Caring for a cypress bonsai can depend on the particular species of tree that is chosen, as there are more than 100 different strains of cypress available for training as bonsai. Popular versions of cypress bonsai include the Lawson — Chamaecyparis lawsoniana, the Japanese Hinoki — Chamaecyparis obtuse, and the Japanese Sawara — Chamaecyparis pisifera. Another common type of cypress bonsai that is recommended for beginners, though not a true cypress species, is the Bald or Swamp cypress — Taxodium distichum. Caring for cypress trees can therefore vary, as some prefer dry climate conditions like the Japanese Hinoki, and some are native to swamp regions and prefer a consistently wet environment like the Bald cypress. As a general rule, however, cypress trees are easy to grow as bonsai, so they have become a very popular choice as of 2011, and are trees that prefer full sunlight and regular fertilization.
Most types of cypress trees are relatively hardy, so they make good bonsai specimens, as adapting a tree to a bonsai lifestyle can be a stressful process for the tree. In terms of watering frequency, the Hinoki cypress is the species that requires the driest of conditions. The soil for the Hinoki should be damp most of the time, but it is a drought-tolerant species that can survive colder and drier conditions than other cypress bonsai. Along this spectrum, the Sawara cypress requires more water, as it is native to damp areas, and the Bald cypress requires an almost constant condition of wet soil as it is native to swamps. Sawara and Bald cypress trees can also die if exposed to cold conditions and need to be wintered over in greenhouses.
Bonsai in general can be prone to more frequent attacks by pests and diseases than their counterparts in the wild due to the confined conditions in which they are cultivated. While the Hinoki tree is fairly resistant to pests and diseases, the Sawara and Bald cypresses are often attacked by root aphids, and have delicate branches that should be pruned by pinching with fingers instead of cutting to prevent undue damage to the trees. The Lawson cypress, which is one of the most popular strains of cypress bonsai grown, also requires constantly-moist soil like the Sawara, but not water-logged conditions that the Bald cypress tends to enjoy. One of the growing conditions that is common to all popular cypress bonsai is that they all prefer full sunlight, which often means that the bonsai containers themselves are best maintained outdoors.
The Bald cypress gets its name from the fact that it is a uniquely deciduous conifer tree that loses its needle-resembling leaves in the winter time. The foliage will first turn orange and then brown, which, in other cypress bonsai, would indicate that the tree is dying. In the Bald cypress, this is a natural autumn event. Determining the proper water level for the Bald cypress can also be done by watching for drooping effects on new foliage, which indicates that it needs more water.
Planting cypress bonsai is also recommended to be repeated every two to three years for all species, though some grow faster than others. The Hinoki tends to grow the slowest, so it can be repotted less frequently than varieties like the Sawara. The Bald cypress grows the quickest and can be repotted safely every year. Because the bark of cypress bonsai can be delicate, care also has to be taken with wiring the trees to grow to particular shapes. As the wire gets tight, it should be removed and replaced with looser windings or none at all.