Plan to keep new trees well-watered, especially in the summer, and feed them annually. You likely won’t have to do much, if any, pruning on your tree unless there’s an unhealthy portion you need to take off. Just inspect it periodically for any signs of distress.
Light
This tree grows best in full sun, meaning at least six hours of direct sunlight on most days. But it also will tolerate partial shade.
Soil
Korean fir trees prefer rich soil with good drainage; they struggle in dense clay soil. They also like an acidic soil pH. The tree can tolerate a neutral pH but won’t thrive in alkaline conditions.
Water
These trees prefer consistent moisture in the soil, but they struggle in soil that remains too wet and soggy. So water your tree whenever the soil begins to dry out, but make sure no water is pooling around the tree. A layer of mulch around the tree can be helpful to retain adequate soil moisture and keep the roots cool.
Temperature and Humidity
Although Korean firs tolerate heat and humidity better than many other fir species, they still prefer a cool, temperate climate. They also can handle some wind but should be sheltered from strong drying winds.
Fertilizer
Feed young Korean fir trees annually in the early spring before new growth picks up, using an organic granular fertilizer. Mature trees should be fed with a diluted half-strength fetilizer unless you have poor soil.
Types of Korean Fir
There are several varieties of Korean fir trees, including:
Abies koreana ‘Aurea’: This variety is commonly known as the golden Korean fir, thanks to its bright golden needles in the spring that turn light green by winter. Abies koreana ‘Compact Dwarf’: This especially small variety only reaches around 5 feet tall and 3 feet wide.Abies koreana ‘Silberlocke’: The needles on this tree curl upward to expose more of their silver-white undersides.Abies koreana ‘Kohout Hexe’: This miniature variety grows only around a foot tall.Abies koreana ‘Silver Show’: This variety features very tightly curled needles that expose their silver undersides. Abies koreana ‘Prostrata: This variety is a low-growing, ground-hugging plant that is ideal as a woody groundcover plant.
Pruning
Korean fir trees don’t require much in the way of pruning. They typically form a symmetrical pyramid shape all on their own. However, you should prune off any dead, diseased, or broken branches as you spot them. And you can prune any unsightly branches as needed. But don’t cut back branches extensively and expect them to regrow. You’ll likely end up with some bare branch stubs where you cut.
Propagating Korean Fir
In commercial trade, Korean firs are normally propagated by grafting branches onto a rootstock of a different species. While firs can be rooted from branch cuttings, it is a very slow process that isn’t practical for commercial propagation. Grafting is not a process that most amateurs can do successfully, so the most practical approach is to propagate from seeds—a slow process but one that is relatively easy. Here’s how:
Potting and Repotting Korean Fir
Smaller cultivars of Korean fir can make excellent potted trees—they are especially popular as living Christmas trees. Choose a large pot—at least twice the width and depth of the root ball of your tree. The larger the pot, the less frequently you will need to repot. As a growing medium, a mixture of 1 part perlite or vermiculite with 2 parts compost works well. Or, an ordinary commercial potting soil is fine. You may be able to grow this slow-growing species for four or five years in the same pot before it becomes root-bound and needs to be repotted.
Overwintering
Provided your climate zone is appropriate, fir trees planted in the landscape require little extra winter protection. Winter burn is less likely for this tree than for other conifers. But it’s a good idea to make sure the tree is well watered in the weeks leading up to winter frost. In colder regions, a potted tree will have its roots quite exposed to winter temperatures, so take precautions to place the tree in a sheltered location and to wrap the sides and bottom of the pot with insulating material, such as bubble wrap. Don’t keep the potted tree on a paved surface, as stone or concrete surfaces will quickly conduct cold up to the tree’s roots. Some gardeners have good luck burying potted trees up to the top rim of the pot for the winter, or heaping dense compost around the pot to guard against temperature fluctuations.
Common Pests and Plant Diseases
These trees don’t have serious issues with pests or diseases, though they don’t do well in areas with high air pollution. They can be susceptible to certain insects, including aphids and adelgids. If these insects are present, the tree’s needles might turn yellow or drop off. Forcefully spraying the needles with water to dislodge the insects every other day or so is a natural way to get rid of them. You also can apply insecticidal soap or horticultural oil, though this can discolor foliage. It’s important to remove and replace any mulch around your tree each spring to prevent any dormant insect pests from returning and infesting the tree. A variety of fungal diseases are possible with Korean fir:
Root rot can occur with trees that are planted in dense, wet soil. Once severe root rot sets in, your tree probably won’t be salvageable.Needle rust begins with small white pustules on the lower surface of the needles, then causes the needles to turn yellow and fall off. Viewed from a distance, the tree will appear to gradually turn yellow. There is no effective treatment for fir needle rust, but because this fungus requires fern as a second host to complete its life cycle, removing ferns in the area often prevents the disease from returning.Twig blight causes branches to die back, beginning at the tips. Lower branches are usually affected first. Have the fungus diagnosed by a local arborist or university extension service, then apply the recommended fungicide. Keeping trees healthy will usually prevent this disease.
Common Problems With Korean Fir
In addition to the pest and disease issues common to this species, keep an eye out for these issues:
Needles Are Yellowish Rather than Green
If your tree seems to be more yellowish than is usual for Korean firs, it may be because the soil is too alkaline, which prevents the tree from properly absorbing soil nutrients. More frequent feeding with an acidifying fertilizer may help your tree, or you can try amending the soil with acidifying organic material, such as pine needles.
Branches Turn Brown in Spring
When the branches on your Korean pine turn brown in spring, at the very time you’re expecting fresh green growth, it usually means your tree has experienced winter burn from cold, dry, winter winds. This often occurs if you live in a borderline zone—the northern part of zone 5 or northward. Young trees can sometimes be protected with a loose tent or shelter made from burlap, but this is an unattractive solution; the better solution is to opt for a species more reliable for your climate.
When grown as a living Christmas tree, a Korean fir can be kept outdoors as a potted above-ground plant for the rest of the year. Or, you can grow it as a landscape tree that’s planted in the ground in its nursery container or another suitable plastic container, then dig it up when the time comes to move it indoors. For a week or so before you plan to move it indoors, shift the potted fir to a sheltered, somewhat warmer location, such as an enclosed garage or porch. The goal is to get the tree acclimated to the warmer temperatures it will experience indoors. Keep the tree well-watered during this time. Just before moving it indoors, spray the tree with an anti-desiccant, which will preserve moisture in the needles. As you move it indoors to decorate, avoid putting the tree in a location near heat ducts or other sources of heat. Keep the soil in the pot moist for the time spent indoors. Within a week of the holiday conclusion, move the tree back outdoors. If you plan to rebury the container, let the potted tree remain above ground for seven to 10 days before you replant it.
