Tom Karwin, on gardening | Evolution of a pair of Monterey cypress trees – Santa Cruz Sentinel

Take care of your garden

Our urban forests contain long-standing trees that eventually must free up their space for other purposes. Today’s column, which may arrive in your backyard, is about one of these trees.

A pair of Monterey cypress trees have grown about 20 feet apart for about 50 years at Carmelita Cottages, a historic property a few blocks from Santa Cruz Beach. According to archival photographs, these trees were planted near the front property line and cut for years into columnar topiaries.

Monterey cypresses (Cupressus macrocarpa) are impressive members of the natural environment and urban forests. There are magnificent specimens in the Monterey Bay area; the attached photo shows a nice example in Point Lobos State Nature Reserve.

The tallest recorded Monterey cypress, growing in San Mateo, California, is 102 feet tall and 111 feet wide. It was added to the National Register of Champion Trees in 2019.

Over time, diligent pruning can cause a tree to assume a shape that will likely appeal to the mower wearer and other observers, but which is far from its natural form.

When allowed to grow without persistent mowing, however, the tree will strive to grow as nature intended. Depending on how long he had been subjected to the mowers, he might have limited success in this endeavor.

As the tree grows into power lines, another set of mowers changes its shape. Public safety and the continuity of electrical service require the sometimes insensitive removal of branches that encroach on the wires, further compromising the shape of the tree.

The two Monterey cypresses in this column developed trunks 30 and 36 inches in diameter, but, following their growth in the urban forest, only reached about 40 feet in height, well below their potential stature. natural.

They are now showing symptoms of another attack.

Almost two years ago, an arborist from Bartlett Tree Experts volunteered to examine the trees and reported the presence of active borers on both trees.

The bark beetles attacked these trees. The culprits could be cypress bark beetle (Phloeosinus cristatus or P. cupressi) or western cedar bark beetle (P. punctatus), but the same damage results. The arborist observed that “the insect infestation encircles the vascular system of the tree and causes the upper crown to die off. “

There are no effective insecticides or other means of controlling such infestations. The recommended action is to remove affected branches, or even the entire tree, to protect other trees. In this case, both trees are already infested, so their future is limited.

The infestation of one of the two trees has advanced enough for Santa Cruz urban forester / arborist Leslie Keedy to approve its removal. The City’s heritage tree policy protects the large members of the urban forest, so its approval is not taken lightly.

These trees are on a property owned by the city of Santa Cruz and leased for decades to the nonprofit Santa Cruz Hostel Society, which maintains the buildings and the landscape of the sites. The Company will bear the substantial cost of removing the first of these two trees and, over time, the second bark beetle victim.

This process is not unheard of in the natural world or in gardening. The continuity of plants is limited by their normal lifespan and external favors, including pests, diseases, forest fires and “who knows what”, as well as thoughtful visions or spontaneous whims of the gardener’s owner.

Mature trees have a stronger hold on their presence than annuals and perennials, but all plants are subject to replacement. The good news is that removing these trees, or other important plants, creates space for new landscaping ideas and new plants.

We can share a quiet moment of respect for long-standing abuse and the eventual loss of a large tree, and then take the opportunity to start over.

Improve your gardening knowledge

As we move into the active gardening season, we can take advantage of the online resource harvesting.

The Arboretum & Botanic Garden at the University of Santa Cruz will present “Gardening in Dry Summer Climates” at 6 pm Monday. For this timely 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.

Last week, the Pacific Horticulture Society’s webinar “Around the World in 80 Plants: A Global Botanical Adventure” was also presented at noon on Tuesday. The presenter will be Jonathan Drori. This free event is also for a speaker’s new book. For more information, go to www.pacifichorticulture.org/digital-classroom/ and scroll down to “Recent Stories”.

The Cactus and Succulent Society will present a webinar on a selected cactus genus at 10 a.m. on June 12. Succulent specialist Rob Skillin will present. We’ll have more information on this free event next week, but mark your calendar now and as the date approaches, visit cactusandsucculentsociety.org/ to register.

The University of California, Berkeley Botanical Garden, announced several free webinars in June. The first events are as follows:

“Cochineal, the art history of a color” (derived from an insect) at 1pm on June 15th.
“Plants, Insects and Molecules: An Introduction to the Chemistry of Plants and Insects” at 1:00 pm on June 17th.
“Eat Insects: A Global Perspective on Entomophagy” (a new takeaway) at 1 pm on June 18.
For more information, go to Botanicalgarden.berkeley.edu and click on “Programs”.

The California Garden and Landscape History Society will present “Japanese Gardens in California” at 6 pm on June 16th. Presenters will focus on the Japanese Tea Garden in San Francisco, the Hakone Estate & Gardens in Saratoga and SuihoEn in the San Fernando Valley. For more information on this paid event, visit cglhs.org/upcoming-events.

The Ruth Bancroft Botanical Garden will present two public service webinars.

“Essential Cacti in Dry Gardens” at 10:00 am on June 19th. Brian Kembel and Cricket Riley will provide ideas and advice on growing these low-water plants.

“Mitigating Fire Risks Through Garden Design and Maintenance,” 10 am June 26. It could be a valuable learning experience for those gardening in areas threatened by this year’s wildfires. Jeniffer de Graaf will describe “a multidimensional and interconnected life of landscape decisions aimed at reducing dangers to your landscape”. Visit www.ruthbancroftgarden.org/events/ to register for these paid events.

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Enrich your gardening days

Gardening, one of the oldest occupations in the world, offers a continuous stream of new ideas, challenges and opportunities to enjoy your garden!

Tom Karwin is the past president of the Friends of the UC Santa Cruz Arboretum, the Monterey Bay Area Cactus & Succulent Society, and the Monterey Bay Iris Society, and UC Lifetime Master Gardener (certified 1999- 2009). He is now a board member and garden coach for the Santa Cruz Hostel Society. To view daily photos of his garden, https://www.facebook.com/ongardeningcom-566511763375123/. To find an archive of previous gardening columns, visit http://ongardening.com.