Trial Garden Procedures and Rules of the American Dahlia Society
A. The American Dahlia Society (ADS) has established trial gardens located in various regions of the country for dahlia
promotion, evaluation, and scoring of undisseminated cultivars (using the current Guide to Judging Dahlias). Introducers
or originators may select the trial garden(s) of their choice and send their prospective cultivar(s) for exposure and
scoring. The American Dahlia Society has established the following rules in order to grow and evaluate all cultivars
B. The location for a potential trial garden must offer accessibility to the public during daylight hours throughout the
growing season. The chosen location should have fertile, well-drained soil with full sun for at least half the day, access
to water, and some wind protection.
C. Upon satisfactory operation as a probationary trial garden for not fewer than two years and upon approval of the ADS
Executive Board, ADS may establish a new trial garden. Growers may enter an undisseminated cultivar in a probationary
trial garden without charge and receive a score, understanding that scores of 85.0 or greater will not be listed in the
classification book, receive a Trial Garden Certificate nor will ADS include the result in Derrill W. Hart or Evie Gullikson
D. A local dahlia society or consortium of societies must sponsor a trial garden. The society or consortium of local
societies shall name a senior judge as the Trial Garden Director and name a committee of willing, capable, and
competent members who also grow dahlias and reside in near proximity to the garden. The Executive Board and the
Trial Garden Chairman must approve the Director of the Trial Garden. Changes in the Trial Garden personnel are
subject to the approval of the Trial Garden Chairman.
E. The Trial Garden Director and society committee will follow good gardening practices, including tilling of the soil prior
to planting, staking, fertilizing, tying, insect and disease control and maintenance of adequate moisture in the soil. The
ADS has established the following rules so that similar conditions exist in each trial garden.
1. Fertilizer. The rate of application and kind of fertilizer will depend upon the nature of the soil, the amount of rainfall,
and the rate of growth of the plants. A professional soil analysis will be made each two to three years to determine
appropriate fertilizer practices.
2. Spacing of plants. The distance between plants shall be determined by the supervising committee and shall be
sufficiently spaced to permit proper care of the plants, air circulation between each plant, and for convenience in judging.
3. Controls: Several standard varieties of dahlias should be placed around the trial plantings to serve as an
experimental control for the conditions that exist in the garden.
4. Planting Date: Planting in the garden will commence depending upon the average frost-free date of the area and at
the discretion of the Trial Garden Director. The Director and Committee should do their best to protect the plants from
late frosts and other adverse weather whenever possible. Shading of the plants, however, during blooming is not
5. Grouping of Sizes and Forms: Plant all "A" and "B" dahlias including Ball, all "BB" varieties, all miniatures, pompons,
stellar, waterlily and all open-centered, such as singles, orchid flowering, anemone, etc. in respective groups, which
promotes uniform treatment. Judges should not, however, be allowed to use the location of the plant as a key input to
the determination of the classification of the entry.
6. Disbranching: Cultivars should be grown in a manner to achieve the bloom size suggested by the originator. Use the
following guidelines: AA and A size, four laterals each plant; B size, five or six laterals each plant; BB, BA, ST, and WL
size, six or eight laterals each plant. Disbud all of the above, removing secondary laterals (except replacements) in order
to allow one bloom on each lateral. All pompons, miniatures and open-centered should be topped and disbudded but
not disbranched beyond one or two pairs of leaves.
7. Deadheading: Remove blooms past their prime for judging from the plant, along with stem/stalk down to a
8. Virused Entries: Remove any cultivar exhibiting signs of stunt or disease and destroy, using care to avoid infection of
remaining stock. Notify the originator of stock destroyed.
9. Destruction of stock: At the end of the growing season, dig all clumps on which originators have requested return of
tubers and destroy all others.
10. Confidentiality of Entries: The Director will create a confidential reporting list of all cultivars planted that identifies the
originator, originator's classification, and assigned identification. Each entry in the Trial Garden will be tagged with this
coded identification on the stakes of the entry and will be used by the judges when scoring. Neither the originator's
name nor the name given to the cultivar nor its proposed classification will be divulged to anyone prior to the end of the
judging season. Upon completion of judging, that information may be placed on the entry
F. Either originators or their agent may enter undisseminated cultivars, using the current official entry blank supplied by
the American Dahlia Society, published annually in the ADS Bulletin, and available on the ADS website.
G. The Director of each Trial Garden will provide the Trial Garden Chairperson with the shipping information for his
garden and the date that roots or plants should be sent for trial. The Trial Garden Chairperson shall prepare an article
including that information for publication in the December Bulletin.
H. After confirming that space is available, an originator or designee shall send the Trial Garden Director three roots or
plants of a cultivar. Originators shall have grown the cultivar for at least three previous years (i.e.: the entry should be
sent to the trial garden in its fourth year or later). Each entry shall be undisseminated, not commercially available
anywhere, and not listed in the Classification and Handbook of Dahlias. Originators will submit a trial garden entry fee
and a picture of the entry. The entry fee is to be set by the ADS Executive Board and published in the December
Bulletin. The Trial Garden Director will acknowledge receipt and condition of roots or plants prior to planting and as
soon as possible if tubers or plants arrive in poor condition.
I. Introducers may request the return of all roots of their introduction(s) at the end of the growing season. This request
must be submitted to the Trial Garden Director by September 1 in addition to the cost of postage and the established
fee as determined by the Executive Board. If the Trial Garden does not provide return service, the Director should make
that information available to originators at the time they make reservations.
J. Records: It shall be the duty of the Trial Garden Director or his agent to:
(a) measure the diameter and the depth of a suitable number of blooms at various times during the growing season in
order to determine the size of the bloom;
(b) record the length and the character of the stem and the position of the flower on the stem;
(c) describe the color according to the current official ADS color standard;
(d) make notes on the plant habit of each plant including the characteristics of the foliage, stalk, and stem;
(e) arrange to have each entry evaluated and scored at least three times, with the majority of those evaluations to be
supplied by a Senior Judge.
(f) record the first bloom date.
K. Judging: For a qualifying final score, at least three judges shall judge each entry, a majority of whom are Senior
(a) The sponsoring society of a trial garden shall encourage its members to manage the garden with good husbandry
and pride, doing whatever it takes to show the garden in its finest array. The society will encourage its judges to judge
the entries and promote this evaluation by providing judging seminars, picnics, etc. in order to entice wide participation
from both its own and other society members who live within the general region of the garden.
(b) If it appears that a cultivar will score more than 80, judges should evaluate the entry a number of times throughout
the season if at all possible. If an entry does not develop blooms worthy of scoring during the season, the defects
should be noted on the report to the originator.
(c) Each Trial Garden Director shall establish a final date for judging cultivars. This date shall be such that the Director
can complete a summary of all the results on all of the entries and send it to the Chairman of the ADS Trial Garden
Committee by October 10 for compilation of scores and classification. This information will also be sent to the President,
the Judges Accreditation Chair, and the Classification Chair for reconciliation with the Seedling Bench Evaluation
Reports for the December issue of the Bulletin. Directors may continue to score entries after that date if conditions in
the garden permit, but they shall not consider them when they determine the average score for an entry.
(d) The Trial Garden Director will record all scores with the name of the judge on the reporting list. The Director will
compile an arithmetic average score. In compiling this score, the scores of Accredited Judges shall be averaged at half
the weight of a Senior Judge as follows.
Average Score = (Sum of Sr. J. Scores + .5 X Sum of Ac. J. Scores) / (# of Sr. J. + .5 X # of Ac. J.). For example,
consider SR1 @ 86, SR2@86 and AC1@81: (86+86+40.5)/2.5 = 85; or SR3@84, SR4@83 and AC2@90:
(84+83+45)/2.5 = 84.8.
The Trial Garden Director shall have the responsibility to exclude from the averaging process scores that are obviously
inconsistent with the quality of the entry. The Director may at his discretion use the scores of Honorary and Candidate
Judges as AC scores in the determination of a final average if s/he can confirm that the score meets the immediately
preceding requirement of reasonability and/or was developed in an appropriately supervised training process. If the
number of AC judges is more than two times the number of SR judges, the Director may delete the lowest and highest of
the AC scores in turn until the number of AC judge scores becomes fewer than or equal to twice the number of SR
judges scores. Once the Director calculates the results, the Director shall not arbitrarily change the number; i.e., an
average of 84.94 should be rounded down to 84.9 and an average of 84.96 should be rounded up to 85.0.
(e) Each Trial Garden Director will notify originators of the final average score and classification of their cultivars. If a
cultivar was not scored, a brief explanation will be given.
(f) All cultivars that score 85 or more will be reported in the December Bulletin. If a cultivar is to be withheld for trial the
second year, it is the responsibility of the originator to notify the Director of Trial Gardens and the Classification
Chairperson. Those entries will be noted in the December Bulletin as NOT FOR RELEASE. The cultivar's name will also
have a two digit numeric prefix as designated by the originator.
(g) No variety is eligible for entry in the ADS Trial Gardens for more than two years, which shall be consecutive and if
entered in the same Trial Garden the second year, the higher score will be certified.
(h) Entries scoring 85 or more points shall receive a Trial Garden Certificate.
(i) Originators or authorized agents must include the name(s) for their cultivar(s) at the time of entry. If the entry does
not score, the name can be used for another entry. The name must be acceptable to the Chair of Classification, and if it
is to be listed in the Classification Book, the cultivar's name will not have a length of more than 22 characters.
(j) For cultivars that achieve a score of 85 or more in three or more Trial Gardens, A Derrill W. Hart medal will be
awarded to the cultivar that has the highest average Trial Garden score as follows:
AA or A (001-195), B (201-295), BB (301-395), M (401-495), BA, MB, or P (501-555), WL (601-615), and ST (561-575)
or Novelty Fully Double (781-795). The highest 3 scores over 85 shall be used to determine the average. In the case of
ties, duplicate awards will be made. (k) For cultivars that achieve a score of 85 or more in three or more Trial Gardens,
one Evie Gullikson medal will be awarded to the cultivar with the highest average three Trial Garden score among the
following categories; PE, AN, CO, S, MS, O, and NO (621-775). All other rules in 19
(i) apply to this award.
(l) The receipt of a Derrill W. Hart medal or an Evie Gullikson Medal shall be construed as a pledge by the originator to
introduce the variety in the year following. If the variety is not to be introduced, the medal shall be awarded to the next
highest scoring cultivar that will be introduced into commerce. Any dahlia having scored 85 points or more at any one
trial garden shall be considered a disseminated variety in the second year following its initial trial garden evaluation.
Amended April, 2007
(501 -> 561, 11 07)