In 1978, when I moved to this property, it already had six trees, each approximately 40 to 50 feet tall. They could have been in place since 1936, when the original owners built the house, or they installed the trees shortly thereafter.

Over time, we removed three of these large trees. The first tree was growing too close to another tree and was overwhelmed by Algerian ivy (Hedera algeriensis), a noxious invasive weed. The tree’s genus was unidentified at the time because ivy had suppressed the tree’s leaves.

Years later, we removed the second tree, a deodar cedar (Cedrus deodara), which had a double trunk with the potential for very heavy branching to split. We needed to remove it for safety and also because its evergreen foliage was shading the south side of the house.

In a recent column, I described the tree work in my garden, including the removal of the third tree — a large, old pittosporum with significant cracks in its trunk, creating a potential hazard for falling. The cracks resulted from a weak, narrow crotch that had developed due to pruning neglect during the tree’s earlier years.

This most recent project inspired reviews of the garden’s three remaining large trees, lessons learned and guidelines for long-term care of trees.

This column’s image gallery typically features blossoms that we all enjoy, but today’s gallery presents close-ups of trees in my garden.

The remaining trees

American sycamore (Platanus occidentalis). The base of this enormous tree is 10 feet from the corner of the residence, and power and communication lines thread through its canopy, requiring pruning every few years. Seasonal attacks of sycamore anthracnose damage the tree’s leaves, compromising its imposing presence. When grown as a lawn tree, the litter from twigs, large leaves, bark and fruiting balls requires regular clean up.

Alaskan yellow cedar (Cupressus nootkatensis). This tree had grown about 15 feet behind the garage and close to the tree that we removed due to an ivy attack. After the removal, we found that this tree had limited branching near the adjacent tree. In time, the branches developed well, resulting in a more natural form with characteristic, attractive foliage.

Atlas cedar (Cedrus atlantica). This tree’s base is located at the center of the 100-foot-wide property, approximately 20 feet from the back fence, making it a commanding presence and a semi-shade region in the garden. It has developed large, heavy, nearly horizontal branches that occasionally break and fall, even in the absence of strong winds. The long-term effect is an arbitrary modification of the tree’s form.

Japanese pittosporum/mock orange (Pittosporum tobira). The garden included three specimens of this shrub, which have grown to small trees about 15 feet tall near the garden’s back fence. Shrubs typically have multiple trunks, whereas trees have only one. In this case, this garden had a grouping of single-trunk specimens, possibly resulting from pruning during their youth. We recently removed one of the three due to cracks in its trunk. The remaining two are much smaller than the garden’s three large trees, and we see them as better suited for the landscape.

Tree care guidelines

The primary guideline is to respect the tree’s natural character. Some tree owners pursue formal shapes, including topiary forms that work well to fit shallow spaces or provide easy access for picking fruit. Generally, trees look their best when they grow naturally.

When establishing a new young tree, provide a solid foundation for a healthy and attractive tree by following this brief list of guidelines.

Develop a central leader for a single strong trunk. Remove any competing leaders.

Ensure that branches are correctly spaced vertically and radially. For smaller trees, spacing should be 6 to 12 inches apart. The branches of larger trees should be 18 to 24 inches apart.

Develop strong branch angles. An angle between 45 and 90 degrees is considered stronger and more resistant to breakage than a narrow-angle (V-shaped or less than 45 degrees).

When pruning branches, cut just outside the branch collar to promote natural healing and minimize damage. The branch collar is a distinctive bulge of tissue at the base of a tree branch where it joins the trunk or another branch. Avoid flush cuts or short stubs.

When shaping the tree, remove entire branches at their origin rather than shortening them.

Remove suckers (growing from the tree’s base) and water sprouts (vertical shoots from branches), which divert the tree’s energy and disrupt its form.

Avoid “lion-tailing,” which involves stripping the interior growth of branches, leaving foliage at the tips. Such pruning weakens the branches and creates an unnatural look.

Schedule pruning according to the tree’s seasonality:

• Prune deciduous trees in late winter before growth begins.

• Prune evergreens in late summer.

• Prune California native trees after flowering or in late summer to avoid disease and preserve wildlife value.

This week in the garden

Review the trees in your garden and consider pruning needs. After observing a few YouTube videos of amateur tree work, including scenes of large trees falling on homes or vehicles, and amateurs falling off ladders, we recommend using tree services licensed by the California Contractors State License Board (cslb.ca.gov). For advice on managing healthy or deceased trees, use an arborist certified by the International Society of Arboriculture (isa-arbor.com). For minor pruning, keep your feet on the ground!

Correction

Last week’s column, “The ‘Chelsea Chop’ and seasonal pruning,” had switched captions for Canadian goldenrod (Solidago canadensis) and stonecrop (Sedum erythrospermum) due to our error. Many readers would have recognized the goldenrod as the more familiar of these two plants.

Advance your garden knowledge

Our future column will focus on the criteria for selecting trees for the garden.

Enjoy your garden!

Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and lifetime member of the Monterey Bay Area Cactus and Succulent Society, a Lifetime UC Master Gardener (certified 1999-2009), past board member of the Santa Cruz Hostel Society and active with the Pacific Horticultural Society and other garden-related societies. To view photos from his garden, visit facebook.com/ongardeningcom- 566511763375123. To review the archive of recent On Gardening columns, visit santacruzsentinel.com and search “Karwin.” Go to ongardening.com to review columns from 2012-2020 (and soon) from 2025. Send comments or questions by email to gardening@karwin.com.