JAPANESE MAPLE
Acer palmatum

The most unique, diversified and graceful group of trees in the world, Acer palmatum (Japanese maple), is made up of over 1000, single or multi-stemmed, cultivars that vary in size, shape, habit, leaf pigmentation, form, texture and fall coloration. This spectacular species includes cultivars that are suitable for an assortment of uses, such as; artistic accent plant, picturesque specimen, mixed border companion, container gardening and bonsai. The red-maroon colored flowers of this Japanese, Chinese, Korean native add a lovely, delicate accent that persists for several weeks in May. Hardy in USDA zones 5 – 9, the Japanese maple sports miniature red samaras in September thru October, the plants winged fruit. Often breathtaking, there is a fabulous, colorful leaf display in the fall. And finally, another reason to familiarize yourself with this four season plant, an exquisite, slender, graceful branching habit that is fully exposed in the winter months.

TYPES
Japanese maples can be broken down into several distinct types:

1) Dissectum – This group of Japanese maples is also called the lace-leaf type. The dissectum group is very showy with finely cut leaves and an arching, twisted, and cascading habit. This group will generally not exceed sixteen feet in height at its slowly reached maturity.

2) Upright – This group is often called the smooth leaf type and its leaves are not as finely cut as those labeled dissectum. This group is more upright in habit but still carries an attractive limb structure. Taller than the dissectum group, the upright Japanese maples may reach thirty feet in fifty years depending on conditions.

3) Dwarf – This group rarely exceeds six feet at maturity but is usually less that three feet high making it an excellent choice for container growing and for bonsai.

CULTURE

Siteing:
Most varieties of Acer palmatum take sun very well but will benefit from some afternoon shade to prevent leaf scorch. Varigated varieties require semi-shade throughout the day as they are more sun sensitive. Red cultivars require full sun for part of the day to develop their rich red colors and some red cultivars may revert to green if sited in too much shade. It is best to locate Japanese maples, especially the dissectum group, in an area protected from prevailing winds to prevent leaf desiccation.

Planting:
Japanese maples have a root system that is fibrous making this tree easy to plant. As the tree matures some of the roots will increase in size and move deeper in the soil. The planting hole should be dug at least two times the diameter of the root mass but no deeper than the soil depth at which the tree is already planted. Soil should be amended with plenty of organic matter, this will allow sandy soils to retain water and nutrients and will allow heavy clay soils to drain more easily. Heavy clay soil will also benefit from the addition of a soil conditioner that will permanently repair this dilemma, we recommend using Permatill or Turface. The hole should be deep enough so that the root collar of the plant, the ground line at which the young plant was grown, is level with the ground surface. If you bury the root collar the tree will eventually die. If you have very heavy clay soil, it will benefit the plant to be planted slightly above grade to assist in drainage. Make sure that roots are adequately covered to prevent them from drying out. Using a root stimulator, such as Schultz Starter Plus or Root Master B-1, is a good idea when planting to avoid transplant shock.

Familiarize yourself with the chacteristics of the Japanese maple that you are purchasing. Know the ultimate size of your cultivar, a little preplanning will help you choose a location where the plant not eventually outgrowing its spot. Japanese maples do not have an overly competitive root system which makes them great planting partners that will easily co- exist with other plants that have the same cultural requirements.

Mulch:
Due to the fact that the root system is not deep, mulching is very important. Soil around shallow rooted plants will dry quickly, mulching will help greatly in retaining soil moisture. Mulch will also protect tender roots from extreme heat and cold by moderating soil temperatures. It may take a newly planted Japanese maple several years to establish its root system well enough to compete with other plants for moisture and nutrients. Grass and weeds are highly competitive for the necessities of a shallow rooted plant. It is a good idea to plant in a garden bed, or, if planting in the lawn, make sure that there is a mulch ring around the base of the plant to reduce competition from weed and grass and to prevent lawnmower damage to the trunk of the tree. The ideal amount of mulch is 2 inches. Always be careful not to mound mulch around the trunk, this will eventually kill the tree.

pH:
Japanese maples prefer a slightly acidic soil, 6.1 -6.5 is preferable, however, these plants are adaptable and only those planted in extremely high pH will not perform well. Containers or raised beds are a viable option where soil conditions or pH are difficult to correct.

Water:
Consistent moisture is required by Japanese maples especially as their roots are developing. If these plants are adequately cared for while they are young and establishing themselves then they will handle stress more effectively if it imposes itself in the later years.

Fertilization:
These plants are not demanding in their need for fertilizer. Fertilize Japanese maples once a year, in early spring, before leaves emerge, with a balanced fertilizer recommended for deciduous trees and shrubs, we suggest Espoma Tree Tone. Please read label carefully for application rate.

Pruning:
Major pruning should be done during the plants dormant season. Prune after leaves have dropped in the fall but before the sap begins to rise in the spring. Corrective pruning may be done at any time of the year except when the sap is rising. Pruning the dissectum group is a great artistic release and is done to open the plant up to expose the graceful structure of the plant.

Container Growing:
Growing Japanese maples in containers is ideal for those with patios, decks, and small gardens or landscapes. Dwarf cultivars lend themselves to this type of growing. There are just a few additional requirements for container grown plants. Make sure that the container that you are using has an adequate drainage to prevent roots from rotting. Plants roots must be protected in the winter as they not withstand temperatures below 14 degrees Fahrenheit. Containers may be grouped against a warm side of the house, pack in- between pots with straw and surround group with bales of straw. Finally, nutrients tend to leach thru the soil quicker in container grown plants, a slow release fertilizer, such as Osmocote, should be used in this situation. Check label for application rate and re-application time.

Insect & Disease:
When provided with the proper cultural conditions these plants are relatively pest and disease free.