Blue Atlas Cedar Bonsai
Blue atlas cedar—Cedrus atlantica 'glauca'—offers some of the most spectacular foliage colors in all the bonsai practice.
Its stunning baby blue color gives it significant ornamental and visual appeal.
But color isn't the only characteristic that lends merit to blue atlas cedar bonsai. The tree’s…
● Rugged, ancient, decrepit bark
● Natural mounding
● Dense clumping
● Subtleties to branching shape, structure, and movement; and
● Significant nebari
… are all characteristics that make this species such an incredibly special bonsai subject to execute the larger impression of nature in miniature.
Caring for Blue Atlas Cedar Bonsai
Blue atlas cedar bonsai is a thirsty species and requires a perfect balance of water and oxygen.
While we want to allow blue atlas cedar bonsai to dry out between waterings, it's important to understand the tree will be using more water, and therefore will be drying out faster than many of its more rugged counterparts.
This is largely due to the fact that blue atlas cedar bonsai is an elongated species with highly transformational foliar mass, and the large amount of water it consumes creates superiorly strong, aggressive vascular tissue production in the fall.
Blue atlas cedar bonsai can tolerate both hot and cold temperatures.
When it comes to heat, the trees can tolerate well over 100° F. If the temperature rises beyond that threshold, it is wise to protect them from the intense afternoon sun. If days are consistently over 100° F, you may want to put your tree under a 20-30% shade cloth.
Blue atlas cedar bonsai are also very tolerant to cold, and the more shallow the container, the more susceptible the tree is to cold temperatures.
Trees cultivated in a shallow container should not sit out in temperatures below 20° F. If the tree is cultivated in a deeper container, it can tolerate temperatures down to 15-20° F.
Blue atlas cedar bonsai prefer full sun.
Excluding the hottest, driest growing regions in the peak of summer, giving blue atlas cedar bonsai a slight degree of protection from the most intense afternoon sun will help maintain the depth of its blue color.
When blue atlas cedar is exposed to an overabundance of sun, its color can wash out, causing the foliage to turn somewhat chartreuse. However, this washing out of color is in no way detrimental to the health of the tree.
Since the trees have very little soil to draw nutrients from, proper blue atlas cedar bonsai care includes periodic fertilization to replenish the tree's nutrients.
Any multipurpose liquid fertilizer can be used for this purpose. You will need to dilute the mixture by 50% with water before applying every two weeks.
In the springtime, blue atlas cedar bonsai’s buds begin to swell and accumulate massive amounts of sugars and starches.
This is the best time to:
● Perform structural reduction of heavy branching
● Prune back finer pieces
● Reset strength; and
● Redistribute shape
Throughout the spring, blue atlas cedar bonsai may be pruned at will—provided the tree is strong and healthy.
Post-flush harden pruning may be done in late spring-early summer through mid-to-late summer. This is the window of time to perform refinement pruning, removing overly elongated tips to direct energy back to the interior.
Blue atlas cedar will push continuously and has the capacity to respond to pruning multiple times over the course of the growing season.
Styling of blue atlas cedar bonsai may be done in spring as well as in the early fall, but a heavy reduction of foliar mass on the trees should be performed only in the early spring.
Since the trees are an elongating species that produce heavy amounts of vascular tissue throughout the fall, heavy reduction in early fall leaves the trees depleted of energy and tends to delay growth.
As a general practice, fall pruning of blue atlas cedar should be avoided.
Blue atlas cedar bonsai are root-sensitive trees, which means you have a very specific window of time for repotting.
The tree should be actively opening its buds and beginning to elongate before beginning the repotting process.
Once these markers take place, you have a 7-day window to reduce the tree’s root mass. To successfully create a bonsai root system, new growth needs to be evident, and temperatures need to be relatively warm.
Attempting to repot a blue atlas cedar bonsai any time before or after the 7-day window will cause problems with the root's ability to transport water to the foliage.
The blue atlas cedar bonsai is a thirsty tree and will grow well in either:
● A 1-1-1 mix of pumice, lava, and akadama; or
● A 2-1-1 mix of akadama, pumice, and lava
Since it is a coniferous species that needs to dry out between waterings, it’s best to use ⅛ to ¼ in (3 mm-6 mm) for interior particle size.
Sirococcus is a disease that affects blue atlas cedar being cultivated in wetter regions of the world.
A fungal blight, sirococcus causes the blue foliage to turn pink and can defoliate an entire tree. If this takes place, the tree will usually recover, but you will need to adjust the balance of water and oxygen at the roots.
An appropriate fungicide may be applied as a preventative on a tree that has suffered partial or full defoliation for multiple years in a row. This can empower the tree to hold its foliage and gain some strength to further fend off sirococcus the following season
Spider mites in the foliar mass are the major insect to be aware of on the blue atlas cedar bonsai. The trees tend to be more susceptible to spider mite infestation in drier regions with low relative humidity.
The young, flexible branches of blue atlas cedar bonsai are easily wired. However, wiring must be done carefully to ensure it doesn’t damage the smooth, sensitive bark.
Older branches are best trained with guy wires as opposed to direct wiring.
Annealed copper wire or anodized aluminum wire are the best choices for training your