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Lonicera (involucrata)

USDA NRCS - Corvallis Plant Materials Center
3415 NE Granger Ave
Corvallis, Oregon 58413

Family Scientific Name: Caprifoliaceae
Family Common Name: Honeysuckle
Scientific Name: Lonicera involucrata Banks ex Spreng.
Common Name: twinberry honeysuckle
Species Code: LOIN5
Ecotype: Crater Lake, around 6,500 feet near vidae falls; park headquarters
General Distribution: Western US including Alaska; upper midwest in Michigan and Wisconsin. Woodlands , moist to wet soils up to high elevations. At Crater lake, near creaks, streams and seeps
Propagation Goal: plants
Propagation Method: seed
ProductType: Container (plug)
Stock Type: 1-gallon containers
Time To Grow: 0
Target Specifications: Well-branched roots and tops; free of foliar disease
Propagule Collection: Ripened berries picked in August / Sept.; berries scarce in some years. Summer softwood cuttings can be collected in July.
Propagule Processing: Seeds processed by breaking up berries in blender with dulled blades (or covered blades with rubber tubing); pour off pulp, rinse, strain and dry seeds on paper toweling. Gently rub seed and hand-screen to remove any remaining chaff. Clean seed approximately 327,000 / lb.
Pre-Planting Treatments: Seed germination of young lots cold-moist stratified for 90 days was up to 55%; a small comparison of 1-year-old vs. 3-year-old seeds showed slightly reduced germination and initially weaker seedling vigor; however these seedlings grew quite well after one season
Growing Area Preparation/
Annual Practices for Perennial Crops:
Seedlings started in shallow propagation trays and transplanted directly into vertically ribbed, 1-gallon pots filled with a rich soil mix of Sunshine #`1 peat-based potting medium amended with low rates of micromax trace elements. Plants should be closely monitored for aphids throughout spring and summer.
Establishment Phase: Seedlings or cuttings sensitive to drying out; media should be kept moist during initial establishment. Intermittent mist especially important for summer softwood cuttings.
Length of Establishment Phase: 6 weeks (8 weeks for cuttings)
Active Growth Phase: Whether established from seed or cuttings, established plants are held over summer in outdoor shadehouse (50% shade) with drip irrigation on elevated benches to provide air flow / air pruning to roots. Peters' Triple-20 fertilizer at 50% strength applied at 2 week intervals in May to July. Shoot pruning often needed in June to head back tall leaders and encourage branching.
Length of Active Growth Phase: May to July
Hardening Phase: Fertilizer withheld in August; watering intervals lengthened to encourage vegetative maturity; shade cloth removed by the end of August. Shoot growth should not be pruned back at this time because it will cause lateral bud break and start a new growth cycle.
Length of Hardening Phase: August - September
Harvesting, Storage and Shipping: Plants overwintered in outdoor lathhouse at PMC; aphids on new growth were a problem in the second spring; treated with Safers' insecticidal soap at label rates. Otherwise plants shipped via refrigerated van in August to a holding facility at Crater Lake NP to acclimate for outplanting in September.
Length of Storage: overwintering outdoors ok; may need repotting / root and shoot pruning following spring.
Other Comments: Watch for aphids!
Softwood cuttings rooted easily under mist in midsummer without hormone treatment; these cuttings were ready for transplant into 1-gallon containers in early fall.
References: Link, Ellen, ed. 1993 Native Plant Propagation Techniques for National Parks Interim Guide; Compiled by Rose Lake Plant Materials Center 7472 Stoll Road East Lansing, MI 48823

Rose, Robin, C.E.C. Chachulski and D. Haase. Propagation of Pacific Northwest Native Plants 1998 Or. State U. Press, Corvallis, Oregon
USDA, NRCS. 2001. The PLANTS Database, Version 3.1 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Young, James A. and Cheryl G. Young. 1986. Collecting, Processing, and Germinating Seeds of Wildland Plants. Timber Press, Portland, OR

Young, James A. and Cheryl G. Young. 1992 Seeds of Woody Plants in North America. Dioscorides Press, Portland, OR


Flessner, Theresa R; Trindle, Joan D.C.. 2003. Propagation protocol for production of Container (plug) Lonicera involucrata Banks ex Spreng. plants 1-gallon containers; USDA NRCS - Corvallis Plant Materials Center Corvallis, Oregon. In: Native Plant Network. URL: http://NativePlantNetwork.org (accessed 2021/03/01). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

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