October Tree of the Month-Japanese Maple

One of the most admired and coveted trees among plant geeks is the Japanese maple, Acer japonicum. The closely related Acer palmatum October Tree of the Month-Full Moon Maple – is often called Japanese maple, although its official common name in our area is full moon maple. The two species have distinct traits despite their similar looks and care requirements.

First, the similarities.

Both species are native to Asia and thrive in zones 5-9 in the US.

Both prefer some part afternoon shade in the southern parts (including St. Louis) of their growing range. Full sun scorches the tender foliage, especially if soils aren’t kept consistently moist.

Pruning for both species should be kept to a minimum, but if needed, do it in late fall to mid-winter, or it often results in significant “bleeding.”

Size is cultivar-dependent for both species,, usually ranging from 6’ to 30’. (RESEARCH!)

Then there are the differences.

Acer japonicum usually has reliable fall color, rarely shows summer stress, and is less prone to early spring frost damage; it also stands up better to cold in fall. It also has better disease and drought resistance and is less prone to powdery mildew in the extreme heat and humidity of July and August.

The leaves differ slightly between the two species and, again, depend heavily on cultivar. Overall, A. japonicum leaves are hairier on the undersides and stems, with thicker stems and new growth. The specific epithet palmatum refers to the leaf shape, which resembles a human hand.

A. japonicum has larger leaves than A. palmatum, at 8-15 cm with 7-11 lobes, compared with A. palmatum’s 5-7 lobed leaves that are 5-10 cm. (Frequent hybridization with A. shirasawanum, sold as a palmatum cultivar, e.g. ‘Trompenburg,’ etc. confuses the issue, sometimes causing more lobes.)

Cultivation of A. palmatum in Japan dates back to the 7th and 8th centuries during the Nara period, when trees were planted around temples and palaces.

Despite the confusion between the species, either way you’ll get an outstanding small tree with beautiful foliage, habit, and history.

What I love about this plant:

-Stunning foliage and habit.

-Long, honored history.

-Zillions of cultivars. A size for every garden, from dwarf weepers to 30’ specimens.

-Multiple foliage choices like burgundy-colored specimens, weeping forms, or dissected leaves.

-Dwarf cultivars can make a great container tree.

What’s not so great;

Prone to stem canker, leaf spots, fusarium, verticillium wilt, botrytis, anthracnose, and root rots. Pest issues include aphids, scale, borers, bagworms, and root weevils. Despite all this, they can be very long-lived.

-Although they are less prone to early frost damage, the risk still exists, especially in the northern parts of the hardiness range. If temperatures call for a freeze after leaves have emerged, cover with a lightweight sheet or tarp for the evening, and uncover in the morning after temperatures rise.

-Fall color can be weak compared to the brilliant spring leaf color, especially if fall conditions are dry.

-Comments or questions? Email Garden-Lou at gardenloustl@gmail.com

Words and photos by Jo Batzer

© Jo Batzer, garden-lou.com-2026, All rights reserved.