Each spring these plants produce an abundance of small white flowers, followed by a heavy crop of red berries in the fall. The display of berries is what makes Pyracantha especially attractive as a candidate for bonsai.
Pyracantha has been in cultivation for a very long time, and as a result, there are many named selections available. Also P. coccinea has been hybridized with the other species and, again, many named varieties are available. The available varieties of Pyracantha differ in size of leaf, plant growth, and berry color. There are lots of varieties to choose from.
Another species in cultivation is P. angustifolia, native to western China. It differs from P. coccinea by having yellow berries and slightly fuzzy leaves. This form seems not to be readily available from local nurseries, perhaps because it is a bit sensitive to cold. It is hardy only to freezing, and not to below freezing temperatures. The yellow berries make it worth seeking out from nursery stocks.
The most obvious thing that you see (or feel) with Pyracantha is that they have formidable thorns. You can make life with Pyracantha more pleasant by cutting the tips of the thorns to remove the sharp points. Do not totally remove the thorns because at the base of each thorns is a flowering bud.
Pyracanthas are lush growers and as a result, can be aggressively pruned in the summer and fall by cutting branches back to one or two nodes. Some growers remove all flower buds every other year to allow the tree to direct energy only on the growth of the trunk and branches. Pyracanthas can be wired, but require care and a gentle hand. Young branches can be moved but are brittle, so care is required to prevent breakage. Older branches quickly become quite stiff and can be moved only with difficulty. Because of the lush growth of Pyracanthas it is no surprise that they can be defoliated without fear in June to increase ramification. The trees respond well to high nitrogen fertilizer applied in the spring and summer. Cuttings taken in late spring or early summer root readily.
A major issue with Pyracanthas as bonsai is that they resent disturbance and should be repotted every other year, or better, every three or even four years. Trees show their sentiments about being repotted by usually having a sparse crop of berries in the year that they are repotted. The plants expend a huge amount of energy producing berries, and some growers remove the flowers on recently repotted plants to allow the tree to recover. The minimal crop of berries that the plant produces after repotting indicates that the tree can adjust to the trauma of repotting on its own.
As a side note, the literature on Pyracanthas allege that the berries are bitter when eaten out of hand, but when cooked can produce delicious jams and jetties. An additional culinary delight comes late in the season when the berries can become slightly fermented as they age. Birds, particularly robins, adore Pyracantha berries and, at this time, can show all the symptoms of being three sheets to the wind after eating them.
So, there you have it. Pyracanthas as bonsai are well worth your interest. Between flowers and berries they produce a spectacular display through the year and, with a little care, are not that hard to grow.