Marin IJ Articles

Japanese maples require little but offer color and more

• Julie Monson

• THIS YEAR, IT began in October. Our native vine maples (Acer circinatum) were the first maples to turn a deep gold, their leaves the size of a child's hand, quietly floating from limb to ground. Next came the exuberant color of our Japanese maples (Acer palmatum), beginning with the smaller maples in pots on the deck, then moving to larger trees around the house. Yellow, gold, coral, crimson, as beautiful on the trees as on the ground. It's a sight I never tire of.
  
  In another week or two, we'll be working hard to collect the fallen leaves to add to our compost pile, a chore made more pleasant by the delicacy and colors of the gathered leaves.

  When we planted our garden 12 years ago, we carefully selected our Japanese maples at the nursery, wrapped them in sheets to bring home in our little truck and fussed over where to plant them. They have thrived in our garden, as they would in most of Marin County, a perfect climate for Japanese maples.

  Our new trees were small, about 8 to 10 feet tall, and skinny, and I made a common mistake: we planted too many too close together, unconcerned that they would soon outgrow their allotted space. The result is a shady garden most of the year, perfect for ferns, azaleas, nandina and mossy ground covers, but not for any plant that requires sun. As the leaves
  fall, leaving bare branches above, the garden welcomes its annual dose of
  winter sun, and so do we. The branching structure of our bare trees is, in
  itself, attractive and a welcome respite from the luxuriant foliage of other
  seasons.

  Of California's two native maples, big-leaf maple (Acer macrophyllum) is gorgeous, but too large for most gardens, growing to 100 feet. In woods, parks and large gardens, it is an excellent shade tree high enough to create a perfect, shady environment for understory plants. The vine maple, on the other hand, is smaller, between a large shrub and a small tree. Ours have interesting multitrunk structures and pale green leaves until they turn gold in fall. Slow growing and therefore easier to shape with gentle pruning, vine maples do well in dappled shade with other shade-loving plants and ground covers.

  Japanese maples come in all shapes, sizes, colors and leaf formation. Before purchasing Japanese maples, check them out at nurseries in summer and fall when they are in leaf. I also recommend references such as the "Sunset Western Garden Book," which has a good section on maples.

  Leaf colors vary from pale green to deep red and some change color from spring to summer to fall. Leaves can be finely cut and delicate, or rounded (like the Canadian maple leaf) and vary in size from as small as a µ-inch to a 5-inch saucer. Some grow straight with a leaf canopy above a slender trunk, creating dappled shade for understory plants. Others have multi-branched trunks creating thick, low shade, suitable for specimen trees in special locations.

  Fairly pest free and healthy, Japanese maples require modest care, primarily shaping when young, and pruning in late winter to preserve their shape. I also prune upper branches to open the canopy to sunlight. A slightly acid, moist soil with good drainage is important. They like neither soggy nor dry roots. For this reason, I find they respond well to good mulching, and given the shade they create, their water requirements are not as severe as one might expect.

  Shade makes a big difference on water retention. They prefer locations protected from strong winds and afternoon sun. Fertilize In the spring, when these trees put enormous energy into creating tens of thousands of leaves. I don't fertilize much more than that, primarily because I don't want my trees to grow larger. I fertilize enough to keep them healthy.

  The reward for these few efforts is an abundance of seasonal variation in form and color. New leaves in spring tend to be pink or pale green, turning darker green or red as the weather warms. Their dappled shade creates a cool summer garden atmosphere, and then it's fall, when they again show off all their magnificent splendor.