Foundamental Studies on the landscape use of Hedera Genus (I)

Abstract

Presently usage of landscape plants is desired to be adapted to alteration of city's structure and environment. We pay attention to Hedera genus which has been taken as the plants for admiration so that people furnish them only for horticulture in Japan.
In order to utilize them for landscape, we treat Hedera genus in outline, discuss six principal species in its genus and consider its adaptability as the plants which cover surface of the earth.
The result that they have enough adaptability.
Of the conditions of each species and forms, we explain 3 species and 21 forms which we have collected until today, from which we select especially 3 species and 9 forms and expect them to be fit for landscape planting as the plants covering surface of the earth.
We explain their conditions for details.
We investigate present utilization of Hedera genus for landscape use and observe external and internal constitution of each species of Hedera genus.
As the result, it become clear that one which has been divided into H. helix “Tricolor” and whose familiar name was “OKAMEZUTA” in Japan, is not H. helix “Tricolor” but H. canariensis “Variegata”.
Leaves of H. rhombea Bean was changed in every stage of growth.
Under investigation of documents, we make clear natural distribution of H. rhombea Bean (which is survived) in Japan.
In short, H. rhombea Bean distributes naturally to almost all extent of “YABUTSUBAKI” and “MIZUNARA-BUNA” groups which was made by Japanese potential and natural vegetational distribution.
Lately, as for growth enviroment of Hedera genus, we outlined each conditions, soil's nature, soil's PH, degree of soil's moisture and nutrition, negativity and positivity, nuisance resistance, salt tolerance, diseases and harmful insects.