The Monterey cypress is one of the worst trees for Southern California.
The Monterey cypress (Cupressus macrocarpa) is an evergreen conifer with heavy masses of tiny, scalelike leaves and round cones roughly an inch and a half in diameter that tend to hang onto branches for many years. Conifers, of course, are members of a class of trees and shrubs that have needle-like or scalelike leaves, generally carry their seeds in cones, and are usually evergreen. (Pines, spruces, cedars, redwood trees, junipers, and araucarias are among other conifers familiar to local gardeners.) In gardens, the Monterey cypress tree grows rapidly in pyramidal form to 40 feet or more, then slowly expands in girth, drops its lower branches, and takes on a picturesque shape. Fine old specimens are as impressive as the fabled Cedars of Lebanon. On the Monterey peninsula, where these trees are native, some venerable individuals have survived hundreds of years, protected from hot weather by coastal fog and whipped by the ocean wind into tortured shapes.
There was once a Monterey cypress growing near the railroad tracks at the end of a street on top of a cliff in old Del Mar. For a hundred years or more, this tree had thrived.
Photo by Sandy Huffaker, Jr.
The Monterey cypress was one of the first nonnative trees brought to San Diego by early settlers. Vintage photos taken in the last half of the 19th Century show specimens that look as if they could be 40 or 50 years old. A photograph taken in 1900 proves that Mission padres used them as windbreaks. Since the 1950s, however, few have been planted here because local nurseries stopped carrying them. Not undone by this, the Monterey cypress seeds itself like mad, and many seedling cypresses make it into adulthood. Years ago my house was surrounded by a grove of these trees—and a great deal of bare ground due to their invasive roots. Cypress trees came up by the dozens in my garden. Almost all of the cypresses in Southern California got their start like this and can trace their ancestry to the original trees planted by early settlers. A few old historic trees still exist, but most have been killed due to widespread misunderstanding of their characteristics.
As a matter of fact, the Monterey cypress is one of the worst trees for Southern California. It drips needles and sticky sap, is prone to beetles and fungus, and its roots are so invasive it’s difficult or impossible to garden under. Books blithely list it as drought resistant, but without water it’s a sick and scruffy tree. If one comes up from seed, think of it as a weed. Quick! Pull it up by the roots before you fall in love with it. Luckily, you can’t buy one. Why write about it, then? Because Monterey cypress trees are like some people. Their faults drive you crazy, but you love them anyway.
Let me give you an example. A few years ago I happened to phone a friend who lives near the cliffs in Del Mar. By the sound of her voice I thought she had a cold, then I realized she was crying. “It’s so sad,” she sobbed. “And I’m spitting mad!” My imagination went into high gear. (Divorce or worse!) “Whatever’s happened?” “Nothing that awful,” my friend managed. “But it does mean a lot to me. It’s about a tree. I mean, it was a tree.” “Thank God,” I breathed, “but tell me about it.” So she did, soon stopped crying, and began to laugh. “Forgive me,” she begged. But there was nothing to forgive. After I’d heard her story, I wanted to cry too.
Here’s what happened. There was once a Monterey cypress growing near the railroad tracks at the end of a street on top of a cliff in old Del Mar. For a hundred years or more, this tree had thrived in pristine grandeur unmolested by people who thought they knew what was good for it As the years ticked by, it took on a lovely windblown shape with a thick and twisted trunk. When its lower branches were no longer necessary, the old tree let them die. Winter winds twisted them loose and buffeted them to the ground. Eventually only three of the lower branches still hung on. They grew almost as thick and tall as the main trunk and sloped gracefully to the northeast, as if the tree were sailing before the wind, spinnakers aloft.
By the time my friend and her husband bought their home in Del Mar, the rounded crown of this old cypress tree was completely covered with healthy green foliage. But hidden inside its verdant head was a sort of upside-down nest of dead branches, twigs, leaves, and debris. Old stuff had simply died and collected there. You could run under it and stay dry through a cloudburst But, other than one or two broken branches that hung down from the outer edges, none of this internal dead growth showed from the outside. My friend loved that tree. She admired it when she came home from work and turned in to her drive. She enjoyed its silhouette against the sea. On summer evenings, she and her husband used to walk down toward her special tree and chat about their day. And as they shared their experiences, they also shared one unspoken thought “How beautiful is that tree!”
Then tragedy struck. New owners bought the house at the bottom of the road and wanted to trim off the dead growth. That would have been okay, but the young man from the pruning company said, “While you’re about it, why don’t you let us dean it out? Monterey cypress trees are subject to beetle attack and fungus problems. Get rid of all that dirt and debris hidden up there inside the tree; it’ll be much healthier.” Right? Wrong! Nonetheless, the tree was pruned.
A man with ropes, hand tools, and a chain saw got right up inside the cypress and hacked away. He did what his boss told him to; he cleaned it out. He tried to take out dead branches only, but up inside the tree you couldn’t tell the difference; several that fell to the ground had green tips. By evening the tree looked different; a month or two later it began to die. All of a sudden one section of foliage went brown and then another. Every year, the owners had the tree trimmers come back and prune off the limbs that had died.
“Like I told you, the Monterey cypress is a sick tree,” said the man from the tree company. This one was doing fine before he cleaned it out, but a few years later it suddenly died. The pruners came back for the last time and cut it down. That was the day my friend cried.
In its native fog-bound habitat on the Monterey peninsula, the Monterey cypress is drought resistant and immune to most of the pests and diseases that afflict it down here. Last spring I drove alone around the 18 Mile Drive and observed how the pine trees — Monterey pines, also native there — grow on the hillsides and canyons a few hundred feet away from the beach. They evidently don’t like to grow right in the teeth of the salt wind and spray. But as soon as the road reaches a turn near the beach, and you feel the first blast of cold sea air, that’s where the Monterey cypress trees are clustered. After you leave the big golf courses at Pebble Beach, cypresses hug the coast and line the shores all the way back to Carmel. They cling happily, obviously by choice, to this rocky, cool, and windy coast, the foggier the better. And foggy it was.
I was staying in Carmel to address the Annual Carmel Garden Show, but my visit had deeper meanings. My husband, Lou, had died just a few months earlier. I decided to stay in the center of old Carmel and revisit the places he and I had loved. I started my drive late in the day, so I was virtually alone on the road. Many times, I parked my car, got out, and communed with nature talking aloud to trees and even to Lou. Glad no one was around! Hoping both Lou and the trees could hear. Hoping also for wisdom to sink in. I’d read something about Buddha sitting under his tree and that we could go out and find our own tree to sit under and gain wisdom.
One piece of wisdom that did sink in was the perfect adaptation of the Monterey cypress tree to its natural home and how ill-adapted it is to Southern California except when it’s growing right on the beachfront. Here, where they belong, cypress trees are like living sermons in courage, tenacity, and grit. They don’t ask for life to be easy, they live in the very teeth of the wind and relish the challenge. A Monterey cypress growing old in its native habitat is a good example of joyous and dignified survival.
I observed that it’s natural for foliage of Monterey cypress trees to die back and drop off in the center of the tree and for lower branches to die and eventually drop off too. Scars left by falling branches eventually are healed over by twisting bark. I remembered a tree in our garden that was a half-dead, dwarfed, and twisted sapling when we built our house and then had taken on a new youth when given adequate water. Gradually, it became a large and healthy tree, until the old self was totally absorbed within it. I hoped my sorrow could heal over in the same way. And also that my body amid cope as well as these old trees did. (I was recovering from a knee replacement that had malfunctioned and been operated a second time, hoping it would get well and hold me up through the years ahead.) I sat on the hard dry ground next to one venerable tree and was swept into its peacefulness. Things had happened to it, but it had overcome them and carried on. I didn’t think of anything in particular, I just sat there, but when I climbed back into my car, an added measure of hope and strength went with me.
In Southern California, unless growing in fog and wind right along the coast, these trees are very prone to fungus diseases, most especially coryneum canker fungus, for which there is no known cure. Coryneum canker fungus is present in the atmosphere and also can be carried by birds, insects, and pruning tools. It enters the tree through insect damage or by bark cuts made by pruning equipment. This fungus disease causes a section of foliage to suddenly turn yellow, then go reddish brown, and sometimes hang there for months or years looking unsightly. First one area of foliage and then another will tall prey to attack, turn brown and die, until after several years the whole tree suddenly expires. Infected trees also tend to drip a lot of sticky sap. The editors of Sunset Western Garden Book suggest destroying trees afflicted with this disease. Once a tree has contracted coryneum canker fungus, it’s just a matter of time before that tree will die; meanwhile, it can infect other healthier trees.
Partly because of dripping sap caused by fungus diseases, the Monterey cypress tree is also highly subject to beetle attack. Beetles bore through the bark leaving round holes and frass. You can often see these if you closely inspect the bark. If you remove a section of bark with a pocketknife you can also see the little winding pathways the beetle larvae create as they chew away at the cambium layer of the tree. The cambium layer is the formative layer of growth cells between the wood and the bark of a tree. It’s also the sap-carrying portion of the tree that acts like a giant blood vessel hauling nutrients and water from the roots of a tree up to its branches, twigs, and foliage. A tree’s sap is its lifeblood; any interruption in the flow is like a tree-size heart attack.
Branches without adequate sap simply die. Beetle problems are exacerbated when the trees are pruned during hot, dry months when beetles are most active. Fresh running sap in spring, summer, or fall attracts large numbers of hungry beetles. The first arrivals send out pheromones, odiferous mating calls, which travel for many miles to attract flocks of prospective mates. After indulging in a joyous beetle-orgy, the beetles bore under the bark and lay their eggs on the sides of the burrow. Once the larvae hatch, they settle down to a happy feast, burrowing in a special pattern according to species through the cambium layer under the bark When full grown they form pupae, mature, emerge as adult beetles eager to mate, and the soap opera starts over. The tree’s best defense is to manufacture one whale of a lot of sap and drown out the beetles. Healthy trees often succeed, but they need a lot of water to do the job. Unhealthy ones growing on bone-dry soil simply can’t produce enough sap. Once beetle damage has girdled a tree, that tree will die.
Apparently healthy Monterey cypress trees are sometimes afflicted with sudden death, usually in summer. It’s not always possible to pinpoint the exact cause, but here is a familiar scenario: During a particularly rainy winter a tree puts on a lot of fresh green foliage, rapidly increasing the size of its canopy. Unfortunately, it also loses some of its roots as a result of root-rot due to poor drainage and water-logged soil. Then comes the hot dry summer. With fewer roots and more foliage, the tree can’t keep up with its own demands, and suddenly it’s no match for the beetle and canker problems it was previously keeping at bay. Due to inadequate irrigation and no nutrients entering the roots, there’s not enough sap to fight them off, so it dies. One or two good waterings in midsummer and fall might have saved that tree.
The best way to maintain the health of a Monterey cypress that is growing in a garden away from the ocean is by regular irrigation, occasional fertilizer, and proper pruning practices. In Southern California, Monterey cypress is not a drought-resistant tree unless it’s grown on the ocean front. In gardens, they do need water. You can often bring back a stressed or lackluster tree with one or two deep waterings. On one occasion I saved a stressed tree for a neighbor by applying lawn fertilizer over the ground under the canopy of the tree and watering it into the ground. I did this once in late spring and again in summer. The tree put on new growth and lived. Never clean out an old tree that has not been pruned regularly through the years. However, if you begin pruning a Monterey cypress when it’s young, you can safely keep it up at regular intervals throughout the life of the tree. Here are the details to clip and save:
Proper Pruning Practices for Monterey Cypress
Prune Monterey cypress (and all conifers) in winter only, never in summer. Use proper pruning practices, such as using clean equipment and cutting branches outside the branch collar in order that cuts may eventually heal. As with all trees, never take off more than 20 percent of the green foliage at one time. Taking off more than this exposes the bark to sunburn. (Sunburn stresses conifers, makes the bark ooze sap, and can lead to wilting of needles. Even pines can suffer from sunburned bark when overpruned.)
Prune young Monterey cypress trees to shape them, lighten up their foliage, remove excess branches, and remove dead wood. Any healthy, young, well-irrigated cypress tree can be safely pruned. As a tree grows older, prune it every few years from youth into age during the winter in order to lighten up the foliage, lace out the center, clean out dead twigs and foliage, remove dead wood, and tip-prune to strengthen branches. During the first 20 or 30 years of the life of the tree, choose well-placed branches you want to keep and cut out others. As the tree grows older, just take out smaller branches as necessary and abstain from removing larger branches over eight inches in diameter unless these threaten public safety or the life of the tree. On old trees that have been pruned correctly, the scars of young branches that have fallen off or been cut off in youth eventually disappear altogether and will be covered over by healthy bark large cuts, however, will remain for the life of the tree.
Old trees that haven’t been pruned in years are in another category altogether. Removing a large branch from a venerable Monterey cypress that’s never been pruned before can endanger its life. It won’t die immediately, but the most likely scenario is that other branches will subsequently die until the whole tree is dead. Occasionally, I’ve seen a mature tree safely survive its first pruning, but only when the tree was still pointed in shape like a youthful tree and had not formed the flattened or rounded crown these trees assume in age. About 40 years ago, shortly after Lou and I built our home and every penny counted, I climbed to the top of a large Monterey cypress tree outside our bedroom and cut off its totally dead top section. The dead portion was over ten feet tall, shaped like a small pointed tree itself, and had plenty of beetle damage. I made the cut at an angle so the rain would roll off. My mother-in-law, Frances Lloyd Wright, glanced out of her living room window, saw me astride a branch on top of the tree, and had a fit. She wanted to know what Lou would think if he knew I were up in a tree. I laughed, stayed up there and finished the job, and gave the cut section a shove. Luckily it fell to the ground. I painted the cut with tree seal from a small can I’d carried up the tree with me. (Tree seal is no longer recommended by experts, but in this case I thought it a good idea; the cut was over a foot in diameter. ) On my way down the tree, I cut off a row of dead branches from top to bottom on the north side of the tree, probably where the beetles had done their worst. As the years went by, the branch I straddled on top of the tree that day bent its tip to the sky, made a right angle turn and grew straight upwards, creating a new top for the tree, which is still alive today— a bit funny looking since it’s lost all lower limbs in recent storms. All that remains is that strange zigzag branch on top, with 30 feet of tree above it But still alive! The answer, I figure, is water and maybe also fertilizer, which it gets from my garden.
It’s the nature of an old Monterey cypress that has never been pruned to have a rounded canopy of green foliage covering a thick interior of dead growth. If an old tree is in stable condition and has developed this nest of dead growth inside a flat or rounded crown of otherwise healthy green growth, do not clean it out Given adequate moisture and closeness to the ocean, it can live almost indefinitely, as long as you do not tamper with it. In this case the dead interior of the tree actually protects the old tree from attack by beetles or canker, much as a fur coat can protect an old person from cold.
If one or two dead branches fall down below the green canopy described above, or if they get blown down by wind, or if dead branches are hanging down on the outer edges of the foliage, it’s safe to cut these off. But if a tree pruner with a chain saw and other pruning tools invades the crown of the tree, climbing up inside it and cutting into and cleaning out the dead growth inside, that tree will surely die. By cutting into this heart of dead growth, tree pruners very effectively strip away the tree’s natural defenses. They open up its more recently grown bark to beetle and canker attack; they create lesions with their pruning tools in younger bark, and these cause the tree’s sap to run. This in turn attracts beetles and allows canker disease to invade the tree. During the 43 years I’ve lived in Del Mar, I’ve seen this tragedy occur many times, though Monterey cypress is a poor choice for planting in Southern California, historic trees that have survived a hundred years or more deserve our love, our understanding, and our protection. Sometimes that means benign neglect.