Six on Saturday: Cacti

Cacti was the topic for my gardening column less than two weeks ago. ( ) Both space and illustrations are limited in the column though. Only a picture of a prickly pear was posted with that main article. The other part of that article, which is a brief description and a picture of white epiphyllum, was posted the next day. ( ) Since then, I have been wanting to get a picture of one of the small but delightful orange flowers of a prickly pear in the private collection of one of my colleagues. Now that I got that picture, I really did not know what to do with it. I got two other pictures of the fruit and stems of the same prickly pear, and three more pictures of other cacti in the same collection so that I could post them here. Instead of saving the best picture for last, the prickly pear flower is posted first just because it is that cool.

1. Prickly pear flower should bloom during the day. They should not be nocturnal. I can not be certain because I am not familiar with this particular species. What I do know is that the flowers have been open early in the morning, and then closed shortly after exposed to sunlight, almost like those of a nocturnal epiphyllum. It took me a while to get this picture of this single peachy orange flower.P80811

2. Prickly pear fruit should ripen right after bloom, but most fall off of this plant while still green. It might be because the plant is potted and watered regularly. Those that ripen are only about two inches long, and quite pithy without much flavor. They would probably be bigger, more abundant and better flavored if the plant could grow in the ground.P80811+

3. Prickly pear pad is not as prickly as those that I got a picture of for the previous article about cacti. I do not know how their flavor is because I have not tried them. This is a small plant that can not spare many pads. Even if there were a few to spare, they are not very big, even when mature. The probably would not taste very goo either, since they take so long to mature in the pot.P80811++

4. Cereus cactus really is nocturnal; cereusly! It produces huge white flowers that are about as big as those of the white epiphyllum that was featured earlier. The flowers do not open until after sundown, and may wait until late at night. While open, they are powerfully fragrant. The fragrance seems to ‘turn on’ immediately when the flower open, and ‘turn off’ as soon as the flowers close before dawn.P80811+++

5. Rat tail cactus, like epiphyllum, is epiphytic, which means that it grows where debris collects in crotches of limbs in big trees. If they grown on the ground, they just sprawl about and maybe form low mounds. This is not an exemplary specimen, although it bloomed well earlier, with reddish orange flowers that are significantly smaller than those of the epiphyllum, and also a bit smaller than those of the prickly pear.P80811++++

6. Epiphyllum is a weird epiphytic cactus. This particular cultivar is even weirder than most. Cacti photosynthesize with their green stems, while using what should be leaves as spines. This cultivar does not seem to be satisfied with that technique, so is outfitted with these weird leafy appendages on its flat green stems, as if it really wants leaves like other plant have.P80811+++++

This is the link for Six on Saturday, for anyone else who would like to participate:


Epiphyllum oxypetalum

80808The common names of ‘Dutchman’s pipe’ and ‘queen of the night’ are not much less awkward the the Latin name of Epiphyllum oxypetalum, which might be why the Latin name is more common than the common names are. Some know it as ‘white ephiphyllum’ or even more simply as ‘white epi’. It is one of the more popular of the epiphyllums; and it is the most popular with white flowers.

The nocturnal flowers appeal to nocturnal pollinators. What we see simply as luminescent white is actually outfitted with exquisite patterns that are only visible to those who can see ultraviolet light, like nocturnal moths. Bats are as blind as . . . well, bats, but can follow the richly sweet fragrance if they choose to. Sunlight disables fragrance immediately, and causes flowers to close soon after.

In the wild, sprawling primary stems can cascade almost twenty feet. Of course, they are much shorter in home gardens. The more pendulous secondary stems that bloom get about a foot long, and perhaps three inches wide. Flowers bloom in summer, and can be half a foot wide and a foot long. Epiphyllums naturally hang from trees as epiphytes, so will do the same from hanging pots.

Stag Party

P80415Staghorn ferns are epiphytes. They cling to tree trunks, rocks or whatever they happen to grab onto. They can root into decayed wood if it is porous enough, but they are satisfied to just cling to the exterior. They do not need soil. They sort of make their own soil by collecting debris that falls from the canopies of trees above. In the jungles where they live, they get all the water they need from rain. They often live in the crotches of branches because that is where they happen to land. (The epiphyte I wrote about earlier was just a palm that landed in the wrong place, but is not really an epiphyte. )

In home gardens, staghorn ferns are often grown on wooden plaques so that they can be moved around like potted plants. Because it does not rain much here, they need to be watered occasionally. They do not grow very fast, but eventually need to be attached to larger plaques, or divided into smaller clumps that fit onto new plaques. Alternatively, they can be grown like plants in hanging pots, but without the pots. Even if they start out in pots, they may eventually envelop and obscure their pots, and form a big rounded hanging mass that only wants water and debris from above. A small bit of fertilizer might improve their naturally light color, but too much will roast leaf margins.

My colleague Brent Green acquired this humongous and well rounded specimen from a client who wanted it removed from an olive tree that it had grown too big for. It had been there for decades. Brent gives it a banana every month or so because it likes potassium. It does not get much debris from above in Brent’s well groomed garden.

Hanging Gardens of Babylon

P80328The ivy in this sycamore did not just climb up from the ground to hang over this big limb. If you look closely, you will see no vine coming up from the ground. This small patch of ivy as well as a small pyracantha, are growing in a decayed cavity on top of the big limb. The ivy may have climbed up a long time ago, and then rooted into the cavity before the original vine was somehow removed. Alternatively, the ivy might have grown from a seed that was dropped by a bird or ivy vines that are higher up in nearby box elder trees. It is impossible to say now.P80328+It is also difficult to say why there is such a large cavity on top of the limb. It could have originated as a large scar incurred from the impact of another large limb that fell from above. There are a few cavities higher up that were caused by large limbs breaking away. Although unlikely, the cavity could have developed from sun scald damage, after the upper surface of the big limb suddenly became exposed by the loss of limbs higher up.P80328++This other aerial patch of ivy hangs from a smaller cavity higher in the same tree. Oddly, among sycamores, such cavities on upper surfaces of large limbs are not uncommon. Sycamores often drop large limbs from high in their canopies, exposing or damaging lower limbs below. Their lightly colored bark is very susceptible to sun scald if suddenly exposed after always being shaded. It is also not very resilient to heavy impact. Of course, more typical cavities develop on trunks where significant limbs broke or were pruned away. Other plants can grow in these as well, as demonstrated by the ‘epiphyte’.


P71108A plant that clings to another plant for support without parasitizing it is an epiphyte. Some do it to get a bit more sunlight closer to the ceiling of a dense forest. Others do it to get up off of the forest floor to avoid competition with conventionally terrestrial plants. Maybe some just want to avoid grazing animals. It is often difficult to determine why plants do what they do.

Spider plants, ephiphyllums and many types of orchids, bromeliads and ferns are some of the more familiar epiphytes. Most do not actually cling to trees. They instead live in the crotches of limbs where debris from the foliar canopy above accumulates. Either way, they do not need much organic matter in which to disperse their roots, and some need none at all. Many collect what they need from the air and precipitation.

This is not about an epiphyte.

It is about a Mexican fan palm that thought it was epiphyte.

You might have though that the picture above depicts a common Mexican fan palm next to a surly London planetree. With closer inspection, you will notice that the palm lacks a trunk at ground level. The utility pole visible below the palm is not attached to it, and does not support it. Yet, the palm does not just hover there. It grew from a cavity in the London planetree.

Most of us know how many plants self sow in weird places. Sometimes they appear where they are welcome. Usually, they end up in pots with other plants, too close to pavement, or in rain gutters that have not been cleaned out enough. Of course, big trees commonly appear under utility cables. Once in a while something self sows in a decaying cavity of a tree.

Most of us have enough sense to remove self sown trees and plants that appears where they can not live for long without causing problems. Those of us who hire gardeners tend to trust and hope that the gardeners would exhibit the same sort of common sense. After all, that is part of what they are payed significant money for.

Unfortunately, Mexican fan palms are not epiphytic. They are just too heavy, even when young.