Christmas Tree Growing Guide
Growing Christmas Trees in New Jersey
Christmas tree production in the Mid-Atlantic requires proactive Integrated Pest Management (IPM), careful site selection, and active monitoring of growing degree days (GDD) to manage pest cycles effectively. Christmas trees are long-term perennial crops that can take 6 to 10 years to reach marketable size, so early site planning and routine field maintenance are essential to preventing chronic pest pressure and tree loss.
Throughout the growing cycle, growers can face a range of insect pests, fungal pathogens, weed competition, and environmental stressors which can degrade foliage quality, deform tree architecture, or lead to total crop loss.
An IPM framework is essential to maintaining plantation health while optimizing economic and environmental sustainability. By aligning cultural operations with targeted IPM strategies, growers can build resilient plantations, protect tree aesthetics, and maximize marketable yields.
Introduction to Christmas Tree Growing and Management
- Target Crops:
- True Firs (Abies spp. – Fraser, Balsam, Canaan)
- Pines (Pinus spp. – Eastern White, Scots)
- Spruces (Picea spp. – Colorado Blue, Norway).
- Soil & Site Requirements:
- Christmas trees (especially true firs) often require deep, well-drained soils, specifically loams or sandy loams
- Poorly drained or saturates soils can lead to anaerobic conditions that foster root rot pathogens
- pH should be maintained between 5.5 and 6.5 for most conifer species
- Test the soil prior to planting, and apply lime or sulfur as recommended
- Weed suppression and ground covers
- Competitive weeds and brush between rows should be controlled using mowed sod grass strips or directed herbicides.
- Weed management reduces competition for soil moisture and nutrients, removes hosts plants for pests, and improves air circulation around the lower limbs to prevent diseases.
- Christmas trees (especially true firs) often require deep, well-drained soils, specifically loams or sandy loams
- Cultural Practices:
- Shearing/pruning schedules:
- Pines should be sheared during active growth in early summer, before new wood hardens. This encourages lateral bud formation on current-year growth.
- Firs and spruces should be sheared during the dormant season (late summer through early spring), or after the shoot growth has expanded and hardened.
- Terminal leader management:
- Terminal leaders are the topmost vertical shoots of the trees that grow straight up. These shoots determine the tree’s height and crowning shape and are essential for Christmas tree grower management.
- Excessively long terminal leaders should be pruned to maintain the ideal tree taper and density.
- If the leader is damaged by pests, prune it back and train a side branch to grow upright using terminal stakes.
- Stress reduction:
- During prolonged summer droughts, use supplemental irrigation to reduce plant stress and prevent secondary pest attacks from opportunistic organisms (i.e. bark beetles and spider mites)
- Shearing/pruning schedules:
Common Tree Types
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True Firs (Abies spp.)
Frasier Fir (Abies fraseri)
- Known for exemplary needle retention and strong branches
- Requires cool sites with well drained, fertile soils
- Susceptible to Phytopthera root rot
Balsam Fir (Abies balsamea)
- Fragrant with good needle retention
- Suited best for cooler northern regions
Canaan Fir (Abies balsamea var. phanerolepis)
- Good mix of traits from Fraser and Balsam firs
- Tolerance for more poorly drained soils than Frasers
-
Pines (Pinus spp.)
Eastern White Pine (Pinus strobus)
- Fast-growing, with blue-green needles
- Flexible branches, so less suited for heavier ornaments
- Requires regular shearing for density maintenance
Scots Pine (Pinus sylvestris)
- Adaptable to various soil types
- Good needle retention
- Susceptible to tip moths and pine needle scale
-
Spruces (Picea spp.)
Colorado Blue Spruce (Picea pungens)
- Known for its bright foliar color and stiff branches
- Good air circulation for fungal cast mitigation
Norway Spruce (Picea abies)
- Rapid grower with dark green foliage
- Best harvested closer to Christmas because of needle drop after cutting
Christmas Tree Primary Pests
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Cryptomeria Scale (Aspidiotus cryptomeriae)
Symptoms on Frasier-fir by Cryptomeria Scale at undersides of needles. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.) - Hosts: Frasier fir, Canaan fir, Hemlock
- Key Symptoms:
- Yellow chlorotic mottling on foliage
- Inner needle drop
- Dirty appearance from scale armor
- Management:
- Management window: Crawler emergence is from 533-820 GDD
- Apply horticultural oil or targeted insect growth regulators
- Click here to be brought to the Cryptomeria Scale Page for more detailed information.
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Balsam Twig Aphid (Mindarus abietinus)
- Hosts: Frasier fir, Canaan fir, Balsam Fir
- Key Symptoms:
- Twisted, curled, or distorted shoot tips on spring growth
- Honeydew accumulation
- Management:
- Management window: scout during early spring, prior to budbreak
- Apply horticultural oil or targeted insect growth regulators
- Click here to be brought to the Balsam Twig Aphid Page for more detailed information.
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Spruce Spider Mite (Oligonychus ununguis)
Although a Fir & not a Spruce, the older needle discolorations are stippling symptoms from spruce spider mites. Photo Credit: Steven K. Rettke of Rutgers Coop. Ext. - Hosts: Fir, Spruce, Hemlock, Juniper
- Key Symptoms:
- Fine stippling
- Bronze/gray foliage coloration
- Delicate webbing on shoots
- Management:
- Management window: this is a cool-season pest, active in the spring and fall
- Apply horticultural oil or targeted insect growth regulators
- Click here to be brought to the Spruce Spider Mite Page for more detailed information.
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Nantucket Pine Tip Moth (Rhyacionia frustrana)
Nantucket Pine Tip Moth infesting multiple twig shoots of this Jersey scrub pine (Pinus virginiana). (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.) - Hosts: Eastern White pine, Scots pine, Loblolly pine
- Key Symptoms:
- Dead, hollowed-out terminal and lateral shoots
- Pitch masses at needle bases
- Management:
- Management window: monitory spring adult flight using pheromone traps
- Apply horticultural oil or targeted insect growth regulators
- Click here to be brought to the Nantucket Pine Tip Moth Page for more detailed information.
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White Pine Weevil (Pissodes strobi)
Often by July, an infested terminal will brown & die as the weevil larvae have destroyed the vascular tissues. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.) - Hosts: Eastern White pine, Norway spruce, Colorado blue spruce
- Key Symptoms:
- “Shepherd’s crook”
- Wilting and death of the main terminal leader
- Management:
- Management window: apply preventative stem treatments in the spring
- Prune out infested leaders before adults emerge in mid-summer
- Click here to be brought to a Plant and Pest Advisory Post regarding this pest.
Christmas Tree Diseases and Abiotic Issues
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Inner Needle Discoloration and Needle Casts in Spruce
Colorado Spruce showing symptoms of undesirable discoloration of older, inner needles. Photo Credit: Steven K. Rettke of Rutgers Coop. Ext. - Hosts: Colorado blue spruce, Norway spruce
- Key Symptoms:
- Browning/purpling of 2-year-old needles
- Premature needle drop starting from lower/inner branches outward
- Management:
- Management window: Apply protective fungicide sprays at budbreak during spring shoot expansion
- Click here to be brought to our Inner Needle Discoloration of Spruce page.
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Phytophthora Root Rot (Phytophtora spp.)
- Hosts: Fraser fir, Douglas-fir, White pine
- Key Symptoms:
- Stunted growth
- Yellowing foliage
- Red-brown wood discoloration beneath bark at the root crown
- Tree collapse
- Management:
- Ensure site selection has adequate drainage
- Apply preventative oomycete-targeted fungicide drenches in susceptible blocks.
- Click here to be brought to our Rood Disease Oomycetes page.