September 1998

September already! Kids are back in school and another chapter of SNA is behind us. The research conference and trade show were great, as usual; and we had a chance to see many old friends. Auburn had three people in the money for scholarships and awards at the research conference as you will read about below. We also had a number of papers with good, practical take-home messages that we will be summarizing in this month's issue of Something to Grow on.

Don't miss the Southern Region Plant Propagator's Meeting in Tulsa, Oklahoma, October 18-21, 1998. I have always considered this one of my top 2 meetings of the year for information I could use for assisting nurseries in the state. Obviously, if you go yourself, you will not need second-hand information from me. It's a great meeting because it is an industry-run Association that offers a blend of nursery on-farm expertise and some added research information from the university faculty throughout the Southeast. The tours of top nurseries are also great. If you have not been out in a while to see what your neighbors are doing, this is a great time and opportunity to do it. The motto of IPPS is "To Know and Share." You will find that people at this meeting live up to that motto. I hope to see you there. Contact me (334-844-5484, or Dr. David Morgan (Executive Secretary of IPPS at 817-882-4148, for more information on the program.

As many of you have probably heard, Auburn University is in the middle of a significant restructuring process. In the School of Agriculture, we have several Deans retiring or leaving and we have just hired an interim Provost at Auburn. We are also in the process of switching to the semester system. While a task force is evaluating 35 proposals for merging and dissolving schools and departments, the administration is asking for input from departments and schools on what should be the top 10 areas that the University should throw its limited resources behind in the future. This is all happening fast.

The faculty in horticulture is trying to get our story across to the "powers that be" to assure we get support for our efforts to serve you. With over 250 students in Horticulture (this figure continues to rise each year) the faculty is using this time of change to be sure we are meeting the needs of our changing industry. In our minds, the Green Industry is one of the largest and fastest growing segments in Alabama's and the Nation's economy. Auburn Horticulture is among the top 5 Horticulture schools in the country and positioned to be even a greater leader in this area. The position Horticulture will occupy for the next ten years within the Department of Agriculture at Auburn University will be decided in the next few months. If you have contacts in the legislature or with the hierarchy at Auburn University, now is the time to toot our horns. The attention our industry receives in research, teaching and Extension depends on who has the best message and support. The value of our industry is obvious to us but, as evidenced by the attempt to build the new Art Museum within the Arboretum, the value is not so clear to others. Efforts by Dr. George Folkerts and the Save the Arboretum Committee, along with support from people all over the country, has educated and changed the minds of the planning committee on the value of the Arboretum to Alabama. The Alabama Nurserymen's Association also wrote a letter to support this cause. The Arboretum has been saved and the Art Museum, which is certainly important, too, will have a better location. So, do not assume that everyone sees the world of Horticulture as you and I do.

As we work through these changes and uncertain times, I see the dedication and the concern that the faculty show for you and your children. It makes me very proud to be part of this Department. If I had any kids that inherited my love for horticulture, I would want them to be in this teaching program. We welcome you to come by and see us any time you are in Auburn. We will be having our traditional friends and alumni gathering at the greenhouse complex 2 hours before kickoff at the Georgia football game on November 14. Drop by and see us on the way to the game.

Have a great September and remember that the joy of horticulture and gardening is sharing your plant treasures and knowledge with others.

Ken Tilt

DISCLAIMER: Please remember that all information presented is a summary of research and not an endorsement of any product or a recommendation of chemicals. The official labels from the manufacturing companies offer the legal and proper use and handling information for all products.


1. The Influence of Light and Temperature on Shasta Daisy

2. How to Control the Growth of Coreopsis Rosea

3. Postemergence Control of Bittercress

4. Influence of Liriope Division Size on Subsequent Growth

5. Recycled Newspaper Reduces Nitrate Leaching from Nursery Containers

6. The Propagation of Hosta

7. Cultivating Clubmosses

8. 'Pocomoke' Miniature Hybrid Crapemyrtle Ready for the Public

9. Students Plant Container Gardens

10. The Joys of Container Gardening

11. Notes from Jackie Mullen from the Plant Diagnostic Lab

12. Upcoming Events


Research has been conducted at Auburn University by Dr. Raymond Kessler to determine what effect extended light (photoperiod) and the imposition of cold temperatures (vernalization) has on the flowering of certain shasta daisy cultivars. Plants of three cultivars, 'Becky', 'Snow Cap' and 'Snow Lady' were placed in different growing environments and carefully monitored relative to temperature and how much light they received. The three cultivars varied in their response to photoperiod and vernalization. 'Becky' required long days of light to completely flower. 'Snow Cap' and 'Snow Lady' were less responsive to environmental conditions. All three cultivars, however, responded very well in terms of shoot height, flower shoot number, decreased time to flower, and market quality rating when vernalization was increased up to six weeks under long periods of light. It was concluded that long days of light in combination with lower temperatures would be needed to ensure rapid flowering and the highest plant quality.

(from J. Raymond Kessler, Jr. and Gary J. Keever, submitted for publication to Southern Nursery Association).



Managing pink coreopsis is often difficult in the nursery because it grows quite rapidly and usually needs to be pruned. This can be costly and time consuming. The use of plant growth retardants (PGRs) seemed to be a viable solution to this problem. Researchers at Auburn University set out to find which growth retardant and in which amount would best manage the plants.

The object of the study was to observe how effective (in cost and time) the PGRs, B-Nine, Bonzi, Cutless and Sumagic would be in controlling the growth of pink coreopsis. PGRs were applied as foliar sprays in different dosages with long periods of light. Date of the first opened flower was noted, as well as shoot height and growth. Plants were rated on their market quality when one third of the flowers were opened. Control plants were rated unmarketable while most treated with PGRs were considered very marketable. Cutless, Sumagic and B-Nine appear useful in the production of a high-quality coreopsis crop. Plant size was reduced without a delay in flowering. The use of Cutless and Sumagic also decreased the number of days required for the plants to flower fully.

(from S.E. Burnett, G.J. Keever, J.R. Kessler, and C.H. Gilliam of Auburn University - presented at SNA 1998).

**Below is a summary of a student paper from the Horticulture Department at Auburn University that won 2nd place in the ANA Student Research Competition - Master's Degree Section**


Weed control is a constant struggle for anyone who works with plants, particularly nursery growers. One of the main problems in controlling weeds is trying to determine how much of a chemical is needed to eliminate the weed problem without damaging the crop. To study this problem researchers at Auburn University looked at the weed bittercress (Cardamine spp.), a very prolific and as yet uncontrolled weed that grows in containers. This study evaluated the effectiveness of postemergence herbicides on the control of bittercress in container grown liriope (Liriope muscari).

Plants were treated with the following herbicides: Manage (halosulfuron), Image (imazaquin), Action (fluthiacet-methyl) and Resource (flumichlorac pentyl ester) at different strengths. Manage and Image are pre-emergence herbicides which, in past studies, caused no observable phytotoxicity to liriope. Action and Resource are experimental postemergence herbicides usually used for broadleaf weed control in corn. Weed counts were tabulated as well as a rating - from no damage to severe damage and death of the plants.

Researchers concluded that postemergence bittercress can be controlled with little phytotoxicity when the correct amount of postemergence herbicides are used. Manage or Image at low rates worked well. Roundup did not control bittercress well and also resulted in high rates of leaf damage. Trimec Southern controlled the bittercress well but damaged the liriope.

(from James Altland, Charles Gilliam, and John Olive of Auburn University - presented at SNA 1998).

**Below is a summary of a student paper from the Horticulture Department at Auburn University that won 1st place in the ANA Student Research Competition - Master's Degree Section**


Liriope is an important component of many landscape plans. It can be used as a ground cover, a foundation plant, in edging, and as an accent plant in combination with perennials, shrubs and trees. Growers know it is an important part of today's market. It is known as 'lilyturf', 'monkey grass' and 'Aztec grass.'

Liriope is produced by division. Stock plants are divided into single plant divisions known as 'bibbs'. It takes about six months from dividing and replanting to harvest. Investigators wanted to find out if cutting back shoots of Liriope muscari slows subsequent regeneration of roots and shoots.

Two experiments were conducted and the results were that liriope with larger root systems at division were expected to do better. Larger root systems should generate new growth faster than plants with smaller root systems. Shoots appear to play a more important role than roots in the generation of new shoots and roots. Liriope producers should minimize pruning back the shoots at division.

(from Christine K. Hayes, Charles H. Gilliam, Gary J. Keever and D. Joseph Eakes, Auburn University - presented at SNA 1998).

**Below is a summary of a student paper from the Horticulture Department at Auburn University that won 3rd place in the ANA Student Research Competition - PhD Section**


Nurseries in the southeastern United States use large quantities of ground and surface water to meet the irrigation demands of their container plants which are grown in pine bark-based media. Plants are highly fertilized with resultant contamination of nursery runoff water, especially with nitrate nitrogen. The evidence of high nutrient levels in runoff from liquid feed fertilizers has motivated many nursery growers to switch to control release fertilizers. This practice improves the situation but not enough. It appears that the containers themselves may provide significant assistance in combating this problem. Reducing the level of leachate before it leaves the container is critical. In past laboratory experiments recycled newspaper was found to absorb and hold nitrates.

The research project utilized ground paper, paper crumble and paper pellets placed 2 to 3 cm. deep in the bottom of containers. Red poinsettia 'Glory' was planted in prepared containers as well as Impatiens balsamina 'Lilac Splash'. The leachate was definitely and appreciably reduced. Plants were found to grow better, however, in 1 cm than 2 cm of pellets.

(Janna O. Sichivitsa, Charles H. Gilliam, James H. Edwards, Jr., Gary J. Keever, and John W. Olive of Auburn University - presented at SNA 1998).



Hosta is a very popular landscape plant which is successful as a singular container plant or in a landscape plan. Plants increase in area by forming offsets, small lateral shoots or branches which develop from the base of the main stem. Unfortunately, the traditional method of propagating hosta has been by dividing the crown. After this practice offsets are slow to develop. The new buds are somewhat stymied by an internal balance in the plants between two hormones, auxin and cytokinins. The use of Benzyladenine (BA), a synthetic cytokinin, appears to promote elongation of otherwise inhibited buds. Research results, however, were often erratic, even though attempts were made to keep factors uniform. It was conjectured that variability in root mass at the time of the treatment may have something to do with the success of BA.

Two hosta cultivars, 'Francee' and 'Francis Williams', were used in this experiment. Their root masses were measured and categorized and different applications of BA were administered. It was found that the administration of BA did positively impact on the outgrowth of buds in hosta but also that root mass seemed to be a significant factor in the amount of offsets (even in the absence of BA).

(H.C. Schultz, G.J. Keever, J.R.Kessler, R.R. Dute, and J.W. Olive of Auburn University - presented at the SNA meeting, 1998).


Ten years ago Michael Heim wrote an article for the Minnesota Horticulturist about the cultivation of clubmosses. We felt that reviewing it now might open some people's eyes to yet another horticultural possibility. Clubmosses are closely related to ferns and produce spores for reproduction. There are many forms native to many parts of the world. There are "ground pines" that resemble miniature conifers; they spread by horizontal below-ground stems and are sometimes used for Christmas decorations.

Clubmosses are tricky to grow but with close attention to their needs, the deed can be accomplished. They need light, well-drained, highly acidic soil (maintain pH between 4.0 and 4.5). A suitable growing medium would be three parts silica sand, two parts leafmold and/or peat moss with occasional light fertilizing made for acid-loving plants. If you grow clubmosses in a container put a thin layer of charcoal at the bottom. Keep soil moist - not saturated and not dry. The plants generally need about two months of cool temperatures to satisfy their dormancy needs.

Ten years ago you couldn't buy clubmosses from local or mail order nurseries. Gathering native species in a forest has been the only way and this practice must be approached with care. Local universities may be able to help.

(from HortIdeas, April 1988,5(4)).


Last month we introduced Lagerstroemia 'Chickasaw' to you and this month we are pleased to share the introduction of another miniature hybrid crapemyrtle: lagerstroemia (indica x fauriei) 'Pocomoke'. The Shrub Breeding Program at the U.S. National Arboretum released the cultivar which may now be propagated, displayed, promoted and sold. If you were at the SNA meeting in Atlanta you may have seen 'Pocomoke'. The cultivar is reliably top hardy to USDA Zone 7b; root hardy to USDA Zone 6. Its flowers are deep rose pink with a high tolerance to powdery mildew.

After 8 years of growth you can expect this cultivar to be approximately 19 inches tall and 35 inches wide. The growth habit is densely branched in a compact mound. Foliage is glossy and dark green. For a list of wholesale nurseries propagating this plant you can contact Dr. Margaret Pooler, U.S. National Arboretum, 3501 New York Ave., N.E., Washington, DC 20002-1958.

(from US National Arboretum Plant Introduction Floral and Nursery Plants Research Unit).


Horticulture, like many other industries, is known for its fads and fashions. One of the fads that has returned in a big way to home and commercial gardens is the use of container gardens and window boxes. Container gardening is a process that combines the best aspects of gardening on a small scale. Students in the Herbaceous Plant Class at Auburn University (spring and summer sessions) developed plans that addressed plant use, color, form, texture, design and scale. Principles of design were combined with an understanding of the habits of plants and their physical requirements. The horticulture students put their new skills and knowledge to the test by designing and planting window boxes and other container displays. This is a cooperative effort by the Horticulture Department at the University, The Alabama Extension System and generous sponsors: Buffalo Company, Inc., Euracast Caffco International; Fafard, Inc.; Village Arbors; Blooming Colors and American Designer Pottery.

Designs were judged in the Funchess courtyard on August 14th by Master Gardeners, students, faculty and staff. Below are photographs of the top scoring 20 containers as well as lists of the plants in each planting for the benefit of domestic gardeners, commercial growers, and nursery owners. Hopefully, if gardeners can find successful designs to use, this gardening feature will cease being a fad and become a standard feature in the home garden.

Those involved in the project were Dee Smith, Ken Tilt, Dave Williams, Raymond Kessler and Bernice Fischman - who look forward to continuing the process with future classes.

Below are photos (thanks to Donna Reynolds) of the top scoring containers in random order:

Hibiscus rosea-chinensis-Chinese hibiscus
Bromeliad sp-Finger tip bromeliad
Pseuderanthemum atropurpureum
-Purple False Eranthemum
Coleus x hybridus-Coleus
Senecio cineraria-Dusty miller
Begonia x semperflorens-cultorum- Begonia
Thymus sp-Thyme
Origanum sp-Oregano
Ipomoea batatas 'Blackie'-Ornamental sweet potato
Ipomoea batatas 'Margarite'-Ornamental sweet potato
Coleus x hybridus-Coleus
Coleus x hybridus-Coleus
Begonia sempervirens-cultorum-Wax begonia
Portulaca grandiflora-Portulaca
Stachys byzantina-Lamb's ear
Pelargonium x hortorum-Geranium
Pelargonium crispum-Scented geranium
Catharanthus roseus-Annual vinca
Asparagus densiflorus 'Sprengeri-Asparagus fern
Catharanthus roseus-Annual vinca
Caladium x hortulanum-Caladium
Pelargonium x hortorum-Geranium
Zebrina pendula 'Purposii'-Wandering Jew
Setcreasea pallida 'Purple heart'-Purple heart
Catharanthus roseus-Annual vinca
Chlorophytum comosum vittatum-Spider plant
Gomphrena globosa-Gomphrena
Coleus x hybridus- Coleus
Senecio cineraria-Dusty miller
Ipomoea batatas 'Blackie'-Ornamental sweet potato
Sansevieria stuckyi-Sansevieria
Achmea fasciata-Living vase plant
Coleus x hybridus-Coleus
Caladium x hortulanum-Caladium
Peperomia scandens-Peperomia
Athyrium felix-femina-Lady fern
Coleus x hybridus-Coleus
Plectranthus-Plectranthus sp
Hibiscus rosa-sinensis 'Cooperi'-Chinese hibiscus
Ipomoea batatas 'Blackie'-Ornamental sweet potato
Salvia splendens -Annual salvia
Lonicera sempervirens-Honeysuckle vine
Ocimum basilicum
Coleus x hybridus-Coleus
Rosmarinus officinalis Rosemary
Thymus sp-Thyme
Ajuga reptans-Ajuga
Catharanthus roseus-Annual vinca
Caladium x hortulanum-Caladium
Asparagus densiflorus 'Sprengeri'-Asparagus fern
Hibiscus rosa-sinensis 'Cooperi'-Chinese hibiscus
Salvia splendens -Annual salvia
Catharanthus roseus-Annual vinca
Ocimum basilicum 'Minimum'-Dwarf basil
Rhoeo spathacea-Moses-in-the-cradle
Catharanthus roseus-Annual vinca
Zebrina pendula-Wandering jew
Coleus x hybridus-Coleus
Ipomoea batatas-'Blackie'-Ornamental sweet potato
Melampodium padudosum-Medallion flower
Thunbergia alata-Black-eyed Susan vine
Petunia integrifolia 'Purple Wave'-Purple wave petunia
Pelargonium x hortorum-Geranium
Senecio cineraria-Dusty miller
Verbena tenuisecta-Moss verbena
Evolvulus glomeratus 'Blue Daze'-Blue daze
Dracaena marginata-Dragon tree
Asparagus densiflorus 'Sprengeri'-Asparagus fern
Coleus x hybridus-Coleus
Impatiens wallerana-Impatien, busy lizzy
Pelargonium x hortorum-Geranium
Dracaena marginata-Dragon tree
Asparagus densiflorus 'Sprengeri'-Asparagus fern
Pelargonium x hortorum-Geranium
Catharanthus roseus-Annual vinca
Evolvulus glomeratus 'Blue Daze'-Blue daze
Thymus sp-Thyme


Container gardening is different from in-ground plantings because the gardener has more control. This is both good and bad. Most of the physical requirements necessary for a plant to grow are provided by the gardener. Nature provides the light and carbon dioxide and you provide the rest. Although more work is required on your part, the rewards are greater because you are also in control of the show you create. You have access to all of nature's colorful pallet to create the design and the vision; you also have the tools and technology to provide the optimum environment to insure success.

Design factors are important as plants grow next to, in front of, in back of, or alongside other plants; and all grow at different rates. Things to consider are current and future dimensions, growth habit, texture, color, and how plants deal with sun or shade. Be aware of the needs of your garden and be willing to provide the necessary care. It is not the kind of gardening for the flippant who may water plants once a week or once a month or the gardener who feels that the main effort was in the purchasing and planting. Container gardeners must be aware of changes in season, knowing which plants will survive the winter and which ones must just be appreciated for their passing brilliance. For those who enjoy the results and not the process, professionally designed gardens can be purchased from your local garden center. You just need to provide care and maintenance. Keeping all of these things in mind, it must be said that well kept container gardens dramatically enhance outdoor living spaces and make special places for your family and friends to enjoy.


An old horticultural adage is that, "if you provide a good environment for the roots, the top will take care of itself." So, what you put in the pot is very important. Soil is not a good term to use because the majority of soils or top soils you would take from your yard have a texture that is too fine, stays too wet, and limits the amount of oxygen available to the roots. Soil can also introduce disease pathogens to the plant. It can be used and the plant will "survive" but it does not provide the optimum environment for the display you envision. You need to buy or concoct a well-drained medium that provides a good balance of air space and water holding capacity. The best option is to buy a "Professional" potting medium containing some of varying proportions of peat moss, vermiculite, perlite, coir, and pine bark. This route assures that you are getting a medium on which people's livelihood depends. You can buy potting soils off the mass market shelf but there is no regulation on what can go into a potting medium. Sometimes the pretty picture on the bag does not represent the results you get from the "stuff" you get inside the bag. There are some good products but try a small bag first to see if water moves through the pot easily and it does not stay too soggy after watering. There is no perfect medium. It is just one part of maintaining a good environment for the roots. The balance of water changes with the height of the container, how tightly the medium is compressed, the age of the medium and how often it is watered. It is not an exact science. This is the point at which the Green Thumbs are separated from the Brown Thumbs.

If you are going to conjure up your own mix, some good starting mixes would be: 3:1:1 Pine bark:peat:sand; 1:1 Peat:perlite; 1:1:1 Peat:perlite:vermiculite. Coir, which is a product that comes from coconuts, can be substituted for peat moss. If you are using free-standing containers which are subject to blow-over then add 10 to 20% sand. If the container is a window box or secured in some fashion to a deck or wall then do not use sand; it is too heavy. The pine bark you buy should have no pieces larger than 1/2 inch but should have some as large as 3/8 to 1/2 inch. If your pine bark medium is staying too wet or too dry, you can correct the problem by adjusting your watering practices or adding to your next medium more peat or coir (too dry) or more perlite (too wet).

These media do not provide many nutrients for the plant. You have to provide these by applying a liquid fertilizer that you get from any of your local garden centers. Follow the directions on the label. Look for products that provide "all" the nutrients needed. There are also "slow release" fertilizers available that allow you to make one application for the whole season. The acidity or pH of a medium is also a concern that must be addressed as well as adding calcium and magnesium to the medium. Simply stated pH refers to the concentration of hydrogen ions in a solution and is measured on a scale of 0-14 with 7 considered neutral. A low number means an acidic condition and a high number indicates alkalinity. If the soil is too acid or alkaline for particular plants, they cannot take up important nutrients, specifically nitrogen, phosphorous, potassium and 12 others in trace amounts. Most plants prefer a pH between 5.5 and 6.5. In an organic medium, adding 1 to 1.5 Tbs. of dolomitic lime for each 1 gallon of container medium will adjust the pH within range for a pine bark based media. This should be mixed with the medium or spread over the top of the pot medium surface and watered.

Media get spent over time and it is necessary to replenish. For containers of annuals - replace the media each year and when you add replacement plants. For perennial plants try to incorporate some new media at least once a year, and for other plants that are not to be re-potted remove some of the media and replace with a new mix when plants start to become root-bound.


Wood, copper, lead and terra cotta are well suited for container plantings because they are durable and also age with the plant. The new fiberglass pots look very good, are lightweight and last a long time. There are also decorative plastic pots for short term use. If using wooden barrels, it is wise to put plastic sheeting around the inside walls to help prevent rot. Make sure all large containers have large drainage holes at the bottom over which broken pottery shards are to be placed. There are large containers (suitable for small trees and large shrubs and many container garden designs), small containers for alpine plantings or one single plant, and window boxes. Containers can be placed on patios, decks, entrances to homes and businesses, in shady or sunny places. Each of these choices requires attention to plant selection and have special design considerations. Smaller containers and window boxes require more frequent watering and re-potting.


Read the tag, talk to your garden center professional, or look at mature specimens to see how large plants will grow and in which form they grow. Plants which work best together have the same basic physiological requirements. Do they need acid or alkaline medium? Are they sun or shade loving? What are their water requirements? Are their growth habits different enough to present an interesting display (large/small, short/tall, small/large leaves, small plain/large dramatic flowers, shiny/dull)? Consider how the plants grow and their form - whether they are upright, weeping, tufted, branching, climbing, prostrate, dense, airy. Small plants should be 1/3 the size of larger plants in one container. A great plant marriage is a trellis with a vine on it and a small shrub in front. Different cultivars of hosta make for fine marriages. You can design a successful grouping of individual pots. When grouping containers the triangular motif works well - incorporating plants of different heights. The selection of plants to use is only limited by your knowledge and imagination and their availability.

Examples of winning combinations:


Crowd in bedding plants. Plants don't like air pockets around them. No more than three colors in each container works best. Vary size and shape of flowers and foliage. Three main factors are: balance, color and shape/scale.


Although assembly is not necessarily required, maintenance is critical. Water is necessary for the life of plants - not too much and not too little. Small plants and window boxes must be watered every 2 to 3 days and, if media does not hold enough water, daily watering in the heat of the summer is required. Large containers can often go 3 to 5 days without watering. As roots fill the pots and become pot-bound more water is required and is a sign that re-potting is needed. Most plants prefer a moist, not wet soil. Drip irrigation is an easy and preferable delivery mode as less water is used, leaves remain dry, and growth of fungal diseases on the foliage is minimized. Garden centers offer drip irrigation kits that are easy to assemble. There are also "self watering containers" that have a reservoir of water in the bottom to ease the maintenance requirements. With frequent, heavy watering, nutrients in the media will leach out water until you get about 20% leaching. Most flowering plants must be deadheaded frequently. Sanitation is important as dead leaves and flowers may spread disease.


Spring and summer are obviously the most prolific times for plants but the other seasons are capable of supporting evergreen plants. Use foliage (variegated or golden) color and berries for color throughout the year. Pansies and ivies at the base of evergreen shrubs will give your garden color before and after less hardy plants. Deciduous plants with interesting bark offer seasonal appeal: oak leaf hydrangea, stewartia, Hearts-a-Busting, kerria, coral bark Japanese maple, contorted willow, red osier dogwood or yellow-twigged dogwood, and others. Ornamental grasses are wonderful for offering year-round seasonal color.


Books on the subject:
Malcolm Hillier - Container Gardening Through the Year
Thomasina Tarling - The Container Garden
Jeff Cox - Plant Marriages

(by Ken Tilt and Bernice Fischman, Auburn University)


Late summer is a busy time for plant samples. Diseases were numerous. Fusarium crown/root rot/wilt seemed to be a more common problem than usual. With many of the situations, environmental stress (heat, drought) seemed to be a possible predisposing factor, increasing disease susceptibility. Impatiens diseases were more abundant than normal with Phytophthora, Pythium and Rhizoctonia causing crown and root rots.
AJUGASclerotium rolfsii
Crown Rot
Stems collapse at soil line; a white mold with brown mustard-seed sized sclerotia present.Sanitation; Solarization.
AUCUBABotryosphaeria Canker (Blotch)Black, large, irregular lesions on leaves and stems; dieback beyond cankers.Sanitation; Cleary's 3336, Domain, or benomyl labelled for ornamentals.
AUCUBAHelminthosporium Leaf SpotBrown, elongate leaf lesion.Sanitation; Cleary's 3336.
AZALEAPhytophthora Crown/Root RotCrowns/roots become brown and wet or water-soaked.See APMH.
BEGONIAPythium Root Rot-Rhizoctonia/Fusarium Lower Stem/Root RotLower stem brown and decayed.See APMH.
CRABAPPLEScab Venturia)Olive-brown circular, slightly raised spots (4-5 mm diam.) develop on leaves and fruit.See APMH.
DAISY, GERBERAPhytophthora Leaf
Blight/Crown Rot
Leaves develop brown blotches; lower stem develop brown lesions; plants collapse.See APMH.
DAYLILYSouthern Blight>
Sclerotium rolfsii)
A wet rot at soil line; sometimes a white fluffy mat of fungus at soil line.Sanitation; solarization.
DOGWOODCercospora Leaf SpotLeaf spot on lower leaves of tree; angular to irregular leaf spots (2-6 mm) which are light brown or gray in the center and dark brown or purple on borders.Sanitation.
DOGWOODPowdery Mildew
Powdery white dusting on leaves; foliage distortion and death.Sanitation in the fall; see APMH.
DOGWOODSeptoria Leaf Spot Leaf spots on lower leaves of tree; angular to irregular tan or brown spots (2-6 mm) sometimes with faint yellow halos.Sanitation.
DOGWOODSpot Anthracnose Tiny red spots on flowers, leaves.Sanitation in fall; see APMH.
Small, whitish spots (1/16 in. diam.) on foliage.Recommended fungicide sprays; see APMH.
FERNRhizoctonia Root RotDark brown, dried, decayed roots.Sanitation; see APMH.
FORSYTHIAAnthracnoseBrown, leaf spots/blotches.Sanitation; crop rotation.
HOLLY, JAPANESEPhytophthora Root RotRoots become brown and water-soaked; plants become yellowed with dieback.See APMH.
HOSTAWhite Mold
(Sclerotium rolfsii)
Lower trunk or stem is rotted and generally soft and limp.Sanitation; possibly solarization.
HYDRANGEACercospora Leaf SpotBrown, circular or angular leaf spots.Sanitation; see APMH.
IMPATIENSRhizoctonia Crown and Root RotCrowns and roots become brown and dry rotted. Sanitation; solarization may help.
IMPATIENSPhytophthora Root RotWet, water-soaked brown lesions on roots. See APHM.
IVY, ENGLISHPhomopsis CankerBrown, gray lesions on stems; dieback.Sanitation; Cleary's or benomyl protective sprays.
JUNIPERPestalotiopsis Needle BlightNeedles turn brown in patchy areas on branches.Sanitation; see the APMH; avoid stress.
JUNIPERPhytophthora Root Rot>See Holly, Japanese. See Holly, Japanese.
LILACPhytophthora Root RotRoots become brown and water-soaked.Subdue 2E may be used as a protective treatment. First test a few plants to be sure phytotoxicity is not a problem.
LIRIOPEColletotrichum Leaf SpotBrown, circular-irregular leaf spots (2-10 mm diam.). When spots coalesce, a large portion of leaf may turn brown and die. Often leaf tips are affected.Sanitation; Cleary's 3336, Domain or a benomyl fungicide labeled for ornamentals.
MAGNOLIA, JAPANESEBacterial Leaf SpotBrown, irregular leaf spots with water-soaked margins.Strict sanitation.
Large, light-brown irregular spots and blotches may kill whole leaves; spots often follow leaf veins.Sanitation; fungicide sprays.
MAPLEPhyllosticta Leaf SpotSpots are circular-irregular, and have brown centers with purple margins (1/8" - 1/2" diam.).Sanitation; fungicide sprays.
MAPLEGanoderma Wood/Root RotDieback; brown wood rot.Sanitation.
Brown blotches often along leaf veins or leaf edges.Sanitation; see APMH for small oak trees.
OAKOak Leaf Blister
Round, slightly convex-concave light brown leaf spots (4-5 mm diam.).Sanitation; see APMH.
OAKPhyllosticta Leaf SpotCircular, brown spots (2-4 mm diam.).Sanitation.
OAKSlime FluxA foul smelling ooze runs down trunk surface. Initial infection of fungi, bacteria, and yeast develops in wound area.Sanitation of infection area when it is still localized.
PAMPAS GRASSPiricularia Leaf SpotGray-brown circular leaf spots.Cleary's 3336.
Brown, sunken cankers on stem sections.Cleary's 3336, Domain, or WP benomyl; sanitation.
PERIWINKLEPhomopsis BlightBrown, sunken cankers on stem sections.Cleary's 3336, Domain or WP benomyl; sanitation.
PERIWINKLEPhytophthora Aerial BlightDark brown, black cankers encircle stems and cause wilt and dieback.Sanitation.
PETUNIAPhytophthora Foliage Blight/Root RotFoliage develops spots, blight, collapse.Sanitation.
PHOTINIABacterial Leaf SpotBrown, irregular leaf spots with water-soaked edges.Strict sanitation.
PHOTINIAEntomosporium Leaf SpotRed-black circular leaf spots.See APMH.
Sunken lesions on branches; trunk with resin flow.Sanitation.
POINSETTIAPythium Root RotRoots become soft, brown, water-soaked.See the APMH.
PYRACANTHASouthern Blight
See Aster.Solarization.
RHODODENDRONBotryosphaeria CankerSunken, brown, dried, cracked, elliptical lesions develop on branches.Sanitation. Protective spray of Cleary's 3336 or Domain.
ROSECercospora rosicola
Leaf Spot
Circular brown spots.See APMH.
SNAPDRAGONPhytophthora Root RotRoots become brown and water-soaked.See APMH.
SYCAMOREPowdery MildewWhite powdery substance on leaves.See APMH.
VERBENAFusarium Crown RotBrown lower stem rot.Cleary's drenches may help.
VINCA MINORAnthracnose
Brown, irregular spots develop on leaves.Sanitation. Cleary's 3336, Domain or a benomyl product labeled for ornamentals.
VINCA MINORPhythium Root RotRoots become brown and water-soaked.Aliette protective treatments or Subdue 2E. (Test a few plants for phytotoxicity).
VINCA MINORRhizoctonia Stem BlightBrown lesions near soil line.Sanitation; Cleary's 3336 or benomyl protective sprays.

For specific disease control recommendations contact your County Extension Agent.


September 3-4, 1998:
TNA's "Tennessee America's Nursery" Trade Show and Conference.
Opryland Hotel Convention Center, Nashville TN. Contact TNA, 931-473-3971; fax 931-473-5883; e-mail

September 1998:
Basic Greenhouse Production 1998 Short Course:
September 9 - Dixie Green, Inc., Centre, AL.
September 15 - Baldwin Wholesale Florist, Inc., Loxley, AL
September 23 - CCC Associates, Montgomery, AL.
For more information contact Linda Van Dyke - 334-821-5148 or J. Raymond Kessler, Jr. - 334-844-3055.

September 22, 1998:
Nursery Crop Production/Landscape Horticulture Field Day.
Mountain Horticultural Crops Research Station, Fletcher, NC. Phone 828-687-7197.

October 7-10, 1998:
Eastern Region International Plant Propagators' Society Annual Meeting.
Toronto Hotel, Toronto, Ontario, Canada. Contact Margot Bridgen, 26 Woodland Road, Storrs, CT 06268; 860-429-6818; e-mail:

October 9-10, 1998:
Middle Tennessee Nursery Association Trade Show.
McMinnville Civic Center, McMinnville, TN. Contact MTNA, Ann Halcomb, Exec. Secr. 615-668-7322; Fax: 615-668-9601; e-mail: or

October 18-21, 1998:
Southern Region International Plant Propagators Society.
Tulsa, OK. Contact David Morgan at 817-882-4148, SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101.

November 5-7, 1998:
Annual Meeting of The Holly Society of America.
Colonial Williamsburg, VA; contact 757-363-3906
November 7-8, 1998
Annual Meeting of the American Bamboo Society.
The Harry P. Leu Gardens and Disney World, Orlando, FL; contact Delores Holland, Registration Chairman, Yellow City Road, Amenia, NY 12501; tel and fax: 914-373-9020; e-mail: Website:

November 20-22, 1998:
Meeting of the Middle Atlantic Chapter of the American Rhododendron Society.
Chamberlain Hotel, Hampton, VA; Contact 304-765-5551

January 28, 29, 30
Alabama Nurserymen's Association Trade Show and Educational Program
Mobile Convention Center, Mobile, Alabama
For information call Linda VanDyke at (334) 821-5148 or

January 13-15, 1999:
Mid-AM Trade Show.
Navy Pier, Chicago, IL. Contact Donn W. Sanford at 847-526-2010; fax 847-526-3993; e-mail

January 30-February 3, 1999:
Southern Region American Society for Horticultural Science Annual Convention.
Memphis, TN. Contact Paul Smeal, 1107 Kentwood Drive, Blacksburg, VA 24060-5656; phone 540-552-4085; fax 540-953-0805; e-mail

February 4-7, 1999:
The Management Clinic.
Galt House, Louisville, KY. Contact ANLA at 202-789-2900;

July 22-27, 1999:
American Nursery & Landscape Association Annual Convention.
Philadelphia, PA. Contact ANLA at 202-789-2900;

July 28-31, 1999:
96th American Society for Horticultural Science.
Minneapolis Convention Center, Minneapolis, MN. Contact ASHA: 703-836-4606, Fax: 703-836-2024; e-mail:

July 30-August 1, 1999:
SNA 99 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636;

August 1-4, 1999:
International Society for Arboriculture Annual Conference. Stamford, CT. Contact ISA at 217-355-9411;

September 10-11, 1999:
TNA's "Tennessee America's Nursery" Trade Show and Conference.
Opryland Hotel Convention Center, Nashville, TN. Contact TNA at 931-473-3971; fax 931-473-5883; e-mail

September 23-25, 1999:
6th Biennial Southern Plant Conference.
Richmond, VA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636;

October 3-6, 1999:
Southern Region International Plant Propagators' Society.
Mobile, AL. Contact David Morgan: 817-882-4148, SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail

January 11-13, 2000
Kentucky Landscape Industries Winter Educational Conference and Trade Show.
The Lexington Center, Lexington, KY. Contact Debbie Cain, KNLA Exec. Dir. at 502-899-3622; fax 502-899-7922

January 19-21, 2000:
Mid-AM Trade Show.
Navy Pier, Chicago, IL. Contact Donn W. Sanford at 847-526-2010, fax 847-526-3993; e-mail

January 29-February 2, 2000:
Southern Region American Society for Horticultural Science Annual Convention.
Lexington, KY. Contact Paul Smeal at 1107 Kentwood Drive, Blacksburg, VA 24060-5656, 540-552-4085; fax 540-953-0805; e-mail

February 3-6, 2000:
The Management Clinic.
Galt House, Louisville, KT. Contact ANLA at 202-789-2900;

July 8-12, 2000:
Ohio Florists' Association Short Course and Trade Show.
Greater Columbus Convention Center. Contact OFA at 614-487-1117; e-mail; web:

July 11-16, 2000:
American Nursery & Landscape Association Annual Convention.
Location TBA; contact ANLA at 202-789-2900;

July 14-18, 2000:
Ohio Florists' Association Short Course and Trade Show.
Greater Columbus Convention Center. Contact OFA at 614-487-1117; e-mail; web:

July 16-19, 2000:
American Society for Horticultural Science 97th International Conference.
Disney Coronado Springs Resort, Orlando, FL. Contact ASHS at 703-836-4606; fax 703-836-2024; e-mail

August 3-6, 2000:
SNA 2000 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636;

August 11-18, 2000:
International Society for Arboriculture Annual Conference.
Baltimore, MD. Contact ISA at 217-355-9411;

September 15-16, 2000:
TNA's "Tennessee America's Nursery" Trade Show and Conference.
Opryland Hotel Convention Center, Nashville, TN. Contact TNA at931-473-3971; fax 931-473-5883; e-mail

October 8-11, 2000:
Southern Region International Plant Propagators' Society.
Norfolk, VA. Contact David Morgan at 817-882-4148; fax 817-882-4121, SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail

January 27-31, 2001:
Southern Region American Society for Horticultural Science Annual Convention.
Fort Worth, TX. Contact Paul Smeal at 1107 Kentwood Drive, Blacksburg, VA 24060-5656, 540-552-4085; fax 540-953-0805, e-mail

August 2-5, 2001:
SNA 2001 - Southern Nurserymen's Association Researcher's Conference and Trade Show.
Georgia World Congress Center, Atlanta, GA. Contact SNA at 770-973-9026; SNA Infoline at 770-973-4636;

October 18-21, 2001:
Southern Region International Plant Propagators' Society.
Houston, TX. Contact David Morgan at 817-882-4148; fax: 817-882-4121; SR IPPS, P.O. Box 1868, Ft. Worth, TX 76101; e-mail:

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Letters to Bernice Fischman - 101 Funchess Hall - Auburn University, AL 36849.