A l a b a m a A & M a n d A u b u r n U niversities Greenhouse Production of Bedding Plant

ANR-1312 Snapdragons

napdragons (Antirrhinum majus) are enchanting and delightful flowers that have been enjoyed for Scenturies. These Mediterranean natives have many pleasing attributes, from their delectable fragrance to their full range of heights and colors. They are popular as bedding and container plants and as cut flowers. The upright flower shoots are covered with buds that open from bottom to top, providing brilliant color for an extended period of time. Snapdragons perform best in the landscape in cool weather, and most cultivars can even tolerate a light frost. They tend to suffer in the summer heat of the southeastern United States, and, therefore, are typically used as fall or early spring annuals. Snapdragons flower the best in full sun and well-drained soil enriched with organic matter. They range in size from 4 inches to 2 to 3 feet tall, depending on the cultivar. Flower colors range from white and yellow to orange, red, and purple to almost black. The only color missing is true blue. Cultivars Snapdragons are classified by height into three categories: dwarf, medium, and tall. Dwarf plants grow to be 6 to 12 inches tall in a dense, bushy habitat and produce abundant flower shoots. These cultivars commonly are used in the landscape for border edging or in mixed containers. In greenhouse production, they are grown in 36-cell market packs or 4-inch pots. The medium-sized plants grow to be 12 to 24 inches tall and often are used as border fillers or as cut flowers. In greenhouse production, they are grown in 36-cell market packs or 4-inch or larger pots. Tall cultivars have a dominant, single flower shoot, grow to be 24 to 48 production in either market flats or containers and used inches tall, and mostly are used as cut flowers, but also may primarily as bedding or flowering potted plants. Series and be used in the back of a border. These are not often grown cultivars of snapdragons for bedding plant and pot culture for bedding application. are in Table 1. There also are trailing types of snapdragons often Seed Propagation used in containers and hanging baskets. Some of the best trailing snaps are theARCHIVE Luminaire series. An unusual Stage 1 butterfly-type flower can be found in the Bell and La Bella Snapdragon seeds are very small but readily germinate series in which the conventional floral tube is flared at the under proper conditions. Seeds should be sown in 406- end, giving the flower a more open appearance. Because cell plug flats containing sterile germination media with of the more recent introduction of dwarf and medium- medium moisture content and a pH between 5.5 and 5.8. sized plants, snapdragons have become more popular as A higher pH can cause iron deficiency in snapdragons. bedding and edging plants than their more traditional roles The substrate temperature should be kept between 64 of background and cut-flower plants. This publication will and 68 degrees F; temperatures higher than 75 degrees F focus on snapdragons commonly grown for greenhouse can delay germination. Because snapdragon seedlings are

www.aces.edu very sensitive to high soluble salts, electrical conductivity to 1,000 footcandles. Removable shade is an easy method (EC) should be less than 0.75 millimhos per centimeter for adjusting light levels as cuttings mature. Use intermittent (2:1 extraction method), and ammonium levels should be mist to maintain humidity around cuttings; the frequency kept at less than 5 parts per million. Light is necessary for should be adjusted based on light levels and temperatures. germination of some cultivars; contact the seed supplier Calluses should form in 5 to 7 days after sowing. Apply for specific cultivar recommendations. Seeds of non-light- a foliar fertilization of 50 to 75 parts per million nitrogen sensitive cultivars can be covered with a light layer of fine using a 15-0-15 or similar fertilizer formulation as needed. vermiculite to maintain adequate moisture levels next to Cuttings are ready for root development once a the seed. Radicle emergence can be expected within 4 to callus has formed and 50 percent of the cuttings have 8 days after sowing; when they begin to emerge, reduce differentiating root initials. Substrate and air temperatures moisture levels to encourage roots to penetrate the media, need to be maintained, and light levels should be increased which should be moist but not saturated. to 1,000 to 2,000 footcandles. Fertilizer also can be Stage 2 increased to 100 to 150 parts per million nitrogen weekly by alternating 20-10-20 with 15-0-15. Reduce the mist as After radicles emerge, remove flats from the seed roots form; roots should develop 7 to 14 days after sowing. germination chamber, if used, and then reduce substrate moisture level. Light levels should increase to 450 to Harden cuttings for 7 days before transplant or sale by 1,500 footcandles. Once a week, apply 50 to 75 parts per decreasing air temperatures to 75 to 80 F degrees during million nitrogen using a 15-0-15 fertilizer or other low the day and 62 to 28 degrees F at night, and increase ammonium fertilizer formulation. If possible, alternate fertilization to twice weekly. fertilizer with clear water. Maintain substrate temperatures Growing On between 65 and 70 degrees F, and dry the foliage before The key to producing appealing, sturdy snapdragons nightfall to prevent disease. Maintain water alkalinity at 60 is cool temperatures. Plants may be exposed to light frost to100 parts per million and ammonium levels at less than if heat is unavailable, but the most economical crops are 10 parts per million. This stage requires 7 to 14 days. produced at cool temperatures. Full sun and sufficient Stage 3 ventilation will help keep stems strong, and plant height in Lower soil temperatures to 62 to 65 degrees F by night, market packs can be controlled if water and fertilizer are and raise light levels to 1,000 to 2,500 footcandles. Allow applied somewhat conservatively. flats to dry between irrigations, but avoid wilting. Increase Transplant the seedlings when roots easily hold the fertilizer to 100 to150 parts per million nitrogen weekly, plug mass together and have two to three sets of true alternating between 20-10-20 and 14-0-14 formulations. leaves; do this in a timely manner to avoid stunting growth. However, avoid ammonium-based fertilizer if growing Bedding snapdragons perform best if transplanted to 18- or below 65 degrees F. During this stage, supplement fertility 36-cell flats and also do well in 4-inch pots or in groups of with magnesium sulfate once or twice and occasionally three to five plants in a 1-gallon container. Trailing snaps leach them with clear water to reduce EC. If stretching should be planted in 4-inch pots or in pairs in 6-inch pots. might be a problem, apply A-Rest 3 to 4 weeks after sowing Four to five cuttings can be planted in a 10-inch at a rate of 10 parts per million. Fungicides can be applied hanging basket. at the lowest recommended rate to control Pythium, Choose a sterile media with a moderate initial fertilizer Rhizoctonia, and Thieleviopsis. This stage requires 14 to rate and a pH of 5.5 to 6.2. Maintain high light levels 21 days. at 5,000 to 6,000 footcandles because low light causes Trailing Cultivars stretching, reduces flowering, and increases crop time. Temperatures should be 72 to 75 degrees F during the Trailing snapdragons, such as the Luminaire and day and 62 to 65 degrees F at night. You may reduce night Playful series, are propagated vegetatively. The best trailing temperatures to 45 to 50 degrees F once plants establish to cultivars are patented; therefore, propagation by unlicensed promote flowering. Once flowering begins, maintain night propagators is illegal. Also, stock plants can carry a temperatures below 60 degrees F. number of latent diseases and should be virus-indexed and maintained in a clean stock system. For these reasons, Apply fertilizer twice weekly at 150 to 200 parts per ARCHIVEmillion nitrogen alternating between 20-10-20 and 15-0-15 growers should buy unrooted cuttings or rooted liners. formulations. Reduce this rate when flower shoots begin to If unrooted cuttings cannot be planted immediately, elongate to increase postharvest life. For trailing snaps, it store them for no longer than 24 hours at 50 to 60 degrees is important to maintain fertilizer levels because low levels F. Stick cuttings in Oasis wedges or in a sterile medium hinder plant branching. with a pH of 5.6 to 5.8. Media temperatures should be maintained at 68 to 72 degrees F with an air temperature of Pinch trailing snaps once the roots reach the edge of he container. Throughout the rest of production, shear 75 to 80 degrees F during the day and 68 to 70 degrees F t plants to maintain shape. Four-inch pots require one pinch; during the night. Light levels should be maintained at 500 6-inch pots, two pinches; and 10-inch hanging baskets, two

 Alabama Cooperative Extension System to three pinches. Also, pinch taller bedding snapdragons Troubleshooting planted in larger pots to promote branching and multiple High pH can cause stunted or uneven seedling growth flower shoots. or poor root development. Also, very high pH can cause Height control can be a problem in bedding plant boron deficiency. A high pH or a cool, wet substrate may snapdragons grown from seed. When grown under cause interveinal chlorosis of immature leaves, resulting recommended cool temperatures and high light, growth in reduced iron uptake. If the problem is high pH, spray retardants should not be necessary. If needed, apply A-Rest the plants with iron sulfate at 33 ounces per 100 gallons of as a 10 to 26 parts per million spray or B-Nine as a 2,500 water. If the deficiency is caused by the cool, wet medium, parts per million spray on snapdragon seedlings. Some dry the substrate and increase the temperature. Symptoms growers tank mix B-Nine and Cycocel with 800 to 1,000 of should diminish within 3 to 4 days. each after transplanting. You also may use Bonzi as a 60 to Botrytis infection or chronically wet substrate can cause 90 parts per million spray or Sumagic as a 25 to 50 parts per the plant to collapse. High nitrogen concentration, applying million spray to control the height of snapdragons, but they too much fertilizer under low light conditions, or low light may delay flowering and can cause less uniform flowering. and overwatering can cause excessive foliage growth. Scheduling Foliage necrosis can be caused by high EC or by the plant drying out between irrigations. Trailing snapdragons that do Crop production time varies depending on cultivar. not branch properly may not be receiving enough light or In general, plug crop time from seed to transplant is 5 to were not properly fertilized during early growth stages. 6 weeks. Dwarf types take 4 to 5 weeks from transplant to finish in market packs and 5 to 6 weeks in 4-inch pots. Medium-sized types take 10 to 12 weeks from transplant to finish in 4-inch pots and 12 to 13 weeks in 6-inch pots. Pests and Diseases Snapdragons have fewer problems than many other bedding plant crops. Fungus gnats and shore fly larvae are the most common insects on seedlings. Aphids, mites, and thrips may injure mature plants. Be careful when applying pesticides to snapdragons because some are known to cause damage to flowers; carefully read the label to avoid problems. Downy mildew, powdery mildew, Pythium, botrytis, rust, Phyllosticta blight, and Anthracnose are common fungal diseases on snapdragons. Tomato spotted wilt virus and impatiens necrotic spot virus also can be problems on vegetatively propagated snapdragons. To help control foliar diseases, avoid wetting foliage. If overhead irrigation must be used, water early in the day to allow foliage to dry before nightfall. ARCHIVE

Greenhouse Production of Bedding Plant Snapdragons  Table 1. Series and Cultivars of Snapdragons for Bedding Plant and Pot Culture in Greenhouse Production1

Series / cultivar2 Company source Garden Comments height (inches)

Bells Series Goldsmith Seeds 8 to 10 9 colors; butterfly-type flower; flowers longer in garden; strong, well-branched plants

Chimes Series Goldsmith Seeds 6 to 8 10 colors; full, bushy plants loaded with fragrant, colorful shoots

Coronette Series S&G Flowers 20 to 24 9 colors; filler in garden or cut flower; withstand wind and rain

Crown Series S&G Flowers 16 to 18 14 colors; fast branching; strong garden performance; mid‑height color in the landscape

‘Floral Carpet Mix’ Benary Seeds 8 16 inches wide; very uniform; free flowering; ideal for group plantings

‘Floral Showers Mix’ Benary Seeds 6 Wide, flat cushions; extremely early for flowering sales

‘Frosted Flames Mix’ Harris Seeds 12 Open pollinated mix; bright, rich colors; unusual white variegated leaves

Freesong Series Bodger Seeds 14 to 18 12 colors; recommended for garden beds, cut flowers, and 4-inch pot production

Kim Series Floranova 10 to 12 11 colors; branching habit; side shoots and flower with central shoot; for pots and landscape

La Bella Series Goldsmith Seeds 18 to 22 6 colors; open butterfly-type flowers on strong, well-branched plants

Liberty Classic Series S&G Flowers 20 to 24 8 colors; sturdy flower shoots and uniform habit

Luminaire Series Ball FloraPlant trailing 6 colors; free‑flowering, trailing plants (cutting) ARCHIVEfor containers and baskets

‘Magic Carpet Mix’ Bodger Seeds 6 to 8 Compact non‑hybrid mixture

Montego Series S&G FLowers 8 to 10 14 colors; early flowering dwarf; strong basal branching for a robust-like plant

 Alabama Cooperative Extension System Palette Series American Takii 6 to 8 11 colors; uniform; early flower; well- branched

Playful Series Ball FloraPlant 6 to 8 6 colors; well‑suited to pot‑tight 4‑inch (cutting) programs

‘Princess White with American Takii 10 to 12 Striking bicolor flower; uniform Purple Eye’ flowering

Snappy Series Hemgenetics 6 to 8 6 colors; very uniform flower time across color range

Snapshot Series Ball Seed Co. 6 to 10 11 colors; bushy, compact plants with closely spaced flower on shoots

Solstice Series Ball Seed Co. 16 to 20 9 colors; quick-finish; flowers 30 to 60 days earlier under short days than other intermediate size, winter-flowering cultivars

Sonnet Series Sakata Seeds 12 10 colors; strong root system; sturdy branches; can take high winds without lodging

Tahiti Series S&G Flowers 8 to 10 14 colors; dwarf plant habit; flats and pots 1 This table is not exhaustive but includes series and cultivars widely available on the U.S. market. 2 Names enclosed in single quotes are single cultivars. Names without quotes are series of cultivars.

Table 2. Recommendations for Tissue Analysis Nutrient Levels in Snapdragon Percent N P K Ca Mg S 3.80 0.30 to 0.50 2.00 to 3.00 1.00 to 1.50 0.84 0.46 Parts per million Fe Mn Zn Cu Mo B 75 139 56 9 0.85 30 Adapted from Mills and Jones, 1996.

ARCHIVERachel Creel, Graduate Associate, and J. Raymond Kessler, Assistant Professor, both at Auburn University For more information, call your county Extension office. Look in your telephone directory under your county’s name to find the number. Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, and other related acts, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension System (Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability. Web Only, New Feb 2007, ANR-1312 ANR-1312 © 2007 by the Alabama Cooperative Extension System. All rights reserved.