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Junipers in Florida1
Dewayne Ingram and William Barrick2Junipers provide Florida gardeners with a wide variety of evergreen plants for use in residential landscapes. American nurseries produce over 40 species of Juniperus and over 170 cultivars or varieties. Although commonly thought of as northern landscape plants, many species and cultivars are well adapted to north and central Florida. However, some species will not perform well south of Orlando.
DESCRIPTION
Foliage characteristics of juniper vary, but there are two primary leaf forms: juvenile and adult. Often both forms appear on the same plant, but as plants mature, the foliage changes to the adult form. Juvenile foliage is sharp, pointed and prickly, while the adult form is softer and somewhat flattened. Another factor that helps to distinguish cultivars is leaf structure and form. Juniper leaves are either needle-like or scale-like.Foliage color of junipers varies with cultivar. Typical foliage color is a deep green, but many varieties have distinct blue or gray-green tones. In addition, many juniper cultivars change to red or purple in the fall.
Junipers differ in form and size and may be observed as horizontal spreading (shrub-like), prostrate (ground cover types), and upright (tree-like) forms. Junipers range in height from 4" to nearly 25 feet, with mature spreads varying from one foot to ten feet. Because of this diversity in form, junipers are well adapted to residential landscape design. Junipers can be used effectively to provide screening as either an informal or formal hedge, prevent erosion by use as ground covers, or provide interest as an accent plant.
GENERAL CULTURE
Maximum growth is achieved by planting junipers in full sun because they become leggy and sparsely foliated in heavy shade. Junipers require well drained soils and grow best in acid soils. However, junipers are not extremely sensitive to soil pH range and may grow adequately in alkaline soils.PROPAGATION
Junipers are commercially propagated by cuttings in order to maintain the true nature of each cultivar. Seed propagation is not often used, since germination and seedling development may take as long as two years.DISEASES
Common diseases of juniper are twig blight, cedar-apple rust and root rots. Juniper decline, a disease caused by root rotting fungi in association with poor drainage, is a common problem in Florida.Twig blight or Phomopsis blight is most severe on new growth. The causal fungus infects the leaves causing leaf death and eventual twig dieback. Infected leaves often exhibit small black, pimplelike fruiting structures of the causal fungus. Control is a two-step process requiring removal and destruction of diseased plant parts followed by application of protective fungicide sprays. Check your local County Extension Office for recommendations.
Cedar-apple rusts are most easily recognized by the reddish-orange gelatinous structures produced on the surface of brown foliage galls or twig cankers during moist spring periods. These rust diseases require the close proximity of an alternate host such as apple, crabapple, hawthorn, pear or quince to complete their life cycles. Control measures can be targeted toward one or both hosts to control these diseases. Prune out galls or twig cankers on junipers in early spring. Undesirable native or planted hosts should be removed within a radius of several hundred yards to achieve a reasonable level of control. Either spring applications of fungicides to deciduous hosts or mid-summer applications to juniper will also achieve control. Contact your local County Extension Office for recommendations.
INSECTS
Red spider mites and bagworms are the most common pests of junipers. Spider mite injury first appears as a yellow or gray cast to the foliage and needle browning and drop occurs in advanced stages. Spider mite infestations build up under hot, dry conditions, especially in landscape areas with poor air circulation and little exposure to rainfall. Consult your local County Extension Office for recommended miticides.Bagworms are characterized by spindle-shaped bags on branches. The immature larvae feed on the foliage and camouflage their cocoons with needles. Control can be achieved by use of labeled insecticides during the early stages of insect development. Control is much more difficult as these bags become larger. It is often more practical to hand pick and destroy the bagworms when only a small number of plants are infected.
SELECTION
The most common junipers available in Florida are categorized by form and presented in Table 1 . The form, scientific name, height and spread, foliage type, color and the region in Florida where each cultivar is grown are included.Table 1 . Junipers for the Florida Landscape
Tables
Table 1.
Name Height/Spread Color Zone* Comments PROSTRATE FORMS Juniperus chinensis var. chinensis `Parsonii' 2-3'/2-3' Blue gray green NCS Relatively fast grower; scale-like foliage; generally pest free `Parsonii Variegata' 2-3'/2-3' Green with yellow variegation NCS Resembles `Parsonii', requires full sun for maximum variegation var. procumbens `Nana' 1-2'/1-2' Blue gray green N Foliage needle-like; seriously attached by spider mite `Aureovariegata' 1-2'/1-2' Blue gray green Yellow tipped N Resembles `Nana' except yellow variegation Juniperus conferta(Shore Juniper) 2'/6-8' Yellow Green NCS Aggressive grower; high maintenance; leaves needle-like with white bands `Conferta Compacta' 1'/3-4' Green NCS Compact selection of `Conferta' `Blue Pacific' 1'/3-4' Blue green NCS Agressive grower, but more compact selection than `Conferta' Juniperus horizontalis `Bar Harbor' 6-8"/Variable Blue green N Fall color bluish-purple; scale-like foliage `Douglasii' 8-10"/Variable Blue green N Fall color bluish-purple `Plumosa' 12-15"/Variable Green N Fall color reddish-purple; scale-like foliage `Plumosa Compacta'(Andorra Compacta) 12-15"/Variable Green N Fall color reddish-purple `Wiltonii' (Blue Rug) 4-6"/Variable Blue green N Extremely compact; blue fall color; scale-like foliage HORIZONTAL SPREADING FORMS Juniperus chinensis var. chinensis `Armstrongii' 5-6'/6-9' Yellow green N Sport of `Pfitzeriana' but flatter profile; scale-like foliage `Blue Vase' 4-6'/3-4' Blue gray green NCS Branches densely foliated with tufted appearance; vase shaped `Hetzii' 15'/5-8' Blue gray green NC Sharply angular form; good for screening; branch tips sparsely foliated `Mint Julep' 3-4'/3-4' Mint green NCS Form resembles `Hetzii' but color distinctly green `Pfitzeriana' 5-6'/6-9' Gray green N Wide spreading; scale-like foliage appears flattened `Aureo Pfitzeriana' 5-6'/6-9' Gray green with yellow variegation N Resembles `Pfitzeriana' but with variegation `Nicks Pfitzer Compacta' 3-4'/6-8' Gray green N Resembles `Pfitzeriana' but compact growth Juniperus squamata `Meyeri' 6-8'/6-7' Blue green N Blue-purple fall color; irregular branching; needle-like foliage UPRIGHT-COLUMNAR FORMS Juniperus chinensis var. chinensis `Sylvestris' 15-20'/3-5' Bright green NCS Same as `Oblonga'; scale-like foliage `Torulosa' (Hollywood) 15-20'/3-5' Dark green NCS Irregular branching; scale-like foliage Juniperus silicola(Southern Red Cedar) 30'/20' Light green NCS Dark blue female cones; more slender twigs than virginiana; scale-like foliage Juniperus virginiana (Eastern Red Cedar) `Burkii' 30'/20' Blue green NC Larger female cones or smaller male cones than silicola; scale-like foliage `Canaertii' 30'/20' Yellow green NC Horizontal branches; scale-like foliage *N = North Florida - Pensacola to Jacksonville and south to Ocala; C = Central Florida - Leesburg south to Punta Gorda and Fort Pierce; S = South Florida - Stuart to Fort Myers and south to Homestead
Footnotes
1. This document is ENH34, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date January 1990. Revised March 1991. Reviewed October 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.2. Dewayne Ingram, former professor; William Barrick, former assistant professor, Environmental Horticulture Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.
U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry Arrington, Dean.
Copyright Information
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