Birds of Paradise- the StrelitziasBy Geoff Stein (palmbob)
January 4, 2009
Ever since I was young, bird of paradise plants intrigued me. My best friend's dad had a small greenhouse in our home in northern New Mexico, one of the last climates you would ever expect to see a bird of paradise. It was so exotic and bizarre that I took some time to believe that such a plant could exist in nature. The flowers look so bird-like that it's hard to believe its mere coincidence. I never imagined I would live somewhere this plant would be so commonplace I would hardly ever give them a second look. But here I am now in southern California where Strelitzias are one of the most commonly planted landscape plants.
Strelitzia is a genus of about 5 or 6 species (depending on who you listen to) of monocot plants closely related to the bananas and even more closely related to Ravenala, the Madagascan plant known commonly as the Traveler's Palm. Strelitzia is a primarily South African genus, though Strelitzia alba is also found in Madagascar. All these plants are subtropical and grow in fairly low rainfall areas, so they tolerate only minimal frost but are fairly drought tolerant.
The leaves of most Strelitzias are ‘paddle-shaped' and resemble banana leaves only with longer petioles. Strelitzia juncea leaves are ‘paddle-less' once the plant is mature, leaving just pointed spikes. When young, most Strelitzias grow in a distichous pattern (leaves in only two ranks/planes), but as older plants begin to offset, the overall effect is of leaves growing in all directions, particularly in the smaller species. However, each individual plant remains truly distichous forever, unlike how bananas grow. The leaves of all these bird of paradise are thick and leathery, also unlike the thin, rubbery leaves of most true bananas. Leaves of this genus are listed as ‘possibly toxic' but few cases of actual toxicity exist in the literature, at least in small animal medicine. The seeds are supposedly more toxic and will cause vomiting if ingested.
(left) Leaves of normal Strelitzia reginae. (middle) A narrower-leaved version, folded in a bit due to the dry climate. (right, or below) Close-up of Strelitzia reginae leaf.
Strelitzia nicolai leaves
Strelitzia juncea leaves (mature on left, immature on right)
It is the flowers of this genus that attract the most attention. In their native South Africa these are also known as crane flowers, as they resemble the heads of the crowned crane. Strelitzia reginae is the most well known species and its flower is the most crane or bird-like. But they are also brilliantly colored with most of the species having a blue ‘tongue' arising from a dark green, blue or purple boat-shaped lower ‘bill' and a fan of orange, yellow or white petals that resemble the head feathers of some exotic birds (notably the crowned crane). An adult Strelitzia reginae plant in full flower looks as if there were a several birds hidden in the foliage craning their necks just above the leaves and looking about in all directions. They are truly marvelous curiosities and extremely ornamental landscape plants. The larger species have less-colorful flowers, but they still look like bird heads, only without the necks.
(left) Strelitzia juncea flower. (middle) Strelitzia nicolai flowers. (right, or below) Strelitzia reginae flower.
top view of flowers with white or orange sepals and blue petals
Double flowers are not unusual (left) Strelitzia juncea (middle) Strelitzia reginae, though normal with Strelitzia nicolai (right, or below)
(left) Strelitzia reginae flower forming a second flower. (right) As it emerges from the spathe (the lower 'beak) base of the first flower.
The flower anatomy is not simply attractive, but functional as well. The blue ‘tongue' of the flower is the actual petals and contains the pollen (which can be seen if you spread apart the split down the middle of these petals.) At the base of the petals is where most of the attractive nectar ‘bait' is located. As a pollinating bird sits upon the petals to drink the nectar, the weight of the bird spreads apart the petals and the feet of the bird are covered in pollen. Then the bird proceeds onto the next flower, usually first alighting upon the stigma (that sticks out like a perch from the blue petals). As the bird sits upon this stigma, which is very sticky, it gets covered with pollen and the flower is fertilized!
Petals split apart a bit to show the white pollen below and the pure white stigma pointing out like a needle; second photo is of older petals spread apart showing most pollen gone and the sticky stigma covered with debris
As the flowers die, the seeds mature and eventually fall to the earth from the dried dead flower. In ideal conditions the seeds take 1 to 2 months to germinate and another 4 to 5 years for a mature flowering plant to develop. Most growers, however, simply divide mature plants to get more plants.
Seed pod and seeds (photos by eliasastro)
All these species are reportedly easy to grow (in zones 9 and above) requiring little nurturing once fully established. As mentioned above, these are relatively drought-tolerant plants only requiring regular watering in desert climates. This is one of the reasons these are so popular as landscape plants and why they are nearly everywhere you look in public landscaping throughout southern California. The smaller plants are more drought-tolerant than the larger ones, and Strelitzia juncea is probably the most drought-tolerant of all (presumably due to the lack of transpiration from its ‘leafless' leaves). All Strelitzias prefer full sun though most will tolerate some shade. However few will flower well in shady environments. Fertilizer is applied as needed but in soils with some clay, frequent fertilization is not needed. Plants will flower more reliably if fertilized at least a couple times a year. Strelitzias are fairly tolerant of most soils, though extremely sandy, fast-draining soils in arid climates may necessitate increased irrigation frequency.
Strelitzia reginae is seen all over southern California in the landscape (first photo); Strelitzia nicolia is nearly as common (second photo); and even Strelitzia juncea shows up now and then (third photo)
Despite their tolerance for neglect, they do respond well to regular fertilization and will certainly flower more reliably if grown in rich acidic soils with a consistent application of balanced fertilizer (most recommend 10-10-10).
Pruning the smaller Strelitzias involves cutting or pulling dead leaves and flowers as close to the ground as possible, though I often see large public landscaped plants given 'hurricane cuts', where all the outer growht was cut down to around six inches above ground level, leaving only a narrow 'shuttle-cock' growth of leaves and flowers in the center. Others will even 'root-prune' around the edges of larger clumps, hacking at the plant a good few inches below the soil level all the way around the plant. This helps to keep plants a constant diameter, as some clumps, left unattended, can grow into shrubs dozens of feet in diameter and quickly outgrow its intended position. I personally prefer to pull out old flowers and leaves, if possible, rather than cutting as this leaves less bulk and width of the clump and keeps the overall plant looking much cleaner. However, this method is no recommended for plants without good, sturdy root systems, or plants in pots (as you may end up yanking the whole plant out of the pot or ground). Keeping ahead on pruning is important as unattended clumps of Strelitzia get very messy and somewhat unsightly, and are very difficult to prune once they form a large, thick shrub.
Pruning the larger species really requires one to keep up with things as these really can get of of control in a hurry. The dead leaves have to be cut as close to the ground as possible (no way to pull these unless they are really rotted and moist), but often even the lower living leaves are cut to keep the plants looking more trim. Eventually these will require ladders to read the higher stems, and pruning will involve not just cutting away the lower leaves, but cleaning of the stems to give them a healthy, neat, smooth trunk.
In general the Strelitzias are fairly easy plants to move. The thick, tuberous, carrot-like roots can be dug up easily, and even hacked apart, and the plants will usually tolerate this abuse well, though flowering cycles may be set back a few years.
potted plant showing some of the thick, succulent roots
Some grow these plants as indoor or houseplants and I have seen Strelitzia nicolai frequently used in this fashion. However I don't know if these plants survive for very long in such low light situations; the plants I see tend to be quite etiolated (stretched ) and look sort of weak. Leaves of these indoor plants develop a weird ultra-dark green coloration and I have never seen an indoor plant with flowers. It is best to give any Strelitzia grown indoors as much light as possible, and move it outdoors for as much of the year as possible to keep it healthy. Fortunately these are pretty adaptable plants.
Strelitzia reginae, aka common bird of paradise or crane flower, is the most common and familiar plant in this genus growing 3 to 6 feet tall depending on lighting, age and variety--some miniature forms don't even get that tall. Leaves are bright green to blue green, leathery and are somewhat boat-shaped with prominent parallel veins. During intense winds the leaves sometimes split along these veins, but for the most part, this plant is extremely wind tolerant and remains in excellent condition despite high winds and inclement weather. Flowers are brilliantly colored with bright blue petals and orange sepals. A variety called 'Mandella's Gold' has yellow sepals. They have multi-colored spathes of blue-green and red, often with various other colors like pink, orange, vermillion, white, lime green, yellow etc. It is no wonder this plant says "Tropics." Inflorescences are hardy and strong and make excellent cut flowers for arrangements and decorating. Flowers can occur year round in the right climate though seem to prefer the warmest seasons. A single inflorescence will usually produce multiple flowers. As one flower ages it becomes more upright and another set of petals and sepals emerge from the spathe. Most spathes will develop up to 3 flowers or more and some flowers will develop yet another complete inflorescence from the spathe (called a double flower). Once the flower heads die, I find it is best to grab the petiole as low to the ground as possible and yank the dead inflorescence from the plant. This keeps the plants relatively neat and tidy over time. Simply cutting off the dead flowers and leaves will leave a plant messy and much less-elegant looking eventually. This species is cold-sensitive, but tolerates frosts pretty well down into the mid 20s--but not colder.
(left) Exceptionally nice clump of Strelitzia reginae (photo by mustangman826). (middle) Close-up of flower. (right, or third photo) Yellow-flowering form called 'Mandella's Gold'
Strelitzia reginae 'Mandella's Gold' photos
Strelitzia nicolai, the giant bird of paradise, is the second most commonly grown species and is a much larger plant than Strelitzia reginae, growing up to 30 feet tall and eventually growing into a massive shrub up to 20 feet in diameter. Unlike the hardier Strelitzia reginaes, the leaves of this species are quite susceptible to wind and often become tattered to shreds in areas with little protection. Leaves are somewhat similar in overall shape with a bit more rounded at the tips and relatively wider overall... and much larger of course. Leaves of this species are usually bright green to deep green though sometimes a bit blue-green. This species is also more prone to frost damage than Strelitzia reginae with severe leaf damage only 3 or 4 degrees below freezing. Flowers are borne on short petioles (3 to 8 inches) preventing these flowers from being popular cut flowers. Also the spathes are often far too sticky from nectar and pollen adhesives to be convenient for use in the flower trade. These flowers are about 2 or 3 times the size of Streliztia reginae flowers with pale blue petals and pure white sepals. The spathes are a deep, dark blue-green to purplish color. But the overall shape is still quite bird-like and easily recognizable as a bird of paradise. And even without the flowers, it is an amazing landscape plant. You can see these growing by the thousands all over the Los Angeles and other southern California metropolitan areas. It is one of the most popular of all the larger public landscape species.
old huge clump of Streltzia nicolai in Los Angeles arboreteum before pruning, and after; clump of young plants that could use pruning as well
Strelitzia nicolai flowers showing very short petioles (not even visible) and dripping sticky material on spathe in second photo
Strelitzia nicolai in the Los Angeles landscape
(left) Differences between Strelitzia reginae on left and young Strelitzia nicolai on right. (right) Nursery-grown giant birds of paradise
Some confuse this species with Ravenala madagascariensis, the traveler's tree. Though very closely related, this latter plant produces less-cupped (i.e., flatter) leaves that have longer petioles and are longer and somewhat less stiff themselves. This plant eventually forms wonderfully stacked leaves in a neat, perfectly two dimensional plane for an incredibly ornamental effect. Flowers of these two species are similar, but traveler's tree flowers have lime-green spathes, no blue tongues and the sepals are a pale yellowy color. Sadly this species is even more cold sensitive and I cannot get one to survive in my climate here in inland Los Angeles.
Ravenala madagascariensis, the 'Traveler's Palm'; young plant (photo by cactus_lover); flowers of Ravenala in third photo (photo by spaceman_spiff)
Strelitzia nicolai is also quite similar to two other species of Strelitzia, S. alba and S. caudata, and frankly I still cannot tell them apart despite reading a few descriptions that try to clear up their differences. One of the common names for Strelitzia nicolai is white bird of paradise, which of course is also the common name for Strelitzia alba. It does not help, no doubt, that most plants in California identified as Strelitzia alba are indeed Strelitzia nicolai, and also that Strelitzia caudata is extremely rare in the U.S. (and I have never seen one in real life). You can read more about these plants on this website and maybe the differences will be more clear to you.
plant labeled as Strelitzia alba in Huntington Gardens... no idea if it's a correct identification or not, though
Strelitzia juncea is the only other relatively commonly grown species of Strelitzia, at least here in the US, though it is still rare and pricey compared to the above two species. This is also known as the rush bird of paradise, narrow-leaved bird of paradise and african desert banana. This ‘species' is a bit of taxonomic puzzle as it is described on various internet sites with nearly equal frequencies as either its own species , as a variety of Strelitzia reginae, or as Strelitzia parvifolia var. juncea. For simplicity I just refer to it as Strelitzia juncea but mostly likely the correct identification is as an extreme variety of Strelitzia reginae, while Strelitzia ‘parvifolia' is most likely in-between variety. This plant has peculiar leaves that have no leaf blade at all, at least once they mature. The petioles just continue on to a point. What is interesting as that as seedlings, these plants are identical to normal Strelitzia reginae, complete with the typical boat-shaped leaves. As they mature the leaf blades become shorter and more paddle-like, eventually shrinking to itty bitty little ‘spoons' and finally disappearing completely. Some Strelitzias have leaves that shrink to paddle-shaped leaf blades but maintain that characteristic on to maturity. Some identify this form of Strelitzia as Strelitzia parvifolia (in other words, another completely unique species). My guess is that a thorough study of these plants in the wild would reveal a continuous gradient of variations in some populations strengthening the argument for all these as being varieties of Strelitzia reginae. However that is only my guess.
Strelitzia juncea sans flowers- not too ornamental?; but looks great when flowering nicely; good plant for cactus gardens
This plant is my favorite Strelitzia because I love weird plants. And of course it's still considered a collector's item. Additionally it appears to be the most drought-tolerant species and so it suits my desert landscaping the best. Flowers are nearly identical as far as I can tell to those of Strelitzia reginae. I don't know much about its cold tolerance, but I would not be surprised to discover it is the most resistant to frost damage, as the leaves are this genera's weakness when it comes to frost, and this plant really doesn't have leaves.
my own Strelitzia juncea on left, Strelitzia reginae 'Mandella's Gold' on right; second two photos are of Strelitzias with little spoon-shaped leaves that I am assuming are immature Strelitzia junceas, but may indeed be some sort of 'in-between' form of Strelitzia reginae (or Strelitzia parvifolia as some call these plants)
There are more species of Strelitzia (S. alba and S. caudata), but as I mentioned already, I cannot tell them apart from Strelitzia nicolai.