Japanese maples (Acer palmatum, A. japonicum, A. shiraswanum, and several other species) are all loved and admired gardening subjects. People often come to me with questions about their culture or problems they are having with their plants. Here are some tips. These maples requre AMPLE watering, good drainage, and reasonable fertile soil. They are easy care. The most important thing with them is to provide adequate water all the time. THINK MONSOON, that is where they originate, in monsoon climates with an abundance of water. An ample supply of moisture will grow a good maple and keep the leaves in good condition until fall, when they will color up (to varying degrees and then drop). Good drainage is important, maples do not like wet feet. If the drainage is poor, it will be reflected in die back of top growth/branches, sometimes the entire tree will die from this. Any reasonably good, fertile soil will grow a good maple if it is well watered. Remember that wild maples in Japan are not coddled, they just simply grow in the sun (they may start out under some shade in the forests, but they eventually grow their canopies into more sunlight as they mature. True, there are some sun sensitive cvs. but for the most part, if you are growing maples, and you place them in full sun (remember that ample watering), they acclimate to the sun condition and grow very well. It is important to have containerized plants leaf out in full sun, that will toughen up the leaves to take any exposure of shade later. But, if you have your plant leaf out in shade, then move it to sun, it will burn. (those leaves are acclimated to shady exposures and burn in more sunshine)
Maples planted in the ground will adjust their leaves to the conditions of the site and be fine as they mature providing enough water is available at all times during the growing season. Their roots can grow far from the canopy, searching for moisture and fertility. They are also somewhat more drought tolerant in heat extremes of weather(hot spells) since their roots can go deeper to get that lower soil level moisture)
Fertilizing your maples is an easy task. They are not heavy feeders. Best to apply less than recommended quantities. Also important to water the plant BEFORE you apply fertilizer and AFTER that fertilizer is applied.
Soil is an important item to consider when growing these plants. It needs to be well drained (especially in winter, when high water tables can drown roots) and you are not aware of it until growth begins in spring and half your canopy is dead(dying in winter since the corresponding roots have drowned). Any well drained soil will grow a good maple, but soils with a higher quantity of soil amendments, compost, fir bark, humus, etc. provides the roots with the ultimate in soil conditions.
A mulch is also good, especially during summer, fall to conserve soil moisture.
Pruning is minimal, You can prune your plants if you wish, especially if you notice poor crotch angles, or dead wood. But pruning is not needed much while the young tree is growing. There are many cvs. which look like gangly teenagers until they mature ar around 20 ft. Pruning them back just delays them reaching their ultimate size. (best to select a cv which will fit the space/site) and then little to no pruning is needed. You just sit back, water, and enjoy your plants!
Watering the root area is important. You have to water ALL the roots when you water. If you irrigate overhead, do so when there is no sun on the plants (can cause leaf burn) Early morning is best so plants are dry when night arrives.
visit the nursery for more info or just to see many kinds of varieties. there are over 100 kinds here