Bonsai Chrysanthemum on a Rock Style:
Develops into a bonsai from a nursery-bought "Mum' in one yearThis is one of the oldest styles of bonsai. It is a rewarding one because it develops into a bonsai from a nursery-bought "Mum' in one year. It is best started in the spring. First, find a rock that has a vertical shape and some hollows or cracks in it, about four inches or so in diameter and six to eight inches high. Set the rock in a shallow tray or bonsai pot, filled with sandy soil. Choose a plant with small, tidy blossoms, not the large, shaggy ones, in a four inch pot size. Remove most of the soil from the roots and spread them downwards following the contours of the rock. Roots would normally follow the hollows or cracks in the rock.
Next, the rock and roots must be covered with a waterproof material. A plastic bottle, such as a pop bottle, with the bottom removed and the top cut to the line where the body of the bottle starts, or flexible heavy plastic, are suitable. Slide the bottle down over the rock and roots, or the material wrapped around them with room between the roots and the material. Sift a good quality soil down into the space between the covering and the roots, to the normal ground level of the plant. Keep this soil consistently damp. After about two months, the plastic is removed from the top a little at a time, revealing exposed roots. As the roots grow downward, the uppermost roots do not need to be in soil. The roots that supply the plant with moisture and nutrients are the newest fine hair roots. Eventually, the roots will reach the soil in the container, and the soil must be watered and fertilizer added periodically.
Chrysanthemums bloom in the fall, when the days become shorter, so keep your plant in a window where it doesn't get artificial light after sunset. It should bloom for some time, but eventually the blossoms will fade and no new ones appear. At that time, cut the stems back and keep it in a cool, bright place for the winter. It needs no fertilizer but keep the soil slightly damp. As the days become longer in the spring, new growth will appear and the plant can be gradually trained as a bonsai, with a lower branch following the contour of the rock. Often, a semi-cascade style is used. Each year, this can be repeated, and the stem becomes thicker and sturdier, giving an appearance of old age.