Arkansas Agriculture
Newsletters
Arkansas Re-leaf
Volume 3, Number 2 -
April 2002
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Jim's Corner • What's Up • Disease Report -
Rose Disease Alert •
Plant Profile •
Upcoming Events
Jim’s Corner
My big news is that after a year of work we have finally finished a landscape plant materials website that includes over 650 photographs of 75 trees, 89 shrubs, 8 ground covers, 15 vines, 6 ornamental grasses and 21 perennials commonly sold or grown in Arkansas. The website was originally designed as a 24/7 review site for the Arkansas Certified Nurserymen
(ACN) test, but it offers additional benefits.
The Cooperative Extension Service is using the site as an educational resource for the industry and homeowners looking for plant material information specific to Arkansas. Several retailers have indicated that they are printing out the “index” pages, using a color inkjet printer, and using these pages as a sales document at their businesses.
Like everything else on the internet, we plan to continually add to this site. The site also includes lists of plants grouped by plant use characteristics. For example, if you are looking for hedge or screen options, you can find examples that are further linked to plant photographs.
The plant material site can be reached from several directions. The Arkansas Green Industry Association
(AGIA) has it located on the
"Become
Certified“ section of their site. The Cooperative Extension Service
has the same information available either under the Home and Garden section or the
Agriculture/Horticulture section. I want to thank Paul Ballantyne for scanning the hundreds of slides and Katherine McMahon for helping us get the site completed in a timely manner.
I know that many of you are either looking for employees or you are looking for job opportunities in the green industry. Remember that the Arkansas Green Industry Association has a
Free
job listing service at their website.
Hot off the wire:
In August of 2001, President Bush signed into law an economic assistance package which is designed to provide states with funding to support “specialty crops,” which means any agricultural crop except wheat, feed grains, oilseeds, cotton, rice, peanuts and tobacco. The Arkansas State Plant Board has received $210,000 which is to be used in the areas of research, promotion and inspection.
Because of limited funds, funding priority will be given to proposals that benefit a group of growers, a cooperative or an industry association. Projects geared towards a single agricultural business will be considered but likely given lower priority. To get additional information, please contact Tim Ellison, director of the Marketing Division, at 501-225-1598 or
Tim.ellison@aspb.state.ar.us.
What's Up?
Interesting websites!
In the last issue, I mentioned that Jeanne Wilson at
Old
Columbus Herb Farm and Soap Company. Wouldn’t it be nice if I had given you the
address.
Somehow in conducting an internet search, I found this site that offers
"organic"
gardening supplies.
Many of you are expressing interest in producing “organic” products. The government has several agencies and boards involved in deciding definitions and production inputs. You can read more at
The
National Organic Program and
USDA
National Organic Program. For example, at the first website I learned that “National Organic Standards do not currently exist for apiculture, greenhouse or mushroom production. Until USDA publishes National Organic Standards for such production methods, producers using such methods may continue to produce and label their products as organic, under the following conditions.”
The invasive plant issue is heating up. I think we may begin seeing more nurseries indicating potential problems. For example, the esteemed
Heronswood
Nursery has a list. I am glad to see they added a note: “Please note that invasiveness may depend on climate.”
The latest edition of Hartmann et al. Plant Propagation book was released in 2002. The new 7th edition contains tons of information, and the new layout is easier to read. Bob Geneve’s Glossary CD-ROM is a wonderful addition. Most of the common forms of propagation
are not only defined but the CD also contains a short video segment that shows how the propagation technique is done. This is great package for the plant propagator.
North Carolina State University has a
Plant
Growth Regulator Calculator that can be downloaded.
Disease Report - Rose Disease Alert
Stephan Vann, Extension Plant Pathologist
As temperatures warm, rose growers throughout the state may need to take steps to deal with black spot, a fungus disease that is perhaps the most serious disease of roses in Arkansas.
Circular black spots with feathered margins or edges give this disease its characteristic feature. Spots may be of varied diameters, often enlarging up to one quarter of an inch. As the number of spots increases, infected leaves become yellow, resulting in premature defoliation. Defoliation weakens the plant and results in a flowering decline.
Infection may predispose the plant to other diseases. During wet periods, the fungus produces spores on infected leaves. Wind and splashing water can spread these spores to susceptible, young, unfolding leaves. Infection takes place only when water remains on the plant surfaces for at least 7 hours.
Black spot is less of a problem in the greenhouse, since the relative humidity can be controlled, thus minimizing moisture on the leaves. During wet conditions in spring, new spots can develop in 5 to 10 days.
Canes can also become infected with the fungus, forming slightly raised lesions, which may turn from reddish purple to black. Since the fungus can survive and produce spores on fallen leaves and dying canes, these portions should be removed and destroyed prior to the appearance of new growth on the shrub. Affected canes should be pruned back to the healthy wood.
Right now is a good time to initiate these sanitation practices. If feasible, remove as many symptomatic leaves as possible and destroy these as well. These practices can
help to prevent disease resurgence in the spring. If black spot has been serious, growers should consider doing these sanitation practices in the fall to reduce the amount of overwintering fungus.
Overhead irrigation, which prolongs leaf wetness, should be avoided if possible, since moisture is a significant factor in infection. If possible, drip tubes or soaker hoses should be used to minimize leaf wetness. If plants are irrigated overhead, watering should be done in the early morning rather than afternoon so that leaves are allowed to dry quickly.
Ideally, fungicides registered for black spot should be applied preventatively starting in early spring before leaves become spotted. Most of these fungicides can be sprayed on at 7- to 10-day intervals when rainy periods are infrequent. During rainy periods, it may be necessary to spray more frequently. Always read and follow label instructions.
It is desirable to provide a layer of protection during rainy periods when black spot can flare up. Fungicides registered for black spot include myclobutanil (e.g., Systhane), propiconazole (e.g., Banner Maxx), tri floxystrobin (e.g., Compass) and thiophanate methyl (e.g., Cleary 3336).
Many rose growers are all too familiar with black spot symptoms. However, if you are unsure, the Plant Disease Clinic can lend a helping hand in the identification. This free service is available for disease identification on your ornamentals.
For further information, contact your local county extension office or call Stephen Vann at (501) 676-3124.
Plant Profile
Monardella macrantha ssp. macrantha A. Gray
Dr. Jon Lindstrom,
Assistant Professor, Univ. of Ark. Dept. of Horticulture
A plant that I have been experimenting with for the past year is the scarlet
monardella, Monardella macrantha ssp. macrantha ‘Marian Sampson.’ This member of the mint family is native to the mountains of southern California extending south into Baja California. Ed Sampson of Mourning Cloak Ranch and Botanical Garden in Tehachapi, California, originally selected the cultivar ‘Marian Sampson’ in the early 1990s and named it for his late wife. I obtained it through Pacific Plant Promotions, a plant introduction program that is a cooperative effort between the journal Pacific Horticulture and several California botanical gardens.
The plant is small, 4 inches tall, but it spreads quickly by underground stems to fill a container. The plant is most vigorous in growth from mid-winter to late spring. During the heat of the summer and through fall, the plant grows little. Characteristic of the family, the leaves and stems produce an odor when brushed or crushed. The leaves are oval-shape, dark green in color with a purple underside.
Although attractive vegetatively, flowering is the real reason to grow scarlet monardella. Flowering begins in mid spring and continues into early summer. As the common name implies, the long tubular flowers, borne in a tight, upright cluster, are scarlet-red in color. A well-grown plant in full bloom is stunning, covered with flowers. As one might expect, hummingbirds are attracted to this plant.
In Arkansas, culture of this plant provides a bit of a challenge. The heat and humidity of our summer is not well tolerated by the plant. Shade in the summer and careful attention to watering are both required in order for the plant to survive. In addition, the soil must be well drained. My plants are grown in a 1:1 mix of Fafard #2 and perlite.
This plant would be best suited for container culture in our state, if sharp drainage is provided. In California, the plant is cold hardy at least to 10Ž F and perhaps colder, since it is always difficult to equate the Sunset Zone map of California to the climate of Arkansas. Nevertheless, provided with sharp drainage, it might be worth trying this plant outdoors in Arkansas. And despite its origin, summer watering during drought will be necessary.
The scarlet monardella is very easy to propagate from cuttings taken in mid-winter from greenhouse-grown plants. Most of the cuttings that I root are first placed in Bio-sponge plugs and kept in high humidity using a Bio-dome greenhouse (both from Park Seed Company). Either
Clonex® or a 1:20 dilution of Dip ’n Grow® work well as rooting hormones. I prefer not to use intermittent mist to root this plant in the winter, because the media stays too wet during cloudy days so the cuttings rot. Cuttings root in two weeks and grow rapidly when transplanted to the greenhouse.
I imagine that a hanging basket of scarlet monardella in full bloom might just catch your eye. If not yours, then hummingbirds. California has many interesting native plants worthy of at least a trial. I never thought that Zauschneria, California fuchsia, would survive outdoors in Arkansas. Perhaps scarlet monardella will do just as well.
Upcoming Events
April 6-13 – Grand Opening Garvan Woodland Gardens. Contact 1-800-366-4664.
April 13 – Saline County Garden Show. Contact Saline County Extension at 501-303-5672.
July 7-13 –
20th
Perennial Plant Symposium. Hyatt Regency O’Hare, Rosemont, Illinois. Contact PPA at 614-771-8431, e-mail,
ppa@perennialplant.org
August 1-4 – SNA 2002 -
Southern
Nursery Association Researcher's Conference and Trade Show. Georgia World Congress Center, Atlanta, Georgia. Contact SNA at
770-953-3311.
August 6 – Multistate Plant Materials Conference. Hosted by University of Arkansas, details forthcoming.
October 4-5 – Tennessee
Nursery Association (MTNA) Horticultural Trade Show, McMinnville Civic Center, McMinnville, Tennessee. Contact
931-668-7322.
By: Jim Robbins, Extension Specialist -
Ornamental Horticulture
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