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 Spathiphyllum in the pond

 Yes you can!
Terrestrial Plants
for the Pond

by Rich Sacher, Louisiana USA
Click images to enlarge

When I was just a kid, I had so many aquariums in our bedroom that to this day, my brother Bob claims it was like "sleeping 20,000 leagues under the sea", because of all the air pumps gurgling and humming, night and day. We lived in Jersey City at the time, and my favorite pet shop was owned by a charming young woman named Evelyn … whose boyfriend was a guy named Herbert. I spent a lot of time at this pet shop and probably had a crush on Evelyn … but I was very young, so what did I know about such things? But I do recall being a little jealous and resentful of her boyfriend.

I remember one time Herbert made Evelyn shriek in alarm when he visited the pet shop, said hello, and then took a long drink out of one of her aquariums. He thought her distress was great fun! Herbert and Evelyn got married, and he went on to travel the world collecting unusual tropical fish and published innumerable books under his Tropical Fish Hobbyist trademark. I did not connect this childhood memory with Herbert Axelrod and TFH Publications for almost 40 years ... but that is another story for another time. Meanwhile, there really is a connection here to the topic of this article!

Even as a young teenager, I was fascinated with the various terrestrial plants that a pet shop could offer for planting under water in the gravel of a fresh water aquarium. There were miniature palms (probably Neantha bella), Chlorophytum (also called spider plant), some variety of Ludwigia, and even an exotic Pilea known as "aluminum plant. There were other plants, too; I expect you will understand if I cannot recall all of them. Even way back then, I was intrigued with the thought that some plants could be coaxed into growing under water … even if that was not what Mother Nature made them for.

It turns out that there are also quite a few common terrestrial plants which can happily adapt to growing in a pond, with their pots totally submerged in water. Many of them do just as well in a pond as they do in the ground. In fact, some of them grow bigger and faster because of their constant access to water and nutrients.

However, it is not often feasible to take a water-tolerant terrestrial plant and place it in a pond. Most potted terrestrial plants are grown in some sort of soil mix high in organic matter, and the plant might be too buoyant. Plants in these lightweight soil mixes usually fall over quickly since they are top heavy. Therefore, the soil must be substituted with a heavier mix like sand, clay, or a mix thereof. Once that is done, a fertilizer tablet can be pushed into the soil, and the plant can be placed in the pond. These land plants should be fertilized on the same schedule as other potted pond plants.

Another consideration for replacing such a soil mix is that a high bark component may create an oxygen deficiency at the roots as the bark decomposes under water ... thus stunting or even killing the plant. That same soil mix would be fine above ground, since some air is always present in the root system after excess water drains away. 


  These photos of a black taro show that its soil mix is mostly pine bark ... it literally falls from the root system when the plant is shaken. Once planted into a heavy sandy soil, it is then ready for the pond.


< Taro unpotted | Root mass ^
Planting medium shaken off >

Spathiphyllum, top of page, in any of its large or small varieties, makes a great show in a shady pond. They can tolerate a few hours of morning sun, but must have afternoon shade. With its shiny white flowers and glossy foliage, they always surprise visitors to the pond, because spaths are most commonly known as indoor plants. To see them growing outdoors in a pond always invites comments and questions. Spaths hate to dry out, so they are sold in soil with lots of peat moss. If the plant is root-bound to the point that this peat cannot be removed without damaging roots, it can be left in place ... as long as the plant is repotted into a larger pot with heavy, sandy soil. Because it is truly tropical, it cannot be left in the pond for the winter in most climates, but it is worthwhile as a summer spectacular.


Root-bound C. papyrus

Papyrus (Cyperus sp.) in most of its forms is well known as a pond plant. But even an aquatic plant may sometimes need special handling before going into the pond. These pictures show a very root-bound plant that needs to be moved to a larger pot. The root system is so dense, that a plant like this can be simply moved to a larger pot without disturbing the root system and then a sandy soil can be filled around it.

The plant at the left actually floated in its original one gallon (4.4 liter) container, but after being transplanted to a 10 inch (25 centimeter) pot, it was quite heavy enough to stay upright in the pond. Papyrus will not survive a hard freeze, but smaller plants can be brought indoors to a sunny window and grown as a house plant until it is warm enough to return them to the pond. 

< Ready to repot

 

Hardy Hibiscus (H. moscheutos) is another water-loving plant for sunny aquatic gardens. There are large "dinner plate" flowering varieties, as well as other species which are perfectly suited to the pond. Here in New Orleans, they go dormant for the winter, and new growth emerges from beneath the water in late spring. You can't get more water tolerant than that! The large flowering varieties are quite striking, and they usually do not get more than three feet tall. However, tropical Hibiscus will not tolerate being submerged like their hardy cousins. 


The large white calla lily, Zantedeschia aethiopica, is well known for inhabiting damp, mostly shady gardens. This is another plant that adapts beautifully to the pond, especially if it has some afternoon shade. Again, if the soil in the pot is too buoyant, it may have to be transplanted to heavier soil. I like to plant three one gallon (4.4 liter) calla lilies in a sixteen inch (40 centimeter) pot for a really nice full plant. We should note here that other varieties of calla lily will not tolerate having their pots submerged in water. The giant white calla lily is the one to use for aquatic gardens. The plant should be moved to a frost free location for winter, and the foliage will die down while the bulbs go dormant until spring. 



Canna 'Pink Sunburst'
Dave Brigante Photo
Cannas come in many different flower and leaf colors, and absolutely love being submerged in water. They should be planted in large and heavy enough pots to keep them from getting top-heavy, since they can easily grow to 3-5 feet (.9-1.5 meters) during a summer season. Some people think they have to use only those small-flowering Cannas sold in the trade as "aquatic", but this is not true. I have never met any Canna that did not thrive with its entire pot under water. In those parts of the country where the pesky leaf roller caterpillar is not present, Cannas make a spectacular plant for the sunny pond, with their long succession of large, vibrant summer blooms. In the deep south, Cannas spend the winter in the pond. Further north, these plants should be moved to a cold but not freezing cellar, where the rhizomes will store quite nicely until spring by allowing the soil to remain just barely damp.

Louisiana Iris are famous for growing in wet soil or in a pond, but many people do not know that Japanese Iris (I. Kaempferi or I. ensata) are equally happy with their roots totally submerged. They bloom a month or so later than their Louisiana kin, so they can extend the iris bloom season in the pond. Variegated Japanese Iris is quite desirable, with its prominent white striped leaves making a striking pond accent long after its deep blue flowers are gone. Here in Louisiana, both varieties are happy to spend the winter under water. In cooler climates, a drier winter rest may be required.


Ruellia species, also known as "summer petunia", do very well in the pond. There are both dwarf and larger growing varieties, in a range of colors. A large pot of dwarf Ruellia, only six inches tall and covered with flowers all summer, is quite a nice addition to the pond for use in the foreground. This is another plant that grows submerged in water all through the winter here in Louisiana. You may have to experiment to see what it tolerates in other climates.

Various trees and shrubs are adaptable for use in a pond, and many annuals and perennials as well. The book has not been written on this subject, but it would include normally terrestrial plants that either tolerate being submerged in the pond … or actually grow more freely in water than they do in soil. Here is a wide open avenue of investigation for pond lovers. Got a suspicion that a normally land-locked plant will do well in water? Try it. If none of your plants ever die, well, you are just not taking enough chances! 

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