How to Grow and Care for Blue Atlas Cedar

Blue Atlas cedar trees are unique, eye-catching needled evergreens with drooping, twisted branches, 1-inch blue needles, and small cones that grow upright on the branches in spring. Blue Atlas cedars are best grown in full or partial sun with well-drained, acidic soil and temperatures between USDA hardiness zones 6 to 9. This tree is easy to care for, has a slow-to-moderate growth rate (1 to 2 feet per year), and should be planted in spring or fall as a ball-and-burlap sapling.

Blue Atlas Cedar Care

• Plant blue Atlas cedar in an open area with plenty of space and no competing trees or shrubs.
• Choose a planting location that receives full to partial sunlight and has well-drained, acidic soil.
• Stake the blue Atlas cedar until it's established, or it may grow close to the ground. Remove stakes after one full growing season has passed (or continue staking to grow it in different shapes).
• Water consistently and deeply for the first year, then add water when the weather is especially hot and dry.
• Shelter young trees from exposure to strong winds.
• Fertilize with a balanced fertilizer in the spring, following label instructions.
• Prune the tree in early spring before the growing season, only cutting branches to maintain the shape. Never remove more than a third of the tree's total size.

Light

In order for the blue Atlas cedar to thrive, it's best planted in a spot in your lawn or landscape that receives at least six to eight hours of full sun a day. This tree can withstand more shade when planted in areas of the country with warmer weather, though it should never be planted in full shade.

Soil

The blue Atlas cedar does best in well-drained, somewhat acidic soil, though it will happily tolerate neutral and slightly alkaline soils. That this tree should be planted in a spot that boasts a deep and wide swath of soil—its roots run deep, and its branches are quite expansive, so it will need room to grow or its size will suffer. Blue Atlas cedar can thrive in a variety of soil mixtures, including loamy, sandy, or clay, provided the soil doesn't retain too much moisture.

Water

The blue Atlas cedar requires consistent and deep watering as its roots become established in your garden or landscape for at least the first year after planting. Once established, the tree is fairly drought tolerant, though it should still be watered with some frequency if the weather has been particularly hot or dry.

Temperature and Humidity

This is a tree suited only for the moderate conditions of USDA zones 6 to 9. Within this range, the blue Atlas cedar can handle a variety of temperature and humidity conditions. It's a good idea to shelter young trees from exposure to strong winds, which can bend or break their limbs.

Fertilizer

Though not a necessity for adequate growth, the blue Atlas cedar can benefit from the application of a balanced fertilizer at the beginning of its growth season each spring. Follow product package instructions to find the right amount.

Types of Blue Atlas Cedar

Blue Atlas cedars generally have decidedly bluish-gray needles and pyramidal shapes when young, but gradually transforming into a flat-topped tree with long, horizontal branches. There are a number of popular cultivars that offer some variety in color and shape:

• Cedrus atlantica 'Argentea': This variety has silvery-blue needles.
• Cedrus atlantica 'Aurea': An unusual variety, this tree features yellowish needles.
• Cedrus atlantica 'Fastigiata': This narrow, columnar-formed variety of the tree has bluish-green needles.
• Cedrus atlantica 'Glauca': This variety has a decidedly conical growth habit.
• Cedrus atlantica 'Glauca Pendula': This variety features drooping branches and blue-green needles.

To grow a similar tree in climates colder than zones 5 or 6, choose a variety of "false" cedars (Calocecrus, Thuja, and Chamaecyparis genera) like Chamaecyparis obtusa (Hinoki false cypress). This tree has a similar growth habit to Cedrus atlantica but is reliably hardy down to zone 4.

Pruning Blue Atlas Cedar

The blue Atlas cedar can be trained as it grows, and popular pruning shapes include cones, ovals, cylinders, or "weeping" shapes. In its natural growth habit, it is pyramidal in shape when young, but it develops a flat top with horizontal branches as it ages.

Though the blue Atlas cedar can be pruned slightly to keep it from encroaching on nearby sidewalks or garden plots, it is largely discouraged, as this can ruin the wild, eccentric natural shape of the tree.

Prune only to maintain or keep the shape of your blue Atlas cedar tree, and do so in early spring before new growth starts for the season. Be sure to keep at least a portion of the young growth on the tree, and never remove more than a third of the tree's overall density.

Propagating Blue Atlas Cedar

Blue Atlas cedar is difficult to propagate by vegetative means. Most gardeners grow new blue Atlas cedar trees by harvesting and growing seeds from the dried cones.

How to Grow Blue Atlas Cedar From Seed

Blue Atlas cedar trees can be grown from seed by collecting ripened cones from mature trees in the fall, then freezing them just until the scales begin to open up. Once your seeds are prepared, here's how to plant them:

1. Shake the cones over a sheet of paper to collect the seeds that fall out. Soak the seeds in water overnight before planting.
2. Plant the seeds 1/2 inch deep in a large, flat tray filled with a sandy seed starter mix.
3. Place the tray in a sheltered outdoor location; the seeds germinate most reliably if they receive a winter stratification period of roughly one month with temperatures under 50 degrees Fahrenheit.
4. Keep the potting mix moist, but not wet, until seedlings sprout. When the seedlings are large enough to handle, transplant them into individual pots filled with a blend of potting mix and sand.
5. Grow the potted seedlings in a protected location for their first two winters (such as in a cold frame).
6. Plant the seedling into the landscape in the spring after its second winter in the pot.

Potting and Repotting Blue Atlas Cedar

Blue Atlas cedar trees have a mature size that is far too large for growing in pots, so most gardeners do not plant them in containers. Young trees growing in containers can be transplanted into the ground outdoors after their second winter growing in the pot. Because these trees do not take well to being transplanted, it's best to choose a planting location where the tree can life for its entire lifespan.

Overwintering

Within its hardiness range, blue Atlas cedar does not require any cold protection for winter, but young, sparse trees may need protection against harsh winds, which can be provided with screens or tents made from burlap and stakes.

Young trees can also be susceptible to breakage from winter snow, so it's a good idea to shake off the snow after heavy snowfalls. Because they can be heavily browsed by deer, a tall cage or sturdy wire is a good idea to protect them from hungry deer in the winter for the first few years.

Common Pests & Plant Diseases

Luckily, the blue Atlas cedar tree is considered to be fairly pest and disease-free, so you won't have to do much to ensure its health and vitality. If it does come down with a pest, it's likely that it will be scale insects or sapsuckers that damage the tree in their search for insects. Still, it's unlikely that the pests will do serious damage to the tree, and therefore it's rare that pest control methods or treatments are necessary.

Tip blight is an occasional fungal disease caused by several different fungi (Sirococcus conigenus,  S. tsugae ,and Kabatina spp), which causes branches to die back beginning at the tips. Shake the branches to dislodge affected needles, and carefully rake up debris to remove fungal spores.

Tip blight normally runs its course in about a year, but spraying with a fungicide containing mancozeb, copper hydroxide, or azoxystrobin may help prevent infection. Fungicides are best applied as new growth is just beginning in the spring.

Common Problems With Blue Atlas Cedar

Planted in the right location and soil conditions, blue Atlas cedar is remarkably carefree. Many landscapers choose this tree for its easy-growing habits and typically low-maintenance care requirements. However, there are a few problems that you may encounter when growing blue Atlas cedar.

Sparse Growth

The most common complaint is that the trees are fairly sparse and messy-looking when they are young. This is entirely natural, so you should avoid the temptation to prune it in an effort to make it look more presentable. Left alone, it will become a much fuller, even picturesque tree within 20 years, and by 50 years of age it can be quite stunning.

Brown Branches or Needles

It's possible that your blue Atlas cedar may experience root rot if its soil is kept too moist. If you notice the branches or needles of your tree turning brown, step back your watering cadence to allow the roots to dry out a bit between waterings.