This slow-growing tree begins with a pyramidal shape, but over the years it branches out into a rounded shape. Kobus is a trouble-free magnolia that has many landscape applications. This tree likes to form multiple trunks. If you prefer the look of a more traditional single-trunked tree, choose a central leader when it is young and train it to be the main trunk.
Light
Plant this tree in full sun or part shade.
Soil
Kobus magnolia prefers moist but well-draining soil, and it does best in neutral to slightly acid conditions.
Water
Kobus magnolia does well with average watering patterns—about 1 inch per week, through a combination of irrigation and rainfall.
Temperature and Humidity
This tree does fairly well in all conditions found in its hardiness range, provided it gets proper water and is grown in well-drained soil. It has moderate tolerance for drought. Late cold spells can damage flower buds in spring, but this does not permanently damage the tree.
Fertilizer
Magnolias can benefit from light fertilizing in spring in the early years of growth. A cup of granular balanced fertilizer applied around the base of the plant in the first three years is recommended, but after this, it is best to avoid fertilizers altogether.
Propagating Kobus Magnolia
You can propagate this magnolia species by germinating the seeds or rooting cuttings. If you are using seeds, they will need to go through stratification (a period of cold storage) before planting. Trees grown from seed will also take longer to start blooming. To propagate from cuttings:
Varieties of Kobus Magnolia
There are two natural varieties of Magnolia kobus, according to some botanists: var. kobus and var. borealis. Some also believe the star magnolia (Magnolia stellata) is a variety of this species, making it var. stellata. An interesting cultivar is ‘Wada’s Memory’. It is sometimes listed as Magnolia salicifolia ‘Wada’s Memory’ or as a hybrid of the two species (named Magnolia x kewensis). It is columnar to pyramidal in form, with large blossoms and blackish-green leaves. M. Kobus has also been crossbred with the star magnolia (Magnolia stellata) and the resulting hybrid is the Loebner magnolia (Magnolia x loebneri).
Comparison With Star Magnolia
Kobus magnolia is very similar to star magnolia (Magnolia stellata) except it is a larger tree. Star magnolia typically grows to only about 15 to 20 feet.
Pruning
Pruning is not usually with Kobus magnolia, although it may be required to remove branches that droop over walkways or driveways, or to remove damaged or diseased branches. Any pruning should be done in the middle of summer once the blossoms have ended and the leaves have appeared.
Landscape Uses
You can use this as a specimen tree to provide early spring interest because it blooms before many other plants do. This is a good magnolia species for those who live in cooler climates. On large properties, it can be used as a tall informal hedge, and it also makes a good tree for woodland borders.
Common Pests/Diseases
Fortunately, there are few problems associated with the Kobus magnolia. Scales may appear, bringing with them honeydew and the possibility of sooty mold. If they do, treat with horticultural oil. The most common problem is damage to flower buds due to cold. This is most common when southern exposures cause the flowers to emerge too early.
