A small leaved, indoor, flowering and fruit bearing bush given to profuse branching, tough enough to withstand most beginners errors, C. piculata and C. microphyla THYMOFOLIA come close to being the ideal bonsai, especially for those new to the art. We prize these two species because their branch structure lends itself so well to bonsai. Other Cotoneaster species that make nice yard plants are altogether too regular for bonsai; they look like fish bones.
We recommend that Cotoneasters be brought indoors during the cold weather. Cotoneaster in the ground is hardy at cold temperatures, but in bonsai containers or growing pots these plants are more tender. Extended cold temperatures below 20 degrees F, a few years ago left us with many dead Cotoneasters in our can field.
Cotoneasters can be kept indoors all year, if they are exposed to bright indirect light, are surrounded by moving air and misted daily.
WORK ON COTONEASTER any time of the year. Transplant them when the leaves of daffodils start to show above the ground. If you don't mist1 newly potted bonsai transplants before they blossom, certainly no later than July.
Cotoneasters normally bloom in May (here in mild western Washington), but the following treatment can force a second blossoming around Christmas:
WINTER FORCING COTONEASTERS:
Leave your Cotoneasters out until well after the first frost. Then bring them into a bright, well aerated place. (An east window in an average size room would be O.K.) Prune small branches back, keeping the general shape of your tree. Fertilize one time in November with 0-10-10 (Bloom). New leaves will grow and flowers buds will set at the tips of the new growth.
Flowers will show anytime between Thanksgiving and Christmas. This works most of the time. We really don't understand which variables control the appearance of blossoms, but they probably include the cold temperature, the length of time they are exposed outdoors, the temperature and the light indoors.
FERTILIZING: "Grow Sticks" are good and simple. Break one in half and put the halves into the two corners of the pot. When those two have almost dissolved, break one more and put the halves in the other two corners. That should last a season. Use Bloom, 0-10-10 ,6-8 weeks before blossoms form. Also use this fertilizer one time in the fall to harden roots.
If you would prefer, use any fertilizer that you use on your house plants diluted about four fold (1:4) each time you water.
PRUNING: Prune every month by removing unwanted new growth; they grow like gangbusters. Prune larger branches once, before new growth begins.
SHAPING RECOMENDATION : Cotoneasters are the ultimate Shohin; Style them to be heavy trunked, but small. They are showy (flowers and berries), active (things happen: flowers, berries identifiable new growth, rapid growth, complex branching.)
CAUTION: Cotoneaster roots are very sensitive to disturbance between August and their Spring gowth period, say March.
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