My Black Dragon Japanese Cedar has a lot of dead branches. The tree is healthy otherwise. A foot of new growth this year. The nursery told me this was normal. Can you give me an opinion?
Apparently, dieback is often seen on Cryptomeria, as the following
information from North Carolina State University Cooperative Extension, no longer available online, suggests:
Cryptomeria can have leaf blight or spot. Branch dieback is common.
Dieback has not been associated with a disease but has been touted as the
nature of the tree. Pathologists are still researching this. There may be
some tip dieback associated with a disease.
There is another discussion of a Cryptomeria with dead branches on
University of British Columbia Botanical Garden’s forum which mentions
rust and needle blight (both fungal diseases) as possible causes.
You may want to bring samples of the affected branches (along with your
photo) to a Master Gardener Clinic for diagnosis.
You may find this University of British Columbia Botanical Gardens Forum discussion of interest.
The growth rate of a foot a year makes sense, considering that this is
not a large tree. See below what Great Plant Picks, a Seattle-based website, has to say about this tree. An earlier version of the page linked here, from Iseli Nursery, indicates a growth rate of only 3-6 inches a year.
Information from Iseli Nursery: Cryptomeria japonica ‘Black Dragon’ (Japanese cedar )
Cryptomeria japonica is one of the most variable conifers you can imagine, with plants ranging from very dwarf rounded shrubs, trees with golden or contorted leaves, and wild forest trees to 80 feet high and 20 feet wide. ‘Black Dragon’ takes the middle road,
neither too small nor too big. It has the deep green, needle-like leaves characteristic of this species and grows to about 7 feet high and 8 feet wide in twenty years. This very dark-foliaged conifer is easy to grow and combines well with plants having larger or variegated leaves.
Japanese cedars thrive in full or part sun in well-drained, humus-rich, acidic soil and average moisture. May grow quickly when it first comes home from the nursery, due to the added fertilizer it gets there, but within a year it will settle into its dense, compact habit of growth.
Cryptomeria japonica ‘Black Dragon’ is an evergreen, coniferous shrub. It grows wider than high, with an overall pyramidal shape. In 20 years it will reach only 7 feet high and about 8 feet wide.
Hardiness: USDA zones 6 to 9