James A. Chatfield
Erik A. Draper
Kenneth C. Cochran
Peter W. Bristol
Charles E. Tubesing
James A. Chatfield, Ohio State University Extension-Northeast District/Horticulture and Crop Science; Erik A. Draper, Ohio State University Extension-Mahoning County; Kenneth C. Cochran, Ohio Agricultural Research and Development Center /Secrest Arboretum/Ohio State University Agricultural Technical Institute; Peter W. Bristol, Holden Arboretum; and Charles E. Tubesing, Holden Arboretum
Ornamental crabapples (Malus spp.) in a replicated plot at the Secrest Arboretum of The Ohio State University's Ohio Agricultural Research and Development Center in Wooster, Ohio, were evaluated for ornamental effectiveness 14 times from October 1994 through September 1995. Crabapples with best overall aesthetic ratings (fruit, flower, foliage, form, disease and pest resistance) for those rating periods were, in order: 'Molten Lava,' 'Red Jade,' 'Sentinel,' 'Prairifire,' 'Donald Wyman,' 'Mary Potter,' 'Strawberry Parfait,' 'White Cascade,' M. sargentii, M. baccata 'Jackii,' 'Ormiston Roy,' 'Bob White,' M. halliana 'Parkmanii,' 'Red Splendor,' 'Sugar Tyme,' M. floribunda 'Indian Magic,' and M. zumi 'Calocarpa.' Of the 45 crabapples in the plot, 37 were rated as "highly ornamental" or better at some point during the year.
Crabapples are woody landscape trees that provide a number of ornamental features throughout the year. Unfortunately, landscapers and their customers often focus their attention on only one feature of a particular crabapple. One example is the focus on the term "flowering crabapple." Crabapples bloom for only a short period each spring (1,2). Conversely, many crabapples exhibit good foliar and fruit displays for many months.
A second example of concentrating solely on one feature is rating crabapples only for disease (3,4,). Disease ratings are quite useful, but are often used by educators, landscapers, and the public as the sole criterion for selection of crabapples. Again, disease susceptibility is only one aspect of the true landscape value of a particular crabapple.
The emphasis of this continuing study is to provide an accurate, year-round profile of selected aesthetic qualities for many of the crabapples available to landscapers and homeowners. Aesthetic qualities can include showiness of buds, flowers, bark, foliage, and fruits; flower and fruit longevity; tree size and form; disease expression or any subtleties that directly influence the ornamental effect of crabapples in the landscape.
Forty-seven crabapples at Secrest Arboretum were rated 14 times between October 1994 and September 1995 (three separate ratings were made during bloom and combined for one average value). Crabapples were rated on 10-7-94, 11-4-94, 12-13-94, 1-3-95, 2-2-95, 3-2-95, 4-7- 95, 4-29-95, 5-6-95, 5-13-95, 6-8-95, 7-7-95, 8-7-95, and 9-7-95. The crabapples are in a completely randomized block design with three replications of each crabapple. The plot was planted in 1984. This is the second year of a multi-year study (5).
Aesthetic ratings include flower, foliage, form, and fruit characteristics, and effects of disease and pest problems. The rating system is as follows:
1 = Exceptionally ornamental crabapple. Based on outstanding flower, foliage, fruit, or form at time of rating.
2 = Highly ornamental crabapple. Good flower, foliage, fruit, or form at time of rating.
3 = Adequate as a landscape crabapple. Not highly ornamental at time of rating.
4 = Substandard as an ornamental crabapple at time of rating.
5 = Ornamentally unacceptable as a landscape crabapple at time of rating. Not recommended for use in the landscape.
Ratings for the crabapples in this study were averaged for the three replications on each evaluation date. These ratings were then added to give an overall average rating for the year for each crabapple species or cultivar. Data presented in Table 1 include ratings for October 1994 - September 1995 as well as cumulative ratings and cumulative descriptive paragraphs for August 1993 - September 1995.
Growing conditions during the period of October 1994 - September 1995 included a mild winter compared to the extreme lows (to -28 degrees F at Secrest Arboretum) in January 1994 (5). Rainfall during mid-spring to early summer was heavy, resulting in numerous apple scab infection periods and heavier apple scab incidence in the spring of 1995 compared to 1993-1994 (3).
The multiple evaluations in this study were made because a single evaluation for disease or a single evaluation for the aesthetic qualities of crabapple is too limiting. Profiles of a selection's landscape effectiveness over the entire year is preferable.
Crabapples feature spring flowering; foliage effects in the spring, summer, and fall; fruits in the summer, fall, and winter; and form and texture characteristics throughout the year. Profiles that reflect the entire year of ornamental ratings are presented in Table 1.
Even with the 12 evaluations (26 over two years) there are many limitations to our study. First, it is only two years of data. Factors such as winter damage or severe disease in a given year may overly influence the ratings for that limited time period.
Second, due to time and experimental design constraints, we limited the evaluations to the 45 crabapples replicated in the plot. Many need to be added, including a number that rate highly in other reports (4,6,7). To address this issue, a new crabapple plot is being planted at Secrest Arboretum to include numerous new selections. A number of selections with consistently substandard ratings in the current plot will be excluded from future evaluations. These include: 'Henningii,' 'Hopa,' 'Madonna,' 'Radiant,' 'Ralph Shay,' 'Red Barron,' 'Royalty,' 'Ruby Luster,' M. tschonoskii, and 'Velvet Pillar.'
Third, the data is for only one site: Wooster, Ohio. Clearly crabapples vary in their ornamental effectiveness and disease susceptibility depending upon local environmental conditions. A number of other studies provide data on effectiveness over a wider range of geographical area (4,6,7). Some effort was made in 1995 to include information from other Ohio sites relative to disease susceptibility (8).
Fourth, aesthetic ratings inevitably involve some subjectivity by the evaluators. Personal preferences relative to plant form, flower color, fruit size, the importance of clean foliage, and other factors enter into the ratings. To partly address this, we involved guest evaluators to a limited extent in 1995 (see Table 2) and plan to include additional perspectives in future years.
In general, these results show that ratings are reasonably consistent, suggesting that ratings by authors Chatfield and Draper are not a major limiting factor to the overall reliability of the study. There are several key divergences, however.
Ratings for 'Strawberry Parfait' differ considerably, probably due to the unusual, erratic shape of this crabapple. As indicated in our above description of 'Strawberry Parfait,' its "unusual shape is not for every landscape."
Ratings for 'Bob White' at the September evaluation diverged a full two points, due to differing views of fruit effect. All evaluators liked the clean foliage and overall plant shape. Lee and Warren thought the abundant still-green fruits were sensational. Chatfield and Draper appreciated the yellow blush starting on the fruits. Bristol and Tubesing felt the green fruits were not yet ornamentally effective.
Ratings for 'Mary Potter' diverged considerably at the September rating, probably reflecting differing perspectives on the extent of the value of its weeping-spreading form in the landscape. Plant form and texture are probably the most subjective criteria involved in the aesthetic rating scheme used in this study.
| Table 1. Average Aesthetic Ratings for October 1994-September 1995, and Cumulative Descriptions, Aesthetic Ratings, and Best and Worst Ratings from August 1993-September 1995. | ||||
|---|---|---|---|---|
| Crabapple | 94-95 Average | 93-95 Average | Best | Worst |
| 'Adams' | 3.1 | 2.9 | 1.3 | 4.6 |
| {Deep red fruits, pink flowers.} Positives include firm, abundant tear-drop shaped fruits, and an attractive winter feature of flaking bark near the crown, grading into striated bark on upper trunk and branches. Negatives include fruit mummies that persisted from summer 1993 through September 1995, detracting from winter appeal, springtime bloom effect and summer appearance. Chlorotic foliage noted during summers. Moderate scab noted. No fireblight noted. | ||||
| M. baccata 'Jackii' | 2.7 | 2.8 | 1.3 | 4.0 |
| {Maroon-red fruits, white flowers, large tree.} Positives include large, glossy green leaves -- by far the best foliage of any crabapple in the plot. In fall, contrast of yellow and rust colored leaves with attractive burgundy fruits is outstanding. Negatives include relative sparseness of fruit clusters and mediocre overall winter appearance. No scab or fireblight noted. | ||||
| 'Beverly' | 3.7 | 3.7 | 1.3 | 5.0 |
| {Bright pinkish-red fruits, white flowers.} Positives include impressive fruit display from late summer through early fall, and pink buds opening to snowy white flowers in spring. Negatives include persistent rotted fruits from mid-fall through winter. Fruits are partially eaten by birds, leaving an unsightly mess on the tree. Sprawling growth habit is somewhat awkward. No scab noted, moderate fireblight noted in 1994. | ||||
| 'Bob White' | 2.8 | 2.6 | 1.0 | 4.6 |
| {Yellow fruits, white flowers.} Positives include persistent, small, firm, yellow-gold fruits maturing by mid-winter into orange-gold color. It is a real standout in the winter landscape. Exceptional floral display of delicate white blossoms opening from pinkish-red buds. Negatives include fruit and floral display that alternates yearly from profuse to sparse. Summer appearance is mediocre, although foliage is clean. No scab or fireblight noted. For overall effect, this is the best yellow-fruiting cultivar in the plot. | ||||
| 'Candied Apple' | 3.3 | 3.2 | 2.0 | 4.0 |
| {Cherry red fruits, pink flowers, weeping aspect of upper branches.} Positives include the irregular weeping habit, red-tinged foliage and namesake fruits. Negatives include fruit scab, which in heavy scab years such as 1995, negated all fruit effect by masking color with brown to grayish scab lesions. No fireblight noted. Unusual weeping nature of upper branches is not for every landscape. | ||||
| 'Centurion' | 3.4 | 3.3 | 1.6 | 4.6 |
| {Glossy red fruits, rose-red flowers, open branching structure.} Positives include attractive blossoms, fruit display in late summer and early fall, rust-orange fall foliage effect, and for some, the unusual open branching structure. Negatives include dull, sparse fruits by mid-fall and gangly nature of tree. Light to moderate scab noted, except in 1995 with extensive scab present. No fireblight noted. This crabapple is not outstanding at any time of year except briefly during bloom. | ||||
| 'David' | 3.1 | 3.3 | 1.0 | 4.0 |
| {Scarlet fruits, white flowers.} Positives include abundant snowy-white flower display, and rounded tree form. Negatives include yearly floral and fruit displays alternating from profuse to sparse, and fruit mummies from late fall to mid-winter. Light scab noted in most ratings, no fireblight noted. Mediocre overall except for impressive flower display in alternate springs. | ||||
| 'Dolgo' | 4.2 | 4.1 | 2.0 | 5.0 |
| {Bright red-purple plum-like fruits, snowy-white flowers.} Positives include edible, almost fluorescent red-purple fruits, striking for a brief period from mid-summer to mid-August. Negatives include major fruit mess problems due to drop, plop, and rot. Lacks ornamental effect for much of the year. No scab or fireblight noted. This is one of the large-fruited cultivars that give crabapples a generally unwarranted bad reputation as a messy landscape tree. | ||||
| 'Donald Wyman' | 2.2 | 2.2 | 1.0 | 4.0 |
| {Bright red fruits, white flowers, large tree.} Positives include excellent floral display, persistent glossy fruits effective into April in 1995, attractive exfoliating bark and good overall rounded growth habit. Negatives include fruit mummies in spring and early summer 1995. Scab blight in 1993-1994, moderate on both fruit and leaves in 1995. No fireblight noted. One of the best red-fruited, white-flowered crabapples in the plot. | ||||
| M. floribunda | 2.9 | 2.9 | 1.3 | 4.0 |
| {Fruit yellow with red blush, white flowers.} Positives include airy floral display with pink-red buds opening to white flowers, attractive blend of yellow and cider-brown fruit colors in fall, feathery effect of pedicels in winter, and good overall form. Negatives include yellow flecking of foliage in summer, and relatively ordinary appearance for much of the year. Slight scab noted in 1995. No fireblight noted. | ||||
| M. halliana 'Parkmanii' | 2.8 | 2.8 | 1.0 | 4.0 |
| {Red fruits, double pinkish white flowers.} Positives include light, airy delicate aspect as bloom emerges, fall and early winter fruit display featuring a commingling of golden yellow and "cider" red-brown fruits. Negatives include a mundane appearance through winter months. Slight scab noted. No fireblight noted. | ||||
| 'Harvest Gold' | 3.5 | 3.2 | 1.6 | 4.6 |
| {Yellow to gold fruits, white flowers.} Positives include attractive fruits and contrast of clusters of yellow fruits with red pedicels in late fall. Negatives include long period of bland green fruit into mid-fall, and serious disease problems. Extensive scab noted. Fireblight severe in 1995 with hundreds of spur strikes following blossom infection. | ||||
| 'Henningii' | 3.9 | 3.9 | 1.6 | 5.0 |
| {Orange-red fruits, white flowers.} Positives include profuse flowering, effective fruit display in early fall, and attractive bark. Negatives include ungainly splayed upright growth habit and unattractive leaves due to scab. No fireblight noted. Growth habit is a significant detriment to landscape use. | ||||
| 'Hopa' | 4.4 | 4.2 | 2.0 | 5.0 |
| {Red fruits, muted purple to pink flowers.} Positives include pastel flower show in spring. Negatives include ungainly overall tree form, and severe scab on leaves and fruits. No fireblight noted. | ||||
| 'Indian Magic' | 2.9 | 2.9 | 1.3 | 4.0 |
| {Red-orange fruits, pink flowers.} Positives include outstanding fall fruit display of autumnal orange-red fruits with golden yellow undersides often contrasting with apricot-orange fall foliage color, appealing pink floral show in spring, and attractive bark. Negatives include yearly scab problems, with nearly complete defoliation from scab in 1995 by mid-to-late summer, although fruit scab is typically minimal. Fruit mummies were unsightly. No fireblight noted. | ||||
| 'Indian Summer' | 3.0 | 3.0 | 1.6 | 4.0 |
| {Red fruits, rose-red flowers.} Positives include prolific mid-summer to fall display of red fruits, the contrast of fruits to orange fall foliage and flaky bark. Negatives include persistent fruit mummies and moderate to extensive scab on leaves. No fireblight noted. | ||||
| 'Jewelberry' | 3.3 | 3.4 | 2.3 | 5.0 |
| {Red fruits, white flowers.} Positives include attractive, three-lobed leaves, good fruit display in fall, and overall diminutive plant form. Negatives include dingy overall appearance in summer months and extensive foliar scab. No fireblight noted. Significant winter injury occurred in 1994. | ||||
| 'Liset' | 3.3 | 3.3 | 2.0 | 4.6 |
| {Maroon-red fruits, rose-red flowers.} Positives include very attractive fruit display from mid-summer to fall, contrast of fruits with peach colored fall foliage, and attractive summer foliage. Negatives include unattractive fruit mummies in late fall, and awkward splayed growth habit. Light to moderate (1995) scab noted. Fireblight not noted. Unusual, apparently normal splitting of bark on stems is characteristic. | ||||
| 'Mary Potter' | 2.3 | 2.5 | 1.0 | 3.3 |
| {Red fruits, white flowers, weeping-spreading habit.} Positives include profuse pink buds opening to exquisite blossom display, elegant spreading growth habit, masses of reddish fruits, and salmon colored young bark revealed as older bark peels away. Negatives include fruit mummies in winter months and some branch dieback due to winter injury in 1994. Light scab and fireblight noted. | ||||
| 'Molten Lava' | 1.6 | 1.7 | 1.0 | 2.6 |
| {Red-orange fruits, white flowers, spreading-weeping habit.} Positives include fiery red fruits, yellowing fall foliage and cascading branch structure, providing an overall "molten lava" effect. Excellent winter ratings due to overall plant structure including layered horizontal branching, feathery red pedicel effect in winter, and attractive blooms. Negatives include dense, somewhat cluttered foliage effect in summer and dinginess from scab in 1995. Slight scab in 1994, moderate to extensive in 1995. No fireblight noted. | ||||
| 'Ormiston Roy' | 2.7 | 2.7 | 1.6 | 4.0 |
| {Orange-yellow fruits, white flowers.} Positives include attractive orange fruits in the fall, deep-furrowed orangish bark, and good floral show. Negatives include mummified fruit, with mummies from 1993 persisting through winter 1995. Slight scab in 1995, slight fireblight in 1994. | ||||
| 'Prairifire' | 2.2 | 2.4 | 1.3 | 4.0 |
| {Purple-red fruits, coral-red flowers.} Positives include attractive show of firm purplish fruits, spectacular bloom with flowers contrasting with emerging red-tinged green foliage, fall contrast of orangish spur leaves with fruits and other foliage, and lenticel-speckled bark. Negatives include nondescript winter and early summer appearance. No disease noted; very clean foliage. | ||||
| 'Professor Sprenger' | 3.6 | 3.5 | 1.8 | 4.6 |
| {Orange-red fruits, white flowers.} Positives include attractive white flowers and orange-red fruits. Negatives include persistent mummified fruits, and overall unsightliness due to heavy frogeye leaf spot, which resulted in significant defoliation. Moderate scab in 1995, extensive yearly frogeye leaf spot. No fireblight noted. | ||||
| 'Profusion' | 3.4 | 3.2 | 2.0 | 5.0 |
| {Red fruits, purple-red flowers.} Positives include effective, abundant, cherry-red fruits in the summer. Negatives include lack of contrast between purple-bronze colored foliage and fruits and flowers, mediocre winter appearance including rotted fruits, and extensive unsightliness and defoliation from apple scab, especially in 1995. No fireblight noted. | ||||
| 'Radiant' | 4.4 | 4.0 | 2.0 | 5.0 |
| {Bright red fruits, deep pink flowers, foliage red-purple fading to bronze.} Positives include pink blossoms and almost neon-red fruits evident in late summer. Negatives include severe scab resulting in prohibitively extensive defoliation and fruit unsightliness. | ||||
| 'Ralph Shay' | 3.8 | 3.5 | 2.0 | 5.0 |
| {Large red fruits, white flowers.} Positives include pleasing floral show and bright red fruits before codling moth larval damage makes fruit unsightly. Negatives include ugliness of fruits throughout most of the year, including rotted mummies. Light scab in 1994, extensive scab in 1995. No fireblight noted. | ||||
| 'Red Barron' | 3.8 | 3.5 | 1.6 | 5.0 |
| {Dark red fruits, reddish-pink flowers.} Positives include interesting pumpkin-shaped fruits and exfoliating bark. Negatives include mummified fruits that persisted from 1993 through summer 1995, gangly overall tree form, and scab problems that were extensive in 1995. No fireblight noted. | ||||
| 'Red Jade' | 1.9 | 2.2 | 1.6 | 4.0 |
| {Red fruits, white flowers, spreading-weeping growth habit.} Positives include graceful spreading growth habit in fall and winter months, attractive fruits, and red flower buds opening into white blossoms. Negatives include some fruit rotting in early winter and moderate scab in 1995, causing some smudginess on fruits. No fireblight noted. | ||||
| 'Red Jewel' | 3.1 | 2.8 | 1.3 | 4.6 |
| {Cherry red fruits, white flowers.} Positives include attractive, persistent fruits into the winter months, clean summer foliage, and attractive blooms. Negatives include unappealing late winter to early spring appearance and some fruit mummies. No scab noted. Fireblight moderate. | ||||
| 'Red Splendor' | 2.8 | 2.7 | 1.6 | 4.3 |
| {Roundish red fruits, rose pink flowers, red tinged foliage.} Positives include exceptional profuse red fruits from early summer to mid-fall, lovely pink flowers, and attractive exfoliating bark. Negatives include poor winter ratings due to rotted, half-eaten fruits. Trace of scab in 1994 and moderate scab in 1995. No fireblight noted. | ||||
| 'Robinson' | 3.8 | 3.6 | 2.3 | 4.6 |
| {Dark red fruits, deep pink flowers.} Positives include peach to burnt orange colored fall foliage, abundant fruits, and attractive flowers. Negatives include poor winter ratings due to rotted fruit and overall coarseness, and extensive to heavy scab in summer months, resulting in considerable defoliation in 1995. No fireblight noted. | ||||
| 'Royalty' | 4.7 | 4.3 | 2.6 | 5.0 |
| {Red-purple fruits, crimson flowers, dark purple foliage.} Offers little ornamentally except where purple leaf color is desired. Negatives include poor ratings in winter due to overall plant form and horrific, blackened fruit mummies, and little contrast between foliage and flowers and developing fruit. Light scab in 1994; extensive scab in 1995. No fireblight noted. | ||||
| 'Ruby Luster' | 4.6 | 4.4 | 3.0 | 5.0 |
| {Rose-purple fruits, pink flowers.} Large tree with ugly, misshapen fruits. Light scab in 1994; tree virtually defoliated by scab in 1995. No fireblight noted. Not an effective ornamental tree. | ||||
| M. sargentii | 2.7 | 3.1 | 2.0 | 4.3 |
| {Red fruits, white flowers, dwarf spreading habit.} Positives include attractive, low-spreading growth habit, fine snowy white blossom show, effective firm fruits in late summer to early fall, and clean foliage except for Japanese beetle feeding. Negatives include shrivelling of fruits by mid-fall persisting into winter. Winter injury in January of 1994. No scab or fireblight noted. | ||||
| 'Selkirk' | 3.8 | 3.7 | 1.6 | 5.0 |
| {Glossy red fruits, rose-red flowers.} Positives include excellent floral show and combination of flowers with glossy red-tinged new foliage, and striking medium-large fruits in mid-summer. Negatives include deformation of fruits from codling moth larval feeding in late summer, unattractive late summer foliage and moderate fruit and foliar scab, and poor ratings in winter due to coarse, dreary overall appearance. No fireblight noted. | ||||
| 'Sentinel' | 2.0 | 2.2 | 1.0 | 4.0 |
| {Red fruits, red-pink buds open to pink-tinged white flowers, vase-shaped growth habit.} Positives include mostly upright habit, sensational floral display, pleasing yellow fall foliage contrast with fruits, and attractive firm fruits persisting well into winter. Negatives include unattractive fruit mummies by spring and into the summer and nondescript summer appearance. Trace of scab noted. No fireblight noted. | ||||
| 'Silver Moon' | 3.1 | 3.4 | 1.6 | 5.0 |
| {Purple-red fruits, white flowers.} Positives include dense upright form, snowy white floral show (limited bloom in 1995), attractive fruits, and very clean foliage. Negatives include poor winter ratings due to cluttered growth habit and significant fireblight problems. No scab noted. | ||||
| 'Snowdrift' | 3.1 | 3.1 | 1.3 | 4.0 |
| {Salmon-red fruits, white flowers.} Positives include excellent flower display, attractive fruits, and feathery effect of pedicels in winter. Negatives include shrivelled fruits by late fall, poor overall foliar color, and extensive scab. No fireblight noted. Most ratings mediocre. | ||||
| 'Strawberry Parfait' | 2.3 | 2.4 | 1.6 | 3.6 |
| {Fruits start yellow with increasing red blush, flowers pink.} Positives include early red-tinged foliage effect, profuse pink blossoms, unusual erratic upright-spreading growth habit, good fall color, and firm fruits in fall and through mid-winter. Negatives include some fruit mummies and unusual shape is not for every landscape. Clean foliage; no scab or fireblight noted. | ||||
| 'Sugar Tyme' | 2.9 | 2.6 | 1.0 | 3.6 |
| {Brilliant red fruits, white flowers.} Positives include stunning sugar-white floral display, showy, persistent and profuse fruits, and good overall form. Negatives include general mediocrity if flowers/fruits are not abundant, as in 1994 due either to winter effects or other factors. Slight scab noted. No fireblight noted. | ||||
| 'Velvet Pillar' | 3.8 | 3.7 | 3.0 | 5.0 |
| {Reddish fruits, pink flowers.} Positives include upright growth habit and feature of purple foliage. Negative include dingy overall foliar appearance, sparseness of fruits, persistent fruit mummies and severe scab problems, including near total defoliation in 1995 by early August. Is not an effective ornamental at any time of the year. | ||||
| 'White Angel' | 3.6 | 3.6 | 2.3 | 5.0 |
| {Red fruits, white flowers.} Positives include attractive flowers, showy, medium-sized, abundant fruits effective into fall (effect obscured by sooty blotch disease in 1995), and interesting red coloration of previous season's growth noted in March. Negatives include awkward growth habit (until tree is considerably older), and unattractive fruit mummies. No scab noted or fireblight noted. | ||||
| 'White Cascade' | 2.6 | 2.5 | 1.0 | 4.3 |
| {Small yellow fruits, white flowers, weeping growth habit.} Positives include exquisite flower display with waterfall of cascading white-covered branches, and appealing overall weeping form. Negatives include dingy appearance throughout summer due to scab, which was heavy by mid summer in 1995, with considerable defoliation. No fireblight noted. Fall and winter features are ordinary. | ||||
| 'Winter Gold' | 3.5 | 3.6 | 2.0 | 4.3 |
| {Yellow fruits, white flowers.} Positives include impressive flower show in years where blooms are present (very sparse in 1995 on some replicates in plot), and attractive, butter-yellow fruits contrasted with bright red pedicels by mid fall. Negatives include extended periods of unattractive green fruits before yellowing in mid fall, and extensive fireblight strikes on replicate that flowered heavily in 1995. Scab extensive in 1995, moderate in 1994. | ||||
| M. zumi 'Calocarpa' | 2.9 | 3.1 | 1.3 | 4.3 |
| {Bright red fruits, white flowers.} Positives include excellent flower show, clusters of abundant, tiny red fruits in fall, and nuances such as fine feature of feathery pedicels in winter. Negatives include shrivelled fruits and overall poor winter ratings. Slight to moderate scab noted. | ||||
| 1 = Exceptionally ornamental crabapple. Based on outstanding flower, foliage, fruit, or form at time of rating. 2 = Highly ornamental crabapple. Good flower, foliage, fruit, or form at time of rating. 3 = Adequate as a landscape crabapple. Not highly ornamental at time of rating. 4 = Substandard as an ornamental crabapple at time of rating. 5 = Ornamentally unacceptable as a landscape crabapple at time of rating. Not recommended for use in the landscape. | ||||
1. den Boer, John H. 1995. Blossom Times. Malus; International Ornamental Crabapple Society Bulletin. 9(1). pp. 10-16.
2. Draper, Erik A. and James A. Chatfield. 1996. Emergence, Longevity, and Aesthetic Evaluations of Flowers in Ornamental Crabapples at Secrest Arboretum in Wooster, Ohio: 1995. Ohio State University and Ohio Agricultural Research and Development Center Special Circular 152. pp. 27-31.
3. Chatfield, James A. and Erik A. Draper. 1995. Evaluation of Crabapples for Apple Scab at the Secrest Arboretum in Wooster, Ohio: 1993-1994. Ohio State University and Ohio Agricultural Research and Development Center Special Circular 142. pp. 10-12.
4. den Boer, John H. and Thomas L. Green. 1995. Disease and Aesthetic Ratings. Malus: International Ornamental Crabapple Bulletin 9(2). pp. 8-56.
5. Draper, Erik A. and James A. Chatfield. Aesthetic Evaluation of Crabapples at the Secrest Arboretum in Wooster, Ohio: 1993-1994. Ohio State University and Ohio Agricultural Research and Development Center Special Circular 142. pp. 1-9.
6. Green, Thomas L. 1991. Malus for All. American Nurseryman. 173 (6). pp. 76-87.
7. Guthery, David E. and Edward R. Hasselkus. 1992. Jewels of the Landscape. American Nurseryman 175 (1). pp. 28-41.
8. Draper, Erik A. and James A. Chatfield. 1996. Evaluation of Crabapples for Apple Scab at the Secrest Arboretum in Wooster, Ohio: 1994-1995. Ohio State University and Ohio Agricultural Research and Development Center Special Circular 152. pp. 22-26.