English Ivy Production Guide

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CFREC-A Foliage Plant Research Note RH-91-15
R.W. Henley, A.R. Chase and L.S. Osborne
University of Florida, IFAS
Central Florida Research and Education Center - Apopka
2807 Binion Road, Apopka, FL 32703-8504

 

Important Notice  

This foliage plant production guide, like other MREC foliage production guides, is meant to inform growers how to produce acclimatized plants specifically for use indoors (interiorscapes).  Although currently not listed on Floridas Exotic Pest Plant Councils list of invasive species, English ivy (Hedera helix) is found on numerous state invasive plant lists as well as Canada's list and several for National Parks and other "natural" areas.  English ivy is not native to North America and can be a very invasive plant.  It is suggested that this potential invasiveness be noted at the retail level and that buyers be advised to only use this plant where it cannot become a nuisance.

 


ENGLISH IVY

The genus Hedera, a member of the aralia family (Araliaceae), is comprised of approximately 5 species of woody vines with evergreen, alternately arranged leaves. Leaves are palmately veined and usually palmately lobed. Of the recognized species of Hedera (H. canariensis, H. colchica, H. helix, H. nepalensis, and H. rhombea), only H. canariensis (Algerian ivy) and H. helix (English ivy) are utilized commercially in the United States. Of the later two species, English ivy, with its many cultivars which vary in leaf size, leaf shape, leaf color and plant growth habit, is by far the most widely grown. The American Ivy Society has developed a simple classification system, based primarily on leaf shape and color, which is useful to horticulturists (Table 1). Most English ivy in the trade is in its juvenile form and is therefore vine-like, usually with lobed leaves, without flowers and easy to root. Very old specimens of English ivy trained on walls or trees will often develop to the mature form which results in thickened-erect stems, non-lobed leaves, flowers and difficult-to-root branches. English ivy is one of the most cold hardy plants used indoors. Some cultivars are used in northern landscapes where temperatures drop to -10F for brief periods. Most cultivars used as potted foliage plants are not so hardy, but should withstand 10 to 20F if acclimatized to some cold prior to exposure to sub-freezing temperatures the first time.


Table 1. Classes of English ivy (Hedera helix) used by the American Ivy Society and examples of cultivars produced by commercial growers in Florida.

Class					Cultivars
-----------------------------------------------------------------------------------
Arborescents - plants with stiffly 	Few in cultivation
upright stems which frequently 
produce flowers	

Bird's foot - leaves with narrow lobes	Brokamp, Green Feather, Irish Lace, 
					Needlepoint, Perfection

Curlies - leaves with ruffles, ripples  Big Deal, Ivalace, Manda's Crested,
or pleats				Telecurl

Fans - leaves broad and fan shaped  	California Fan, Fan
with leaves of equal length	

Heart shapes - leaves shaped like 	My Heart, Sweetheart
a valentine	

Ivy ivies - leaves typical of species,  Hahn, Pittsburgh
with pronounced terminal, lateral and 
basal lobes	

Miniatures - leaves less than 		Jubilee
1/2 inch long	

Oddities - plants with unusual form,	Few in commercial production
such as fasciated stems or distorted 
leaves	

Variegated - leaves multi-colored	Glacier, Gold Dust, Gold Heart, Hahn 
					Variegated, Jubilee, Kolibri

English ivy is an excellent foliage plant for hanging planters and other applications which require a cascading or trailing plant. It is also used effectively in dish gardens and other combination planters. In large interior plantings, English ivy makes a good ground cover and cover in free-standing planters containing interior trees. The plant can also be trained into formal shapes on trellises or made into topiary figures. Depending upon a particular application, some cultivars are much superior to others.

English ivy should be rooted and grown in a well-drained, peat-based potting medium with high water holding capacity. Calcium and magnesium is normally supplied by dolomite blended with the potting medium at the rate of 4 to 10 pounds per cubic yard to adjust the pH to approximately 6.0. The amount of dolomite used will depend upon the initial acidity of the medium. Micronutrients can be premixed with the potting medium or added as part of a liquid fertilizer program. Most growers now use commercially prepared peatlite potting mixes which have been blended with amendments to provide proper physical and chemical properties.

A fertilizer with approximately 3-1-2 or 2-1-2 ratio should be used at the rate of 2.5 to 3.0 pounds of actual nitrogen per 1000 square feet per month. If 20-20-20 fertilizer is used, it should be applied at the rate of 14.4 pounds/1000 square feet/month.

Ivy grows well at light intensities of 1500 to 2500 foot candles and a temperature range of 65 to 85F. When temperatures rise above 90F root and grow poorly. Use of greenhouses is strongly recommended for the production of high quality plants that require careful manipulation of irrigation, nutrition, light intensity and temperature.


PHYSIOLOGICAL PROBLEMS

1) Loss of variegation in young leaves

Symptoms -
Some of the variegated cultivars will lose most, if not all, of their color pattern in young foliage when placed in very deep shade. This is most frequently observed during winter production.

Control -
Since changing the level of shade or shifting plants to brighter light restores the typical color pattern in young leaves, it is not regarded as a serious problem.

2) Loss of variegation in older leaves

Symptoms -
Another type of leaf color shift is observed in the older leaves of a few of the variegated cultivars, particularly some of the yellow and green ones. The loss of variegated pattern is accelerated by low light levels.

Control -
Grow only those variegated cultivars which retain the desired color pattern as the leaves age.

3) Permanent change in leaf color or significant change in leaf shape

Symptoms -
One or more shoots on a plant will develop with leaves which are distinctly and genetically different from the rest of the plant. Differences in leaf color pattern and leaf shape are relatively common in certain cultivars.

Control -
Prune out the unwanted growth. Use only cuttings with leaves typical of the cultivar for propagation. Some cultivars, such as `Gold Heart' and `Kolibri', are much less stable than others.

4) Slow growth and rooting of cuttings

Symptoms -
Plants lack normal vigor and root slowly, a condition frequently observed during the summer in the South.

Control -
English ivy grows best when temperatures can be maintained below 90F. Shading, keeping hanging plants low in the greenhouse and supplementing ventilation with either evaporative pads or fog will help reduce high temperatures.

The Ivy Book and Ivies are suggested for those interested in additional reading on growing English ivy on an amateur basis.

Reference Pest Control Guides Here


BACTERIAL PROBLEM

1) Xanthomonas leaf spot (Xanthomonas campestris pv. hederae)

Symptoms -
Xanthomonas leaf spot of ivy cultivars is characterized by brown to black circular to irregularly shaped spots found first on the oldest foliage. Many times the spots have a bright yellow halo or margin and a water-soaked edge. Disease occurs throughout the year. Infection of immature leaves results in speckling and deformity of these leaves.

Reference Pest Control Guides Here


FUNGAL PROBLEMS

1) Botrytis blight (Botrytis cinerea)

Symptoms -
Botrytis blight first appears as relatively large grayish or tan areas on leaf margins and in their centers. Spots enlarge rapidly and can encompass the entire leaf. The dusty gray-tan spores of the pathogen form readily in the dead tissue and can be easily seen with the naked eye. Affected leaves generally become covered with spores and collapse.

Control -
Botrytis blight occurs during the winter months when days are cool, short and humidity in the greenhouses is high.

2) Colletotrichum leaf spot (Colletotrichum trichellum)

Symptoms -
Colletotrichum leaf spot, (also called anthracnose) appears very similar to Xanthomonas leaf spot. Sometimes lesions appear black with tiny black specks in their centers which are the fruiting structures of the pathogen. Diagnosis of these symptoms by culturing is recommended to ensure choice of the appropriate control methods.

Control -
Reduce overhead watering as much as possible since it is necessary for disease development and spread.

3) Phytophthora leaf spot and stem rot (Phytophthora palmivora)

Symptoms -
Infected plants exhibit poor growth and color and basal leaves turn brown and curl downward. Root rot sometimes occurs, although leaf spot and stem rot appear to be more common. Leaf spots are large gray to black and water-soaked.

Control -
Cultural controls include use of pathogen-free potting media, pots and plant material as well as minimal water applications.

4) Rhizoctonia aerial blight (Rhizoctonia solani)

Symptoms -
Rhizoctonia blight occurs primarily during the hot summer months when humidities are very high in the growing area. Disease development is rapid and can occur in less than one week if conditions are optimal. Brown, irregularly-shaped lesions form all over the plant. Although the first symptoms sometimes appear on the top of the plant, the pathogen inhabits the potting medium and is not as readily spread by air movement as many other fungal leaf spot organisms. The lesions spread rapidly and the reddish-brown spider web-like mycelium can cover the entire plant.

Control -
Cultural control of this disease is the same as that listed for Phytophthora leaf and stem rot.

Reference Pest Control Guides Here


INSECT AND RELATED PROBLEMS

The major arthropod pests of Hedera helix include aphids, fungus gnats, mealybugs, mites, scales, whiteflies, thrips and larvae of certain moths. Mealybug, mite, and scale infestations are typically the result of introducing infested plant material into the greenhouse. Aphids, moths, thrips and whiteflies have the ability to fly and thus invade the greenhouse from weeds and other infested plants outside. In the control section for each pest, a few of the many registered and effective pesticides will be listed. For a complete listing, please consult the references at the end of this report. Because of the numerous varieties grown in the greenhouse, a small group of plants should be tested for phytotoxicity prior to treating the entire crop. The list given in this section should be used only as a guide to the sensitivity of this plant to pesticides.

1) Aphids

Symptoms -
Aphids are pear-shaped, soft-bodied insects which vary in color from light green to dark brown. Infestations may go undetected until honeydew or sooty mold is observed. Aphids can cause distortion of new growth or, in extreme cases, infested plants can be stunted.

Control -
Aphids are relatively easy to control with many registered materials. Phytotoxicity to this plant has been caused by many different chemicals. Please conduct your own tests to see what is safe under your conditions. Root aphids have been controlled with soil drenches.

2) Caterpillars (worms)

Symptoms -
Infestations are easy to detect because worms, their excrement and the damage they cause, are usually quite visible to the unaided eye. Damage appears as holes in the center or along the edges of leaves. Damage by worms is often confused with slug or snail damage. The only way to determine which pest is involved is to find a specimen. Old damage can be distinguished from new by the calloused appearance of the older damaged areas (worms are usually gone by this time).

Control -

3) Fungus gnats

Symptoms -
Fungus gnats are small black flies (1/8 inch long) and are frequently observed running around the soil surface or on leaves and are often confused for Shore flies (see later section). The adults have long bead-like antennae and their legs hang down as they fly. These insects are very weak fliers and appear to "flit" around randomly. The larvae are small legless "worms" with black heads and clear bodies that inhabit the soil. The larvae spin webs on the soil surface which resemble spider webs. Damage is caused by larvae feeding on roots, root hairs, leaves in contact with the soil and lower stem tissues. Feeding damage may predispose plants to disease and they are often found in close association with diseased plants or cuttings. Adults do not cause any direct damage, but are responsible for many consumer complaints to growers. Adults emerge and fly around in retail shops, homes, or offices and are therefore a nuisance. For further information please consult Extension Entomology Report #74 (Management of fungus gnats in greenhouse ornamentals).

Control -
Reduce the amount of water applied to each pot where possible. Avoid algae growth where possible. Soil drenches or soil-surface sprays are effective at controlling the larvae. Nematodes that seek out insects in the soil are sold commercially and have been shown to control these pests without causing any negative effects to the host plants. Adults are very sensitive to most chemicals.

4) Mealybugs

Symptoms -
Mealybugs appear as white, cottony masses in leaf axils, on the lower surfaces of leaves and on the roots. Honeydew and sooty mold are often present and infested plants become stunted, and with severe infestations, plant parts begin to die.

Control -
Systemic materials are preferred. Control of root mealybugs is accomplished with soil drenches with an insecticide. When pesticides are applied to the soil, care must be taken to assure that the pots have good drainage and that no saucers are attached, or phytotoxicity may result.

5) Mites (Broad mite and false spider mites)

Symptoms -
Mites are very small and go unnoticed until plants become severely damaged. Broad mites cause foliar necrosis of the vegetative shoot apex. Initial symptoms of injury show new leaves cupped downward, puckered, stunted and have serrated margins. Broad mite eggs are covered with many tubercles which give them the appearance of being jeweled. False spider mites (Brevipalpus spp.) are red in color and sedentary. Eggs are bright red and oval-shaped and are laid on both surfaces of leaves. Initial infestations are indicated by faint brown, scruffy flecks, later becoming bronze or reddish in color. Basal leaf areas are affected, vegetative shoot apexes may be killed, and severe leaf drop may occur.

Control -
The critical point in any control program is thorough coverage with the pesticide. The best control program is to minimize the possibility of introducing mites into the growing area on infested plant material.

6) Mites (Two-spotted spider mite)

Symptoms -
Two-spotted spider mites are very small and go unnoticed until plants become severely damaged. Damaged foliage begins to turn yellow or become speckled due to the feeding of mites. Webbing, loss of leaves and plant death can occur when mite populations reach high levels. Often the presence of this pest is overlooked because the cast skins and webbing produced by this mite are confused for dust on underside of leaves. Mites have round pale yellow to reddish eggs deposited on the undersurfaces of leaves; nymphs and adults have two dark patches on either side of their bodies.

Control -
The critical point in any control program is thorough coverage with the pesticide. The best control program is to minimize the possibility of introducing mites into the growing area on infested plant material. Biological control programs have worked in small scale studies but remain unproven in commercial greenhouses.

7) Scales

Symptoms -
Infested plants become weakened or stunted and begin to die. Scales can be found feeding on leaves, petioles, or stems. They are usually distinct from the plant material on which they are feeding. Their shape (round to oval), size (pinpoint to 2 mm long), and color (light to dark brown) are quite variable and many scales are hard to distinguish from the plant material on which they are feeding.

Control -
See Mealybugs

8) Shore flies

Symptoms -
Shore flies small black flies (1/8 inch long) and are frequently observed sitting on the tips of leaves or on the soil surface feeding on algae. The adults have very short antennae. These insects are very strong fliers and exhibit directed flight (straight between 2 points). The larvae inhabit the soil and are small legless "worms" with clear bodies and no obvious heads. No known damage is caused by larvae. This insect is believed to feed only on algae. Adults do not cause any direct damage, but may be responsible for spreading plant pathogens, reducing value by defecating on the leaves (small black to green spots) and for many consumer complaints to growers. Adults emerge and fly around in retail shops, homes, or offices and are therefore a nuisance.

Control -
Reduce the amount of water applied to each pot where possible. Avoid algae growth on walkways, benches, and cooling pads. Chemicals are not believed to be very effective in the control of this pest.

9) Slugs

Symptoms -
Slug and caterpillar damage are similar and determining which pest is present can be difficult. Snails and slugs are voracious feeders, with small stages feeding on surface tissue and larger ones eating irregular holes in foliage. Generally, the culprit can be found on close examination of the plant. Slugs often live under benches or in dark, moist protected places close to the damage. These pests are nocturnal and can be found feeding at night.

Control -
Sprays or baits applied to moistened soil around plants are effective. Repetitive applications are necessary. Good sanitation with removal of extraneous plant material and debris which might shelter these pests aids in control.

10) Thrips (Western Flower Thrips and Banded greenhouse thrips)

Symptoms -
Thrips are small (less than 1/20), thin insects. Adult thrips can be identified by a long fringe of hair around the margins of both pairs of wings. Color varies between species with western and other flower thrips being yellow to light brown and banded greenhouse thrips and a few other thrips that feed mainly on leaves being dark brown to black. Feeding takes place with rasping type mouth parts. Infested leaves become curled or distorted, with silver-gray scars or calloused areas where feeding has occurred. Thrips can transmit the tomato spotted wilt virus to many different ornamentals. Any unusual symptoms should be investigated.

Control -
Many materials are registered and effective at controlling thrips.

11) Whiteflies

Symptoms -
Infested leaves often have small yellow spots where adults or immature whiteflies have fed. When populations become dense the leaves become yellowed and lower leaves are covered with black sooty mold. The immature stages of the sweetpotato whitefly are small scale-like insects and can be found on the underside of infested leaves.

Control -
Many materials are registered and effective at controlling whiteflies. To minimize additional resistance problems, one of the above insecticides should be applied two times per week throughout one life cycle (3 weeks) to control an established infestation. Monitor the population to determine if the particular insecticide being applied is reducing whitefly numbers. Some populations may be resistant to one or more of these insecticides. If the infestation persists, use another compound for the above list following the same schedule. Do not apply tank mixes as they may enhance resistance. If low numbers of whiteflies persist, apply one of the above insecticides once per week for 3 weeks then switch insecticides. Underside of leaves must be covered thoroughly to achieve satisfactory control. For additional information on this pest please consult Plant Protection Pointer #73 (Sweetpotato whitefly on ornamental plants)



Pesticides should be applied according to label directions.

Regardless of the pesticide or mixture of pesticides used, it is
strongly recommended that the effects be evaluated on a few
plants, under your particular conditions before treating all plants.

Mention of a commercial or proprietary product in this paper
does not constitute a recommendation by the authors,
nor does it imply registration under FIFRA as amended.


Reference Pest Control Guides Here


REFERENCES

1. Bailey, L.H., E.Z. Bailey and Staff of Liberty Hyde Bailey Hortorium. 1976. Hortus Third. Macmillan Publishing Company, Inc., New York, NY. 1290 pp.

2. Chase, A.R. 1990. Phytotoxicity of some bactericides and fungicides on ornamental plants. Nursery Digest 24(5):11.

3. Conover, C.A. and R.T. Poole. 1990. Light and fertilizer recommendations for production of acclimatized potted foliage plants. CFREC-A Research Report RH-90-1. 13 pp.

4. Pierot, Suzanne Warner. 1974. The Ivy Book - The Growing and Care of Ivy and Ivy Topiary. Macmillan Publishing Co., New York, NY. 164 pp.

5. Price, J., D.E. Short and L.S. Osborne. 1989. Management of fungus gnats in greenhouse ornamentals. Extension Entomology Report #74.

6. Rose, Peter Q. 1980. Ivies. Blandford Press, Poole, England. 180 pp.

7. Short, D.E., L.S. Osborne, and R.W. Henley. 1984. Phytotoxicity of insecticides and miticides to foliage and woody ornamental plants. Extension Entomology Report #57. 23 pp.

8. Short, D.E., L.S. Osborne, and R.W. Henley. 1991. 1991-1992 Insect and related arthropod management guide for commercial foliage plants in Florida. Extension Entomology Report #52. 13 pp.

9. Short, D.E., J. Price and L.S. Osborne. 1989. Sweetpotato whitefly on ornamental plants. Extension Entomology Report #73.

10. Simone, G.W. and A.R. Chase. 1989. Disease control pesticides for foliage production, Revision 4. Extension Plant Pathology Report No. 30. 54 pp.

11. Sulgrove, Sabina Mueller. 1982. The care of ivies and the American Ivy Society Ivy collection, Second edition, The American Ivy Society, Dayton, OH. 16 pp.