Control Board (the group who decides what species are listed and how to deal with them), meaning control is suggested by not required. Despite this, many nurseries in our area carry various cultivars adorned with extra showy leaves and variegation. Common Ivy, another problematic plant for native forests is also a Class C plant but as of August 2025 it is quarantined and cannot be sold or distributed in any form across Washington.
The presence of Holly on the Hill is a throwback to a time when the tree was en vogue for gardeners and landscaping. We can even thank a single person for its ubiquitousness across Western Washington: Lillian McEwan. A socialite, ardent gardener, and the wife of a local lumber magnate, McEwan founded the Washington State Society for the Conservation of Wildflowers and Tree Planting in 1927. Despite the main society’s focus being on protecting native plants, McEwan used her social status and the organization as a platform of spreading Holly around Seattle and beyond. McEwan was apparently holly crazed, pushing for it to be planted along roadsides, lobbied for Washington to be renamed the “Holly State,” and helped boost an already thriving holly farming industry. Records show that over a decade of these pushes, McEwan helped over 30,000 holly seedlings get planted in Western Washington parks and forests, primarily by school children.
If people planted thousands of hollies and they are all over the Hill, growing in places like Volunteer Park and the Arboretum, what exactly is my beef with them? Mainly it’s because they are so tenacious and worse, they can happily grow in the shade. A stand of native trees might be doing just fine, but unlike many introduced species like Scotch Broom or Himalayan Blackberry, holly can thrive in their shade. A well meaning person might go in and cut a rogue holly down, thinking they are doing the forest a favor. But like so many broadleaved trees, holly can resprout from stumps and even sprout brand new trees from shallow roots – slowly but surely spreading across the understory. These hydras will even reroot from branches that touch the ground, a process called layering. I thought it was fun when I was able to reroot a brand new Osoberry from a layered branch in my yard – I was less excited when I realized the holly the previous owners let go in a corner of the yard had actually become a dozen with individual root systems.
Holly has the potential to choke out native plants that normally grow in the understory like ferns, Salal, and a close lookalike, Oregon Grape. Should something catastrophic happen to the overstory, it could also transition to a dominant monoculture (because it can also grow just fine in the sun), a worst case scenario that ecologists and foresters fear. These abilities demonstrate why Common Holly is a well adapted pioneer species across its normal range and why it’s a menace here in the Pacific Northwest, a place climatically akin to the plant’s homeground and a reason why we have a thriving holly trade in our region.
A comparison of Common Holly (top) with alternate leaf arrangement vs Oregon Grape (bottom) with opposite leaf arrangement. Plant anatomy geeks, don’t @ me, I know it’s technically leaflets on the Oregon Grape. PC: Brendan McGarry
Despite the alarm bells ringing for several decades, Common Holly wasn’t listed by the State Weed Control Board until 2025. This is because of the holly lobby. Growing it for sale is big business here, with over 100 years of history as a crop in Washington. The Pacific Northwest grows ninety percent of US grown Common Holly – there’s a strong chance if something has holly in it, a farmer from Washington or Oregon grew it. For a number of years one of the members of the Washington State Noxious Weed Control Board, was a holly grower (conflict of interest much?). Ken Bajema, resident of Washougal, Washington, secretary of the Northwest Holly Growers Association, and former member of the Board spent over a decade trying to make sure holly never got listed. From his perspective it was bad for his business to list holly and he believed many of the claims about the plant were false or overstated. Thankfully concerned citizens and a growing body of evidence prevailed, (and I doubt it hurt this business one bit).
You might think I am being a bit of a scrooge and if I take a step back, I can certainly appreciate the plant. They can be stately, take nicely to hedging (if you are into that kinda thing), are tenaciously tough, and look nice year-round. I understand that sprigs of them can add cheer to your holiday hearth. And to be fair, I really only have beef with one out of around 500 species of plants in the genus Ilex – a successful group that has found niches as native trees, shrubs, vines, and groundcovers across much of the temperate and subtropical world. I even enjoy carving spoons and turning bowls with holly; piano keys and chess pieces are among the many traditional uses for Common Holly’s dense, hard wood. All these things can be true, and I can also be very upset by what escaped hollies are doing in our region’s forests. Multiplying.
Ten years ago I would have never considered using herbicide for any purpose. But when I became the steward of a space where holly had started to take hold, I realized cutting and digging wasn’t going to be enough. Lucky for me, I was working for a Land Trust and had access to an EZ-Ject lance. This tool let me treat the holly in my yard with mazapyr, a nasty, tarry herbicide that is extremely effective and if applied right has minimal impact beyond the treated plant. I ran around ramming .22 shells full of herbicide into every tree I couldn’t rip up with a weed wrench (the other tool of choice for control). Their seeds still linger in the seed bank and birds bring them in from time to time, but I am mostly free of holly today.
Now, hopefully I haven’t ruined your holiday decorations with my tirade against this truly impressive plant. No matter what I say, the Hill will still have hollies, and it’s unlikely a day will come when you can’t buy it to adorn presents or in a holiday wreath. But hey, if you do choose to buy cuttings of this prickly yuletide plant, do everyone a favor and put it in the municipal compost. Cuttings can root if disposed of improperly and the seeds lurking inside each cute red fruit aren’t destroyed. Even if you want to connect to ancestral plant worship, you still might want to reconsider celebrating the new year with unintentional holly propagation.
A BRIEF HOLIDAY MESSAGE FROM CHS
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