Trees We Care For: Maples

Maples are some of the most beloved trees in the world, but people often enjoy them for different reasons. 

Some love the syrup derived from their sap, others appreciate the value they provide wildlife, and kids find the “helicopter” seeds they produce delightful. Meanwhile, homeowners and property managers in the Central Coast region tend to prize maples for the beauty and shade they lend to local landscapes. 

But no matter why you like these trees or which species you have on your property, it’s important to provide them with the care they require. We’ll try to help by identifying the species common in our area and outlining their general care requirements. 

Common Maple Trees in the Greater Bay Area

A number of maple tree species are commonly encountered between Monterey and Santa Cruz, including both native and exotic varieties. 

Native Maples in the Greater Bay Area

The following maples are all native to California, though some are not especially common in the Central Coast region. 

• Bigleaf Maple (Acer macrophyllum): Bigleaf maple is the dominant native maple along California’s Central Coast, where it commonly grows in moist canyons, riparian corridors, and shaded slopes around Aptos and the Santa Cruz Mountains. Its big leaves and fast growth make it a good shade tree, though its brittle wood breaks easily. 
• Vine Maple (Acer circinatum): Vine maple is a smaller, understory species that thrives in the shaded, moist forests of the Santa Cruz Mountains, often forming arching, multi-stemmed structures beneath taller trees. It requires regular pruning to maintain good structure and prevent it from causing access issues.
• Mountain Maple (Acer glabrum var. torreyi): Mountain maple is a less common native species in California, typically restricted to high elevations and cool microclimates. It generally remains small and shrub-like, making it a low-risk species, but it is sensitive to drought stress and environmental changes.
• California Boxelder (Acer negundo var. californicum): California boxelder is a fast-growing maple often found along streams and floodplains, where it provides food for wildlife. However, its rapid growth and weak wood structure can make it prone to storm damage, especially in exposed or urbanized settings.

Exotic Maples Common to the Greater Bay Area

In addition to our native maples, the following species are commonly planted as street, specimen, or landscape trees. 

• Japanese Maple (Acer palmatum): Japanese maple is a popular ornamental species in coastal California landscapes, valued for its refined form, delicate foliage, and seasonal color changes. It performs best in protected sites with filtered light and consistent moisture, as it is sensitive to heat and drought. 
• Norway Maple (Acer platanoides): Norway maple is another ornamental species that can tolerate urban conditions but often performs poorly in California’s dry summers. Its dense canopy can suppress understory growth, and it may develop structural weaknesses or decline without consistent care.
• Sycamore-Leaf Maple (Acer pseudoplatanus): Sycamore-leaf maple has become naturalized in parts of coastal California, particularly in disturbed areas and along waterways. It is tolerant of a wide range of conditions, but its ability to spread aggressively can make it invasive and undesirable in some situations.
• Red Maple (Acer rubrum): Red maple is widely planted as an ornamental tree, but it can struggle in our local Mediterranean climate and alkaline soils. Without careful site selection and irrigation management, it may exhibit stress symptoms such as leaf scorch, dieback, and reduced vigor.
• Silver Maple (Acer saccharinum): Silver maple is a fast-growing tree that is occasionally planted for quick shade, but it is generally not well-suited to California’s climate or soil conditions. Its brittle wood, aggressive root system, and high water demand often lead to structural issues and maintenance challenges over time.
• Freeman Maple (Acer × freemanii): Freeman maple is a hybrid of Red Maple and Silver Maple, bred to provide the former’s fall color and the latter’s fast growth and adaptability. While it performs better than either parent in some landscape settings, it can still struggle with California’s dry summers and may develop structural issues.

Mistaken Identity: Two Maple Lookalikes

Two trees in the Central Coast region can slightly resemble maple trees, sometimes leading to confusion:

• California Sycamore (Platanus racemosa): Sycamore leaves can resemble bigleaf maple leaves at a glance, but you can distinguish sycamores by noting the alternate (rather than opposite) leaf arrangement, as well as their peeling, multi-colored bark.
• Sweetgum (Liquidambar styraciflua): Sweetgum leaves look somewhat similar to Japanese maple leaves, but you can identify sweetgums by noting their alternate leaf arrangement. You may also see the infamous “sweetgum balls” growing on mature specimens.

Caring for Maple Trees in California’s Central Coast: The Basics

Many maples are hardy trees that will usually thrive in the Greater Bay Area. However, they will benefit from a few key care practices, which we’ll discuss below. 

Matching Trees to the Proper Location: Plant the Right Tree in the Right Place

The easiest way to set your trees up for success is by planting them in a suitable location. There are countless factors involved in site selection, but the following are among the most important:

• Sun Exposure: Japanese, vine, mountain, and bigleaf maples will thrive best when provided with light shade (particularly in the afternoon). Meanwhile, box elders, red maples, Norway maples, sycamore-leaf maples, silver maples, and Freeman maples can survive (and often prefer) full sun exposure. 
• Space Requirements: It’s always important to select planting locations that offer enough space for the tree’s mature size. Mountain, vine, and Japanese maples will fit in relatively tight locations and rarely exceed 25 feet in height, but all other species will typically reach at least 40 feet in height, with some exceeding 80 feet. 
• Moisture Needs: All of these species require well-drained soil, but boxelders, bigleaf, red, and silver maples have relatively high water demands. Mountain and vine maples, on the other hand, are adapted to our local climate and fairly drought tolerant once established.  

Climate & Geographic Concerns: Supporting Non-Natives

While our native maples have evolved to live in our local climate over millions of years, exotic species adapted to the climate and soil characteristics common to other places. So, you need to put in a little extra effort to keep exotics healthy and happy.

• Monitor the pH: Most maples prefer slightly acidic soil, but red and Japanese maples are especially intolerant of alkaline soils. You may need to provide these trees with acidic fertilizers, amend the soil with sulfur, or add some pine-based mulch (needles or bark) above the root zone.
• Shield Them from Salt: Maples usually don’t tolerate coastal salt exposure, which can be a problem for property owners along California’s Central Coast. You can use fences or salt-tolerant plants to help block coastal winds, and you may need to rinse your trees periodically to wash salt off the leaf surfaces. 
• Watch the Winds: Strong winds can create problems for many maples, including native and exotic species alike. For example, consistent winds can desiccate Japanese and red maples, while strong winds can rip box elders and silver maples apart or even partially defoliate our native bigleaf maples. 

Pruning Maple Trees: Timing, Technique, & Best Practices

For the most part, you’ll want to leave tree-pruning to the professionals. This will not only ensure the best results, but it will also help keep you safe — amateurs should never climb trees or use a ladder for pruning. However, there are a few things you’ll want to keep in mind, whether you’re pruning your trees yourself or enlisting the help of a certified arborist. 

• Timing: Maples are best pruned in mid-winter, when the trees are completely dormant, though you can prune them in the late summer if need be. Pruning maples during the spring, when the sap flow is actively flowing, will cause lots of unsightly “bleeding.” 
• Use Care with Japanese Maples: You’ll generally want to prune Japanese maples very lightly and only after developing a very clear plan of attack. Many amateurs over prune these delicate trees, which leads to health problems and poor form for the rest of the tree’s life. 
• Be Proactive with Weak-Wooded Maples: Silver maples, bigleaf maples, and boxelders are somewhat brittle species that are prone to limb drop. So, it’s important to remove hazardous branches promptly, before they can cause injuries or damage property.  

Troubling Signs: Why Is My Maple Tree Dying?

Maple trees can suffer from a number of ailments, which may cause them to exhibit poor growth, decline, or die completely. Many of these problems can be addressed with prompt care, so be on the lookout for any of the following signs or symptoms:

• Yellowing Leaves: Called chlorosis, this is often a sign of iron or manganese deficiency, though it can also be caused by poor drainage or compacted soil.
• Brown Leaf Edges: Brown leaf edges (something arborists call leaf “scorching”) can indicate drought stress, salt damage, or verticillium wilt.
• Wilting Leaves: Wilting leaves are always a concerning symptom, which may indicate the tree is dealing with root rot, drought, or a vascular disease.
• Premature Leaf Drop: Maples that shed their leaves well before fall arrives may be suffering from disease, pests, or environmental damage.
• Branch Dieback: Branches that start dying at the tips and progress inward may be suffering from verticillium wilt, drought stress, or canker diseases.   
• Sunken, Discolored, or Oozing Bark: Called “cankers,” these can be caused by fungal or bacterial infections, which can kill branches or the whole tree.
• Insect Infestation: Aphids, scale insects, wood-boring beetles, and other insect pests can all cause significant damage to maples. 

While these signs and symptoms often indicate potentially serious health problems that necessitate prompt action, there are also a number of signs associated with less serious issues. Examples include: 

• A Powdery White Coating on Leaves: This is a classic sign of powdery mildew — a fungal condition that generally doesn’t threaten the long-term health of a tree. 
• Black Leaf Blotches: Caused by a fungus in the genus Rhytisma, “tar spot disease” is usually a cosmetic issue that rarely becomes life-threatening.
• Unusual Leaf Growths: Bumps and projections emerging from leaves are typically caused by mites or insects and rarely cause significant damage. 

It’s still a good idea to have an ISA-certified arborist inspect trees displaying these issues, but they’re generally not as serious as those mentioned earlier. 

Common Maple Tree Pests & Pathogens in the Santa Cruz Region

There are a variety of organisms that can cause problems for maple trees in our part of California. However, the following bugs and diseases are among the most notable:

• Verticillium Wilt (Verticillium dahliae): Likely the most serious pathogen affecting maple trees in the Central Coast region, verticillium wilt causes branch dieback and wilting. There is no cure once the disease is established, thereby highlighting the importance of maintaining tree vigor. 
• Phytophthora Root Rot (Phytophthora spp.): Phytophthora root rot can cause significant root damage, leading to poor health and structural instability. It is most common among maples grown in damp, water-logged soils. There is no true “cure” for this disease, but it can be managed with phosphonate-based products. 
• Cottony Maple Scale (Pulvinaria innumerabilis): Named for their cotton-like appearance, these scale insects can cause significant dieback in a maple’s canopy if their populations are allowed to proliferate unchecked. Fortunately, there are a number of treatments arborists can use against these pests.  
• Maple mealybugs (Phenacoccus acericola): Easy to recognize thanks to their waxy white covering, maple mealybugs can cause maple leaves to turn yellow or, in some cases, lead to premature leaf drop. You can often wash them away with insecticidal soap, but it’s best to catch infestations early for the best results. 
• Flatheaded Borers (Agrilus spp.): Flatheaded borers rarely target healthy maples and instead prefer those already weakened by drought. These insects can be tricky to treat once present, so it’s vital to support the health of your maples and offer supplemental water during droughts. 

In addition to these potentially serious threats, powdery mildew and tar spot (both of which were discussed earlier) are common issues, though they’re rarely fatal for otherwise-healthy maples. 

Safety Alert: Signs Your Maple May Be Hazardous

Unfortunately, maples can suffer from issues that will put them at increased risk of failure. And because tree failures can result in injuries, property damage, or worse, it’s imperative that you monitor your trees for any of the following issues:

• Narrow, V-shaped branch junctions, which are structurally weak (and unfortunately common in some maples)
• Mushrooms or conks growing on the trunk, branches, or root system, as they are a sign of fungal activity
• Large hollows or cavities, as they’re often associated with significant decay
• Mounding soil near the base of the tree, which may indicate a compromised root system
• Large cracks that demonstrate a tree (or some portion of it) is already actively failing
• A sudden lean or an increase in the angle at which a tree leans

If you notice any of these signs, contact an ISA-certified arborist immediately and have an assessment performed. 

Maple Trees in San Jose: FAQ

Have more questions about maple trees in the Greater Bay Area? We’ve rounded up a few of the most common questions we hear and answered them below. 

Which maple trees make syrup?

Technically, all maples produce sap that can be boiled down into syrup. Sugar maples are the “gold standard” for syrup production, but bigleaf, red, and silver maples are also tapped in some places. Nevertheless, our local climate is not conducive to generating the kind of sap flow that northeastern states achieve. 

Do maple trees have flowers?

Yes, like all angiosperms, maple trees produce flowers. However, they’re often relatively small and lack the typical flower structure most would expect. With that said, many maple flowers are brightly colored. 

When do maple trees drop their seeds?

Different maples drop seeds at different times of the year. In our region, the red and silver maples will release seeds first in early spring. Norway and sycamore-leaf maples will drop seeds shortly after, while bigleaf, Japanese, vine, and mountain maples release seeds in late summer through fall. 

When should you prune maple trees?

Mid-winter is the best time to prune maples, though you can prune them in the late summer if need be. Avoid spring pruning, as this often leads to excessive sap “bleeding.”

Are maple trees toxic to dogs?

Most maples are considered relatively nontoxic to dogs, though eating large quantities of any plant material may lead to gastrointestinal distress. It’s also worth noting that red maples (and potentially other maple species) are toxic to horses. 

Do maple trees grow fast?

Some maples commonly found in the Central Coast region are fast growers, including boxelders, silver maples, red maples, and Freeman maples. The other species all have slow to moderate growth rates. 

Which maple trees turn red in fall?

Many maple species have variable fall color; some individuals may be red, but others may produce yellow or orange foliage. However, red and Freeman maples are reliably red in the autumn, as are several Japanese maple cultivars. 

Get Your Maples the Care They Need: Trust Adney Tree Service

The best way to keep your maple trees healthy and looking their best is to solicit the help of a tree-care service that’s led by an ISA-certified arborist — like Adney Tree Service. We’ve been providing artisan-caliber tree care to residents in Scotts Valley, Santa Cruz, Watsonville, and everywhere in between since 2015. 

Contact us today to request your free estimate and see why we’ve built a reputation as the leading tree care service provider along the Central Coast. 

Sources & References

• Pacific Northwest Plant Disease Management Handbook – “Maple (Acer spp.) – Verticillium Wilt”
  This technical guide describes the fungal pathology, diagnostic symptoms, and integrated management practices for controlling soil-borne vascular wilt in maple species.
  https://pnwhandbooks.org/plantdisease/host-disease/maple-acer-spp-verticillium-wilt
• U.S. Forest Service – “Acer negundo L. Boxelder”
  This comprehensive silvics manual provides detailed data on the life history, habitat requirements, and ecological characteristics of the Boxelder maple across North America.
  https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/acer/negundo.htm
• Stanford University – “Acer freemanii: Freeman Maple”
  This encyclopedic entry examines the horticultural attributes and growth patterns of the Freeman maple, a naturally occurring hybrid known for its structural strength and fall color.
  https://trees.stanford.edu/ENCYC/ACEfre.htm
• California Native Plant Society – “Acer circinatum (Vine Maple)”
  This botanical profile outlines the native range, moisture requirements, and landscaping utility of the Vine maple as a foundational species in Pacific coastal ecosystems.
  https://calscape.org/Acer-circinatum-(Vine-Maple
• National Park Service – “Bigleaf Maple”
  This resource highlights the ecological role, identifying features, and unique epiphytic relationships of the Acer macrophyllum within temperate rainforest environments.
  https://www.nps.gov/articles/000/bigleaf-maple.htm