A method is described for producing bare-root shade tree whips in containers. Whip production is begun in February in heated greenhouses by sowing seed. Seedlings are transplanted to copper-treated containers and grown in a greenhouse until May, when they are moved outdoors and transplanted to No. 3 copper-treated containers. In October (8 months after seeding), plant heights range from 1 to 2 m. Several media have been developed that result in rapid growth, while separating readily from the root system by hand-shaking. Bare-root plants placed in refrigerated storage for 6 months and repotted, retained high survival and regrowth potential. The system combines the handling ease of bare-root stock with the high survival and regrowth potential of container stock.
Daniel K. Struve
Chris Starbuck, Daniel K. Struve, and Hannah Mathers
Two experiments were conducted to determine if 5.1-cm-caliper (2 inches) `Summit' green ash (Fraxinus pensylvanica), and 7.6-cm-caliper (3 inches) northern red oak (Quercus rubra) could be successfully summer transplanted after being heeled in pea gravel or wood chips prior to planting in the landscape. Spring harvested trees of each species were either balled and burlapped (B&B) or barerooted before heeling in pea gravel or wood chips. Compared to B&B `Summit' green ash, bareroot stock had similar survival and shoot extension for three growing seasons after summer transplanting. Bareroot and B&B northern red oak trees had similar survival and central leader elongation for 3 years after summer transplanting. In the third year after transplanting, northern red oak bareroot trees heeled in pea had smaller trunk caliper than B&B trees heeled in wood chips. These two taxa can be summer transplanted B&B or bareroot if dormant stock is spring-dug and maintained in a heeling-in bed before transplanting. This method of reducing transplant shock by providing benign conditions for root regeneration can also be used to extended the planting season for field-grown nursery stock; the method is called the Missouri gravel bed system.
Jeffery K. Iles
Rewholesalers, garden centers, and other sellers of deciduous shrubs routinely receive bare-root stock in late winter or early spring for potting; however, bare-root plants are sometimes slow to establish in containers. Potted liners with well-developed root systems show potential for shortening the production cycle and permitting the development of higher-quality plants earlier in the growing season. To study the effect of nursery stock type and size on subsequent growth, two bare-root sizes and one potted liner size of `Cardinal' red osier dogwood (Cornus sericea L.), `Goldflame' spirea (Spiraea xbumalda Burv.), and `James MacFarlane' lilac (Syringa xprestoniae McKelv.) were grown in polyethylene containers of different sizes. Bare-root plants (15 and 30 cm in height) were grown in 2.7- and 6.1-L, and 6.1- and 10.3-L containers, respectively. Potted liners (0.4-L container size) were grown in 6.1- and 10.3-L containers. Plant performance was evaluated 10 and 20 weeks after potting. In general, plant quality ratings increased with container volume for all species. For `Goldflame' spirea and `James MacFarlane' lilac, best plant quality ratings occurred with 30-cm plants grown in 10.3-L containers. But for `Cardinal' redosier dogwood, plant quality ratings were highest and not significantly different for 30-cm bare-root plants and potted liners grown in 10.3-L containers.
Hannah M. Mathers
Container nurseries are generally more productive than field nurseries because plants can be produced faster and at higher densities. Increasingly, nursery stock is being propagated, grown, and marketed in containers. The prime biological advantage of container stock over bareroot and field-grown balled and burlapped (B&B) stock is that the root system is packaged and protected from transplant or mechanical stress; however, temperature stress limits container production. Plants overwintered in containers suffer greater winter injury than those in the ground because the roots are surrounded by cold, circulating air rather than the insulating environment of the soil. There are several methods for providing protection from cold winter temperatures that are used in the nursery industry; however, all are labor intensive, expensive and vary in effectiveness. Container stock also suffers from elevated summer root zone temperatures. Cultivar differences in the degree of summer injury have been reported. With increasing human population pressures and decreasing availability of fresh water supplies, the need for more water-efficient nursery cultural practices becomes increasingly important. Water and nutrient use efficiency are predominant factors restricting nursery container production. Cultural factors that improve root function and reduce root injury and container heat load are considered key to improving these efficiencies. This paper examines temperature stress issues and the effects of different nursery cultural environments such as conventional overwintering systems, conventional gravel production surfaces, pot-in-pot production, and retractable roof greenhouses.
J.J. Ferguson, K.E. Koch, and T.B. Huang
Fruit were removed 8, 16, and 24 weeks after peak bloom from 3- and 4-year-old, `Hamlin' orange [Citrus sinensis (L.) Osbeck] trees on `Carrizo' citrange root-stock [C. sinensis (L.) Osbeck ×Poncirus trifoliata (L.) Raf.], planted as bare root or containerized trees, to determine if fruit removal enhanced vegetative growth. Bare-root trees had a greater stem diameter and tree height than containerized trees at planting and after years 3 and 4. Fruit of bare-root trees had lower fresh and dry weights, refixed less of their respiratory CO2 during development, and lost water less rapidly after harvest. In addition, fruit removal treatments did not increase growth of either bare-root or containerized trees relative to trees from which no fruit had been removed. In fact, tree diameters were slightly higher when fruit were not harvested. Carbon cost of fruit production may have been countered by other factors under field conditions, such as known enhancement of photosynthetic rates by fruit load and/or diurnal contributions by fruit to leaf water demands.
Andrew Jeffers, Marco Palma, William E. Klingeman, Charles Hall, David Buckley, and Dean Kopsell
and Landscape Association (ANLA) American Standards for Nursery Stock do not specifically address attributes of quality often described by bare-root liner buyers and growers (see Sections 6: Young Plants, 9: Understock, and 10: Seedling Trees and
Ursula K. Schuch, H. Brent Pemberton, and Jack J. Kelly
. González-Moro, M.B. Lacuesta, M. Muñoz-Rueda, A. 2001 Storage duration and temperature effect on the functional integrity of container and bare-root Pinus raidata D. Don stock-types Trees (Berl.) 15 289 296
Emmanuel A. Torres-Quezada, Lincoln Zotarelli, Vance M. Whitaker, Bielinski M. Santos, and Ixchel Hernandez-Ochoa
in Florida uses bare-root transplants, with three to four intact leaves ( Bish et al., 2002 ), which are established by overhead irrigation during daylight hours for up to 10 d. Bare-root transplants for Florida are usually grown in southern Canada
Anthony L. Witcher, Fulya Baysal-Gurel, Eugene K. Blythe, and Donna C. Fare
used for commercially grown flowering dogwood in Tennessee ( Halcomb, 2002 ). Plants can be harvested as either bare-root or balled and burlap (B&B), depending on the plant size and intended use. Although field production is the least expensive method
Fumiomi Takeda and Jorge Soria
). Layering is a rooting method by which adventitious roots are stimulated on the primocane while it is still attached to the stock plant ( Hartmann et al., 2010 ). Before the introduction of TC propagation, tip layering was a common nursery practice for