Growth and flowering of bleeding heart were promoted by 14 to 24 hour photoperiods or light interruptions in the middle of the night. Cold treatment of crowns promoted growth and flowering at short photoperiods. Light at 9 klx promoted growth and inflorescence formation, but greater intensities were required to achieve anthesis. Growing temperatures of 15-22.5°C were most desirable.
A single spray application of succinic acid-2, 2-dimethylhydrazide (daminozide) at 2,500-15,000 ppm at pinch was effective in retarding growth of bleeding heart, reducing plant height 33 to 75%. A single spray or drench of (2-chlorethyl) trimethylammgrium chloride (chlormequat) had little retarding influence. Spray application of (2-chloroethyl) phosphonic acid (ethephon) had little effect on plant height, but considerably increased the number of nodes and delayed flowering.
The urban soil environment is usually not conducive to healthy root growth and function, leading to problems with plant establishment, growth, and aesthetic quality. The objective of this study was to determine if the addition of compost with or without the application of shallow tillage or aeration will improve soil physical and chemical properties and plant growth compared with an unamended control in simulated new residential landscapes. Twenty-four mixed landscape plots were established in a randomized complete block design to simulate new residential landscapes. Each plot was constructed using 10 cm of subsoil fill material over a compacted field soil and planted with Stenotaphrum secundatum and mixed ornamental plant species. Composted dairy manure solids were applied as an organic soil amendment at a depth of 5 cm (≈256 Mg·ha−1) in combination with two mechanical soil treatments (tillage to 15 cm and plug aeration) for a total of five soil management treatments plus an untreated control. Soil physical and chemical properties, plant growth, and quality and plant tissue nutrient concentrations were assessed periodically to determine the effect of soil treatment on soil and plant quality. Applications of compost to soils significantly reduced soil bulk density and pH and increased soil organic matter, electrical conductivity, and Mehlich-1 phosphorus and potassium concentrations. All ornamental plant species, with the exception of Raphiolepis indica (L.) Lindl. ex Ker Gawl., exhibited more growth when grown in soils amended with composted dairy manure solids. In most instances, plant tissue nitrogen and phosphorus concentrations were higher for plants grown in soils receiving compost. Results of our study suggested that the addition of composted dairy manure solids to soils can improve soil properties and enhance plant growth in residential landscapes when sandy fill soils are used. In contrast, shallow tillage and aeration had little effect on soil properties or plant growth.