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Preparing Your Trees for Winter

Cold Hardy Varieties

As winter temperatures will often go well below freezing it is necessary to ensure the root system is protected. Need to protect from the freezing-thawing cycle which could kill them and protect from drying winds and excessive sun.

  1. Remove dead leaves, needles, etc., from the soil surface.

  2. Check for insects, diseases and fungus; if found,spray with insecticide, fungicide, copperspray or soap mixture.

  3. If insects found in the soil; set pot in a water solution with insecticide added. (Ortho – Volck Oil, etc.)

  4. Check wiring, may need to remove some if necessary. If left on for the winter, you need to keep an eye on it in the spring as the tree starts to grow.

  5. Apply a light top dressing of bonemeal; this will provide nutrients for the spring.

  6. Wrap pantyhose around the pots to keep the bonsai soil and pot clean.

Location and Light Requirements

As the trees are in small pots and the roots are the main key to winter survival, selecting the right location in your garden with good protection from excessive damage, extreme freezing temperatures, sun and wind is important. The best location would be on the south side of your garden if possible, as it would not heat up too quickly in the spring.

Deciduous trees have no need for light once their leaves have dropped. There however are many differing views on the requirement for conifer species. The requirement of light in conifer species is temperature dependent; the rate of photosynthesis drops as the temperatures approach freezing. In conifers, exposure to direct sunlight during periods of sub-zero temperatures can cause damage, though this is repaired during the next growing season. A balance has to be struck, light is still required through the winter as photosynthesis still takes place but strong light or long period of direct sunlight should be avoided during periods where temperatures are below freezing. (as per Harry Harrington)

Burying your trees
  1. Water the trees thoroughly.

  2. Bury the trees just below the lowest branch. Bury them tightly together and place a burlap screen around the area. Thoroughly water the whole area after.

  3. Try to protect your trees from rodents, using mothballs, mice bait and I hear squirrels hate burlap.

  4. Check the origin of the tree; e.g. a tree grown in B.C. may not be hardy here. Make sure the tree is suited for your climate zone.

  5. Trees in a pot need more protection than trees grown in the ground. Some trees may need a cold frame, greenhouse or storage in a shed.

Indoor Trees

All indoor bonsai must be taken inside before the first frost. These will be grown under lights unless they require a dormancy period, in which case they will be kept in a cool room with good lighting. All others will require a minimum of 15 – 18 hours of fluorescent light of at least 40 watts per tube, and preferably one tube to be grow-lux or equivalent.

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