Taking an environmentally sensitive approach to pest management


Missouri Environment & Garden



AUTHOR

David Trinklein
University of Missouri
Division of Plant Sciences
(573) 882-9631
trinkleind@missouri.edu

Of Dragons and Dracaenas

David Trinklein
University of Missouri
(573) 882-9631
trinkleind@missouri.edu

Published: January 8, 2021

dragon

Tales of reptilian creatures able to breathe fire and wreak havoc on humanity are common in the folklore of many ancient civilizations. In certain cultures, dragons were symbolic of good luck; in most cultures, however, they were considered malevolent monsters. Indeed, the legend of St. George slaying a dragon is symbolic of good triumphing over evil, as depicted in Durer's famous wood carving. Today, dragons still captivate the imagination of many individuals, because of the success of movies and TV series that romanticize them as they showcase their surreal powers. Suffice to say, if dragons ever existed, their importance today primarily is symbolic.

A grotesque-looking creature that is difficult to kill would appear to be an unlikely name for a plant, but such is the case with the dracaenas. The latter is a genus of plants that derives its name from the ancient Greek drakaina, or female dragon. Additionally, when the bark or leaves of certain members of this genus (e.g. Dracaena draco) are cut, a reddish resin is secreted. This resin is the source of "dragon's blood," a substance that has been used from ancient times as a medicine for intestinal and skin problems, a dye and in incense.

There are about 120 species in the genus Dracaena, several of which make excellent interior (house) plants. Although there are a few tropical species native to Central America, most of the dracaenas are native Africa, central Asia and northern Australia. Tree-like members of the genus have woody stems and clusters of leathery leaves at the tops of the stem that give them somewhat of a palm-like appearance, as they develop into large plants. It is their durable leaves that make them a very useful interior plant.

tree

The dracaenas are durable plants for several reasons. First, they are tolerant of poor light. Although they hold their leaves longer and lower on the stem in good light, certain species (e.g. Dracaena deremensis) can be used in areas with light as low as 50 foot-candles. Second, they are tolerant of somewhat erratic watering patterns, provided they are not allowed to become excessively dry. Excessive drying usually results in pronounced leaf drop as well as browning of leaf tips. Dracaena should be kept "slightly moist" at all times to maintain an attractive appearance and promote new growth. Third, their leathery leaves make them less susceptible to problems associated with the low humidity characteristic of most interior environments, especially during winter months.

corn like leaves

One of the most popular and durable of all dracaenas is an old-fashioned interior plant know as corn plant dracaena (Dracaena fragrans 'Massangeana'). It derives it common name from the fact its leaves are about the size of a corn leaf and they also arch in a downward direction, similarly to a corn leaf. However, unlike leaves of a corn plant which develop in a flat plane on each side of the stem, the leaves of corn plant dracaena radiate out from all sides of a central stem. With adequate light, leaves of this attractive plant have a wide yellow stripe down their center. Under low light conditions, leaves often revert to being entirely green, without variegation.

Corn plant dracaena develops into a small tree in its native tropical habitat. Given good conditions indoors, they hold the potential of becoming fairly large, although growth is slower indoors. Plants that become too tall can be cut back to develop new shoots from dormant buds located next to leaf scars in the main stem. The latter is often is referred to as a cane. Plants with a cane-type of growth normally drop bottom leaves as they add leaves to their top. The tendency is worsened under low light conditions.

green leaves with red edges

Another very popular and attractive dracaena is called Madagascar dragon tree, or red-edged dracaena (Dracaena marginata). This species has shorter and much narrower leaves than corn plant dracaena. Its long, slim leaves have a margin with a red edge. The stems of this plant remain thinner than that of corn plant. Therefore, the plants often are placed several per pot for fullness, or grown with multiple branches. Red-edged dracaena drops its lower leaves quite easily if not given enough light or water. Cultivars are available (e.g. 'Colorama') with different and more vivid colors of variegation along with the red, for added ornamental appeal.

green leaves with red edges

As mentioned earlier, Dracaena deremensis is valued for its ability to tolerate low light conditions. Two cultivars dominate sales of this species. 'Warneckii,' or striped dracaena, has sword-shaped, leathery leaves that are held densely along its stem. The center of each leaf has a strip of grey-green with bands of white, green or chartreuse along each side. Maturing indoors to a height of about 36 inches, it represents one of the most colorful choices for an interior plant able to tolerate low light conditions.

green leaves with red edges

Dracaena deremensis 'Janet Craig' has been described as an interior plant "work horse" that has been used for decades to add plant mass to interior spaces. A mutation of 'Warneckii' that was discovered in 1930, 'Janet Craig' is one of the most durable and prized plants for offices and other settings where large plants are needed. It bears long, elegant leaves with a rich, green color and matures to a height of about 48 inches under indoor conditions. Because of its size, it most often is used in floor planters or tubs, planted in multiples for added mass effect. Few interior plants are as easy to grow as 'Janet Craig' dracaena.

green leaves with red edges

Not all dracaenas are large. One of the best small members of this genus is Dracaena sanderiana, or ribbon plant. Its small leaves are only about six inches in length and striped with grey-green and white. Very tolerant of indoor conditions, it is useful in dish gardens. A green variant of ribbon plant is sold under the trade name of 'Lucky Bamboo,' whose stems often are braided for a novel appearance.

A few plants previously considered to be close relatives of the dracaenas have been reclassified into the genus Two of these are Malaysian dracaena (Dracaena reflexa) and lance dracaena (Dracaena thalioides). They are taller, thinner plants that tend to hold their short leaves longer than most other dracaenas. D. reflexa 'Variegata'is a very colorful form of Malaysian dracaena that is marketed as 'Song of India.' It bears short, vividly-striped leaves that are radially arranged around the stem of the plant. Lance dracaena is a small species known for its dark green, lanceolate leaves.

As mentioned above, the dracaenas are relatively care free. Spider mite, mealybug and scale are insect pests that can become problematic, if left undetected. It is best to quarantine new plants before moving them into the home to make sure they are pest free.

Unfortunately, dracaenas are very sensitive to fluorides. Typical symptoms include leaf tip and edge necrosis. Plants rarely succumb to this disorder, but their aesthetic value is reduced. Prevention is the only cure. Therefore, it is advisable to use a potting mix that does not contain perlite, since the latter contains fluorides. Additionally, since many water sources contain fluorides, the use of rain water or deionized water can help prevent symptoms from occurring.

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REVISED: January 8, 2021