Lotus is an impressive flowering rhizomatous, perennial, aquatic herb, which has a long history in the diverse cultures of the Orient. The plant is sacred in the Hindu and Buddhist religions. Sacred lotus has been cultivated in Asia for thousands of years and has been a prestigious crop in China for nearly 5,000 years. A developing and open world economy has led to increasing exchanges and meshing of cultures, ideas and horticultural treasures. With the exciting discovery of viable 2,000 years old lotus seeds, this plant has moved into the spotlight and the lotus industry is blooming in the world.

Little research is available on nursery production of Nelumbo nucifera Gaertn. (lotus). ‘No1’, an unnamed seedling (medium sized, with few emerging leaves and flowers) was used in testing the effect of fertilization rates. Lotus rhizomes were divided and planted. After planting, all pots were filled with water. The application of soluble fertilizer increased growth parameters. One teaspoon of 20-10-20 (Pro•Sol) every 20 days was sufficient for good growth in a 15 gallon container. Two teaspoons increased root weight, number of propagules and number of expanded internodes but also stimulated proliferation of algae growth in the beginning stage. ‘Embolene’ (medium sized, with numerous leaves and flowers) and ‘98 Seed’ (large unnamed seedling with numerous leaves, few but large flowers) were used in examining the effect of container soil level on the growth of lotus. Containers half filled with soil worked better than those three fourths full. Treatments of fertilizer rate and soil level had little effect on the concentration of macronutrients but significantly influenced concentration of some micronutrients especially B in young leaves.

Pine bark (PB) and peat (P) are two of the most common substrate components currently used in horticultural crop production. The supply, consistency, and cost of these materials has often been a concern for growers throughout the United States. These concerns have prompted the search for alternative substrates and substrate components that can be successfully utilized for quality crop production. Cotton is a major agronomic crop grown in the southeast United States. Cotton gin trash (CGT) is the term used to describe the by-products of the cotton ginning process that includes the leaves, stems, hulls, and some lint. Composted cotton gin trash (CGC) has been shown to be a useful substrate component for production of bedding plants, floral crops, and woody ornamentals.

Frequently excluded from horticultural research, root growth and root system architecture are important factors influencing plant performance and survival. A healthy, functioning root system increases the surface area available for the uptake of water and nutrients. In addition, roots provide physical support, storage, and anchorage needed by plants. Understanding root growth and development is important to improving plant quality and production success.

The objective of this study was to utilize the Horhizotron™ to evaluate root growth of weeping fig (Ficus benjamina) and ‘Hot Country’ lantana (Lantana camara Mill. ‘Hot Country’) when grown in various blends of PB and CGC. The Horhizotron provided a simple, non-destructive method for measuring root growth and development in various root environments and substrates, and it allows roots to be observed and quantified as they grow from the original root ball and penetrate into the surrounding substrate .

Treatments were four substrate blends of milled PB and CGC that included by volume: 100:0 PB:CGC, 60:40 PB:CGC, 40:60 PB:CGC, and 0:100 PB:CGC. Pine bark substrate was used as the control. Dolomitic limestone was added where needed to achieve pH levels of 6.0. Weeping fig and ‘Hot Country’ lantana were removed from 3 gallon containers and placed in separate Horhizotrons on greenhouse benches at the Paterson Greenhouse Complex, Auburn University. Root balls of all plants were positioned in the center of each Horhizotron and each quadrant was randomly filled with one of the substrate blends to the height of the root ball. Plants were hand watered daily and fertilized once weekly.

Root length and location in the quadrant profile were measured as newly formed roots grew out from the root ball and along the face of the glass quadrants. A transparent grid placed on the two glass sides of each quadrant allowed observation and measurement of the five longest roots on each side of the quadrant. Over the course of the study root measurements were discontinued when roots reached the end of the Horhizotron quadrant. Root development in all CGC blended substrates was considerable enough to firmly hold the substrates together when plants were removed from the Horhizotrons. The quadrant containing 100% PB shattered upon being pulled from the Horhizotron, a result of less root proliferation in that substrate. This experiment provides strong evidence that roots can grow effectively and vigorously in substrates containing CGC, facilitating successful establishment and production of horticultural crops.

Cut snapdragons are a multimillion-dollar crop but there are very few growers in Alabama where direct marketing has great potential. This study examined the possibility of exploring that potential by the use of high tunnels which have been used extensively in Europe and the Middle East for production of vegetables, annuals, biennials, and other horticultural crops.

High tunnels are covered with a single layer of six-mil polyethylene and are ventilated by manually rolling up the sides. There are no permanent heating or cooling systems in the high tunnel but water is supplied for drip/trickle irrigation. Pennsylvania State University has extensively investigated production of many horticultural crops grown in high tunnels (including snapdragons - Antirrhinum majus). Their high tunnel production system utilizes many of the traditional production methods of field plasticulture.

Recent research has shown that snapdragons grown inside a high tunnel had longer stems than those field grown. The objective of this study was to evaluate preplant nitrogen (N) rates with a control release fertilizer and to determine optimum snapdragon spacing. A single high tunnel (21’x96’) was constructed utilizing the Pennsylvania State University design at the Wiregrass Research Station located in southeast Alabama. Plants were grown on black plastic mulched beds (18 inches) that were prepared with a mulch-bedder (Reddick Fumigants, Williamston NC) and underlain with Tee-tape (0.45 gpm/100ft) for irrigation purposes. Irrigation was applied once a week at a rate of 1.0 acre-inch.

Total stem length and inflorescence length peaked at the 240 lbs. N/A rate with the Polyon 19-6-12. Stem diameter did not peak at this rate. The stem diameters from the 240 lbs N/A rate were only 0.1mm smaller than the 360 lbs. N/A rate and 0.2mm smaller than the 160 lbs N/A rate. The 3x4 inch spacing yielded longer inflorescence length, stem length, and larger stem diameter compared to plants in the 4x4 or the 4x5 inch spacing. Our system (growing three rows on each black-plastic row) would allow for the greatest number of snapdragons per square foot of bed space (in our high tunnel the yield would be 6,750 plants per planting in about 6-8 weeks).

Samples from this experiment were delivered to three local florists for a non-replicated evaluation. All of the florists rated these snapdragons in the ‘excellent’ category and indicated that they would purchase comparable snapdragons if grown locally throughout the year.

Liverwort (Marchantia polymorpha) is an increasing problem in container-grown ornamental production within the Southeast. Prostrate leaf-like structures of liverwort known as thalli create a mat over media surfaces in containers. Not only is liverwort unsightly, it can impede water and nutrient movement into the root zone. It thrives in low UV light, high fertility and high moisture environments. Since it is an emerging problem, little research exists on preemergence controls. There are promising new products for postemergence liverwort control, but preventing liverwort infestations would be more desirable.

Full-gallon containers were filled with a 6:1 pine bark to sand substrate amended with 14 lb of Polyon 18-6-12, 5 lb of dolomitic lime, and 1.5 lb of Micromax per cubic yard. Twelve granular herbicides were applied at the recommended rate: Broadstar (150 lb product/A), Kansel Plus (100 lb product/A), OH2 (100 lb product/A), Pendulum 2G (200 lb/A), Regal 0-0 (100 lb/A), Regal Kade (200 lb/A), Regal Star (200 lb/A), Ronstar (200 lb/A), Rout (100 lb/A), and Snapshot (200 lb/A). Treatments were applied using a handheld shaker. After treatment, each replication was placed around a container of mature liverwort for inoculation. The study was conducted under 47% shade. Overhead irrigation was split into two cycles per day with a total of 0.25” applied.

This study showed that Broadstar and Ronstar provide superior preemergence control of liverwort compared to the other herbicides tested. It should be noted that there are no preemergence herbicides registered for use in enclosed structures.

Liverwort continues to spread throughout the Southeast as a weed problem in container-grown ornamental crops. Liverwort thalli can cover the entire media surface of a container and restrict water and nutrient movement into the root zone, as well as reduce the marketability of a crop. Propagation houses, shade houses, and other covered structures provide ideal conditions for liverwort.

One herbicide with potential is quinoclamine which has been used as an algaecide in Japan for decades. It is produced as a 25% wettable powder. Quinoclamine has proven to be very effective on postemergence liverwort control, and it is safe on a broad range of ornamental crops. Previous research suggests that lower rates and spray volumes provide adequate postemergence control. The nursery industry in Germany has used diuron for liverwort control. Diuron is a substituted urea herbicide widely used in cotton production within the Southeast. It is highly active and inexpensive. The objectives of this study were to evaluate lower rates and spray volumes of quinoclamine than current recommendations and any interaction between rate and volume, as well as evaluate the effectiveness of diuron for liverwort control.

This study was conducted at Auburn University. Liverwort was grown in full-gallon containers consisting of a 6:1 pine bark to sand substrate amended with 14 lb of Polyon 18-6-12, 5 lb of dolomitic lime, and 1.5 lb of Micromax per cubic yard. Postemergence treatments were applied when liverwort covered at least 60% of the container surface. Diuron 4L and Linuron (another substituted urea herbicide with similar chemistry to diuron) 4L were each applied. All treatments were applied with a CO2 backpack sprayer fitted with an 8004 flat fan nozzle at 30 PSI. A non-treated control group was maintained. In addition to liverwort, all treatments were also applied to 6 single pot replications of Humata tyermanii (Rabbit foot fern) and Euphorvia pulcherrima (Poinsettia). The study was conducted in a temperature controlled greenhouse under 0.25 inch overhead cyclic irrigation per day split into two cycles.

Main effects of quinoclamine rate, volume, as well as the interaction thereof were found to be significant. In general, control increased as rate and spray volume increased. Among quinoclamine treatments, higher spray volume provided greater control with lower rates. Conversely, lower spray volumes (54 gal/A) can provide adequate control at higher rates (1.0 and 2.0 oz product/A). By 70 DAT, 2.0 oz product/gal applied at 54 and 109 gal/A had the least percent liverwort coverage among the quinoclamine treatments with 40% and 22% coverage. All other quinoclamine treatments had a higher percentage of liverwort coverage. Quinoclamine treatments were compared to Diuron and Linuron treatments as well as the non-treated control group. No injury was recorded on Humata tyermanii or Euphorvia pulcherrima at any time throughout the study.

The research data showed that quinoclamine rate and volume of application influence postemergence liverwort control. Rate and spray volume may best be determined by individual growers. This study also recognizes Diuron as a promising treatment for liverwort with excellent long term control.

Container nursery crops are among the most valuable crops produced in the Southeast. Weeds can reduce the value of nursery crops by reducing growth through competitive effects and reduced salability due to consumer demand for weed free crops. Growers primarily use preemergence herbicides for weed control. However, demand has increased for nursery crops grown in large containers. Preemergence herbicides are often impractical as the increased spacing between containers results in over 50% of the herbicide falling outside of the containers. Hand weeding is another expensive option and and labor costs continue to increase.

Fresh pine bark nugget mulch could be an alternative. It has been used for many years in landscape beds to control weeds and could be an option for use in container crops. Physical properties of fresh pine bark are conducive to weed control as it is hydrophobic with limited water holding capacity due to the large particle size. Pine bark is well suited to be spread uniformly as a mulch, covering the entire surface of the container while other mulch type products may leave cracks for weeds to establish. What needs to be determined is whether it can be effective for weed control; and the depth of mulch required for that purpose.

These studies were conducted in Auburn, Alabama. Crapemyrtle (Lagerstroemia x ‘Acoma’) were transplanted from trade gallon containers into 7 gallon containers. The substrate used was a 6:1 (v:v) aged pine bark: sand amended with 2.3 kg (5lb) of dolimitic lime, 6.4kg (14lb) of Polyon 18-6-12. and 0.68kg (1.5lb) of Micromax. All plants were potted to equal depths, approximately 3 inches below the top of the container and were irrigated twice prior to treatment. Three treatments consisted of broadcasting 25 bittercress (Cardamine hirsuta) seed on the surface of the substrate of each container, then coarse pine bark nugget mulch was hand applied at 0, 1.5 and 3 inches respectively. The nuggets averaged in size from 0.79 in to 2.36 in flakes. Two other treatments consisted of first applying mulch at 1.5 or 3 inches, then broadcasting the bittercress seeds on top of the mulch. These procedures were also applied to five more treatments and a granular herbicide (Broadstar 0.25G at 150 lb product/A) was applied after all mulch and seed were present.

In a similar study, common gardenia (Gardenia jasminoides) were transplanted from trade gallon containers into 7 gallon containers. The same treatments were applied to the gardenia except 25 oxalis (Oxalis stricta) seed were used per container instead of bittercress. In both studies, data collected were weed number per container at 30, 60, 90 and 180 days after treatment (DAT) and percent coverage of weeds at 60, 90, 180 DAT. These studies show that pine bark mulch can provide effective weed control for nursery crops grown in large containers. At 180 DAT oxalis was present in the no mulch, no herbicide treatment which contained 3.9 weeds and averaged 35 % coverage of container surface. All other treatments resulted in minimal oxalis growth . The combination of mulch plus herbicide provided complete oxalis control 180DAT.

At 180 DAT bittercress was growing vigorously in the control containers (no mulch-no herbicide). These containers averaged 8.1 bittercress, 100% coverage of container surface and 59.6 g of bittercress per container. In comparison no herbicide, 1.5 inches of mulch treatment with seeding after mulching, averaged 2.6 weeds, 44% coverage of container surface and 33.7 g per container. Both treatments resulted in greater bittercress growth than all other treatments. Similar to the oxalis study, the combination of mulch plus herbicide provided complete bittercress control 180 DAT and no herbicide or mulch application affected growth of crapemyrtle or gardenia.

Our research shows that the use of tree shelters in the production of tree-form crapemyrtles can increase height growth while minimally affecting caliper growth. ‘Dynamite’ and ‘Potomac’ were 124% and 61% taller at the end of the season when grown in tree shelters, while height growth of ‘Tuscarora’ was not affected by tree shelters. Caliper of sheltered and non-sheltered ‘Tuscarora’ and ‘Dynamite’ were similar at the end of the season, while caliper of ‘Potomac’ was 35% less when grown in shelters. Tree shelters may provide growers with a low-input way to accelerate production of tree-form crapemyrtles.

Crapemyrtle are vigorous growers under nursery conditions; however, most cultivars begin flowering by early summer, resulting in a reduction in vegetative growth rate, particularly growth in height. This problem is often compounded by heavy fruit set later in the growing season. Pruning of inflorescences is labor-intensive and results in rapid re-bloom. For production of standard (single trunk) or multi-trunk (usually 3) tree-forms of crapemyrtle with a central leader and four to six feet of clear trunk, pruning exacerbates the problem by stimulating new shoot formation, often from the main trunk. Flowering and heavy fruit set can result in longer production cycles.

Tree shelters, translucent tubes placed around tree seedlings, create a beneficial microclimate within the shelter of increased humidity and CO₂ levels and reduced drying and mechanical damage from wind. Growth increases of 60 to 600% from using tree shelters have been reported. Shelters can typically increase height growth but reduce the rate of trunk diameter growth which may result in trees without enough structural support to stand upright. Tree shelters have been broadly used in Great Britain and other countries to cut costs of establishing small forest and landscape trees.

Blue-X tree shelters (McKnew Enterprises, Elk Grove, CA) are fabricated from partially transparent blue-tinted polyester film and that amplifies blue light and reduces UV light within the shelter. According to the manufacturer, the amplified blue light increases photosynthetically active radiation resulting in increased trunk diameter in addition to accelerated growth in height and enhanced transplant survival. The objective of this research was to determine the effects of Blue-X tree shelters on height and caliper growth of tree-form crapemyrtle, with a goal of shortening the production time.

‘Dynamite’ grown in Blue-X tree shelters were consistently taller than non-sheltered trees: 118%, 128%, and 124% taller in August, September, and October, respectively, than controls. Calipers of ‘Dynamite’ in shelters and controls differed in early to mid season but not at the end of the season. In July, 30% of the ‘Dynamite’ controls were flowering while none of the trees grown in shelters had begun flowering. Height growth of ‘Potomac’ was also promoted by shelters, with trees grown in shelters 61% taller than the controls at the end of the season. Caliper growth for non-sheltered ‘Potomac’ was 35% greater than those with shelters at the end of the season. By August the ‘Potomac’ controls had flowered but not the sheltered trees. Height of ‘Tuscarora’ was not influenced by the Blue-X tree shelters, whereas caliper was 47% less in July when grown in shelters. However, by the end the season, calipers were similar for trees in the two treatments. ‘Tuscarora’ exhibited similar flowering characteristics as the other two cultivars in response to the treatments, with trees grown in the shelters flowering later than the controls. No cultivar had any flowering inside the tree shelters.

Blue-X tree shelters significantly increased height growth in two of the three cultivars tested without affecting caliper at the end of the season. Growing crapemyrtles in Blue-X tree shelters may shorten production time by enhancing height growth.

Auburn Plant Disease Report-July 2005 (J. Mullen)
Many of the 267 July plant samples were ornamentals submitted by the State Department of Agriculture. These plant submission were part of a state and national survey of nurseries to detect Phytophthora ramorum (Sudden Oak Death). Forty-eight ornamental samples were submitted from nurseries by State Department of Agriculture Inspectors in July; 198 total samples were submitted from Nurseries (May 9-July 22). These samples were tested using visual study, microscopic study, and ELISA testing for Phytophthora. For all ELISA positive samples (There were none in July, 47 total nursery samples; 51 total samples), the DNA was extracted and sent by overnight mail to the USDA Beltsville molecular lab. PCR analyses were performed and results were sent to the Alabama State Plant Health Director (USDA-APHIS). From USDA-APHIS in AL, results were forwarded to the State Plant Regulatory Official and our lab. The State Plant Regulatory Official contacts the Inspectors who communicate with the growers. So far we have results back on 21 nursery samples, and all 21 analyses have been negative. It is too hot right now to sample for P. ramorum, but more survey work is planned for this fall.