Home Native Plant Network
NPN Protocol Details Image

Tridens (flavus)

John M. Englert
USDA NRCS - Norman A. Berg National Plant Materials Center
Bldg. 509, BARC - East, E. Beaver Dam Road
Beltsville, Maryland 20705
(301) 504-8175
(301) 504-8741 (fax)

Family Scientific Name: Poaceae
Family Common Name: Grass Family
Scientific Name: Tridens flavus (L.) AS. Hitchc.
Common Name: Purpletop Widens
Species Code: TRIFLA
Ecotype: Great Smoky Mountains National Park, Tennessee, 1400-1800' elevation, The Sinks, Cades Cove; Cumberland Gap National Historical Park, Kentucky, Sugar Run; Shenandoah National Park, Virginia, Skyline Drive
General Distribution: Tridens flavus grows in fields, roadsides, and open woods from New Hampshire to Nebraska and south to Florida and Texas.
Propagation Goal: plants
Propagation Method: seed
ProductType: Container (plug)
Stock Type: Container plugs
Time To Grow: 12 Weeks
Target Specifications: Height: 8-10" after cutbacks; multiple stems. Root System: Full, firm plug which leaves no loose soil when pulled.
Propagule Collection: Collected in Great Smoky Mountains National Park by NPS staff on 9/19/94 and 10/14/99; Cumberland Gap National Historical Park by NPS staff on 10/15/91; Shenandoah National Park by J. Englert on 10/21/92; National Plant Materials Center by D. Dusty on 10/22-24/96, 10/20-30/97 and
Propagule Processing: Seed Processing: Seeds are harvested from our production field with a combine, and are cleaned using a 2-screen seed clipper.
Seed storage: In seed bags in cooler @ 40F, 35% relative humidity.
Seeds/Kg: 900,000.
Germination: 66% average (test) Germination in greenhouse has varied from 2-5%, and 18 to 70 plugs per gram of seed sown. Production goals are met by increasing rate of seeding and second sowings.
Purity: 87.51% average.
Pre-Planting Treatments: Seed Treatments: T. flaws seed may take 30 to 49 days to germinate. 3-4 weeks of cold stratification @ 40 F may improve germination, but probably not enough to warrant the extra time in the cooler. In February,2000, after 2 weeks under mist and on heat mats with little germination, unstratified plug trays were covered with clear, lightweight plastic and exposed to full sunlight in the greenhouse. Media was kept continually moist. Germination occurred rapidly (within 7-10 days). Production increased from 19 to 40 plugs per gram of seed. Direct sunlight appeared to help since plastic-covered flats protected from full sun did not germinate well. Bottom heat (@ 80 F) and mist did not increase speed or % of germination. Seeds sown on blotter under mist failed to germinate.
Growing Area Preparation/
Annual Practices for Perennial Crops:
Propagation Environment: Greenhouse with alternating day/night temperatures (set at
75/68F) and 12-14 hours of daylight extended with high-pressure sodium lights

Seed Propagation Method: hand sown in germination plug trays.

Container Type and Volume: Seeds are sown in 392 plug trays; seedlings are transplanted to either 72 plug trays or Ropak multipots depending whether out-planted with a planter or hand-dibbled.

Growing Media: Seeds are sown in Fafard Germinating Mix. Seedlings are transplanted into a 2:1 mix of Sunshine #5:Compro, (1 bale Sunshine, 2 bags Compro) with 180 day Nutricote Total 18-6-8 SR incorporated @ 0.15lb/cu ft mix. Compro is used to prevent chlorosis, which may occur in warm season seedlings grown in soilless media. Other organic substitutes for Compro are being evaluated.
Establishment Phase: Sowing Date: December or January depending on outplanting date.

Emergence and Date: See "seed treatments".

Sowing/Planting Technique: Seeds are hand-sown heavily into 392 plug trays at a rate computed to produce target number of plugs and compensate for low germination rate. Seeds are lightly covered with germination mix, and watered. See "Seed Treatment".

Establishment Phase: Seedlings in germination trays are kept continually moist. They are transplanted to 72 plug flats or Ropak multipots, usually when plugs can be pulled, however seedlings have been dug and transplanted within several days of germination resulting in more uniform maturation of plugs. Avoid over-watering transplants.
Active Growth Phase: Rapid Growth Phase: T. flavus plugs grow rapidly after transplant when greenhouse solar levels increase in the spring (March). Plugs are cut back periodically to 6-8" to enhance root and stem growth and to manually eliminate insect pests. Plugs are fertilized as needed (or every 1-2 weeks) with Technigro 16-17-17 Plus, @ 100 ppm.
Hardening Phase: Hardening Phase: 2-3 weeks prior to out-planting, fertilization is stopped, water is decreased, and greenhouse temperatures are reduced or plugs are moved outdoors.
Harvesting, Storage and Shipping: Total Time to Harvest: About l0-12 weeks from germination to finished plug. If second sowings are required to meet goal, staggered maturation of plugs will result.

Harvest Date: Plugs are ready for out-planting about 10-12 weeks after seedlings germinate.

Storage Conditions: N/A - Plugs are seeded in winter and planted the same spring.
Length of Storage: <b>Storage Duration: </b>N/A.
Other Comments: Low germination of seed in the greenhouse (between 2 and 5%) has required extremelyheavy sowing to produce the park target of 2,000-4,000 plugs. Covering trays with plastic and exposing to full sun in the greenhouse may help. Have not tried starting plugs in summer and over-wintering established plugs in storage for spring out-planting.
References: Manual of the Grasses of the United States, Hitchcock, 2nd edition, U.S. Government
Printing Office, 1950.


Kujawski, Jennifer L.; Davis, Kathy M.. 2001. Propagation protocol for production of Container (plug) Tridens flavus (L.) AS. Hitchc. plants Container plugs; USDA NRCS - Norman A. Berg National Plant Materials Center Beltsville, Maryland. In: Native Plant Network. URL: http://NativePlantNetwork.org (accessed 2021/06/17). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

Personal tools