Select a small weeping blue atlas cedar. Consider shopping at a nursery specializing in trees to find a wider variety of shapes and sizes. Check the tree's limbs for pliability because training a weeping blue atlas cedar requires gradually bending the tree into the desired shape without breaking its trunk or limbs.
Locate your weeping blue atlas cedar outdoors in an area providing full sun. Use garden or potting soil suitable for trees. Make sure that the soil you use will drain properly, or your tree will not thrive. If you are training your weeping blue atlas cedar to spread over a trellis, ensure that the structure will bear the weight of the tree when it's fully grown. Weeping blue atlas cedars can achieve a height and width of 15 to 20 feet, depending on how they're trained. Thus, ensure the tree will have enough room when it is mature and in the desired shape. weeping blue atlas cedars are slow growing trees, and achieving the full effect of shape you desire along with significant stature can take several decades.
Situate a stake next to the trunk of your weeping blue atlas cedar. Use bungee cords or garden ties to securely wrap the parts of the tree you're training into the desired positions against the stake next to the tree's trunk. Don't wrap too tightly or cut into the tree's bark. Focus on the tree's tension when bending it; bending too far can cause breakage.
Inspect your tree once a week. Check its moisture level, and inspect the wrapping material to ensure that it's secure and not damaging your tree. Adjust the ties against the stake or other training framework as necessary to encourage your tree to grow in the desired manner.
Use pruning shears or concave clippers to remove unwanted branches from your weeping blue atlas cedar, but avoid overpruning, which can shock the tree and ruin its naturally draping appearance. Prune the tree so that it has a leading trunk; remove any suckers or branches growing vertically and upward from the trunk. Establish one or more horizontal branches, and tie them to a horizontal support to promote a right angle or "T" shape. You can also train a weeping blue atlas cedar to spiral around a central stake. Bend the tree around a central stake, and tie it in several places to maintain the spiraling around the stake. Replace the ties and stake as necessary during the training process.