Take care of your garden
There are old trees in our urban forests that should eventually make way for other uses. Today’s column, which might happen in your garden, is about one such tree.
A pair of Monterey cypress trees have grown about 20 feet apart for about 50 years at Carmelita Cottages, a historic estate a couple of blocks from the beach in Santa Cruz. Archival photographs show that these trees were planted near the front edge of the site and were trimmed like columnar topiary for years.
Monterey cypress trees (Cupressus macrocarpa) are impressive elements of both the surrounding nature and urban forests. There are excellent specimens in the Monterey Bay area; The attached photo shows a beautiful example from Point Lobos State Nature Reserve.
The largest recorded Monterey cypress growing in San Mateo, California is 102 feet high and 111 feet wide. It was added to the National Register of Champion Trees in 2019.
Over time, careful pruning can cause the tree to take on a shape that is expected to please the clipper owner and other onlookers, but is far from its natural shape.
However, left to grow without constant pruning, the tree will tend to grow as nature intended. Depending on how long he was clipped, he may have limited success in this endeavor.
As the tree grows into power lines, another set of clippers reshape. Public safety and the continuity of the power supply sometimes require rough removal of branches that touch the wires, further degrading the tree’s shape.
The two Monterey cypresses in this column developed trunks 30 and 36 inches in diameter, but as a consequence of their growth in the urban forest, they reached about 40 feet in height, well below their natural potential growth.
They are now showing symptoms of another attack.
Almost two years ago, an arborist at Bartlett Tree Experts volunteered to investigate the trees and reported active dull insects on both trees.
These trees were attacked by bark beetles. Cypress bark beetles (Phloeosinus cristatus or P. cupressi) or western cedar bark beetles (P. punctatus) can be the culprits, but the same damage is inflicted. Arborist noted that “the insect encircles the vascular system of the tree and causes the death of the upper crown.”
There are no effective insecticides or other means to control such infestations. The recommended action is to remove the affected limbs or even the entire tree to protect other trees. In this case, both trees are already infected, so their future is limited.
The contamination of one of the two trees became so severe that Santa Cruz city forester / arborist Leslie Keedy approved its removal. The Urban Heritage Tree policy protects the larger urban forest, so it is not easy to endorse it.
These trees are located on the property of the city of Santa Cruz and leased for decades to the Santa Cruz Hostel Society, a non-profit organization that maintains the buildings and landscaping of these sites. Society will incur significant costs to remove the first of these two trees, and eventually the second victim of the bark beetles.
This process is not unfamiliar in the natural world or in horticulture. Plant lifespan is limited by their normal lifespan and external benefits, including pests, diseases, wildfires and who knows what, as well as thoughtful visions or spontaneous whims of the owner-gardener.
Mature trees cling more strongly to their presence than annuals and perennials, but all plants must be replaced. The good news is that removing these trees or other significant plants creates space for new landscaping ideas and new plants.
We can share a silent moment of respect for long-standing violence and the possible loss of the great tree, and then seize the opportunity to start over.
Develop your knowledge of gardening
As we move into the busy gardening season, we can enjoy the harvest of online resources.
The University of Santa Cruz Arboretum and Botanical Gardens will present a presentation on “Gardening in a Dry Summer Climate” at 6:00 pm on Monday. For this well-timed free event, mentioned in last week’s column, photographer Saxon Holt will present ideas and images from his new book of the same name. For more information visit arboretum.ucsc.edu/education/ray-collett.
Also last week at noon on Tuesday will be the Pacific Horticultural Society’s webinar Around the World in 80 Plants: A Global Botanical Adventure. Jonathan Drori will be the moderator. This free event also applies to the new speaker book. For more information, go to www.pacifichorticulture.org/digital-classroom/ and navigate to Recent Stories.
The Cactus and Succulent Society will host a webinar on the selected genus of cactus at 10am on June 12th. Succulent specialist Rob Skillin will introduce him. We’ll have more information on this free event next week, but mark it now on your calendar and, as the date approaches, visit cactusandsucculentsociety.org/ to register.
UC Berkeley Botanical Garden announced several free webinars in June. The first events are as follows:
“Cochineal, the art of coloring” (insect repellent) at 13:00 on 15 June.
Plants, Beetles and Molecules: An Introduction to Plant and Insect Chemistry at 13:00 on June 17th.
Let’s Eat Bugs: A Global Perspective on Entomophagy (a new word to remember) at 13:00 on 18 June.
For more information visit botanicalgarden.berkeley.edu and click Programs.
The California Society for the History of Gardens and Landscape will present “Japanese Gardens in California” at 6:00 pm on June 16th. Speakers will focus on the San Francisco Japanese Tea Garden, Hakone Estate and Gardens in Saratoga, and SuihoEn in the San Fernando Valley. For more information on this ticketing event visit cglhs.org/upcoming-events.
Ruth Bancroft Botanic Gardens will host two webinars of public interest.
“Basic Cacti in Dry Gardens” at 10:00 am June 19th. Brian Kembel and Cricket Riley share their ideas and tips for growing these plants with low water consumption.
Reducing Fire Risks through Garden Design and Maintenance, 10 am June 26th. This can be a valuable experience for those gardening in areas threatened by wildfires this year. Jeniffer de Graaf will describe “the multifaceted, interconnected life of landscape solutions designed to reduce the threats to your landscape.” Visit www.ruthbancroftgarden.org/events/ to register for ticket events.
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Diversify your gardening days
Gardening, one of the oldest activities in the world, offers a continuous stream of new ideas, challenges and opportunities to enjoy your garden!
Tom Carwin is former president of the Friends of the University of California Santa Cruz Arboretum, the Monterey Bay Cactus and Succulent Society, and the Monterey Bay Iris Society, and Life Chief Gardener at the University of California (certified 1999–2009). He is now a board member and garden coach of the Santa Cruz Hostel Society. To view daily photos from his garden, https://www.facebook.com/ongarndingcom-566511763375123/. To search an archive of previous Gardening topics, visit http://ongaroding.com.