hort.net Seasonal photo, (c) 2006 Christopher P. Lindsey, All Rights Reserved: do not copy
articles | gallery of plants | blog | tech blog | plant profiles | patents | mailing lists | top stories | links | shorturl service | tom clothier's archive0
Gallery of Plants
Tech Blog
Plant Profiles
Mailing Lists
    Search ALL lists
    Search help
    Subscription info
Top Stories
sHORTurl service
Tom Clothier's Archive
 Top Stories
New Trillium species discovered

Disease could hit Britain's trees hard

Ten of the best snowdrop cultivars

Plant protein database helps identify plant gene functions

Dendroclimatologists record history through trees

Potato beetle could be thwarted through gene manipulation

Hawaii expands coffee farm quarantine

Study explains flower petal loss

RSS story archive

Re: Re: CULT: B. Y. Morrison Project

wmoores wrote:

I knew when I opened this message of John's and read the BYM article that it was not the one I had reference to.

Ok, here is the first article. If anyone would like a copy in Word document form with the tables neatly arranged, please email me privately (requests sent to the list will be ignored) :>))

I have done some slight rearranging of the footnotes.


Effects of Mulches on Bearded Irises
E.Einert1 and C O. Box
B. Y. Morrison Iris Research Project Horticulture Department
Mississippi Agricultural Experiment Station State College, Mississippi Bearded irises are popular perennials in most home gardens. They produce graceful spring flowers in a wide range o# color with few basic cultural requirements. Most recommendations for iris culture in the home garden are the result of observation by hobbyists without benefit of data from controlled experiments. Recognizing this situation, members of Region 24 (Mississippi-Alabama) of the American Iris Society established the B. Y. Morrison Iris Research Fund in 1965 to support cultural studies of irises at the Mississippi Agricultural Experiment Station. Matching contributions were made by the national society. Contributions of rhizomes largely by Schreiner's Gardens, Salem, Oregon, were also made toward the research program. Experiments under the Morrison project were established to investigate areas of culture as requested by iris growers in this area. An effort was made to obtain specific recommendations for the mid-South. Studies initiated were mulching, time of planting and rhizome handling, fertility tests, herbicide and fungicide trials. This report covers the mulching study which has been underway for two years. Continuous tests in 1967 and 1968 were used to evaluate mulches on newly planted and established iris beds.
Materials and Methods Rhizomes of the variety PINNACLE were planted in November 1966. Prior to planting they were sorted according to size to assure uniformity of planting material. Sound, healthy rhizomes were set with the top surface exposed in newly prepared and fumigated beds. Methyl bromide (Dow- fume MC-2) was used as the fumigant at the rate of 2 pounds per 100 square feet.
The following mulching treatments were initiated immediately after planting: perlite, gin trash2 (sterilized), fresh pine sawdust, black plastic (4 mil. polyethylene), ground corncobs (deleted second year), leaves, peat moss, black plastic covered with 2 inches of washed gravel, pine straw and a 1 unmulched control. All mulches except plastic were approximately 2 inches deep and were maintained on a year-round basis.
After growth began each spring, all plants were sprayed weekly with a fungicide (Manzate) and an insecticide (DDT) at the rate of 1 tablespoon each per gallon of water. In September of both years, the foliage was cut back to 8 inches from the top of the rhizomes. The cut leaves and dead flower stalks were removed and burned.
Data were recorded on several factors of growth and flowering. Degree of weed control was judged by observation throughout the year. All other data were collected during the flowering season.
Results The effects of mulching and of various mulching materials are shown for first-year iris plantings in Table 1 and second-year plantings in Table 2. Bloom DateThe first year, all mulches, except corncobs, hastened the date of the first bloom over the unmulched control. Several materials accelerated blooming by as much as 9-11 days. The degree of bloom date acceleration by mulching was reduced the second year, yet all mulches, with the exception of plastic, tended to cause earlier flowering.
Flower Stalks per PlantAfter the first season mulches had no effect on flower stalk number.
Flowers per Stalk  During the second year, bloom number was increased by from 1 to 1.5 flowers per stalk by mulches of perlite and plastic with gravel as compared to unmulched plots. With the exception of gin trash, all mulches tended to increase flower number. Plant HeightMulching, with any of the materials tested, increased plant height over unmulched plants the first year. In the second year however, there were no height differences caused by mulches.
Weed ControlThe best continuous weed control was by plastic with gravel and plastic mulches. Growth into the plots by creeping grasses was not inhibited by the organic mulches. SurvivalPlant survival was greatest under the pine straw mulch and the greatest losses occurred under a sawdust mulch and in the unmulched plots. Table 1. The effects of several mulching materials on bearded irises (PINNACLE variety) growth and flowering the first year after planting.

Mulching Material (inches) Ave. Ht. flowering stem Flower stalks per plant Ave. flowers per stem Ave. number plants with no bloom Ave. date First bloom (April- 1967)
Pine Straw 26.00 a * 2.00 a 5.22 a 1.8 ab 19 a
Leaves 25.00 ab 1.90 ab 4.67 a 1.0 a 16 b
Peat Moss 24.38 bc 1.88 ab 4.80 a 2.5 bcd 20 a
Perlite 23.56 cd 1.83 ab 4.61 a 3.0 bcd 16 b
Gin Trash 24.13 bc 1.82 ab 4.62 a 4.0 d 21 a
Plastic and gravel 24.63 bc 1.81 ab 4.61 a 3.0 bcd 14 b
Sawdust 22.88 d 1.63 bc 4.81 a 3.5 cd 21 a
Ground corncobs 20.38 e 1.62 bc 4.64 a 7.5 f 24 c
Plastic 22.75 d 1.30 d 4.76 a 5.3 e 21 a
No Mulch 18.88 f 1.49 cd 4.64 a 7.3 f 25 c

* The means in any one column with the same letter are not significantly different. Different letters in any one column designates a significant difference at the 5% level of probability by Duncan's multiple range test. Table 2. Effects of several mulching materials on several factors of growth and flowering of bearded iris (PINNACLE variety) the second year after planting.

Mulching Treatment Ave. date First bloom (April- 1968) Flower stalks per plant Ave. flowers per stalk Ave. plants with no bloom Ave. number dead plants
Pine Straw 24 ab * 6.5 a 5.25 ab 0 0
Leaves 24 abc 6.4 a 5.63 abc 0 2
Peat Moss 25 ab 6.0 a 5.38 ab 0 3
Perlite 25 ab 6.1 a 5.98 bc 2 3
Gin Trash 22 c 6.8 a 4.95 a 0 2
Plastic and gravel 25 ab 7.2 a 6.50 c 1 3
Sawdust 23 bc 5.2 a 5.60 abc 4 7
Plastic 26 a 6.6 a 5.55 abc 1 2
No Mulch 26 a 5.8 a 4.88 a 3 4
* The means in any one column with the same letter are not significantly different. Different letters in any one column designates a significant difference at the 5% level of probability by Duncan's multiple range test. Summary Mulching of new iris plantings proved beneficial to subsequent growth and flowering. During the first year, mulches induced earlier flowering, more flower stalks per plant and taller flower stalks as compared to no mulch. They also increased plant survival. The beneficial effects of mulching were less pronounced the second year planting. The bloom date was only slightly accelerated and the number of flowers per stalk only slightly increased by mulches, depending upon the material. Mulches the second year had no effect on plant height or the number of flower stalks per plant.
Light mulches such as perlite and leaves were easily removed by wind and washed by heavy rains. These materials had to be replaced each year. Sawdust, peat moss and gin trash retained excessive moisture. This excessive moisture was apparently responsible for the increased weeds and incidence of soft rot and leaf spot observed in these plots.
For continuous mulching, pine straw and black plastic covered with gravel appeared to be the best materials. In addition to promoting good growth and flowering, they possessed good weatherability, were inexpensive and readily available. Survival was best in pine straw for the continuous 2 year period. Weed control was not as good though as with plastic with gravel. (considering all factors, the black plastic with gravel is probably the best mulch.
It appears that with any mulch, a regular fungicidal spray program to control leaf spot is beneficial.
1 Graduate Assistant, Department of Horticulture
2 Debris from cotton gins containing leaves, burr particles, line and other trash.

John | "There be dragons here"
| Annotation used by ancient cartographers
| to indicate the edge of the known world.

List owner iris@hort.net and iris-photos@yahoogroups.com
For your Iris gift needs, visit the AIS Gift Shop at:

USDA zone 8/9 (coastal, bay) Fremont, California, USA Visit my website at:
Director, American Iris Society
Chairman, AIS Committee for Electronic Member Services

Subscribe to iris@hort.net by sending:
Subscribe iris
To: majordomo@hort.net
Archives at: http://www.hort.net/lists/iris-talk/

Subscribe to iris-photos at:
Archives at:http://www.hort.net/lists/iris-photos/

To sign-off this list, send email to majordomo@hort.net with the

 © 1995-2017 Mallorn Computing, Inc.All Rights Reserved.
Our Privacy Statement
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index