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Publication #ENH1192

'Jon Jon' Magnolia: A Late-Flowering Deciduous Magnolia for Northern Florida1

Gary W. Knox2

Introduction

'Jon Jon' magnolia (Magnolia 'Jon Jon') is a large-flowered, hybrid, deciduous magnolia that flowers profusely in late spring, about 2 weeks after most saucer magnolias (Magnolia × soulangeana selections) but before foliage emerges. This later blooming period usually allows 'Jon Jon' to miss spring freezes that often damage saucer and other spring-flowering magnolias.

Plant Characteristics

A long-term evaluation of 'Jon Jon' magnolia in the southeastern United States found 'Jon Jon' magnolia grows as a vigorous, deciduous tree in an upright-rounded form (Figure 1) (Blythe et al. 2010; Knox et al. 2011). After 9 years of growth in northern Florida, the height of three 'Jon Jon' plants ranged from 12 to 18 feet. Mature height is expected to be about 30 feet.

Figure 1. 

'Jon Jon' magnolia tree in full bloom in northern Florida.


Credit:

G. W. Knox


[Click thumbnail to enlarge.]

'Jon Jon' magnolia is cold hardy in USDA hardiness zones 6b–9a. However, 'Jon Jon' magnolia is not recommended for zone 9a (Central Florida) and south because of poor plant growth and flowering (Knox et al. 2011).

'Jon Jon' grows best in full sun or partial shade and is adapted to all but wet soils. Although drought tolerant once established, it grows best in moist, well-drained soils.

Flower and Leaf Characteristics

Large, fuzzy flower buds develop into goblet-shaped flowers the first day, with flowers gradually opening wider on subsequent days (Figures 2 and 3). Flowers are white to creamy white with a basal purple blush. Flowers are large with diameters up to12 inches. Individual petal-like tepals are creamy white with a deep reddish-purple blush at the base and a length of 5.5–6.0 inches. Leaves are 6–8 inches long and medium green, sometimes turning yellow before falling in autumn.

Figure 2. 

'Jon Jon' magnolia flowers.


Credit:

G.W. Knox


[Click thumbnail to enlarge.]

Figure 3. 

A fully open 'Jon Jon' magnolia flower.


Credit:

G. W. Knox


[Click thumbnail to enlarge.]

Plants flower as early as 3 years after planting (Knox et al. 2011). Flowering usually occurs about 2 weeks later than saucer magnolia. Peak bloom ranges from late February and early March in zone 8b to late March and early April in zones 6b and 7a. Flowering lasts from about 2 weeks (zone 6b) to 5 weeks (zone 8b, North Florida), depending on weather. 'Jon Jon' usually flowers late enough to avoid freeze damage.

History

'Jon Jon' magnolia was bred by the late Todd Gresham and was selected and named by the late John Allen Smith (Magnolia Nursery, Chunchula, AL) from Gresham hybrids planted at Gloster Arboretum (Gloster, MS). Although Gresham did not leave records of parentage, recent research indicates 'Jon Jon' is a hybrid of M.× soulangeana and Magnolia × veitchii with a genome size of approximately 15.2 pg, corresponding to a ploidy of approximately 6.9x (Parris et al. 2010). 'Jon Jon' was named and introduced in the mid-1980s but was not widely grown until recently.

Commercial Propagation

'Jon Jon' magnolia may be rooted from softwood cuttings taken as soon as new spring growth reaches a length of about 6 inches (Knox 2001). Although timing of cutting collection is more important than rooting hormone concentration, a 5-second quick dip in rooting hormone of 3:1 K-IBA:K-NAA has been used successfully at rates ranging from 5,000:1,500 to 15,000:4,500 ppm. IBA in talc at concentrations of 3,000–16,000 ppm also successfully rooted 80% of cuttings.

References

Blythe, E. K., W. Dunwell, E. Bush, J. W. Adelberg, M. Arnold, R. Bracy, Y. Chen, D. Fare, W. Klingeman, P. Knight, G. Knox, A. V. LeBude, J. Lindstrom, A. X. Niemiera, A. Owings, J. Robbins, J. Ruter, and T. P. West. 2010. "Nursery Crop and Landscape Systems Plant Evaluations by SERA-27 in the Southeastern U.S.: 2010 Update." Comb. Proc. Intl. Plant Prop. Soc. 60 (forthcoming).

Knox, G. W. 2001. "New and Improved Deciduous Magnolia Cultivars." Comb. Proc. Intl. Plant Prop. Soc. 51: 601–603.

Knox, G. W., J. Lindstrom, T. Ranney, E. Bush, A. Owings, W. Dunwell, and R. Beeson. 2011. 'Jon Jon' Magnolia: A Late-Flowering Deciduous Magnolia Recommended for Zones 6b to 8b in the Southeastern U.S., Final Report. Southern Extension and Research Activities/Information Exchange Group 27 (SERA-IEG-27) for Nursery and Landscape Systems.

Parris, J. K., T. G. Ranney, H. T. Knap, and W. V. Baird. 2010. "Ploidy Levels, Relative Genome Sizes, and Base Pair Composition in Magnolia." J. Amer. Soc. Hort. Sci. 135 (6): 533–547.

Footnotes

1.

This document is ENH1192, one of a series of the Environmental Horticulture Department, UF/IFAS Extension. Original publication date October 2011. Reviewed December 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Gary W. Knox, Extension specialist and professor, Environmental Horticulture Department, North Florida Research and Education Center, UF/IFAS Extension, Gainesville, FL 32611.


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U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.