The Christmas Tree program at OSU receives valuable assistance from crop specialists and Extension agents from a number of disciplines and locations across OSU. Recent retirements and position changes have thinned these ranks beginning in 2012. This type of web resource will likely become a prime source of information in trying to maximize scarce time and budgets.

Chal Landgren is the OSU Extension Christmas Tree Specialist for Oregon. His program covers information from site preparation through harvest. Current extension and research efforts include sustainability certification, tree selection/breeding and fertilization.

Latest Publication available for purchase:

Identifying and Managing Christmas Tree Diseases, Pests, and Other Problems PNW 659

 

IPM in Christmas Trees Workshop Materials

IPM-A conceptual and practical overview, Paul Jepson-OSU

IPM and Pesticides, Bruce Alber-Wilbur Ellis

Developing a treatment plan, Chal Landgren-NWREC-OSU

Identifying Root Rot in Conifers, Kathleen M. McKeever-WSU Puyallup Research & Extension Center

 

Associations and Organizations:

Pacific Northwest Christmas Tree Association

National Christmas Tree Association

Soil & Water Conservation Districts

ODA Pitch and Needle Newsletters

Production and Management:

Christmas Tree Nutrient Management Guide

Pest Management Strategic Plan for Christmas Trees in Oregon, Washington and Idaho

Growing Christmas Trees in the Pacific Northwest-PNW 6 publication

Buy-Sell Directory and Resource Guide

 

Industry Statistics and Regulations:

NASS/National Agricultural Statistics Service-

Christmas Tree Shipping Regulations

Publications

April 1, 2010

A comparison of substrate amendments for the adjustment of hydrangea flower color based on data collected from studies conducted at Oregon State University North Willamette Research and Extension Center in Aurora, Oregon.

October 1, 2009

Research was conducted to take advantage of the reduction in plant size and vigor often associated with induced polyploidy. The principle objectives were to induce polyploidy in seedlings from H. acetosella ‘Panama Red’ and to evaluate the effects on growth, morphology, and fecundity.

March 1, 2011

The purpose of this article is to report on progress in the development of Phytophthora-ID and the validation of its data sets using an extensive sample of Phytophthora spp. It is expected that Phytophthora-ID will also help in development and maintenance of culture collections.

August 1, 2011

The Oregon State University affiliated authors strive to answer the question of whether plant physiology and breeding research can work collectively to develop more water-efficient and drought tolerant plants that will benefit the green industry.

March 1, 2012

A guide to help growers develop an effective weed management plan. Different strategies are presented on how to deal with annual and perennial weeds along with strategies for the growing issue of herbicide resistance in weeds.

December 1, 2003

Very informative and useful publication for nursery management and workers. Discusses the history of Phytophthora ramorum in Oregon and its biology, hosts and symptoms. In depth information on the management and prevention of the pathogen.

September 1, 2010

Phytophthora species are some of the most problematic plant pathogens in nursery production systems. The Oregon State University affiliated author provides these top 10 tips which will help prevent this group of pathogens from taking hold.

June 1, 2012

A recent report described a simple technique to double Cryptomeria japonica chromosomes. The objectives of this research was to evaluate the effectiveness of the technique and determine optimal treatment duration for doubling chromosome numbers in oriental arborvitae, american arborvitae, and western red cedar.

January 1, 2011

A comprehensive guide on P. ramorum. Topics discussed include; morphology, genetics, growth, distinguishing characteristics for identification, disease history, impacts in the forest, forest and wildland hosts and symptoms, and management and educational materials.

October 1, 2011

Correctly diagnosing a plant problem for nursery growers can be challenging. However, the right diagnostic resources coupled with an early and appropriate diagnosis can prevent pests or pathogens from spreading, saving time and money.

April 1, 2012

A comprehensive discussion about the issues concerning pre-packaged fungicide mixes, which can elevate the risk of developing pathogens that are resistant to treatment. Strategies for avoiding resistance are included in the discussion.

October 1, 2010

As interest in compost grows, so does the need to better understand what compost is, and to learn about the limitations and advantages of particular composts. Suggestions are provided for how to use compost testing as a tool to get greater value from compost use.

June 1, 2012

This study on interspecific hybridization in Tecoma Juss. was conducted to develop novel forms for the nursery industry. The selection of species used in the study included T. garrocha, T. stans, T. guarume, and T. capensis.

January 1, 2012

A systems approach for the production of healthy nursery stock. The manual, published by the Oregon Association of Nurseries, is divided into 3 main parts. A systems approach introduction, voluntary best practices for your nursery, and the next step: systems approach certification.

November 1, 2011

Pest management researcher discusses the Interregional Research Project No. 4, commonly known as IR-4, a federally funded program that assists growers of ornamental horticulture crops in obtaining safe and effective pest management tools.

June 1, 2012

Researchers report on a study conducted to test the efficacy of soil additives in promoting plant growth and reducing mortality. The species included in the trial were Hydrangea macrophylla ‘Endless Summer’, Berberis thunbergii ‘Rose Glow’, and noble fir (Abies procera).

A hearing is scheduled to discuss proposed changes to the quarantine area and allow use of an oak from disease free area.

November 1, 2010

Oregon State University affiliated authors discuss production costs and product pricing which has a great impact on the profitability of a nursery business. Specific topics addressed include identifying plant costs and preparing for the future.

April 1, 2006

A comprehensive guide for forest managers, Christmas tree growers, and forest-tree nursery operators in Oregon and Washington on sudden oak death, the disease caused by the recently introduced Phytophthora ramorum.

April 1, 2011

A report on Oregon State University affiliated research conducted with the purpose of documenting the chromosome number and genome size of Callicarpa species to add to the available information on the genus.

December 1, 2011

Oregon State University researchers discuss their investigation of a new microscopic pest, eriophyid mites, which causes damage to linden trees. Identification and detection, distribution and behavior, and damage and control strategies are specifically discussed.

July 1, 2012

Researchers at Oregon State University evaluated the potential of a remote soil-moisture-sensing technology in ornamental container production systems. The authors discuss the system they used, implications of the study, and their conclusions.

This new quarantine could impact ornamental growers shipping to Washington state.

January 1, 2011

Researchers, extension agents and growers affiliated with Oregon State University provide fertilizer recommendations for growing bare-root shade, flowering and fruit trees in Oregon's northern Willamette Valley.

September 1, 2012

A review of the different means by which the potential for invasiveness in woody ornamentals can be reduced using genetic methods. Progress is reviewed in conventional breeding and transgenic biotechnology approaches to producing sterile forms of ornamental woody plants.

April 1, 2011

No matter how small, slugs and snails can cause huge headaches for growers. Fortunately, there are many ways these pests can be managed and eliminated. The author discusses the importance of and the different factors involved in a good integrated pest management plan.

December 1, 2011

The purpose of this study was to investigate the influence of water stress (as induced by irrigation frequency) on growth and nitrogen (N) uptake of one deciduous and two evergreen cultivars of Rhododendron grown with different rates of N fertilizer in containers.

August 1, 2012

A look into the world of plant breeding and the tools ornamental plant breeders have at their disposal to expedite breeding for specific traits. Topics addressed in the article include flow cytometry and molecular genetics.

Most recent information on stopping the spread of SOD included in this revised extension publication.

February 1, 2011

Pests and pathogens are a threat for growers that produce containerized nursery stock. The authors discuss how to reduce these threats by considering the type of containers and growing media they use, where they are sourced, how they are handled, and how they are stored.

January 1, 2009

A proposal for a system naming clonal lineages of Phytophthora ramorum, the causal agent of sudden oak death and ramorum blight, based on a consensus established by the P. ramorum research community is discussed.

June 1, 2011

John Lambrinos, assistant professor of horticulture with Oregon State University, discusses how the fields of horticulture and restoration ecology can work together in a mutually beneficial way to improve the environment.

October 1, 2007

The intent of the study was to expand current knowledge of nitrogen (N) uptake and allocation by container-grown Rhododendron by characterizing the plant growth, the extent of N uptake, and the changes in N storage that occur during the autumn and winter.

October 1, 2012

A discussion about cold hardiness and effective plant protection strategies to minimize cold damage. The Oregon State University affiliated author addresses how plants become cold hardy, stages of hardiness, and effective protection.

Boxwood blight, Cylindrocladium buxicola, a fungal plant disease relatively new to North America, has been detected in an Oregon nursery.

September 1, 2009

An experiment was performed to determine a more effective protocol for germinating C. americana seeds. It was hypothesized that scarification with sulfuric acid would aid in breaking seedcoat dormancy, thereby resulting in more rapid and uniform germination.

December 1, 2008

Oregon State University affiliated author discusses the top 10 tips for preventing disease in nurseries. Specific topics addressed include site selection and drainage, sanitation practices, disease free plant sources, plants in container, and irrigation.

July 1, 2011

Researchers at Oregon State University have been studying how soilless substrates can be used together with moisture monitoring equipment to get the best results while reducing the need to irrigate. Topics specifically addressed include soilless substrate and water management.

January 1, 2012

Researchers evaluate selections from this sometimes underappreciated genus of landscape shrubs. Specific topics discussed in the article include landscape performance, disease resistance, and developing sterile cultivars.

November 1, 2012

An initial report on research conducted on two intelligent, or precision, sprayers designed for use in the ornamental horticultural industry. The goal of this research is to develop efficient and affordable sprayers that use technology to respond to crop size and presence.

September 1, 1974

Cylindrocladium scoparium, a wilt disease of azaleas was a major problem for the azalea industry across the country in the mid 1960's. Studies were conducted to determine the cause of the wilt and identify control measures, observations and results are discussed.

February 1, 2010

Japanese-cedar (Crytomeria japonica) performs well under a range of soil and environmental conditions but has been underused in landscapes, in part, due to winter browning. In previous studies, chance seedlings that did not exhibit winter browning were identified as tetraploids. This study was conducted to induce polyploidy in Crytomeria japonica.

March 5, 2012

A discussion about live plant imports as an important invasion pathway for non-native plant pests. The authors discuss the effect of current regulation, the need for updated regulation, and the recent and proposed changes to plant import regulation.

September 1, 2011

Plant pathologists track where Phytophthora ramorum came from and how it has managed to spread. The author specifically discusses Phytophthora ramorum clones and mating types and tracking the migration of the pathogen.

February 1, 2012

Growers can minimize their risk of exposure to plant diseases and reduce pesticide use by ensuring that their irrigation water is free of Pythium and Phytophthora species. The authors discuss several different disinfestation methods for nursery and greenhouse operations.

December 1, 2012

Researchers evaluated regionally available alternative substrates for ornamental crop production in the Pacific Northwest. The objective was to investigate the physiochemical properties of the substrate and ensure no biomass is phytotoxic to ornamental crops.