‘Centennial Spirit’ crapemyrtle, Lagerstroemia indica L., is a vigorous upright shrub with strong stems which may reach 2 to 3 m. Leaves are smaller and thicker than the species, and are dark green and red-orange in the fall. Inflorescences are 20 to 30 cm tall and 10 to 20 cm wide. Petals are dark wine-red. ‘Centennial Sprint’ is cold-hardy to −20°C and is very resistant to drought and powdery mildew.
A self-contained solar-heated greenhouse was devised consisting of a quonset structure covered with 3 layers of polyethylene which serves as a solar collector. Water mist circulates between the inner 2 poly layers and the heated water is stored in a sand bed in the floor.
Immediate feedback techniques for students completing an exam are not new, but their use is extremely limited. After many years of using this teaching technique to assist students in learning plant identification, I have found it is equally well received and effective with students in lecture classes.
Hardwood chips of post oak, Quercus stellata Wangh, and Siberian elm, Ulmus pumila L., were used as components of container growth media for Pyracantha X ‘Mojave’ and Formosan sweetgum, Liquidambar formosana Hance. Both species grew at least as well in the wood chip media as in conventional pine bark medium. Micronutrients were of little benefit to plants in the oak chip medium but did increase plant growth in the elm chip medium. Drainable pore space decreased dramatically during the growing season, indicating decomposition; however, roots appeared normal when the study ended. Adding additional N above the level generally used with a pine bark medium did not improve growth.
Since the urban population of American elms (Ulmus americana L.) was ravaged by Dutch elm disease fungus [Ceratocystis ulmi Buism. (C. Moreau)], attention has focused on the development of disease resistant elm hybrids. The cultivars ‘Sapporo Autumn Gold’, ‘Urban’, and ‘Regal’ are highly resistant to Dutch elm disease (7, 8, 9); however, they are extremely susceptible to the elm leaf beetle, (Pyrrhalta luteola Muller), because the susceptible Siberian elm Ulmus pumila L.) is a common parent (10). On the other hand, Ulmus parvifolia Jacq. (syn. U. sempervirens), U. chinensis Pers., sometimes listed incorrectly as the lacebark elm (syn. leatherleaf elm, Chinese elm) is highly resistant to Dutch elm disease and the elm leaf beetle (1, 2, 4, 10). Lacebark elm is native to central China, Japan, and Korea, is drought tolerant, and withstands the severe conditions often associated with urban sites (10). Like most other members of the genus Ulmus, lacebark elm is propagated by seed collected in the fall; however, Schopmeyer (6) indicated that less than 50% of the seeds are viable, and only 5% to 12% of the viable seed sown can be expected to produce saleable trees. Four asexually produced cultivars, ‘Sempervirens’, ‘Drake’, ‘True Green’, and ‘Dynasty’ (5), currently sold provide improved consistency and quality.
Slow-release nutrient sources produced larger, higher quality Ilex crenata Thunb. ‘Hetzi’ plants than liquid fertilization at the same rates. Salable quality plants were produced in one growing season by using Osmocote in the propagation medium and incorporating isobutylidene diurea (IBDU) and fritted potassium (K-frit) or Osmocote plus dolomite, single-superphosphate, and micronutrients into the container-growing medium prior to transplanting liners. A wide range of IBDU,K-frit gave satisfactory results. Nutrition during propagation was essential for best growth and utilization of subsequent container nutrition. Cuttings from plants grown with IBDU, K-frit rooted better than those grown with Osmocote or liquid fertilizer.
Trifluralin applied as a spray to a growing medium in nursery containers remained near the surface over a 42 day period at all rates. Oryzalin moved readily through the containers at all rates and after only a small amount of leaching. Nitralin was intermediate in movement. Top and root growth measurements of Ilex cornuta (Lindl) ‘Burford’ treated with the 3 herbicides showed that as herbicide movement increased, fresh weights of tops and roots decreased. When herbicides were applied a second time during the growing season, damage from nitralin and oryzalin increased. Trifluralin did not damage established holly plants at the 4.5 or 8.9 kg rate after 1 or 2 applications.
A container was designed with 4 internal stair-step sections that prevent roots from growing in circles, and stimulates root branching. The additional root branching increased root growth away from the container following transplanting of Virginia pine (Pinus virginiana Mill.), and improved the number of branches per plant on Gardenia jasminoides Ellis., Pyracantha x ‘Mojave’, Photinia x ‘Fraseri’ and Lagerstroemia indica L.
‘Prairie Lace’ Crapemyrtle, Lagerstroemia indica L., is a compact, upright, semidwarf shrub which may reach 1.2 to 2 m in height. Leaves are smaller and thicker than the species average and are very dark green. Inflorescences are 12 to 25 cm tall and 8 to 12 cm wide. Individual petals are medium pink bordered by pure white. ‘Prairie Lace’ is cold hardy to -20°C, and is very resistant to drought and powdery mildew.
Woody ornamental shrub species with varying leaf size maintained as hedges were found to be effective in attenuating sounds from sources such as a random noise generator, a rotary lawnmower, and an automobile. The nature of the sound and leaf characteristics of the plant appear to be more important than the specific width of the hedge.