June’s Tree of the Month: Irish Yew

By Cypress Lawn Arboretum Director Josh Gevertz

The worldwide tradition of two Irish yew trees, growing stoically to either side of a cemetery monument or headstone, dates back to the English countryside churchyards of the 1700s and even earlier. The folklore of yews near British churches is a rich vein of history, and it is understood that several “consecration yews,” such as the Totteridge Yew at St. Andrew’s Church and the Crowhurst Yew at St. George’s Church in Sussex, are actually older than the neighboring buildings of worship. The spiritual connection between people and yew trees is a long-lived legacy.

A headstone of polished granite — ornate, intricately detailed, and artfully inscribed — stands to commemorate a life gone by. Stone is a stoic thing; as eternal tributes to beloved people, we intend for our mausoleums, statuary, and monuments to remain immutable, as sacrosanct vessels of cherished memories.

Truly, here at Cypress Lawn, this proud tradition and familial legacy endures across the years; in its totality, the collection of stone monuments on our centurial East Campus comprise an outdoor museum, filled with artifacts, artistry, and illustrious California history. In the celebration of life, however, it is befitting to honor our heritage and ancestry in an additional way, and really, a different way entirely.

At the Cypress Lawn Arboretum, the most numerous trees in our living collection are none other than Taxus baccata “Fastigiata,” often found just as this pair of yews grow. With their dense crown of foliage and stout posture, two Irish yews such as these are a fitting living tribute to the cherished memories of those we still celebrate.

To either side of many headstones throughout our historic grounds, as living monuments to eulogize a soul no longer with us, stand two faithful, stout, and upright Irish yews. These special trees are also known as Taxus baccata “Fastigiata” in the scientific Latin. In cemeteries throughout the world, a pair of yews astride a grave is a most common sight; indeed, the yew is known across cultures and continents as “the tree of the dead.” This almost mythic association can be traced back across the ages. From the yew’s ancient symbolic affiliation with Hecate, the Greek goddess of death and necromancy, on to countless plantings of this tree in English churchyard cemeteries of the 1700s and on, then throughout the rich horticultural tradition of the “rural cemetery” movement across America, and all the way to the present here at Cypress Lawn.  The yew, today as ever, is steadfastly rooted in the human relationship to our own mortality.

The deep evergreen foliage of the Irish yew is brightened by the vigorous new growth of spring each year. In this image, one can clearly see the emergent, chartreuse green leaves at the end of each sprig and branch, adorning the canopy with vibrant new life!

Yews, with their verdant evergreen foliage, are some of the longest-lived trees known to science. They often thrive for over half a millennia, on occasion surviving for 2,000 years and beyond. Naturally, this remarkable capacity has led to a cultural association of yews with the “everlife.” Indeed, a vigorous young yew planted astride a grave today, given the proper care, may live for longer than the carved inscription upon a granite monument would remain legible, due to natural erosion over time. Which is really most stoic: the stone or the yew? The most ancient of all for this species is the “Fortingall Yew” of Perthshire, Scotland, which is estimated to be between 2,000 and 3,000 years in age, and so is believed to be the oldest tree in the entire United Kingdom.

As a native to the very same island nation of the U.K., the parent species Taxus baccata, or the common yew, is one of the most widely and diversely propagated trees in the nursery trade. The Irish yew is one of nearly 200 cultivars, or cultivated varieties, of Taxus baccata, each of which expresses a signature variation from the parent plant form. The Irish yew, specifically, is known by the Latin name “Fastigiata,” and traces its horticultural ancestry back to a singular “mother tree” discovered in County Fermanagh in Northern Ireland in the year 1780.

At the iconic Belgrano family monument on the East Campus of Cypress Lawn, a backdrop of five regal and poised Irish yews, well-manicured and growing proudly into maturity, frames the ever-flowing memorial fountain. This is a truly idyllic space, where people and trees are celebrated in kind, growing a lasting legacy together.

This one tree differed from the common yew in its tight, fastigiate crown, with side branches growing upright and nearly parallel to the main stem. Additionally, the yew of Fermanagh had very dense foliage, with individual needles, or leaves, radiating all around the central branch instead of only in two rows, as with the common species. These horticulturally desirable traits naturally mutated in the field, a phenomenon which is not altogether uncommon in the wide world of trees. On occasion, either an entire plant (or just a single branch, known as a sport) will grow with a distinct physiological variation from the parent organism. This could be a change in the color of leaves, a new pattern in branching structure, or the development of oddly shaped fruits. In some instances, as with the fateful yew of Fermanagh, these chance genetic mutations result in a desirable or beneficial form of plant. With the Irish yew, the unique growing nature of this singular specimen was recognized by botanists as a potentially valuable addition to the nursery trade. So, cuttings were collected and propagated, grown and sown into the earth, initiating what would become an intercontinental diaspora of an individual tree, as Taxus baccata “Fastigiata” has emerged as a staple species of the global cemetery plant palette.

Algerian ivy, or Hedera canariensis, is a clever temptress throughout the Arboretum — at the outset of life, this winding vine is simply a beautiful accent plant. As time marches ever forward, however, the indefatigable ivy will grow to threaten the lives of many trees across our grounds, including our Irish yews.

At Cypress Lawn, we have nearly 300 individual Irish yews now living across the hundreds of acres of our Arboretum collection. With this many trees, ongoing management and care for all is a marathon effort.  Some of the oldest trees in the Arboretum are Irish yews, and as all venerable trees do, these specimens bear the marks of decades of rugged, perseverant life. From windstorm branch failures to fungal infection, from sun scorch to root dehydration, there are many nemeses of nature with which the yew is in a seemingly eternal struggle. One scourge, in particular, is deeply interwoven with the living history of the many Irish yews of Cypress Lawn: the indefatigable exotic vine known as Algerian ivy.

Emerging out of the dense canopy of an Irish yew next to the Crane family headstone, a sprig of Algerian ivy foliage is a perfect example of how this vine incrementally overtakes its tree host. When the ivy leaves soak up all the sun’s rays, there is no light let through to the yew underneath; this inhibits photosynthesis, the sustaining life practice of all trees that converts sunlight into sugars for the plant to grow by.

Hedera canariensis begins as a beautiful accent plant — its deeply lobed and luscious evergreen leaves seem to grow fast enough almost for the naked eye to see. A single seed, germinated in the remains left behind by a berry-scavenging bird, perhaps, in the shade of an otherwise healthy yew, will begin to root and develop a vigorous patch of groundcover foliage at the base of the tree’s trunk. This friendly foray, however, if unimpeded by a conscientious and stewardly human, will lead to dire consequences for the yew’s eternal fate.

This example of ivy overgrowth shows a yew now in a desperate struggle for survival, against a foe that is increasing in vigor with each passing day; beyond a certain point, the dense nature of growth for the Irish yew will make this ivy problem an inextricable one. In the end, yews this far gone will likely need to be removed and replaced, with a more careful ivy management regime moving forward with new yew plantings.

With each passing season, the Canary Island native subtropical vine will grow ever onward, and in the case of our friend the Irish yew, upward.  The mostly vertical, fastigiate branch architecture of this cultivar provides an ideal scaffolding for the climbing Hedera, which will ascend into the canopy of the tree and encircle each stem in a winding pattern. As new ivy leaves emerge at higher and progressively higher points in the yew tree canopy, more and more of the evergreen yew needles are blocked from soaking up the sun’s rays by the broad Hedera leaves. Slowly but surely, the snaking ivy will grow to outcompete the tree at its own life’s work: photosynthesis.

In this image, we see what has become an “ivy tree” – by using the Irish yew branching structure as the perfect scaffold, Hedera canariensis has climbed all the way into the upper reaches of the yew canopy, winding and progressively constricting each branch as it grows. There is no saving this yew tree now, but it does serve as a poignant example of what to avoid in future ivy management here at the Cypress Lawn Arboretum.

The evolutionary objective of Hedera canariensis, as with all flowering plants, is to produce fruit and seed viable offspring. This is the underlying reason for the vine to climb our poor, defenseless Irish yew. By using the strong wooden skeleton that is the tree itself, the woodless vine may manage to climb high enough to increase the dispersal distance of its multitudinous berries. The higher the ivy climbs, the more it can reproduce and grow anew, a positive feedback loop for the ivy that spells disaster for the tree host. By using a tree to become a “tree,” Hedera canariensis employs a duplicitous trick of nature, one which may be lethal for our friend, the yew.

Friends of the Arboretum, consulting arborists Roy Leggitt (right) and Aaron Wang (left) of San Francisco-based firm Tree Management Experts, are seen here finishing up the installation of an irrigation project for a row of nearly 50 yews on the southern boundary of our West Campus. With the help of our collaborators and colleagues at Tree Management Experts, the future of these yews and many other trees throughout our living collection are in good hands.

The culmination of this damaging cycle, if uninterrupted by intentional management to carefully clear away Hedera canariensis growth, is the death of a yew tree. This process will be very slow, branch by branch, as the thickening of ensnaring vines eventually overwhelm the scaffolding tree. The very nature of the Irish yew, a growth pattern so sought after from the county of Fermanagh to half the world away, makes this tree uniquely susceptible to Algerian ivy demise. With such a compact branching arrangement, ivy growth of a certain density makes management to eradicate the vine without damaging the branch all but impossible. Sadly, there are several ancient Irish yews at Cypress Lawn today that have suffered with ivy overgrowth for decades, and at this time, are beyond helping. Efforts on a tree-by-tree basis to remove ivy are regularly underway, but in some instances, replacement with a new yew seedling is the only feasible option for restoring health to the Arboretum collection.

Across the centuries, and throughout cultures around the world, the pairing of human memorials with steadfast Irish yew trees is a legacy to be embraced. As a keen representation of the “everlife,” these sacred trees have long stood with us. In the years to come at Cypress Lawn, this living heritage will grow as we do — in a tradition worth celebrating.

Thankfully, the next generation of yews is beginning to grow vigorously here at Cypress Lawn. In collaboration with both Davey Tree Company and the San Francisco-based consulting arborist group Tree Management Experts, a recent planting and irrigation installation of a row of nearly 50 Irish yew seedlings has been carried out at the southern boundary of our West Campus. TME’s Roy Leggitt and Aaron Wang are both regular colleagues of mine in various facets of tree management at Cypress Lawn and were key associates in the implementation of this project. Moving forward, the Irish yews of Cypress Lawn’s future are in stewardly hands.

As perhaps the most keen representation humanity calls upon in our global culture to symbolize the “everlife,” the Irish yew is indubitably a sacred tree, worth knowing and, indeed, celebrating. In the summer months ahead, should you feel the need to connect with the natural world and find a pillar of the past to share a moment with, come visit us at the Cypress Lawn Arboretum and spend an hour in the shade of an ancient yew. The trees are always there, waiting for us to return, rooted in place and growing with purpose. The inspiration is alive in every branch, if you only choose to seek it.