When people think of Japanese maples they usually think of Acer palmatum. There are over 150 cultivars varying in height, spread, bark-color and, most strikingly, foliage. There are red-leaved, green leaved and variegated cultivars. Some have finely, dissected leaves while others have wide, palmate leaves. Most have stunning fall color.
The cultivar names of some Japanese maples can seem incredibly complicated unless you are fluent in Japanese. Fortunately, some have both Japanese and English names. Many have been hybridized (bred) in Japan, while a number of fine selections have been hybridized here in the United States.
Japanese maples are understory trees and do best with some afternoon shade. Many can withstand sunny conditions, but their leaves get scorched if it gets too hot. This will not harm the tree, it will just look unsightly. They need some sun to produce their best leaf color. Japanese maples do well in slightly acid soil, with good drainage and organic mater. In colder climates, it is important to apply a few inches of mulch evenly around the base or rooting zone of the tree (but not touching or piled around the trunk) to help moderate soil temperatures.
Some of the low-growing, dissected-leaved varieties benefit from staking when they are young so that a trunk can form, otherwise they will sprawl on the ground. You can lightly prune your Japanese maple at almost any time of the year. For a heavier pruning, late spring (June) after the tree has leafed out, before the leaves drop in fall, or around Thanksgiving, immediately after the leaves drop, is a good time to shape your tree. Prune to accentuate its natural shape or to clean out inside growth that detracts from its form.
Some popular, upright cultivars are 'Bloodgood', with deep red foliage all summer and bright red samaras (seedpods); 'Butterfly', with foliage tinged with pink in spring and summer; and coral bark maple (Acer palmatum 'Sango-kaku'), with striking, orange-red bark.
Some favorite spreading cultivars are 'Viridis', a mounding, dissected-leaved variety whose green foliage turns a golden-scarlet in the fall; 'Red Filigree Lace', one of the finest red-leaved, mounding cultivars; and 'Garnet', a mounding tree that has a rich, red leaves with orange overtones. One unusual cultivar is 'Seiryu'; while most laced-leaved or dissected maples (Acer palmatum var. dissectum) have a mounding or weeping habit, this one grows upright into a small tree.
Bamboos: Please proceed with caution!
Bamboos are woody-stemmed members of the grass family. There are 70 genera and over 2400 species. Bamboos are fairly adaptable in either sandy or clay soil. Some types thrive in shade to part-shade while others need the sun. Many are edible; the sweetshoot bamboo (Phyllostachys dulcis) is most commonly used for its sweet, nutty flavor.
There are two types of bamboo; "clumping" and "running". The clumping varieties are non-invasive. New shoots form on the sides of the parent plant to create a nicely formed clump. Clumping bamboos tend to be hardy, (generally to Zone 5) and usually require some shade and protection from winds to remain evergreen through the winter. If they are placed in the hot, midday sun, their leaves often curl and brown. The most popular clumping bamboos are in the genus Fargesia. The hardy dragon bamboo (Fargesia dracocephala) grows to about 7 feet tall. It has a weeping habit and forms a dense clump that is good for screening. Fargesia rufa 'Green Panda' TM is another clumping bamboo that grows 8 feet tall and makes a nice screen. The umbrella bamboo (Fargesia murieliae) is a taller species that has a nice green-blue tint to its culms (stems).
Running bamboos have rhizomes that spread underground. Depending on the species and the conditions, many can be fast growing and fairly aggressive. They need some kind of a barrier to contain them. These running bamboos come in three different sizes.
The giant bamboos such as Phyllostachys range from 10 to 100 feet tall (not in this country). They are happiest with full sun to part shade. Medium bamboos, such as Sasa, range from 4 to 15 feet tall and prefer part shade. The 1 to 4 foot tall, ground-cover bamboos, such as Pleioblastus, tend to prefer full sun to part shade. Many of the smaller bamboos are aggressive growers and tend to be invasive unless contained by a barrier. One exception, Shibataea kumasaca, is a 3-foot evergreen bamboo that spreads slowly.
Two varieties of the taller, running bamboos to look for are the black bamboo (Phyllostachys nigra), which grows to 12 feet with black culms that color up in the second year of growth, and the yellow, groove bamboo (Phyllostachys aureosulcata), which grows to a 2 foot tall, evergreen bamboo that is very popular in traditional Japanese gardens.
Many bamboos thrive in containers and make nice specimen plants on a patio or even indoors. For bamboo on rooftop gardens, the specimen will need a container that is at least 2-by-2 feet to anchor the plant. The plants can be sprayed with anti desiccants to keep them green in the winter and the container can be wrapped for extra insulation. Two good candidates for indoor are the golden variegated bamboo (Hibanobambusa tranquillans 'Shiroshima') and the tropical Bambusa multiplex.
For planting bamboo into the ground, dig a hole that is twice the width and one-and-a-half times the depth of the bamboo's pot. Amend the soil with compost or aged, cow manure. Water consistently during the first year; generally once a week is sufficient. Once the plant is established, you can fertilize in the early spring with a high nitrogen fertilizer (e.g., 10-6-4). Protect the plant with several inches of mulch in the winter.
Bamboos can be contained by planting them near a wall or concrete edge. A metal or synthetic barrier (polyethylene or fiberglass) can be placed in the ground. It has to be at least 2 to 3 feet deep with the barrier extending 3 inches above soil grade to be effective. Depending on the product and how secure the barrier is fastened together, the overlap should be between 6 and 24 inches. The general thickness used is between 40 and 80 mils, depending on the bamboo and the climate (warmer climates have higher growth rates).
One expert has suggested a nice method for creating a clumping bamboo feature in the garden: take a 40-gallon garbage barrel. Cut out the bottom of the barrel, leaving a 1-inch lip. Add two layers of coarse, plastic, window screens to cover the bottom and sink the homemade container in the ground so that it rests 3 inches above soil level. However you choose to do it, keeping your bamboo contained is a good idea and will spare you of the headache of trying to remove it once it had gone astray (and it will).