The yuccas comprise the genus Yucca of 40-50 species of perennials, shrubs, and trees in the agave family Agavaceae, notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal clusters of white or whitish flowers. They are native to the hot and dry parts of North America, Central America, and the West Indies.

Yuccas have a very specialized pollination system, being pollinated by the yucca moth; the insect purposefully transfers the pollen from the stamens of one plant to the stigma of another, and at the same time lays an egg in the flower; the moth larva then eats some of the developing seeds, but far from all.

Yuccas are widely grown as ornamental plants in gardens. Many yuccas also bear edible parts, including fruits, seeds, flowers, flowering stems, and more rarely roots, but use of these is sufficiently limited that references to yucca as food more often than not stem from confusion with the similarly spelled but botanically unrelated yuca.

CARE

Its main characteristics are summarized into these two: extremely hardy and not demanding. Can handle neglect, it will even survive through your holidays.

Yuccas love and can stand hot summer sun, even during the hottest hours of the day but they do well enough in semi-shaded spots. Water approximately once a week with little water and more scarce during winter. Its soil must drain well so it would be helpful to ad grovel at the base of the pot and mix some sand into the soil.

Its hard sword-like leaves end to spikes that are very hard and may injure you, so take special caution when you bend towards the plant in order to water or dig its soil.

Since its leaves are flat and wide, they easily capture dust so whenever you get the chance clean up the plant with water, either into the shower or using a sponge if yours is an indoor plant

When yuccas reach maturity, they flower during the summer months. Its flowers appear in groups, are large white and impressive, bell-shaped, but this is a sight seldom seen.

It is possible to propagate yuccas but the process is not so simple, especially if performed by novice gardeners, and is probably not worth the effort given that it is very easy to buy new healthy plants in any nursery and at affordable prices.

If you want your plant to grow higher, you can cut some of the bottom leaves in order for the plant to focus its strength in growing new leaves. Keep in mind though, that you will get a high plant but it will be standing on a leggy, naked trunk. Also, keep in mind that yuccas are not fast growers especially during winter.

If you get snow or ice where you live, cover the plant with a plastic sheet in order to protect it, if you don’t make it in time try to discard any snow that has settled on its leaves. A few days of low temperatures will not kill your plant but if it lasts for long you will notice brown spots on the leaves and you should move the plant inside your home or any protected area until the temperature returns to normal levels.

DISEASES

• Coniothyrium or brown leaf spot (Coniothyrium concentricum)
  Symptoms
  Coniothyrium leaf spot first appears as tiny clear zones in older leaves of yucca. Lesions turn yellow and finally brown as they mature. Lesions are generally elliptical and scattered across the entire upper leaf surface. After about 4 months, black perithecia or pycnidia form in the sunken lesion centers and are easily seen with the naked eye. Sometimes a chlorotic halo and/or dark-purple or black margin forms around older lesions which rarely exceed 1/2 inch in diameter.
  Control
  The most important aspects of control are removal of older infected leaves and elimination of overhead watering and exposure to rainfall. Since most yuccas are grown exposed to both overhead watering and rainfall, regular applications of fungicides are needed to prevent this disease.
• Cytosporina or gray leaf spot (Cytosporina sp.)
  Symptoms
  Cytosporina or gray leaf spot of Yucca aloifolia (Spanish-bayonet) has not been adequately described. Symptoms include tip and marginal necrosis with a predominantly gray color and brown margin. Lesions often reach 3 inches, have concentric rings of light and dark tissues and are most common on older leaves. The pycnidia of Cytosporina sp. can be found in these lesions.
  Control
  Use the methods and fungicides described in the UF/IFAS Control Guide for Coniothyrium leaf spot to control Cytosporina leaf spot of Yuccas.
• Fusarium stem rot - (Fusarium spp.)
  Symptoms
  One of the most common diseases of rooted yucca cuttings is caused by Fusarium spp. Soft rot of stem ends develops with destruction of leaves as well. There are two types of fruiting bodies for the pathogen which are commonly produced on the infected tissue. These are the bright red perithecia which are round and relatively easy to see with the naked eye and the powdery clusters of conidia which are ochre-colored.
  Control
• Southern blight - (Sclerotium rolfsii)
  Symptoms
  This pathogen attacks all portions of the plant but is most commonly found on stems. White, relatively coarse mycelia grows in a fan-like pattern and may be seen on the soil surface or stems. The round sclerotia form almost anywhere on the plant or soil surface. Sclerotia are initially white and cottony and approximately the size of a mustard seed. As sclerotia mature, they turn tan and eventually dark brown and harden.
  Control
  Although this disease can be avoided through cultural methods, it continues to cause losses in production of foliage plants today. Chemical control of Southern blight has been investigated on several foliage plants as well as non-ornamental crops.

INSECT AND RELATED PROBLEMS

The major arthropod pests of this plant include mealybugs, scales, thrips and weevils. In the control section of 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 the potential for phytotoxicity prior to treating the entire crop. The list in this section should be used only as a guide to the sensitivity to pesticides.

• 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.
• 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
• Thrips
  Symptoms
  Thrips are small (less than 1/20), thin insects. Adult thrips can be identified by a long fringe of hairs 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.

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