Wiregrass Propagation at the Andrews Nursery in Florida

Tim Pittman and Robert P Karrfalt

KEYWORDS: container nursery, seed collection

NOMENCLATURE: ITIS (1998)

Figure 1 • A single stalk of wiregrass. For our preharvest seed quality survey, we sample 100 stalks from 100 plants per site.

iregrass (Aristida beyri therefore, undertaken. Bareroot random samples per site. A sample is Wchiana Trin. & Rupr. production could produce plants but composed of 100 individual stalks [Poaceae]) is a major component of was an inefficient use of bed space, (Figure 1) cut from 100 individual the longleaf pine ecosystem. This and plants were difficult to handle plants spread over at least 4 to 5 species was formerly named because of the widely spreading root stops per site. This composite sample Aristida stricta. However, A. stricta systems. Containers were later found for each site is then taken to the Michx. (Poaceae) is now consid- to be much more workable. nursery where 20 stalks are drawn at ered confined to North Carolina random for a viability test. Seeds are and northern tier counties of South Seed crops striped from the stalk by pulling the Carolina, while A. beyrichiana Seed crops are unpredictable and stalk, base end first, through pinched occurs from southern South hard to find. Although seeds may fingers. We immediately place the Carolina through Georgia to appear to be present, they often do seeds into a petri dish containing a Florida and west to Mississippi not germinate. Causes for the lack of cross-linked polymer used for (Peet 1993). germination are not well known but treating plant roots at transplanting. In the late 1980s, water almost surely involve insect feeding, The polymer is moistened with management districts in Florida fungi, and environmental factors. water to form a gel. The fine grade needed wiregrass plants for site One trend that appears to hold is of the polymer is preferred as it restoration. The demand was high, that the most consistent crops are makes a firmer gel. One container of but stock was unavailable. Vegeta- found on sites that have had summer polymer is used for a number of tive propagation from the wild was burns on 3-y cycles for at least 10 y. years to help keep the evaluations too expensive and counterproduc- As a result of the unpredictable uniform from year to year. Germina- 45 tive because it required removal or germination, a great deal of sam- tion is done under natural light at 2000 SPRING at least disruption of plants already pling in the field is necessary to find room temperature in the nursery established in the wild. Develop- a crop worth collecting. Our office. Germination is complete in ment of nursery propagation technique is to walk many hectares 12 to 30 d at ambient conditions techniques from seeds was, at many sites, making numerous

VOLUME 1 • NUMBER 1 The number of lines was increased collected seeds. These tests are made from 4 lines per row to 16 and 17 on 2 samples containing 100 seeds per row. Bristles were staggered from each. Seeds are individually pulled row to row to give a brushing effect. from the barrel and placed on the gel Two rows of 16 and 2 rows of 17 in plastic boxes (10.2 X 15.2 cm bristles make up the head. Bristles [4 X 6 in]). Germination rates range are held in place by pop rivets. A from 17% to 30%. We weigh seeds hook was used to hold the rivet in to determine the number of seeds the hole (Figure 4) until the filament per gram by counting out replicates was in place. of 100 seeds and placing them on a We collect seeds from mid balance until 1.0 g of seeds is Figure 2 • Preharvest seed samples are November to mid December. obtained. The range of seed weights tested for viability in petri dishes on a cross- Collection intervals depend on has been from 1400 to 2500 seeds linked polymer gel. Sites producing adequate numbers of viable seeds are then revisited for weather—harvesting as a tropical per g (39,200 to 70,000 per oz). We harvest. inversion approaches is not a good estimate purity. idea. Low humidity days (< 75%) are best because the awns open, Propagation (Figure 2). A growth chamber at a exposing seeds and allowing seeds to Seedlings are grown in Ropak Multi- constant 30 °C (86 °F) can give fall freely without clinging to plant Pot #3–96 containers that have a germination results in 6 to 12 d. No stalks. Seeds will not shatter from volume of 98 ml (6 in3), are 12 cm light is required but some light helps the plant even when humidity is (5 in) deep, and have a density of make the seedlings easier to see 441 cavities per m2 (41/ft2). We fill because they have chlorophyll containers with Vergro Poly Mix B initiation and are green. Those sites (Verlite Corp, Tampa, Florida). The that produced viable seeds are mix contains 5:3:2 peat moss:poly- revisited for seed collection. styrene beads:coarse vermiculite and controlled release Osmocote plus

Collection minors (17N:6P2O5:10K2O; 8 to 9 Because wiregrass sites are ecologi- mo at 21 °C [70 °F]) added at 1.54 cally sensitive, wheeled machinery is kg/m3 [4.5 lb/yd3]. Comparable prohibited. However, hand collec- mixes would also likely work. tion alone is not practical. We tested Sowing must be done before hot a prairie seed striper (Figure 3) weather arrives and after danger of purchased from Prairie Habitats in frost is fully past—target sowing Figure 3 • Prairie seed stripper used for seed Argyle, Manitoba, Canada, and collection on wiregrass sites. date in Chiefland, Florida, is 1 found it to be a good device for April. Seeds are mixed well with rapidly collecting seeds. This device medium or course grade vermiculite is a string trimmer motor and drive high. However, animals walking in a ribbon mixing machine at a rate shaft connected to a rotating shaft through the grass will dislodge seeds. of 150 to 200 g (5.4 to 7.1 oz) of that has monofilament lines coming Seed yields on dry days are twice as seeds per 0.12 m3 (4 ft3) of vermicu- out of it in staggered rows. As the high as those on humid days. We lite. The vermiculite and growing shaft rotates it strips the seeds from recommend collecting after 09:00 medium is used just as it comes from the plant into the collection basket AM. the bag. Adding water is not done that is mounted behind it. The Seeds should be held in barrels at because this causes seeds to stick in filaments on the sweeper head ambient temperatures for 5 mo as the mixing machine. We spread the supplied by the vendor were found viability increases during this period mix on filled, pressed Multi-Pots at a to be too stiff for wiregrass. Instead (Hermann 1999) and used within 8 depth of 6 to12 mm (0.25 to 0.5 of stripping the seeds, they cut the mo. Beyond 8 mo, viability drops in). Trays are watered and placed in entire stalk. With the assistance of rapidly. Long–term storage studies an outdoor growing area. Shade 46 Frank Osteen of Port White, are under way to determine methods cloth is spread over the trays and Florida, the head was redesigned and for storing beyond 6 mo so that a weighed down with lumber, now uses 0.065 gauge “Starline” seed bank can be developed and otherwise hard rain storms can wash string trimmer line. This line is star dependance on annual collection all the vermiculite-seed mix out of shaped in cross section and more avoided. In February or March, the containers. We allow seeds to pliable than that originally used. germination tests are made on germinate and seedlings to grow

SPRING 2000

NATIVE PLANTS JOURNAL through the shade cloth. Some 6 to 15 d after sowing, seedlings will have grown about 25 mm (1 in) tall and the shade cloth should be removed because taller plants will begin tillering and not slide freely through the cloth when it is Figure 4 • Closeup of prairie seed stripper head that was removed. We irrigate modified by using more and softer filaments on the rotating the crop daily (because central shaft. of the well-drained mix) with an overhead fixed system, receiving 2.5 to 4 cm (1 to 1.5 in) of irrigation water per container. Seed- lings are ready for planting in 3 mo, although depending on planting site, seedlings may remain at the nursery for up to 12 mo (Figure 5). Most top growth is done after 5 mo, at which time most plants begin flowering. Unfortunately, seeds Figure 5 • Wiregrass seedlings pulled from the containers collected from nursery and ready for shipping to planting site. plants have very low viability. We extract seedlings from containers before shipment to Author Information planting sites. Plants required to be Tim Pittman in boxes for more than 2 d are Container Nursery Supervisor refrigerated. Seedlings can be stored Andrews Nursery in refrigerators for a month. Seedling Florida Division of Forestry PO Drawer 849 production cost (US$170 per 1000 Chiefland, FL 32644 plants) is less than 15% of the cost of vegetatively multiplied plants Robert P Karrfalt Director collected in the wild. National Tree Seed Laboratory USDA Forest Service References Rt 1 Box 182-B Hermann SM. 1999. Personal communica- Dry Branch, GA 31020 tion. Tallahassee (FL): Tall Timbers rkarrfalt/[email protected] Research Station. [ITIS] Integrated Taxonomic Information System. 1998. Biological Names, Version 4.0 (on-line database). URL: http:// 47 www.itis.usda.gov/plantproj/itis/ 2000 SPRING itis_query.html (updated 15 December 1998). Peet RK. 1993. A taxonomic study of Aristida stricta and A. beyrichiana. Rhodora 95(881):25– 37.

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