In the 1800's numerous tree
species from all over the world were planted in an arboretums on the Leighton Hall estate in England. In 1888 several unusual seedlings were noticed at Leighton Hall, apparently from a rare intergeneric cross between an
Alaska-Cedar mother tree and a nearby Monterey Cypress. Both parent trees are native to the North-American Pacific coast. The new hybrid was called a cypress since the Alaska-Cedar is a "false cypress" and the Monterey
Cypress is a "true cypress". Neither are related to our southern cypress (baldcypress).
There are at least seven, and probably more, clones or "cultivars" (cultivated varieties) of Leyland cypress in
existence, each from a different cross between the parent species. The cultivar planted almost exclusively for Christmas Trees in the southern United States to date is `Leighton Green'; however, other cultivars such as
`Castlewellan' and `Silver Dust' show promise for those customers preferring something different.
Leyland cypress has been planted in South since about 1965, but it was only considered for use as a Christmas Tree after Clemson
University began studying it about 15 years ago. The production of Leylands for Christmas Trees has since spread from South Carolina to other parts of the South.
Leyland cypress Compared to Virginia pine
Why
all the fuss about Leyland cypress, and how does it compare to Virginia pine as a Christmas Tree? The short answer is that Leyland grows faster, requires less maintenance and produces a far greater proportion of quality, salable
trees than does Virginia pine. More detailed answers will be discussed below.
Survival
Leyland cypress
survival varies widely depending on field conditions and the quality and handling of planting stock. However, if healthy plants are properly planted in a well-prepared field, it's not uncommon to obtain survival rates in excess of
95%.
Insect and Disease Control
One of the most significant advantages offered by Leyland cypress is its resistance to almost all insects and diseases (a likely result of the phenomenon of "hybrid
vigor"). The only significant insect problem seems to be rare infestations of bagworm, and the only major disease is cypress canker.
In seven years of growing Leylands we have had no
insect damage of any kind with virtually no insect or disease control. We have had three or four smaller trees die from what may have been cypress canker, but this has not become a significant problem. Cypress canker is caused by a fungus which infects the tree through wounds in the bark. It produces bleeding of sap and may kill limbs and even the entire tree.
Chemical Requirements
Of lessor note it has been observed that under older
Leylands (two years plus) there is slower regrowth of weeds. The reason for this is not known, but it appears to be the result of some type of natural pre-emergent herbicide produced by the Leyland cypress itself.
Interplanting
Interplanting Virginia pine in skips from previous years' planting has not been effective. Younger pines just never seem to do well when surrounded by older, larger ones. But Leyland cypress does well when interplanted,
especially when interplanted in last year's Virginia pine. The Leylands grow fast enough that, by the time the field goes to market, they are as large or larger than the pines. With proper interplanting it's possible to keep
practically 100% of a field producing either pine or Leyland cypress through an entire rotation
.
