The slow growing Bald Cypress, native to hot, moist marsh sites of the southern US, is a very popular tree for bonsai with its beautiful bark and green airy growth. It can be cultivated in a wide range of soils from boggy marsh sites to well-drained areas where it would not grow naturally. This low maintenance, moisture loving tree is excellent for the bonsai beginner as it is so easy to grow. Bald Cypress bonsai are frequently planted in groups in a single container, forming a "Bonsai forest." Or “grove”.
Presented as a grove of several individual trees, the bald cypress’s delicate, lime-green foliage beautifully contrasts its cherry-colored bark. Its branching has an open, airy quality that’s particularly appealing during hot summer months. It is loved as a bonsai for the unique quality of its light, feathery foliage and orange-brown fall color. When grown in boggy, swampy conditions, the trunk has a wonderful tendency to develop thick “knees” making it an interesting addition to any garden.
The Bald Cypress requires a consistent climate with hot summers for ideal growth; when planted in areas with cooler summers, growth is healthy but much slower. As a deciduous tree, this bonsai is healthiest when kept outdoors year round. Adequate protection from winter weather is essential; be sure to insulate the roots of your bonsai with an ample covering of leaves and needles and give it shelter from wind and extreme cold temperatures. The use of a cold frame or shed would be beneficial during dormancy.
This bonsai thrives in full sun, and because of this, special attention must also be paid to its mutual desire to be in moist conditions. If it is desirable to bring your Bald Cypress grove indoors, it should only be for very limited periods in a bright southern facing location that receives ample sunlight, and not during its natural dormancy period.
The rot resistant Bald Cypress Bonsai thrives in a very wet almost swampy soil making it a perfect plant for people who enjoy watering. Too much water for other plants will be the Bald Cypress’s heaven! Water the bonsai from overhead to simulate rain falling from above, and fill the pot almost to the rim with water. During the summer months, especially if kept outside— which is preferred for this type of bonsai— you may have to water your bonsai twice a day or keep the pot submerged almost to the rim during the summer months; this method allows greater freedom for travel and mimics the natural environment in which this type of tree thrives.
You will want to fertilize your Bald Cypress Bonsai once a week during the springtime, tapering off to once every two weeks during the late spring through fall. Stop fertilizing in late fall to early winter, so your tree can go dormant until next spring.
Pruning / Training:
You will want to allow the trunk to develop well before pruning in order to prevent a straggly look. Bald Cypress naturally grow fast in the ground in their first years when grown in warm climates because they are usually found in a swamp, and must grow out of the water quickly before succumbing to the elements. To get good knees on your bonsai, you will have to grow the plant in wet swampy soil which can be achieved by planting in an un-drained deep swampy bonsai pot. Allow the tree ample time to grow and develop thickness of the trunk before cutting back. Because Bald Cypress are fast growing trees it is important to understand that wires will damage the bark if they are not watched closely. Branches can be tied town using a soft raffia twine, tied near the end of the branch to be pulled down, tying the other end to the base of the tree trunk, or to something else. If the branch to be pulled down is thick, you can make a V-shaped incision at the underside of the limb where it joins the trunk. This incision will close when the branch is pulled down, and the wound will heal quickly. You can shape the foliage by pinching back new growth. Let a branch grow for a season if you want to thicken it, then cut it back the following spring. New growth will sprout at the site of your most recent pruning. Twigs sprout at sharp, acute angles, so it is not difficult to develop a gnarled-looking branch. You will want to prune throughout the summer, leaving the task of shaping in the fall just before dormancy. Pluck off leaves that sprout from the trunk unless you want them to develop into a branch. A hallmark quality of the Bald Cypress is the “knees” of the mature tree. They are easily developed by going up to 3 years without repotting or root pruning promoting a root bound situation wherein many of the roots will have bent almost double. If you carefully bring one of these doubled bends to the surface and let it protrude through the moss cover, you will be forming a knee which should thicken and develop well over subsequent years. The bald cypress lends itself to formal upright, informal upright, slanting, literati, twin-trunk and group styles.
Insects / Pests:
The bald cypress is quite hearty and is very resistant to insect attack. It can sometimes develop Twig blight which is caused by a weak pathogen usually present on dead or dying plant tissue. When the tree is stressed the fungus can kill branch tips. In order to prevent this, dead tips should be pruned and do not allow dead or diseased branches remain on the tree.
Air-layering is the most successful way to propagate the Bald Cypress and can be accomplished in late spring. To air layer, cut a small strip of bark away from the desired branch. Wrap the cut area with a small bag filled with moist sphagnum and peat- keep uniformly moist and wait about 6-12 weeks, at which time roots should begin to grow. Take the cutting once it has enough roots to live on its own in a new pot cutting just below the root ball and transplant into a container. Keep the peat/sphagnum mix around the roots when potting and enjoy your new bonsai.
Potting and root pruning should be done in spring, just as little green nubs are showing up on the branches and trunk. If the tree is kept in standing water root pruning is advised every year -- every 2 years at least. A heavy soil is best such as compact mushroom compost. If the tree is not kept in water, a heavy soil is essential since it needs to retain as much moisture as possible. Do not worry about rotting the roots of a cypress…it cannot be done.
Since bald cypress' preferred habitat is low, swampy terrain, smooth surfaces are recommended for pots that are kept in water, since it is easier to clean the pot when you bring the tree inside for a brief display.
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