LA Course #GCE-1-1402
Cultivars & Clones - Crabapple and Flowering Plum
Written and/or Edited by Len Phillips & Richard W Gibney RLA/ISA
Sections Go directly to the section by clicking on the title below
Cultivars & Clones - Crabapple and Flowering Plum
Written and/or Edited by Len Phillips & Richard W Gibney RLA/ISA
Sections Go directly to the section by clicking on the title below
Note: Click on green text in each section for more information and photos.
Cultivars & Clones
Often we will use the terms “cultivars” and “clones” interchangeably. As you will see there is a difference between these two and other closely related terms that landscape architects and professional arborists should be aware of. Clones may not be cultivars, and cultivars may not be clones. Few, if any, of our currently popular trees are clones, but with increased success in biotechnology (tissue culture), some will certainly be cloned in the future. All it takes to make a cultivar a clone is naming it a clone and growing it on its own roots.
Definitions
Cultivar or Grafted Cultivar: Cultivars are named selections. In landscape trees, cultivars are generally propagated by some asexual means, be it cuttings, budding, grafts, divisions, or tissue culture from the preferred tree onto seedling rootstock of the same species. The above ground portion of all trees will be genetically identical, but there will be genetic variability among rootstocks. What you lose with these genetically identical plants is diversity. Over a series of generations, if the plants can reproduce, you decrease the gene pool and the ability of the population to adapt to change.
Clone: A clone is propagated by asexual propagation (rooting cuttings or micro propagation) from a single tree and grown on its own roots. All members of the clone will be genetically identical from root tip to apical meristem. More often than not, a cultivar name will have been given to the clone.
Seedlings: These plants are derived from seed collected from a single tree. Granted that most landscape trees are naturally cross-pollinated and are highly heterozygous, the progeny from a single parent tree will be more genetically uniform than seedlings derived from several parent trees.
Seed-Orchard Seedlings: Seedlings derived from pollination among trees selected for certain desirable attributes (such as pest resistance) and propagated and planted in a “seed orchard”, specifically for seed production. There will be a high degree of genetic uniformity with regard to the traits that constituted the original selection criteria but, still, a reasonable amount of genetic diversity.
Provenance Seedlings: Seedlings coming from native trees in a particular geographic area, assuring that the seedlings will be adaptable to the general climatic conditions pertaining to that area.
Mixed Seedlings: Seedlings of unknown geographic origin with unknown adaptabilities or seedlings of different known provenance. This potentially high level of diversity may occur among the products of a single nursery and will nearly always occur when seedlings are obtained from several different nurseries.
Clones
A clone consists of a group of plants of absolute genetic uniformity and is the ultimate in monoculture. Commercial farmers extensively utilize clones and plant large monocultures with minimal genetic diversity. One of the principal reasons commercial farmers utilize genetic uniformity is that most commercial crops are the products of generations of genetic research, bred and selected to be resistant to major pests and specific herbicides, are adapted to specific localities, and/or are drought and heat tolerant. Commercial farmers plant clonal monocultures to capture the advertised superiority of these plants and uniformity in sowing, culture, and harvesting. Also, as most agricultural plants are annuals, when pest problems do arise, an army of scientists are ready to battle the pest with new genetic combinations, chemicals, or bio-control agents.
The landscape architect selecting urban trees is not as fortunate as the commercial farmer. Few trees currently grown and sold as clones in the nursery trade have been purposely developed and thoroughly tested for pest resistance. The trees must endure for decades, often in difficult situations where environmental and biotic stresses are continually changing. The development of a new “replacement” for a clone, with similar characteristics of growth and pest resistance may require decades of research. Some of the clones now available for city planting were originally selected for certain aesthetic reasons, propagated by budding and grafting, and marketed as named cultivars .
Cultivars
The use of seedling understock, whether of the same or a different species, introduces an element of diversity that might affect tree performance. Tree monocultures may only pose major problems when the numbers of trees are large and the area occupied by the trees is restricted. In other words, twenty to fifty trees of a single species, or even a single clone, planted along a few blocks of city streets do not constitute a “dangerous” monoculture. If 75% of the trees in the city were the same cultivar, that might become a problem.
Advantages of Cultivars
The most obvious advantage of cultivars is their reliability, especially those cultivars that have been in the nursery trade for 20 years or more. They can be counted on to develop the form, color, and growth rate for which they were selected. Their longevity in the trade and their widespread planting has provided the testing necessary to determine both their good and bad characteristics. The landscape architect should know what to expect of such trees.
One other characteristic of most cultivars, especially those that had been traditionally propagated by budding and grafting, is their genetic capacity for strong wound compartmentalization. Studies have shown that every cultivar tested, in a wide range of genera and species, were strong compartmentalizers. The conclusion was made because the grafting and budding process constituted an inadvertent “screening” and only strong compartmentalizing trees would be amenable to long-term commercial propagation by these techniques. Some of the cultivars formerly propagated by budding and grafting are now propagated on their own roots and have retained this important trait.
Uncertainties of Cultivars
The major uncertainties of cultivars relate to the possibility of long-term graft incompatibility. Recent research has determined that graft compatibility is dependent on the similarity of stock and scion in cambial peroxidase enzymes, which mediate the production of lignin. In Castanea mollissima, Quercus rubra, and Acer rubrum graft incompatibility is a major problem because there is considerable tree-to-tree variability in enzyme patterns. On the other hand, Acer saccharum, Acer platanoides, and Gleditsia triacanthos appeared to be quite uniform in enzyme pattern and no graft incompatibility has been reported.
Limited work on Cornus, Fagus, Fraxinus, and Koelreuteria indicated that graft incompatibility could cause problems in these genera. For those genera and species that are difficult to propagate from cultivars or by micro-propagation, the careful matching of enzyme patterns of stock and scion will produce graft-compatible combinations.
However, there are still many species that have not been studied and the city forester should be cautious in their use of new grafted cultivars of Celtis, Maclura, and Tilia.
Conclusion
It is recommended that you plant clones and cultivars that have been in the nursery trade for a long time and have proven their reliability. Use, somewhat cautiously and on a trial basis, some of the untested new cultivars of “unfamiliar” species or genera. These newer introductions have been developed through scientific research and have been selected for survival traits such as pest resistance or salt tolerance, but should be tested in your region for trial.
For uniformity, use seedlings of known geographic origin (or, in the case of exotics like Tilia cordata, from proven seed sources) so the plants will be able to tolerate the general climatic conditions in your area. For diversity, use the best clones, cultivars, and seedlings of many species and genera distributed throughout the city or as mixes of individual trees.
For the education of the next generation, plant a catalpa, a hickory, a horse-chestnut, a sassafras, and even a thorny honeylocust in park areas that can and should be used to stimulate an interest in the diversity of nature.
Sources
The following are two popular ornamental trees and their cultivars – Crabapples and Flowering Plums.
Cultivars & Clones
Often we will use the terms “cultivars” and “clones” interchangeably. As you will see there is a difference between these two and other closely related terms that landscape architects and professional arborists should be aware of. Clones may not be cultivars, and cultivars may not be clones. Few, if any, of our currently popular trees are clones, but with increased success in biotechnology (tissue culture), some will certainly be cloned in the future. All it takes to make a cultivar a clone is naming it a clone and growing it on its own roots.
Definitions
Cultivar or Grafted Cultivar: Cultivars are named selections. In landscape trees, cultivars are generally propagated by some asexual means, be it cuttings, budding, grafts, divisions, or tissue culture from the preferred tree onto seedling rootstock of the same species. The above ground portion of all trees will be genetically identical, but there will be genetic variability among rootstocks. What you lose with these genetically identical plants is diversity. Over a series of generations, if the plants can reproduce, you decrease the gene pool and the ability of the population to adapt to change.
Clone: A clone is propagated by asexual propagation (rooting cuttings or micro propagation) from a single tree and grown on its own roots. All members of the clone will be genetically identical from root tip to apical meristem. More often than not, a cultivar name will have been given to the clone.
Seedlings: These plants are derived from seed collected from a single tree. Granted that most landscape trees are naturally cross-pollinated and are highly heterozygous, the progeny from a single parent tree will be more genetically uniform than seedlings derived from several parent trees.
Seed-Orchard Seedlings: Seedlings derived from pollination among trees selected for certain desirable attributes (such as pest resistance) and propagated and planted in a “seed orchard”, specifically for seed production. There will be a high degree of genetic uniformity with regard to the traits that constituted the original selection criteria but, still, a reasonable amount of genetic diversity.
Provenance Seedlings: Seedlings coming from native trees in a particular geographic area, assuring that the seedlings will be adaptable to the general climatic conditions pertaining to that area.
Mixed Seedlings: Seedlings of unknown geographic origin with unknown adaptabilities or seedlings of different known provenance. This potentially high level of diversity may occur among the products of a single nursery and will nearly always occur when seedlings are obtained from several different nurseries.
Clones
A clone consists of a group of plants of absolute genetic uniformity and is the ultimate in monoculture. Commercial farmers extensively utilize clones and plant large monocultures with minimal genetic diversity. One of the principal reasons commercial farmers utilize genetic uniformity is that most commercial crops are the products of generations of genetic research, bred and selected to be resistant to major pests and specific herbicides, are adapted to specific localities, and/or are drought and heat tolerant. Commercial farmers plant clonal monocultures to capture the advertised superiority of these plants and uniformity in sowing, culture, and harvesting. Also, as most agricultural plants are annuals, when pest problems do arise, an army of scientists are ready to battle the pest with new genetic combinations, chemicals, or bio-control agents.
The landscape architect selecting urban trees is not as fortunate as the commercial farmer. Few trees currently grown and sold as clones in the nursery trade have been purposely developed and thoroughly tested for pest resistance. The trees must endure for decades, often in difficult situations where environmental and biotic stresses are continually changing. The development of a new “replacement” for a clone, with similar characteristics of growth and pest resistance may require decades of research. Some of the clones now available for city planting were originally selected for certain aesthetic reasons, propagated by budding and grafting, and marketed as named cultivars .
Cultivars
The use of seedling understock, whether of the same or a different species, introduces an element of diversity that might affect tree performance. Tree monocultures may only pose major problems when the numbers of trees are large and the area occupied by the trees is restricted. In other words, twenty to fifty trees of a single species, or even a single clone, planted along a few blocks of city streets do not constitute a “dangerous” monoculture. If 75% of the trees in the city were the same cultivar, that might become a problem.
Advantages of Cultivars
The most obvious advantage of cultivars is their reliability, especially those cultivars that have been in the nursery trade for 20 years or more. They can be counted on to develop the form, color, and growth rate for which they were selected. Their longevity in the trade and their widespread planting has provided the testing necessary to determine both their good and bad characteristics. The landscape architect should know what to expect of such trees.
One other characteristic of most cultivars, especially those that had been traditionally propagated by budding and grafting, is their genetic capacity for strong wound compartmentalization. Studies have shown that every cultivar tested, in a wide range of genera and species, were strong compartmentalizers. The conclusion was made because the grafting and budding process constituted an inadvertent “screening” and only strong compartmentalizing trees would be amenable to long-term commercial propagation by these techniques. Some of the cultivars formerly propagated by budding and grafting are now propagated on their own roots and have retained this important trait.
Uncertainties of Cultivars
The major uncertainties of cultivars relate to the possibility of long-term graft incompatibility. Recent research has determined that graft compatibility is dependent on the similarity of stock and scion in cambial peroxidase enzymes, which mediate the production of lignin. In Castanea mollissima, Quercus rubra, and Acer rubrum graft incompatibility is a major problem because there is considerable tree-to-tree variability in enzyme patterns. On the other hand, Acer saccharum, Acer platanoides, and Gleditsia triacanthos appeared to be quite uniform in enzyme pattern and no graft incompatibility has been reported.
Limited work on Cornus, Fagus, Fraxinus, and Koelreuteria indicated that graft incompatibility could cause problems in these genera. For those genera and species that are difficult to propagate from cultivars or by micro-propagation, the careful matching of enzyme patterns of stock and scion will produce graft-compatible combinations.
However, there are still many species that have not been studied and the city forester should be cautious in their use of new grafted cultivars of Celtis, Maclura, and Tilia.
Conclusion
It is recommended that you plant clones and cultivars that have been in the nursery trade for a long time and have proven their reliability. Use, somewhat cautiously and on a trial basis, some of the untested new cultivars of “unfamiliar” species or genera. These newer introductions have been developed through scientific research and have been selected for survival traits such as pest resistance or salt tolerance, but should be tested in your region for trial.
For uniformity, use seedlings of known geographic origin (or, in the case of exotics like Tilia cordata, from proven seed sources) so the plants will be able to tolerate the general climatic conditions in your area. For diversity, use the best clones, cultivars, and seedlings of many species and genera distributed throughout the city or as mixes of individual trees.
For the education of the next generation, plant a catalpa, a hickory, a horse-chestnut, a sassafras, and even a thorny honeylocust in park areas that can and should be used to stimulate an interest in the diversity of nature.
Sources
- Adams Garden, “Dealing with Cultivars and Clones”, Native Plants with Adams Garden, 2012.
- Santamour, Frank S., Jr., “Uniformity and Common Sense”, METRIA 7 Proceedings, 1990.
The following are two popular ornamental trees and their cultivars – Crabapples and Flowering Plums.
Disease Resistant Crabapple Cultivars
Crabapples are known for their early summer flowers and many are also known for their persistent fruits that last all winter long. Despite these desirable features, crabs are susceptible to many diseases that cause early leaf drop, disfigurement and in the worst cases, early death of the trees. The first part of this article describes crabapples in general and the cultivars listed after this are crabs that have been bred to resist the four main diseases that attack most crabapples.
Common Name: Crabapple
Botanical Name: Malus species
Family: Rosaceae
Parentage: native
Bark: Dark brown or gray
Habitat: Does very well throughout the U.S.
Culture: Well drained acidic soil
Growth Rate: Medium, full size in 25 years
Storm Resistance: Good
Salt Resistance: Good
Planting: Fibrous roots allow any transplanting technique, including bare root, in spring only, does well in CU-Structural Soil planting
Pruning: Prune at planting and 3 years later to mature form
Propagating: Budding, grafting, softwood cuttings in summer
Design Uses: Excellent for residential, park, and open spaces, as well as under utility wires
Companions: Does well with most perennial groundcovers and other crabapples
Site Requirements: Likes most sites, moist soils, and almost full sun
Other Comments: Dense leaves, vigorous growers, very popular trees
Disease resistant crabapples rated to have excellent resistance to all four diseases – apple scab, fire-blight, cedar-apple rust and mildew are:
Adirondack Crabapple, Malus 'Adirondack' – Zone: 4 – 7; Height: 18’; Spread: 10’; Shape: densely upright, an inverted cone; Foliage: medium green; Flower: white; Fruit: bright red, 1/2”. Adirondack is an important cultivar because of its form and outstanding flower display. It is a compact, dense tree that produces one of the heaviest flower displays of the crabs. A Don Egolf, U.S. National Arboretum introduction. Fact Sheet
Firebird® Crabapple, Malus sargentii ‘Select A’ – PP #12621 – Zone: 4 – 7; Height: 8’; Spread: 10’; Shape: rounded, spreading; Foliage: dark green; Flower: white, opening from red buds; Fruit: bright red, 3/8", persistent, high quality. This compact selection of M. sargentii features an annual fruit display that is more persistent than other natural dwarf crabapples. Fact Sheet
Pink Princess™ Crabapple, Malus ‘Parrsi’ – Zone: 4 – 7; Height: 8’; Spread: 10’; Shape: low, spreading; Foliage: purple becoming bronze-green; Flower: rose pink; Fruit: deep red, 1/4". This tree is a pink flowered, red leaf form of Sargent Crab. A naturally dwarf tree with all the desirable features of Sargent, but in a new color. Fact Sheet
Sargent Crabapple, Malus sargentii – Zone: 5 – 8; Height: 8’; Spread: 12', Shape: low, spreading; Foliage: dark green; Flower: white; Fruit: red, 1/4”, persistent. This tree is a natural dwarf with horizontal spreading branches. These are laden with bright red fruits that persist long into the winter months. Outstanding when planted in groups. Fact Sheet
Disease resistant crabapples rated to have excellent resistance to three of the diseases and good resistance to the fourth disease are:
Cardinal Crabapple, Malus ‘Cardinal’ – PP #7147 – Zone: 4 – 7; Height: 16’; Spread: 22’; Shape: broadly spreading; Foliage: dark purple to red, glossy; Flower: magenta pink to red; Fruit: deep red, 1/4". Foliage holds its rich color throughout the summer and has the best disease resistance of crabs with deep purple leaf color. This is an excellent Malus hupehensis hybrid. Fact Sheet
Centurion® Crabapple, Malus ‘Centzam’ – Zone: 4 – 7; Height: 20’; Spread: 15’; Shape: narrow upright; Foliage: reddish-purple, fading to bronze-green in summer; Flower: rose-red; Fruit: bright red, 5/8”. Red buds open to rosy red flowers. Form is strongly upright when young, becoming upright-spreading as it matures.
Fact Sheet
Prairifire Crabapple, Malus 'Prairifire' - Zone: 4 – 7; Height: 20’; Spread: 20’; Shape: upright, spreading, rounded; Foliage: purple, becoming reddish green; Flower: bright pinkish red; Fruit: dark red, 3/8”-1/2”. One of the best red leafed crabs, Prairifire makes an impressive landscape impact. Attributes include long lasting bright red flowers, excellent red fruit, and attractive reddish bark. Fact Sheet
Robinson Crabapple, Malus 'Robinson' – Zone: 4 – 7; Height: 25’; Spread: 25’; Shape: upright, spreading, becomes rounded with age; Foliage: bronze-green; Flower: deep pink; Fruit: red, 3/8”. This fast growing crabapple becomes established and makes an impact in the landscape quickly, yet matures at normal crabapple size. Fact Sheet
Sargent Tina Crabapple, Malus sargentii ‘Tina’ - Zone: 4 – 7; Height: 5’; Spread: 6’; Shape: small rounded dwarf tree; Foliage: medium green, small leaves; Flower: bright red buds opening to single white flowers; Fruit: bright red, 1/4”. This is a very petite crabapple that is grown as a top graft at the top of a long trunk (giving it a 5' diameter lollipop appearance at the top of a long trunk). Flowers, fruit and leaves are all quite small. Fact Sheet
Zumi Calocarpa Crabapple, Malus × zumi ‘Calocarpa’ - Zone: 5 – 8; Height: 20’; Spread: 24’; Shape: rounded, gracefully spreading; Foliage: green; Flower: red buds, white flowers; Fruit: red, 3/8”, persistent. Very popular, widely used and time tested; this is a standard for comparison of all white flowered crabs. Fact Sheet
For more information on other crabapple varieties and their disease resistance, please refer to the Crabapple Information Chart.
Crabapples are known for their early summer flowers and many are also known for their persistent fruits that last all winter long. Despite these desirable features, crabs are susceptible to many diseases that cause early leaf drop, disfigurement and in the worst cases, early death of the trees. The first part of this article describes crabapples in general and the cultivars listed after this are crabs that have been bred to resist the four main diseases that attack most crabapples.
Common Name: Crabapple
Botanical Name: Malus species
Family: Rosaceae
Parentage: native
Bark: Dark brown or gray
Habitat: Does very well throughout the U.S.
Culture: Well drained acidic soil
Growth Rate: Medium, full size in 25 years
Storm Resistance: Good
Salt Resistance: Good
Planting: Fibrous roots allow any transplanting technique, including bare root, in spring only, does well in CU-Structural Soil planting
Pruning: Prune at planting and 3 years later to mature form
Propagating: Budding, grafting, softwood cuttings in summer
Design Uses: Excellent for residential, park, and open spaces, as well as under utility wires
Companions: Does well with most perennial groundcovers and other crabapples
Site Requirements: Likes most sites, moist soils, and almost full sun
Other Comments: Dense leaves, vigorous growers, very popular trees
Disease resistant crabapples rated to have excellent resistance to all four diseases – apple scab, fire-blight, cedar-apple rust and mildew are:
Adirondack Crabapple, Malus 'Adirondack' – Zone: 4 – 7; Height: 18’; Spread: 10’; Shape: densely upright, an inverted cone; Foliage: medium green; Flower: white; Fruit: bright red, 1/2”. Adirondack is an important cultivar because of its form and outstanding flower display. It is a compact, dense tree that produces one of the heaviest flower displays of the crabs. A Don Egolf, U.S. National Arboretum introduction. Fact Sheet
Firebird® Crabapple, Malus sargentii ‘Select A’ – PP #12621 – Zone: 4 – 7; Height: 8’; Spread: 10’; Shape: rounded, spreading; Foliage: dark green; Flower: white, opening from red buds; Fruit: bright red, 3/8", persistent, high quality. This compact selection of M. sargentii features an annual fruit display that is more persistent than other natural dwarf crabapples. Fact Sheet
Pink Princess™ Crabapple, Malus ‘Parrsi’ – Zone: 4 – 7; Height: 8’; Spread: 10’; Shape: low, spreading; Foliage: purple becoming bronze-green; Flower: rose pink; Fruit: deep red, 1/4". This tree is a pink flowered, red leaf form of Sargent Crab. A naturally dwarf tree with all the desirable features of Sargent, but in a new color. Fact Sheet
Sargent Crabapple, Malus sargentii – Zone: 5 – 8; Height: 8’; Spread: 12', Shape: low, spreading; Foliage: dark green; Flower: white; Fruit: red, 1/4”, persistent. This tree is a natural dwarf with horizontal spreading branches. These are laden with bright red fruits that persist long into the winter months. Outstanding when planted in groups. Fact Sheet
Disease resistant crabapples rated to have excellent resistance to three of the diseases and good resistance to the fourth disease are:
Cardinal Crabapple, Malus ‘Cardinal’ – PP #7147 – Zone: 4 – 7; Height: 16’; Spread: 22’; Shape: broadly spreading; Foliage: dark purple to red, glossy; Flower: magenta pink to red; Fruit: deep red, 1/4". Foliage holds its rich color throughout the summer and has the best disease resistance of crabs with deep purple leaf color. This is an excellent Malus hupehensis hybrid. Fact Sheet
Centurion® Crabapple, Malus ‘Centzam’ – Zone: 4 – 7; Height: 20’; Spread: 15’; Shape: narrow upright; Foliage: reddish-purple, fading to bronze-green in summer; Flower: rose-red; Fruit: bright red, 5/8”. Red buds open to rosy red flowers. Form is strongly upright when young, becoming upright-spreading as it matures.
Fact Sheet
Prairifire Crabapple, Malus 'Prairifire' - Zone: 4 – 7; Height: 20’; Spread: 20’; Shape: upright, spreading, rounded; Foliage: purple, becoming reddish green; Flower: bright pinkish red; Fruit: dark red, 3/8”-1/2”. One of the best red leafed crabs, Prairifire makes an impressive landscape impact. Attributes include long lasting bright red flowers, excellent red fruit, and attractive reddish bark. Fact Sheet
Robinson Crabapple, Malus 'Robinson' – Zone: 4 – 7; Height: 25’; Spread: 25’; Shape: upright, spreading, becomes rounded with age; Foliage: bronze-green; Flower: deep pink; Fruit: red, 3/8”. This fast growing crabapple becomes established and makes an impact in the landscape quickly, yet matures at normal crabapple size. Fact Sheet
Sargent Tina Crabapple, Malus sargentii ‘Tina’ - Zone: 4 – 7; Height: 5’; Spread: 6’; Shape: small rounded dwarf tree; Foliage: medium green, small leaves; Flower: bright red buds opening to single white flowers; Fruit: bright red, 1/4”. This is a very petite crabapple that is grown as a top graft at the top of a long trunk (giving it a 5' diameter lollipop appearance at the top of a long trunk). Flowers, fruit and leaves are all quite small. Fact Sheet
Zumi Calocarpa Crabapple, Malus × zumi ‘Calocarpa’ - Zone: 5 – 8; Height: 20’; Spread: 24’; Shape: rounded, gracefully spreading; Foliage: green; Flower: red buds, white flowers; Fruit: red, 3/8”, persistent. Very popular, widely used and time tested; this is a standard for comparison of all white flowered crabs. Fact Sheet
For more information on other crabapple varieties and their disease resistance, please refer to the Crabapple Information Chart.
Cultivars of Flowering Plum
Purple leafed flowering plums provide a welcomed spot of color in the urban environment. These hardy and colorful trees are often neglected in cities because of their perceived weaknesses, short life span, and suitability for ornamental value only. As you will see when you read about these trees the perceptions are wrong and these cultivars are quite suitable for use as a city street tree especially under utility lines.
Characteristics of Prunus that are similar to all the cultivars mentioned below:
Botanical Name: Prunus
Family: Rosaceae
Bloom Period: May
Flower: Showy pink to pinkish white flowers, clusters of flowers
Fruit: Varies by cultivar, generally sparse, small
Summer Foliage: Varies by cultivar, purple or green
Autumn Foliage: Bright purple and red
Winter Color: Bark provides winter interest
Bark: Dark bark with bright prominent lenticels
Culture: Average, well drained soil, full sun, tolerates heat and drought
Growth Rate: Moderate to fast, up to 18” per year, full size in 10 years
Pest Resistance: Excellent tolerance to insects, disease issues are regional
Planting: Transplants easily bare root or B&B in spring, moderately suited for CU-Structural Soil planting
Salt Resistance: Fair to good
Storm Resistance: Good
Pruning: Prune while dormant or after flowering
Propagating: Mostly own root from cuttings, are budded onto Prunus understock
Design Uses: Excellent specimen for lawns, parks, and streets especially where red leaves are desired
Companions: Use with Vinca, Juniperus, and other low-growing evergreens
Other Comments: Excellent for winter color
Big Cis® Plum Prunus × cistena ‘Schmidtcis’ – Zone: 4 – 7; Height: 14'; Spread: 12'; Shape: rounded, dense; Foliage: purple; Flower: light, pink, very fragrant. A sport of Cistena, Big Cis® Plum grows quickly to a heavily trunked, sturdy tree that is intermediate in size between Cistena and Newport. Cistena-like flowers are followed by dark purple foliage that keeps its fresh, clean appearance later into the season. This tree is a J. Frank Schmidt& Son introduction. Fact Sheet
Cistena Plum Prunus x cistena – Zone: 3 – 8, Height: 8’; Spread: 8’; Shape: rounded shrub; Foliage: purple red; Fall Color: reddish; Flower: very light pink, fragrant. This extremely hardy large shrub is very fragrant in bloom. Cistena holds its purple color all through the summer. This plant should be used in raised planters or locations where it can grow as a large shrub. Also excellent when massed on hillsides or planted as an informal hedge. Fact Sheet
Crimson Pointe™ Plum Prunus cerasifera ‘Cripoizam’ – Zone: 4 – 8; Height: 25’; Spread: 10’; Shape: columnar to narrow oval; Foliage: purple red to purple bronze; Fall Color: reddish; Flower: pink buds, white
flowers; Fruit: purplish red, 1 inch long, more abundant than other cultivars. The flowers contrast nicely with the emerging purple foliage. This outstanding columnar selection develops a narrowly oval mature canopy. The strong central leader and a fast growth rate make this tree easy to produce in the nursery.
Fact Sheet
Krauter Vesuvius Plum Prunus cerasifera ‘Krauter Vesuvius’ - Zone: 5 – 9; Height: 20'; Spread: 15'; Shape: upright; Foliage: dark purple; Flower: light pink. Similar to Thundercloud in appearance, but a little smaller and more upright. Due to its tolerance of hot dry weather, it seems to be the best flowering plum for southern climates. Fact Sheet
Mt. St. Helens® Plum Prunus ‘Frankthrees’ – Zone: 4 – 8; Height: 20'; Spread: 20'; Shape: upright spreading,
rounded; Foliage: purple; Flower: light pink. Dark purple leaves emerge earlier in the spring and hold their rich color longer into summer than other cultivars. A sport of Newport, this cultivar grows faster and develops a dense head supported by a stronger, sturdier trunk. This very hardy ornamental plum performs well in cities and where climates are extreme. This is a J. Frank Schmidt & Son introduction. Fact Sheet
Newport Plum Prunus 'Newport' – Zone: 3 – 8; Height: 20’; Spread: 20’; Shape: upright, spreading, broadly, oval to round; Foliage: purple red; Fall Color: reddish; Flower: light pink. This hardy and widely used plum is quite adaptable and performs well in tough climates. Fact Sheet
Princess Kay Canada Plum Prunus nigra ‘Princess Kay’ – Zone: 3 – 8; Height: 18'; Spread: 12'; Shape: upright, narrow oval; Foliage: medium green; Fall Color: red; Flower: double white flowers in small clusters. A very hardy small tree with a neat upright habit. Selected from a native source in northern Minnesota and introduced by Minnesota Landscape Arboretum. This is the only non-purple leaf plum in this list of cultivars and is included because of its extremely high value as a city street tree. Fact Sheet
Thundercloud Plum Prunus cerasifera ‘Thundercloud’ – Zone: 5 – 8; Height: 20'; Spread: 20'; Shape: upright
spreading, dense, rounded; Foliage: dark purple; Flower: light pink. One of the best purple-leaved plums because it retains deep purple foliage color through the growing season. It has maintained steady popularity since its introduction in 1937. However, this tree is known to have a short life span if it is not grown in a proper site. Fact Sheet
The test that follows contains 30 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
LA CES will award 1.0 PDH (HSW) credit for a passing grade. North Carolina Board of LA and New Jersey Board of Architects have approved this course for 1.0 credits.
The cost for taking this test is $20 per credit. If you purchase an annual subscription for 12 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report your passing test score to LA CES. If you are also ISA* certified we will report your passing score to ISA for no additional cost. Please be sure to add your ISA Certification number when you sign in. Tests with passing scores may be submitted only once to each organization.
*ISA has approved this course for .5 CEUs per section for a total of 1.5 CEUs applied toward Certified Arborist credit or 1.0 CEU may be applied toward BCMA Practice credit and .5 Science credit.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. If you are an ISA and/or CLARB member, please be sure to include your certification/member number(s) along with your LA license and ASLA numbers.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our
Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks after that.
LA CES maintains a record of earned PDH credits on their website http://laces.asla.org/
ISA maintains a record of earned CEU credits on their website http://www.isa-arbor.com/