Read about
Dave Brigante


Myosotis scorpioides ‘Pinkie’

Threatened with dropping out of the trade,
some aquatic marginals are
Living on the Edge

by Dave Brigante, Oregon USA
Click images to enlarge
 

As a grower of pond plants I, like so many others, am always on the lookout for new and unusual additions to strengthen the nursery’s plant palette. The challenge of finding unique plants can take on many forms: does one go to the far reaches of the planet to discover something yet unseen; do we search in our own native surroundings to capture a new specimen that hasn’t been tested in a wet growing environment; or do we take the approach of getting seeds from various sources to grow on and test as well?

While we look for the new, some old favorites are disappearing from the trade, at least in my area. I have noticed over time some of the plants that have shown the most potential are in very short supply. Because some of these need a bit more care to go through the various seasons, they may be less available in nurseries than you would think.

I try to keep little bits of a lot of my specialty plants around, but it can get pretty tenuous when the numbers dwindle down. Most often it is a case of how much of this variety do I need to cover next year’s production plus keep enough in good health and vigor for current stock requirements. One of the worst case scenarios is to sell off so much that you don’t have enough for the next season, without a reliable secondary source. Of course selling off all that you have of something special is the last thing you ever want to do.

Of the plants that I have grown over the years and have selected for this article, you will see trends as to why they may be considered “worthy” or not, and why they are teetering on the marginal edge. To begin with, if a particular variety is selling poorly or attracts little interest in plant circles, it just makes sense to reduce the production for it. We have certainly had a few fall by the wayside due to just those circumstances.


Lack of sales appeal

There are two sweet flags that have unique characteristics but just don’t seem to sell. The first is Acorus gramineus pusillus, a dwarf dark green sweet flag that is great for small setups but is limited by its not too striking appearance. Then there is Acorus gramineus 'Licorice'. This one smells great but, if that doesn’t do it for you, it becomes just another dark green grass.

A couple of more also seem to lack appeal, marsh spurge (Euphorbia palustris) has beautiful yellow flowers in late spring but, as is the case in most of the plant world, the color yellow is not a favorite. The new growth is a beautiful hot pink, one of its finer attributes.

Next is Siberian pink cups (Baldellia ranunculoides f. repens). This petite ground cover is a bit sporadic in its bloom time, so it may be getting missed when it is in its prime. The summer heat can be an issue and a lack of light in our winters can hinder its return in the spring. I do recall its beauty back when I was growing a lot of it. Maybe more is better.  


Acorus gramineus pusillus


Acorus gramineus 'Licorice'

Weak growers


Lindernia grandiflora 
If a plant is a weak grower, or the variety has less than ideal vigor, it’s hard to justify growing too many of them. Blue moneywort (Lindernia grandiflora) is a cute little surface grower that will persist on a ponds edge through the prime growing season, but it seems to require too much warmth through the winter to warrant wide use. Once the weather is warm enough in late spring, it begins to come to life; it may be misrepresented as being hardier than it really is, though it has not survived here in zone 8. Its blue flowers are extraordinary once it’s all settled in; good water bowl candidate for sure.  

Two others that have always been among my favorites are a bit iffy. The pink and white forget-me-nots (Myosotis scorpioides ‘Pinkie’ [top of page] and Myosotis scorpioides ‘Snowflake’) both do well in spring yet fade in summer. If these two are given a cool pond edge with a little afternoon shade, they can do quite well. I feel that these two are very much under-utilized. Getting through winter is not one of their strong suits even in the greenhouses and that may be why they aren’t seen too often.

Myosotis scorpioides ‘Snowflake’ >


Disappearing

There are a few that I rarely see anymore, one of which would be Calla palustris, the northern calla lily. What a great plant! It grows on the water’s surface much like a bogbean (Menyanthes trifoliata) and has a small calla lily-like flower that lifts out of the water to a height 4-5" (10-13cm). I grew this for quite a few years until the numbers were so small that it inexplicably disappeared one winter. I’d like to bring this one back into the mix but have yet to find a source.

There is an unusual pickerel weed called Crown Point (Pontederia cordata ‘Crown Point’) that I struggle to keep going, I still have a little bit of stock on hand and once again it is pretty unusual to find it in any great quantities. I like the way it has the traditionally beautiful blue pickerel weed flowers but stays much more compact. It is under-used, so I stay on the lookout for it. 


Invasive!

Sometimes aquatics wear out their welcomes in various states. Here, it is the common reeds family (Phragmites australis) that is now being banned. Once it takes hold watch out. It is similar to an aggressive running bamboo, but it will live in water. Yikes! If controlled it can be okay but just having it around may allow it to get into the natural environment and wreak havoc. 

We also have two others that are not long for this world. Parrot’s feather (Myriophyllum aquaticum) and pennywort (Hydrocotyle umbellata) are very nice plants for water bowls but, if they are let loose in a pond or a lake, it can be a disaster. They may be great filtering water in a contained enclosure but the monoculture they could create in waterways would lead to undesirable eradication processes that most of us would not like to undertake.

Myriophyllum aquaticum >

I used to grow giant pennywort (Hydrocotyle bonariensis) but the problem with rust that required bi-weekly fungicide applications was too much. Nice plant but too high maintenance. One more intruder we used to offer is the colorful pink flowering rush (Butomus umbellatus). It moved onto some noxious weed lists in a couple our neighboring states. It rarely flowered for us here at the nursery so I won’t miss it too much.
     

Downsides

The marginals in this group were given quite a few years of attention until it became evident that it was less than fruitful to continue growing them. Canna 'Stuttgart' was all the rage for a while. It is uniquely variegated with bright green and white splotches that were irresistible. The biggest issue with it is that it sunburns. When blended in with shade lovers it never received the attention to warrant further production.


Canna 'Stuttgart'  
   

There was also a white water bluebell (Ruellia squarossa ‘Alba’) that seemed to show promise as something new on the scene. Unfortunately the flowers would turn from a nice pure white to brown so quickly that it was laden with brown flowers most of the time. Whoops! 

Another problem to consider is plants that have a tendency to self-sow too profusely. Ragged robin (Lychnis flos-cuculi) has delicate finely cut flowers of pink and white but the upkeep left by its progeny is too much. The next one, a native to the northwest USA, is yellow monkey flower (Mimulus guttatus) that is quite a bloomer in spring. If it is kept isolated in a wet ravine or allowed to proliferate freely, it can put on quite a show. It would probably be best to be careful with it if left unchecked in a nursery, backyard bog or a streambed. It may be all that there is after a few years. Off our list but not forgotten. 


Pure torture

The last ones are what I refer to as torture plants. They entice you with their beauty and make you think of how bright the future may be, and then they just don’t live up to what you had been hoping for. The variegated umbrella palm (Cyperus alternifolius variegata) fits in here just perfectly. Wow! If only it would stay variegated and not revert back to green so readily, it certainly could have been a mainstay in the aquatic plant industry. It occasionally puts up a few new shoots of variegated foliage just to tempt and then they are gone. Another in this category is the variegated corkscrew rush (Juncus effusus ‘Blonde Ambition’). Talk about a seductress. I tried to grow that quaint curly girl for a couple of seasons but it was too finicky. The variegated spirals of yellow and green were outstanding when they were healthy, but sadly it never really kicked in for me. It may be out there somewhere but I haven’t heard about it for years now.

I hope that most of these plants will not be left on the edge forever. The natural and the unnatural growing conditions that I work with may not be the best suited for them. They may do just fine in other regions, grown in better suited environments. I would be very interested to hear about other aquatic plants that growers have had go through their hands over the years with success or failure. One thing is for certain -- we will all keep searching.

WGI ONLINE Journal Table of Contents

Water Gardeners International
Home | Join WGI | Members' Exclusive | Gateway to Water Gardening