Forty-five ornamental crabapple (Malus spp.) selections were evaluated for time of blossom emergence, blossom longevity, and duration time of ornamental effectiveness of fruits. Flowers were evaluated daily during bloom, while fruit qualities were evaluated bi-weekly from petal fall to bud emergence in the spring of 1996. Blossom Time Index and blossom longevity are reported as an average of cumulative ratings of the past two years. 'Strawberry Parfait' had the most durable blossoms for 14.5 days while 'Hopa' and 'Velvet Pillar' averaged only six days. The longest season of effective fruit was nearly nine months, while the shortest was just over three weeks. In addition, 12 crabapple selections in the plot never had ornamentally effective fruit.
The use of flowering crabapples (Malus spp.) in the landscape tends to focus attention on floral colors and effects while ignoring the aspect of fruit. In our opinion, fruit appeal and retention will create a much longer lasting impact in the landscape than will blossoms. Traditionally, many older crabapple selections had large fruit creating huge messes and headaches for homeowners when fruit drop occurred. Consequently, to sell crabapples, retailers began to emphasize the flowering characteristics and de-emphasize fruit. This tendency is still a common practice in most garden and landscape centers today.
However, with the release of many new superior, small-fruited crabapples, the season of fruit effectiveness can and should be a major selling point. Bloom is directly affected by environmental factors (e.g., wind, rain, freezes, frosts, high and low temperatures) which usually decrease bloom longevity and aesthetics. On the other hand, crabapple fruit tends to be less reactive to those same environmental impediments. Some fruit will even increase appeal while maturing during such environmental stimulus.
This study was initiated to determine relative times of blossom emergence, longevity of bloom, and season of fruit appeal. By comparing effective bloom length to total length of fruit effectiveness, less emphasis may be placed on bloom, and greater emphasis more appropriately placed on season of fruit effectiveness in the landscape.
Forty-five selections of crabapples at the Secrest Arboretum in Wooster, Ohio, were evaluated daily, 27 total times, from April 26, 1995, through May 22, 1996. Recorded observations for each crabapple included day of first blossom fully open, through and up to the date when blooms were past effectiveness (50% or greater loss of overall blossoms). Den Boer (1) offered a method, Blossom Time Index, to standardize blossom emergence. Using the earliest flowering crabapple as a reference base, all subsequent crabapple bloom emergence was based on number of days after the reference bloom. The reference base for the Secrest plot was the crabapple, 'Dolgo.' The Blossom Time Index and the duration of bloom will be reported as averages of 1995 and 1996 findings.
The same 45 crabapples were also evaluated to determine the season of fruit effectiveness. Observations were recorded bi-weekly from petal fall (mid-May 1995) until all selections of crabapples lost their aesthetic appeal, fruitwise, or upon emergence of new buds (mid-April 1996). The season of effective fruit defines days 110 of each month as early, days 11-20 as mid, and days 21-31 as late.
These crabapple selections were planted in 1984 in a completely randomized design with three replications of each selection. The cultural practices used to maintain the crabapple plot are minimal pruning, a 68 foot diameter mulch ring of 1- to 2-inch depth around each tree, and removal of rootstock suckers and dead branches, thereby mimicking those cultural practices of an average landscape.
The reference base crabapple, 'Dolgo,' bloomed on April 26, 1996, and 14 days later, on May 10, 1996, both 'Mary Potter' and 'Silver Moon' were the last to begin flowering in the plot. 'Strawberry Parfait' had the most durable flowers, averaging 14.5 days. Conversely, 'Hopa' and 'Velvet Pillar' averaged the shortest duration of six days. The average bloom length for 30 crabapple selections was 10-14.5 days. The remaining 15 selections had an average bloom length of 6-9.5 days.
Overall, the average number of days of bloom duration was shorter this year than last year. This was due to uncontrollable environmental factors that occurred this year during bloom, like rain on six of the 27 total days. Torrential rain showers knocked the petals off many selections one afternoon. Also, a light frost caused flowers on some selections to yellow or brown early, which contributed to reduction of days of effective bloom. A few trees showed an increase in days of effective bloom which could be attributed to the "profuse flowering year" of a selection that alternates yearly on a profuse to sparse cycle.
The same 45 crabapples showed great variability in length of fruit effectiveness. The longest season of effective fruit was at least nine months for 'Indian Magic' and 'Indian Summer.' The shortest season of effective fruit was just over three weeks for M. floribunda, M. halliana 'Parkmanii,' and 'Silver Moon.' Eight crabapples exhibited at least six months of effective fruit. Nine selections exhibited only a three- or four-month fruit season; 13 selections exhibited only a one- or two-month season; and 12 crabapples never had a season of effective fruit. Thirty of the total 45 crabapples showed at least one month of effective fruit. The highest total number was in the group of greater than one month but less than two months of effective fruit with 10 crabapples, followed by the greater-than-three-months-but-less-than-four-months group which contained six crabapples.
If one were to compare 14.5 days of bloom against at least nine months of effective fruit, there really is no question as to which event has the greatest impact in the landscape. Even the shortest season of effective fruit (>3 weeks) is almost double the time of the longest bloom duration (14.5 days). Continuing to promote, sell, design with, or use crabapples simply as attractive "flowering trees" is to ignore the most prominent feature of this tree, namely the "crabapple." With landscape trends moving towards multiple season effects, who would pass up a chance to impact an area with color for months? Why not promote "a great tree providing such colored fruit for this amount of time" that just happens to have gorgeous flowers also. There is so much more to crabapples than just flowers, and in our opinion, it is the fruit!
To be a viable landscape element, additional aspects must be factored into the "crabapple use equation" other than just fruit or flower.
It must be noted that these fruit and flower observations are limited to one site, Secrest Arboretum in Wooster, Ohio. The flower observations reflect only two years of data while the fruit observations are for one year only. Other limitations of this study include preferential biases which may influence evaluators, the inability to maintain equivalent weather conditions throughout the blossom period, and lack of environmental modifications to reduce tree stress cycles, which can affect bloom initiation and fruit retention.
| Table 1. Fruit and Flower Observations of Selected Crabapples |
|---|
| 'Adams' {Deep red fruits, pink flowers.} Firm, abundant tear-drop shaped fruits were effective late July through mid-December. Mummified fruit is a real problem, with some persisting as long as three years. Average days of bloom - 10. |
| M. baccata 'Jackii' {Maroon-red fruits, white flowers.} Very attractive, round burgundy fruits were effective late September through mid-November. Although flowers are consistent and plentiful, fruit tends to be relatively sparse and scattered throughout the tree. Prolific, large white blooms are impressive. Average days of bloom - 9.5. |
| 'Beverly' {Bright pinkish-red fruits, white flowers.} Fruits were effective mid-August through late September. Unfortunately, blackened rotting fruits persist through winter. Fruits are partially eaten by birds, leaving an unsightly mess on the tree. Snowy white flowers from pink buds are splendid. Average days of bloom - 11.5. |
| 'Bob White' {Yellow fruits, white flowers.} Small, firm, yellow-gold fruits maturing into orange-gold were effective mid-October through late January. Birds readily eat the fruit within a week's time. Exceptional floral display of delicate white blossoms opening from pinkish-red buds. Fruit and floral displays can be somewhat erratic, alternating from profuse to sparse. Average days of bloom - 12. |
| 'Candied Apple' {Cherry red fruits, pink flowers.} Round, namesake fruits were not effective at any time during the past two years due to intense scab infections. Unfortunately, all fruit effects were negated by masking "namesake red" with brown to grayish-green scab lesions. Large pink blooms are consistent and charming. Average days of bloom - 11.5. |
| 'Centurion' {Glossy red fruits, rose-red flowers.} Abundant fruits were effective early September through mid-October, becoming dull thereafter. Large consistent flowers provide an outstanding display. Average days of bloom - 11. |
| 'David' {Scarlet fruits, white flowers.} Medium-sized round fruits were effective late September through early November. Fruit and floral displays can be somewhat erratic, alternating from profuse to sparse. Abundant snowy-white flower display in the "on" year is enchanting. Average days of bloom - 10.5. |
| 'Donald Wyman' {Bright red fruits, white flowers.} Persistent round, glossy fruits were effective late September through mid-April. Fruit remained firm the entire time, turning a muddied-red after a few hard freezes. Mummified fruit may be a problem in some years. One of the best red-fruited crabapples with a superb floral display. Average days of bloom - 10. |
| M. floribunda {Fruit yellow with red blush, white flowers.} Attractive blend of yellow maturing to a cider-brown colored fruit effective mid-October through early November. Pink-red buds open to white flowers creating a pleasing, airy floral display. Average days of bloom - 12.5. |
| M. halliana 'Parkmanii' {Red fruits, double pinkish white flowers.} Small round commingled golden yellow and "cider" red-brown colored fruits effective from mid-October through early November. Light, airy, delicate blooms from red-pink buds create an astonishing floral display. Average days of bloom - 13. |
| 'Harvest Gold' {Yellow to gold fruits, white flowers.} When the bland green fruit finally did mature (late October), the yellow fruits were so dull and dingy from sooty blotch fungus that they were never effective. Could be very attractive with red pedicels setting off the clusters of yellow fruit. Average days of bloom - 9. |
| 'Henningii' {Orange-red fruits, white flowers.} Small, round fruit was effective late September through early November. Very profuse flower display. Average days of bloom - 11.5. |
| 'Hopa' {Red fruits, muted purple to pink flowers.} Due to severe scab the large fruit was gnarly and deformed from the feeding of the codling moth larva. This "wormy" fruit drops all summer long. Consequently, this fruit was never effective. Pastel flower show in spring is beautiful. Average days of bloom - 6. |
| 'Indian Magic' {Red-orange fruits, pink flowers.} Exceptional display of autumnal orange-red, oval-shaped fruits with golden orange undersides effective early June through late March. Outstanding pink floral show is consistent performer. Average days of bloom - 10.5. |
| 'Indian Summer' {Red fruits, rose red flowers.} Prolific round, medium-sized fruits were effective early June through mid-February. Large flowers create a wonderful sight. Average days of bloom - 13. |
| 'Jewelberry' {Red fruits, white flowers.} Scanty fruits were ravaged early by scab infections, and those that escaped the fungus were rarely noticed. Fruits that do color up tend to shrivel and drop rapidly. Tiny, petite flowers enhance the diminutive form of this crabapple. Average days of bloom - 12.5. |
| 'Liset' {Maroon-red fruits, rose red flowers.} Dark, glossy fruits were effective late July through mid November. Fruits were scattered throughout the tree and never really attained an "eye catching" appeal. Flower display was very enjoyable but lacked contrast with the new foliage. Average days of bloom - 12. |
| 'Mary Potter' {Red fruits, white flowers.} Profuse small fruits outline branching structure mid-August through late November. Fruit and floral displays can be somewhat erratic, alternating from profuse to sparse. Masses of pink buds open to provide a glorious flower display. Average days of bloom - 8. |
| 'Molten Lava' {Red-orange fruits, white flowers.} Prolific fiery red fruits were effective early August through mid-November. Exquisite flower display is dependable and unrivaled year after year. Average days of bloom - 10. |
| 'Ormiston Roy' {Orange-yellow fruits, white flowers.} Glossy, oval-shaped fruits are an attractive orange-yellow blush with creamy yellow underside. Fruits were effective mid-September through mid-April, remaining firm and turning a muddied red-orange color. Splendid floral show from pink buds. Average days of bloom - 11. |
| 'Prairifire' {Purple-red fruits, coral-red flowers.} Attractive, shiny, firm purplish fruits with white speckles were effective early July through mid-November. Bloom color is unique and spectacular. Average days of bloom - 9.5. |
| 'Professor Sprenger' {Orange-red fruits, white flowers.} Large yellowish-green fruits mature in late September to orange-red. Fruit appear dull, dingy, and occluded from sooty blotch and fly speck fungus covering the skin. The lack of fruit finish and problems with persistent mummified fruits result in a lack of an effective fruit season. Very attractive large white floral display. Average days of bloom - 9.5 |
| 'Profusion' {Red fruits, purple-red flowers.} Abundant cherry-red fruits were effective mid-July through mid-October. Unfortunately, the unfailing floral show is muted by the lack of contrast with the newly emerged foliage. Average days of bloom - 8. |
| 'Radiant' {Bright red fruits, deep pink flowers.} Because of severe scab problems this fruit was ruined almost as fast as it developed. Those that escaped scab infections were virtually a neon-red, but inclined to create additional problems by mummifying and clinging to the tree well into the next summer. Pink blossoms are pleasant. Average days of bloom - 8.5. |
| 'Ralph Shay' {Large red fruits, white flowers.} Very large, bright red fruits can be effective early September through mid-November if they could develop before insect damage (codling moth) makes fruit gnarly and unsightly. Mummified fruit can be a problem also. Very pleasing floral display. Average days of bloom - 8.5. |
| 'Red Barron' {Dark red fruits, reddish-pink flowers.} Unique pumpkin-shaped fruits blacken early and are very susceptible to scab, hence this fruit is never effective. Fruits mummify easily and may remain on the tree for as long as two years. Mediocre flower show in part due to sparseness. Average days of bloom - 10. |
| 'Red Jade' {Red fruits, white flowers.} Attractive medium-size fruits were profuse and effective late September through mid-November. Small red flower buds swell to large pink buds, opening into snowy white blossoms. Reliable fruit and flower display year after year. Average days of bloom - 11. |
| 'Red Jewel' {Cherry red fruits, white flowers.} Phenomenally attractive, persistent fruits were effective early September through mid-April. Fruits remained firm and turned a muddy-red color. Abundant blooms of sugar white envelop the tree. Fruit and floral displays can be somewhat erratic, alternating from profuse to sparse. Average days of bloom - 9.5. |
| 'Red Splendor' {Roundish red fruits, rose pink flowers.} Exceptional, profuse red fruits are effective from late May through mid-December. In the late fall fruit begins to fade to an orange salmon color. Rotted, half-eaten fruits can be unsightly in the winter. Lovely pink blooms are quite persistent. Fruit and flower arrays are exceptional, profuse, and never falter. Average days of bloom - 13. |
| 'Robinson' {Dark red fruits, deep pink flowers.} The combination of murky green leaves with maroon highlights does little to contrast the fruit which is lost in the foliage. This lack of contrast and small size of fruit result in the fruit never being effective. Flower display is quite attractive. Average days of bloom - 9. |
| 'Royalty' {Red-purple fruits, crimson flowers.} Due to the deep red-purple foliage, not only were the fruits vaguely noticed but the flowers were lost as well. Fruit mummies blacken then fade to gray and remain well into the next summer. Fruit never was effective. Average days of bloom - 10.5. |
| 'Ruby Luster' {Rose-purple fruits, pink flowers.} Fruits were large with a rough, scaly finish, muddied color and generally misshapen from the codling moth larva. Fruits were never effective. Diminutive flowers are hidden by newly-emerged foliage. Average days of bloom - 10.5. |
| M. sargentii {Red fruits, white flowers.} Small, round firm fruits were effective mid-August through late November. Fruits go bad rapidly, shriveling and wrinkling, which can be effective for a few weeks and persist raisin-like into winter. Fine snowy white blossom show. Average days of bloom - 9.5. |
| 'Selkirk' {Glossy red fruits, rose red flowers.} Medium-large fruits were effective from early June through mid-August. Fruits lose their impact due to disfiguration by codling moth larvae feeding and apple scab. Excellent floral show complements emerging glossy, red-tinged foliage. Average days of bloom - 11. |
| 'Sentinel' {Red fruits, red-pink buds open to pink-tinged white flowers.} Attractive firm, small round fruits persisted from early September through late March. Fruit mummies are sometimes a problem in the spring and summer. The bud and flower display is spectacular and reliable. Average days of bloom - 11. |
| 'Silver Moon' {Purple-red fruits, white flowers.} Dark, unique colored, high-gloss fruits were effective early September through early October. Fruit and floral displays can be somewhat erratic, alternating from profuse to sparse. One of the last crabapples to bloom offering a snowy white floral show. Average days of bloom - 8.5. |
| 'Snowdrift' {Salmon-red fruits, white flowers.} Distinctly colored, small round fruits were effective late September through mid-November. Excellent flower display that is consistent year after year. Average days of bloom - 10.5. |
| 'Strawberry Parfait' {Fruits start cream yellow with increasing red blush, pink flowers.} Profuse firm fruits were effective early June through mid-February. Incredible pink flower display is one of the most durable. Average days of bloom - 14.5. |
| 'Sugar Tyme' {Brilliant red fruits, white flowers.} Persistent, showy, firm medium-sized fruits were effective mid-September through mid-April. Fruits remained firm and turned a reddish brown color. Sugar-white floral display is stunning. Average days of bloom - 11. |
| 'Velvet Pillar' {Reddish fruits, pink flowers.} Lack of contrast between fruit and foliage and overall meager fruit inhibit this crabapple from ever being effective. Fruit which does appear tends to mummify and remain on the tree well into the spring. Floral show is typically unnoticed. Average days of bloom - 6. |
| 'White Angel' {Red fruits, white flowers.} Medium-sized abundant fruits were effective mid-November through mid-December. Fruit finish was marred by sooty blotch and flyspeck fungus resulting in a dull, dingy look until late into the season. Very attractive, large, showy white flowers. Average days of bloom - 9.5. |
| 'White Cascade' {Small yellow fruits, white flowers.} Sadly, fruits rarely created an impact and were never effective because scab covered almost the entire fruit. An exquisite flower display on cascading branches. Average days of bloom - 11.5 |
| 'Winter Gold' {Yellow fruits, white flowers.} Bright red pedicels contrast with clusters of butter yellow fruits which were effective early November through mid-December. Fruits were some of the last to color up. Fruit and floral displays can be somewhat erratic, alternating from profuse to sparse. Attractive flower show in years where blooms are present. Average days of bloom - 12.5. |
| M. zumi 'Calocarpa' {Bright red fruits, white flowers.} Clusters of abundant, tiny, glossy fruit were effective mid-September through mid-December. Excellent flower show from red-pink buds. Average days of bloom - 10.5. |
| Table 2. Emergence, Duration of Bloom, and Season of Effective Fruit of Selected Crabapples | |||
|---|---|---|---|
| Crabapple | 2-Yr. Avg. Days from Ref. Base | 2-Yr. Avg. Days of Bloom Duration | 1995-1996 Season of Effective Fruit |
| Very Early | |||
| 'Dolgo' | 0 | 13.5 | late Aug. - late Sept. |
| Early | |||
| 'Beverly' | 4 | 11.5 | mid Aug. - late Sept. |
| 'Red Splendor' | 4 | 13 | late May - late Sept. |
| 'Selkirk' | 4 | 11 | early June - mid Aug. |
| 'Strawberry Parfait' | 5 | 14.5 | early June - mid Feb. |
| M. baccata 'Jackii' | 5.5 | 9.5 | late Sept.- mid Nov. |
| 'Indian Summer' | 6 | 13 | early June - late Mar. |
| 'Jewelberry' | 6.5 | 12.5 | See description |
| Mid-Season | |||
| 'Candied Apple' | 7 | 11.5 | See description |
| M. floribunda | 7 | 12.5 | mid Oct. - early Nov. |
| M. halliana 'Parkmanii' | 7 | 13 | mid Oct. - early Nov. |
| 'Ormiston Roy' | 7 | 11 | late Sept. - mid April |
| 'Ralph Shay' | 7 | 8.5 | early Sept. - mid Dec. |
| 'Radiant' | 7.5 | 8.5 | See description |
| 'Sentinel' | 7.5 | 11 | early Sept. - late Mar. |
| M. adstringens 'Hopa' | 8 | 6 | See description |
| 'Ruby Luster' | 8 | 10.5 | See description |
| 'White Cascade' | 8 | 11.5 | See description |
| 'Red Barron' | 8 | 10 | See description |
| 'Bob White' | 8.5 | 12 | mid Oct. - late Jan. |
| 'Red Jade' | 8.5 | 11 | late Sept. - mid Nov. |
| 'Sugar Tyme' | 8.5 | 10.5 | late Sept. - mid April |
| 'Adams' | 8.5 | 10 | late Aug. - mid Dec. |
| 'Centurion' | 8.5 | 11 | early Sept. - mid Oct. |
| 'Henningii' | 8.5 | 11.5 | late Sept. - early Nov. |
| 'Indian Magic' | 8.5 | 0.5 | early June - late Mar. |
| 'Royalty' | 8.5 | 10.5 | See description |
| 'Professor Sprenger' | 9 | 9.5 | See description |
| 'White Angel' | 9 | 9.5 | mid Nov. - mid Dec. |
| 'Winter Gold' | 9 | 12.5 | early Nov. - mid Dec. |
| 'David' | 9.5 | 10.5 | late Sept. - early Nov. |
| 'Molten Lava' | 9.5 | 10 | mid Aug. - mid Nov. |
| 'Profusion' | 9.5 | 8 | late July - mid Oct. |
| 'Snowdrift' | 9.5 | 10.5 | late Sept. - mid Nov. |
| Late | |||
| 'Robinson' | 10 | 9 | See description |
| M. zumi 'Calocarpa' | 10 | 10.5 | late Sept. - mid Dec. |
| 'Donald Wyman' | 10.5 | 10 | late Sept. - mid April |
| 'Liset' | 10.5 | 12 | late July - mid Nov. |
| 'Red Jewel' | 11.5 | 9.5 | early Sept. - mid April |
| 'Harvest Gold' | 12.5 | 9 | See description |
| 'Prairifire' | 12.5 | 9.5 | early July - mid Nov. |
| 'Velvet Pillar' | 13 | 6 | See description |
| 'Mary Potter' | 13.5 | 8 | mid Aug. - late Nov. |
| M. sargentii | 13.5 | 9.5 | mid Aug. - late Dec. |
| 'Silver Moon' | 15.5 | 8.5 | early Sept. - late Sept. |