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What Are Cycads: Learn About Growing Cycad Plants

What Are Cycads: Learn About Growing Cycad Plants


By: Susan Patterson, Master Gardener

Going as far back as the dinosaurs, cycad plants are great for beginner and seasoned gardeners alike. These appealing plants will not only add interest both indoors and out, but they’re easy to care for. Let’s learn more about how to grow cycads.

What are Cycads?

Cycad plants are hardy, evergreen gymnosperms (cone-bearing plants) that grow in sand or hard rock. Cycads are dioecious plants; there are separate male and female plants. The female plant produces seeds, and the male plant produces cones filled with pollen.

The most popular cycad is the sago palm. They are slow growing and have a long life. They usually grow to 3 to 5 feet (91 cm-1-1/2 m.) in height, although they can sometimes reach 10 feet (3 m.)in height.

Species of Cycad

Cycads have been referred to as “living fossils” because they have existed before the dinosaurs. There are roughly 300 known species of cycads and new species of cycad are still being discovered. Although botanists are discovering new species of cycads, they are becoming extinct; the main threats to the cycads are habitat destruction and the harvesting of the plant.

Cycads are often confused with palms in appearance, but they are not related, as the cycad does not produce flowers or fruit. However, the cycad is closely related to the pine tree.

How to Grow Cycads

Because cycad plants are hardy, they are relatively easy to grow. The most important requirement is good drainage. If water is stagnant, the roots will rot. Cycads do well in terra cotta pots with a cactus mix or potting soil. Don’t expect rapid growth; these plants are slow growing, and like being root-bound, so there is no need to re-pot too often.

If you are planting the cycad for landscaping purposes, it is best to transplant a young plant from a container. The cycad does not like to have its roots disturbed until a trunk is visible. It is best to transplant during the spring when the temperatures are starting to increase. Remember that the cycad needs good drainage.

Cycad Care

Indoor cycads should never dry out. The soil needs to be kept moist but not saturated. In the summer months, your indoor cycad will need to be watered twice a week as opposed to the winter months when the plant will need little water. Keep this plant away from any direct heat sources and place it in a location where there is natural light.

If your cycad is outside, it will need full sun and your average temperature should be 70 F. (21 C.).

Fertilizing four times a year will ensure proper nutrition and growth. Typically, a granular fertilizer for palms with nitrogen (N), phosphorus (P), and potassium (K) that contains additional magnesium (Mg) and a complete micronutrient amendment is sufficient for cycads and will supply all the necessary nutrients.

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Cycas, an alternative to palm trees

The specific care that’s needed for a cycas, how and when it should be repotted and watered and diseases that infect it.

Core Cycas facts

NameCycas
FamilyCycadaceae
Type – indoor plant

Exposure – well-lit, full sun
Soil – soil mix
Foliage – evergreen

These are the answers to the many questions that can arise when one has the luck of owning a magnificent cycas.

Not quite a palm tree but still an amazing ornamental plant, cycas is very appealing.


Cycad Garden

This group of unusual cone-bearing plants were so common during the time of the dinosaurs that many refer to the Jurassic Period as the “Age of Cycads.” Today they are the most threatened plant group on the planet. Lotusland’s Cycad Garden, sometimes called a “million dollar garden” because its development coincided with the auction of Madame WaIska’s enormous jewelry collection, was the last garden created by Madame Walska. Upon its completion, Charles Glass, the renowned plantsman who designed the garden, told Madame Walska, ” … this will be one of the greatest achievements of our lives.” Glass was not exaggerating. Lotusland’s collection is thought to be one of the most complete in any American public garden, with over 450 specimens and almost half of the known species.

Shrinking wild populations of cycads are threatened by over collecting, deforestation, agricultural clearing, and urban sprawl. While some species have found homes in public and private gardens, their desirability has also spawned poaching concerns. Zaitoon Rabaney, executive director of the Botanical Society of South Africa made the comparison, “Our cycads are rarer than the rhino and are more in danger of extinction.” Lotusland cares for many species of threatened cycads with five species in the collection that are believed to be extinct in the wild.

Of Beetles and People: Reproduction in cycads provides an intriguing look into the sophistication of plant evolution. Long before flowering plants needed bees and butterflies, cycads were being pollinated by highly specialized beetles. All cycads are either exclusively male or female, a phenomenon known as dioecious. As a side note, you may be able to spot the difference on your walk through the garden: Female cones are generally wider, more egg-shaped, while male cones are generally longer and more narrow. To ensure pollination, the male cones attract insects by emitting an odor. They then produce a higher amount of that odor and heat up to send the insects away, who are then attracted to a female cone by a similar mechanism of producing heat and odor. Cycads are some of very few plants that actively both attract and repel insects! In the absence of these beetles at Lotusland, our plant curators hand pollinate our cycads. People are pollinators, too!


Types of Palms

One of the critical factors that determines where palms and cycads can be grown in South Carolina is their cold hardiness. Most of the palms listed below can be grown a half zone colder than that listed, if provided with protection during the winter, such as a wind block and adequate mulch. Expect some cold damage to occur in severe winters to all but the hardiest of palms.

Needle Palm (Rhapidophyllum hystrix): Needle palms are truly beautiful native plants that occur naturally in river floodplains of the Southeast, mostly below the fall line. They are rare to the point of endangerment and are often found growing over limestone. They are a clumping understory palm with many palmate, deep-green leaves that have silvery undersides. Numerous very sharp needles protect the crown of the plant, hence its name, needle palm.

Needle palm is a very adaptable palm. It is considered the world’s hardiest palm, and large, established specimens in good sites can easily take short periods of -5 °F. New growth is damaged at -10 °F. Fifteen degrees below zero is usually fatal, although plants have been known to recover from this temperature. Needle palm is hardy in all areas of South Carolina.

Native needle palm.
Ted Bodner, Southern Weed Science Society, www.ipmimages.org.

Needle palms can be used in clumps or as single specimens. The typical size of the clump is about 5 feet high and wide, although it can eventually reach 10 feet high and wide. The growth rate is slow. They grow best in light shade with adequate moisture and are not very tolerant of salt spray.

Dwarf Palmetto (Sabal minor): This palm appears to be a clumping type of palm, but it actually has a trunk that is either very short or below the ground. Unlike the saw palmetto, the dwarf palmetto does not have spiny leaf stems and does not spread over a large area. The fan-shaped foliage of this dwarf palm may be green to a bluish-gray. There are usually no more than a half dozen leaves on a single plant. They differ from the leaves of other native dwarf palms by having a split ‘V’ right in the middle. The native habitat is similar to the needle palm, but the dwarf palmetto is much more common. The usual size is 4 to 5 feet high and wide and the growth rate is slow.

The dwarf palmetto is hardy in all areas of South Carolina. It is almost impossible to transplant, therefore it is best to use container-grown plants. It will tolerate some salt spray.

Windmill Palm (Trachycarpus fortunei): These palms have a single, slender (1 foot or less in diameter) trunk with fan-shaped leaves similar to the needle palm. Leaves are dark green and can be 2 to 3 feet across. The trunk of this palm is brown and is usually covered with a burlap-like substance. The trunk is often wider at the top than the bottom. The average height in our area is 20 feet and the growth rate is moderate to somewhat fast. Under good growing conditions this palm can grow 1 to 2 feet per year.

Windmill palms are one of the most cold hardy of palms and are hardy in South Carolina from zones 7b to 8b. In the Southeast, this palm grows best in light to medium shade. It must have some shade in zone 8b. Prefers a rich, fertile, loamy soil, but will tolerate most types of soil. The windmill palm grows best with ample water, but will not tolerate standing water or a high water table. Windmill palms cannot take direct salt spray.

Cabbage Palm or Palmetto (Sabal palmetto): The cabbage palm is the state tree of South Carolina and is commonly seen near coastal areas. It has large, blue-green leaves with threadlike strands of fiber hanging off of each leaf. The trunk is massive (can be a foot and a half across) and wild plants retain old leaf-stems (often called “boots”) on their trunks in a crisscross pattern. They are common in their native habitat, which ranges on the southeastern coast from southern North Carolina to the northern panhandle of Florida. Their growth rate is usually moderate and a mature height of 30 feet is common in our area

Distinctive leaf bases on cabbage palm
Karen Russ, ©2007 HGIC, Clemson Extension

Cabbage palms prefer full sun to light shade. They are very adaptable to different soil types, but do best in sandy soil with some limestone, such as might be found in old shell-mounds near the beach. They are hardy in South Carolina from zones 7b (protected) to 8b, and do best with ample water. They are very tolerant of salt spray.

Mediterranean or European Fan Palm (Chamaerops humilis): This palm is a small, clumping fan palm with stiff leaves and spiny leaf stems. The growth rate is slow, and in the Southeast a height of 5 feet is common. They are hardy in South Carolina from zones 8a to 8b. Plant this palm in full sun to light shade. They need well-drained soil and will thrive on a site with limestone. Once this palm is established it is extremely drought-tolerant.

Mediterranean or European Fan Palm
Karen Russ, ©2007 HGIC, Clemson Extension

Saw Palmetto, Scrub Palm (Serenoa repens): Saw palmettos are native to coastal areas of the Southeast and most areas of Florida. They are a low, spreading, fan-type palm with stiff leaves and saw-tooth-like leaf stems. The trunks usually creep along the ground, rooting and branching as they grow. In coastal regions, they are an aggressive spreader.

Saw palmettos grow best in a location that has full sun or very light shade and is well-drained. They are hardy in South Carolina from zones 8a to 8b. They tolerate salt spray and are drought-hardy once established.

Jelly Palm, Pindo Palm (Butia capitata): This is the most commonly cultivated exotic palm in the Southeast. It is a feather-type palm with gray-green to blue-green fronds 6 to 8 feet long and a massive trunk up to a foot and a half across. Ten to 20 feet is a common height and the growth rate is slow to moderate. This palm is not quite as hardy as the palmetto palm and requires winter protection below 15 ºF. They are hardy in South Carolina from zones 8a to 8b.

They grow best in full sun in a location that is well-drained. They are reasonably drought-hardy once established and will tolerate some salt spray.

Jelly Palm
Karen Russ, ©2007 HGIC, Clemson Extension

California Fan Palm (Washingtonia filifera): This palm can be truly immense and fast-growing. In warm climates plants can grow up to 100 feet tall. No plants have been grown to this size in the Southeast. The trunk can be up to 2 feet across. Leaves are yellow-green and palmate with spiny stems. In South Carolina this palm is considered hardy in zone 8b and marginally hardy in zone 8a. The large size and fast growth rate require special consideration in the landscape. It has moderate salt tolerance.

Mexican Fan Palm (Washingtonia robusta): This palm is native to Baja California and greatly resembles the California fan palm when young. The Mexican fan palm however, has a slender trunk usually less than one foot across. Although the Mexican fan palm grows reasonably well in zone 8b, a better choice for most of the Southeast would probably be a hybrid of the two species known as Washingtonia x filibusta.


Contents

Cycads have a cylindrical trunk which usually does not branch. Leaves grow directly from the trunk, and typically fall when older, leaving a crown of leaves at the top. The leaves grow in a rosette form, with new foliage emerging from the top and center of the crown. The trunk may be buried, so the leaves appear to be emerging from the ground, so the plant appears to be a basal rosette. The leaves are generally large in proportion to the trunk size, and sometimes even larger than the trunk.

The leaves are pinnate (in the form of bird feathers, pinnae), with a central leaf stalk from which parallel "ribs" emerge from each side of the stalk, perpendicular to it. The leaves are typically either compound (the leaf stalk has leaflets emerging from it as "ribs"), or have edges (margins) so deeply cut (incised) so as to appear compound. Some species have leaves that are bipinnate, which means the leaflets each have their own subleaflets, growing in the same form on the leaflet as the leaflets grow on the stalk of the leaf (self-similar geometry).

Due to superficial similarities in foliage and plant structure between cycads and palms they are often confused with each other. They also can occur in similar climates. In reality, they belong to completely different phyla, and are not closely related at all. The similar structure is evidence of convergent evolution.

Beyond those superficial resemblances, there are a number of differences between cycads and palms. For one, both male and female cycads bear cones (strobili), while palms are angiosperms and so flower and bear fruit. The mature foliage looks very similar between both groups, but the young emerging leaves of a cycad resemble a fiddlehead fern before they unfold and take their place in the rosette, while the leaves of palms are never coiled up and instead are just small versions of the mature frond. Another difference is in the stem. Both plants leave some scars on the stem below the rosette where there used to be leaves, but the scars of a cycad are helically arranged and small, while the scars of palms are a circle that wraps around the whole stem. The stems of cycads are also in general rougher and shorter than those of palms. [8]

The three extant families of cycads all belong to the order Cycadales, and are Cycadaceae, Stangeriaceae, and Zamiaceae. These cycads have changed little since the Jurassic, compared to some major evolutionary changes in other plant divisions. Five additional families belonging to the Medullosales became extinct by the end of the Paleozoic Era.

Based on genetic studies, cycads are thought to be more closely related to Ginkgo than other living gymnosperms. [9]

Classification of the Cycadophyta to the rank of family.

Class Cycadopsida Order Cycadales Suborder Cycadineae Family Cycadaceae Suborder Zamiineae Family Stangeriaceae Family Zamiaceae

Relationships between the extant genera, according to Nagalingum et al. (2011): [10]

Ginkgo, conifers, and gnetophytes

The probable former range of cycads can be inferred from their global distribution. For example, the family Stangeriaceae only contains three extant species in Africa and Australia. Diverse fossils of this family have been dated to 135 mya, indicating that diversity may have been much greater before the Jurassic and late Triassic mass extinction events. However, the cycad fossil record is generally poor and little can be deduced about the effects of each mass extinction event on their diversity.

Instead, correlations can be made between the number of extant gymnosperms and angiosperms. It is likely that cycad diversity was affected more by the great angiosperm radiation in the mid-Cretaceous than by extinctions. Very slow cambial growth was first used to define cycads, and because of this characteristic the group could not compete with the rapidly growing, relatively short-lived angiosperms, which now number over 250,000 species, compared to the 1080 remaining gymnosperms. [11]

Origins Edit

The cycad fossil record dates to the early Permian, 280 million years ago (mya). [ citation needed ] There is controversy over older cycad fossils that date to the late Carboniferous period, 300–325 mya. This clade probably diversified extensively within its first few million years, although the extent to which it radiated is unknown because relatively few fossil specimens have been found. The regions to which cycads are restricted probably indicate their former distribution in the Pangea supercontinent before the supercontinents Laurasia and Gondwana separated. [12] Recent studies have indicated the common perception of existing cycad species as living fossils is largely misplaced, with only Bowenia dating to the Cretaceous or earlier. Although the cycad lineage itself is ancient, most extant species have evolved in the last 12 million years. [10] Though the Mesozoic is sometimes called the "Age of Cycads", the foilage of cycads is very similar to other groups of extinct seed plants, such as Bennettitales and Nilssoniales, that are not closely related, and cycads were probably only a minor component of mid-Mesozoic floras. [13]

The family Stangeriaceae (named for Dr. William Stanger, 1811–1854), consisting of only three extant species, is thought to be of Gondwanan origin, as fossils have been found in Lower Cretaceous deposits in Argentina, dating to 70–135 mya. The family Zamiaceae is more diverse, with a fossil record extending from the middle Triassic to the Eocene (54–200 mya) in North and South America, Europe, Australia, and Antarctica, implying the family was present before the break-up of Pangea. The family Cycadaceae is thought to be an early offshoot from other cycads, with fossils from Eocene deposits (38–54 mya) in Japan, China, and North America, [14] indicating this family originated in Laurasia. Cycas is the only genus in the family and contains 99 species, the most of any cycad genus. Molecular data have recently shown Cycas species in Australasia and the east coast of Africa are recent arrivals, suggesting adaptive radiation may have occurred. The current distribution of cycads may be due to radiations from a few ancestral types sequestered on Laurasia and Gondwana, or could be explained by genetic drift following the separation of already evolved genera. Both explanations account for the strict endemism across present continental lines.

The living cycads are found across much of the subtropical and tropical parts of the world. The greatest diversity occurs in South and Central America. [ citation needed ] They are also found in Mexico, the Antilles, southeastern United States, Australia, Melanesia, Micronesia, Japan, China, Southeast Asia, India, Sri Lanka, Madagascar, and southern and tropical Africa, where at least 65 species occur. Some can survive in harsh desert or semi-desert climates (xerophytic), [15] others in wet rain forest conditions, [16] and some in both. [17] Some can grow in sand or even on rock, some in oxygen-poor, swampy, bog-like soils rich in organic material. [ citation needed ] Some are able to grow in full sun, some in full shade, and some in both. [ citation needed ] Some are salt tolerant (halophytes). [ citation needed ]

Species diversity of the extant cycads peaks at 17˚ 15"N and 28˚ 12"S, with a minor peak at the equator. There is therefore not a latitudinal diversity gradient towards the equator but towards the Tropic of Cancer and the Tropic of Capricorn. However, the peak near the northern tropic is largely due to Cycas in Asia and Zamia in the New World, whereas the peak near the southern tropic is due to Cycas again, and also to the diverse genus Encephalartos in southern and central Africa, and Macrozamia in Australia. Thus, the distribution pattern of cycad species with latitude appears to be an artifact of the geographical isolation of the remaining cycad genera and their species, and perhaps because they are partly xerophytic rather than simply tropical. Notes: The distribution area on the map should be expanded to include the range of Macrozamia macdonnelliana in the central region of Australia, Zamia boliviana in Bolivia and Mato Grosso, Brazil, Cycas thouarsii on Comoros and Seychelles, and Cycas micronesica on the islands of Guam, Palau, Rota, & Yap. Also, the depiction of cycad distribution in Africa, particularly the western boundary, should be improved to show the actual range limits, rather than national borders.

In Vanuatu, the cycad is known as namele and is an important symbol of traditional culture. It serves as a powerful taboo sign, [18] and a pair of namele leaves appears on the national flag and coat of arms. Together with the nanggaria plant, another symbol of Vanuatu culture, the namele also gives its name to Nagriamel, an indigenous political movement.


Cycads



Cycads

Cycads are ancient seed plants dating back over 200 million years. In the Jurassic Period cycad-like plants dominated world vegetation, which is why this era is sometimes referred to as ‘The Age of Cycads’. However, through the centuries cycads have declined both in number and distribution. Today three families are commonly recognised, with 11 genera and 250 species. There are many Australian native cycads and three endemic genera: Bowenia, Lepidozamia and Macrozamia. Although they are very popular garden plants, cycads are threatened, endangered or extinct in the wild.

Cycads thrive in tropical and subtropical areas with moderate to high rainfall. They resemble palms or tree ferns, and have a thick, soft trunk and a crown of large divided leaves. These primitive plants are dioecious (i.e. male and female reproductive structures are borne on separate plants). Male plants produce pollen in cones and female plants produce large, brightly coloured seeds on the edges of leaf like structures. The seeds are highly poisonous, and must be treated with care.

Sago Palm

Peter Valder is very fond of the sago palm (Cycas revoluta), and he is not alone. This is the most widely cultivated cycad in the world. It is native to the Ryukyu Islands of southern Japan, and it has been grown in China and Japan as a garden plant for hundreds of years. It is slow growing to around 3m (10′) tall, and has a compact crown of dark green, feather-like leaves, made up of crowded, narrow, spiky leaflets. Sago palms are hardy, and will tolerate drought and light frost. They do best in a sunny position with good drainage, and benefit from applications of mulch and fertiliser during the warmer months.

Cycads on the net

The Cycad Pages – Royal Botanic Gardens Sydney http://plantnet.rbgsyd.gov.au/PlantNet/cycad/

Palm and Cycad Societies of Australia http://www.pacsoa.org.au/index.html

Further reading

‘The Garden Plants of China’ by Peter Valder. Published by Florilegium, 1999, ISBN 1876314028, rrp $80 (pre GST).
‘A Guide to Palms and Cycads of the World’ by Lynette Stewart. Published by Angus & Robertson, rrp $49.95 (pre GST).


Watch the video: Cycad - Always