Threatened with dropping out of the
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
nurserys 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
hasnt 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 years 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 dont
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 dont 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 doesnt 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'
If a plant is a weak grower, or the variety has less than ideal
vigor, its 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 its
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
arent seen too often.
Myosotis scorpioides Snowflake >
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 waters 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. Id 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.
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
We also have two others that are not long for this world.
Parrots 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 wont miss it too much.
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.
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
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 dont 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 havent
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