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  • Author or Editor: W. L. Ackerman x
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Nine dwarf seedlings among 34 arose from interspecific hybridization between Camellia sasanqua Thunb (Plant Introduction 319285) and C. oleifera Abel (Plant Introduction 162561). One dwarf plant flowered and appears to have potential horticultural value.

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Since its release by the US DA in 1960 Pyrus calleryana Dene. cv. Bradford has experienced outstanding popularity for landscape and street planting purposes. Grown widely throughout the Mid-Atlantic States and westward to the Mississippi, it is listed among the “Ten Most Recommended Trees” of several states. ‘Bradford’ has a broad globular crown up to 12 m across and a height of over 15 m at maturity (1, 2).

Open Access
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One of the facets of the National Arboretum's landscape plant improvement program is to extend the range of cultivation of the genus Camellia beyond its present limits. Climatic limitations for camellias grown out-of-doors have been the East Coast from Maryland to northern Florida, westward through the Gulf States, and along the West Coast from California to coastal Oregon and Washington. This region, described roughly as the “Camellia Belt”, contains most of the camellias grown in the United States. Beyond this region there are scattered plantings, usually under protected microclimatic conditions. North of this region, plants are subject to severe winter injury, while in the extreme south they are subject to high heat and light intensity. Significant advances have been made in extending the range of camellia culture northward (2, 3). Efforts are also underway to extend camellia culture south of its present limits. The cultivar, ‘Two Marthas’, is the first release coming from this research.

Open Access
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It is now more than 2 decades since the release of Pyrus calleryana Dcne. cv. Bradford by the U.S. Department of Agriculture (3, 5). During this time it has become a very popular shade tree for landscape and street planting purposes. Widely grown throughout the Mid-Atlantic States, westward to the Mississippi and in parts of the West Coast, it is listed among the “Ten Most Recommended Trees” of several states. ‘Bradford’ has a broad globular crown and may grow to over 15 m in height and in width at maturity.

Open Access
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Abstract

An unusual flowering phenomenon has been observed for 4 consecutive years on an unnamed Camellia japonica clone, PI 276119. While many faded blossoms dropped from the plants, others remained firmly attached. The inner portion of the tightly folded center of each persistant faded blossom remained pinkish-white. These centers expanded and were similar to emerging flower buds except they did not have bud scales. Elongation of the old flower axis placed the new bud slightly above the old flower. Following a resting stage of 6 weeks to about 4 months, new blossoms developed on the same axis and directly above the old flowers. During the 1970 season as many as 3 successive blooms were observed one upon the other.

The physiological aspects of this phenomenon are contrary to normal flower bud development in camellia. Repetitive flowering from a single floral axis appears to violate the principle of determinate growth of flower buds.

Open Access

Abstract

A series of crosses were made between genera within Theaceae including Camellia, Franklinia, Stewartia, and Tutcheria. Two valid intergeneric hybrids were obtained between Camellia and Franklinia alatamaha Marsh. The first, a C. japonica L. (2n=30) × F. alatamaha (2n=36) hybrid with 33 chromosomes, was intermediate in phenotypic characteristics. The second, a C. sasanqua Thunb. (2n=90) × F. alatamaha (2n=36) with 63 chromosomes, was phenotypically very similar to the C. sasanqua parent.

Open Access

Abstract

Camellias are grown out-of-doors along the East Coast from Maryland to Florida, westward through the Gulf States to Texas, and along the West Coast from southern California to coastal Oregon and Washington. This region, described roughly as the “Camellia Belt” is responsible for most of the camellias grown in the United States. Beyond this region there are scattered plantings, usually under protected microclimatic conditions, subject to severe winterkill during periodic colder than normal winters.

Open Access

Abstract

A screening method based on senescent leaves and dormant bud scales was developed to predict flower color among segregating seedling populations of Rhododendron Japonicum (Gray) Suringar.

Open Access