With their vibrant fall color, Japanese maples rank among the most beloved autumn trees. But that hot September weather this year pushed back their annual show.
"I'm seeing some of our Bloodgoods starting to get red," said Faye Zwakenberg of Lakes Nursery in Newcastle. "But most aren't showing any color yet. They need cooler weather. Some years, we don't get full color until Thanksgiving."
With about 200 cultivars and thousands of trees, Lakes Nursery is a major resource for Japanese maple lovers and a gauge for what these trees should be doing at a particular date.
"In September, we were starting to see some color, then it stopped," Zwakenberg said. "That heat was hard on all of us, and it followed a long, hot summer. Even sun-tolerant varieties took a beating because the heat lingered so long."
But now, the color show should come on strong.
"We are seeing some nice reds," noted Zwakenberg. "There's so much variety red, orange, yellow, purple, even pink, plus all shades of green. They're all very pretty.
Among the most popular for fall color:
Acer japonicum "Aconitifolium": Also called fern-leaf or full moon maple, this cultivar can carry a rainbow on one tree.
"If it's not too cold, you'll see red, orange, purple and yellow all on one leaf," Zwakenberg said. "If the weather gets cold enough, it turns brilliant red."
Fireglow: It's a 12-foot compact upright variety with bright red fall foliage similar to the taller Bloodgood.
Osakazuki: With larger leaves, it shows off its intense red foliage in fall.
Orangeola: A low-growing lace-leaf variety with cascading limbs.
"When it starts getting cold, it turns orange-red," Zwakenberg said
Hogyoku: Its foliage glows a bright pumpkin-orange in early November.
Why are Japanese maples so popular? Slow-growing and compact, these deciduous trees can fit into smaller spaces. During Sacramento's hot summers, they especially appreciate the partial shade of taller trees or buildings.
In Asia, Japanese maples (Acer palmatum) have been cultivated for hundreds of years as specimen and companion plants. Many varieties stay short and compact, usually in the shade of other trees or structures. Except for a few examples, the tallest Japanese maples top out at between 25 and 30 feet. Dwarf varieties rarely exceed 6 feet.
Unlike their full-size cousins, these little maples can't stand full days of direct sun, although some cope better than others. Green-leaved varieties tend to withstand direct sun and heat better than other colors such as red, orange, gold or variegated cultivars. To avoid sunburn, all need some afternoon shade.
But they do need some sun to trigger pigmentation; otherwise, the deep red or bright orange hues never materialize.
Naturally drought-tolerant, these maples like well-drained soil and minimal moisture or fertilization. Deep watering once a week encourages deeper roots. They do best with mulch to keep roots evenly cool (but don't let it mound around the trunk).
When first planted, they need more water at least twice a week until their root system gets established.
In the right conditions, these small trees can live generations. They like slightly acidic soil and grow well with other acid-loving plants such as azaleas, rhododendrons, ferns and dwarf conifers. These maples can tolerate slightly alkaline soil, too. Their fibrous root system gets along well with underplantings of bulbs and perennials.
The unusual color of these maples is due to leaf pigment and hereditary factors. Sun, shade and tree age will influence the intensity of leaf color. Too much sun and heat will bronze out red hues. Too much shade will make a red variety appear pale green. Also, leaves on very young trees may not look like their parents' foliage until they mature.
When selecting trees, choose the right tree for the right spot. Japanese maples generally fall into two groups:
Dissectums: Also known as lace-leaf, these small trees have a naturally cascading look that makes them attractive near water, a winding path or in a rock garden. The leaves have a finely cut, lacy appearance. Among the most popular varieties are Crimson Queen, Garnet, Red Dragon, Red Filigree Lace, Emerald Lace and Waterfall.
Upright: These mini-maples make great accent trees. They stand tall (up to 20 feet), but can also spread. Careful pruning can keep them compact. Among the best-known varieties: Bloodgood, Emperor I, Glowing Embers, Autumn Glory and Katsura.
Lakes Nursery, 8435 Crater Hill Road, Newcastle, (530) 885-1027: This nursery boasts the largest collection of Japanese maples in Northern California with about 200 cultivars.
Bushnell Gardens, 5255 Douglas Blvd., Granite Bay, (916) 791-4199: This nursery's shady demonstration garden features dozens of Japanese maples.