Sizes of E. horemanii

> Subject: E. horemanii
> George,
> Since you mentioned your horemanii, How tall is the tank that you have it in,
>and how tall is the plant?  I have a less than 1 year old 'Rubin' Sword (which
>is a horemanii x barthii cross) that is big enough that the leaves lay all
>over the surface of the tank.  I'm planning to move it to my 75G, but this
>tank isn't _that_ much taller either.  How big a tank do you actually need to
>show off one of these suckers properly?  Is the 120 big enough?
>  E-mail from: Karen Randall, 17-Jun-1995


E. horemanii, red and green varieties, are beautiful plants. They are among
my favorites and are the only large Echinodorus that I currently have. Their
potential size, however, can be a problem. I have mine in three tanks. In my
experience, the green variety, does not grow as large and is easier to
manage. Light intensity may be an important factor.

I have one green horemanii in a 55g (~200l), 20 inch (50cm) tall tank - but
the more important measurement is the 14.5" (36cm) height of the water
column.  After all, once does have to account for the substrate and tank
frame! In this tank, the plant occupies the rightmost 40%; the leaves nicely
reach the water's surface and do not bend over enough to dry out...this tank
has 120w of fluorescent lighting and no CO2. It has been growing there for
22 months. 

I also have the green variety in my 70g whose water column is ~ 10% taller.
The tank gets similar lighting (with 4 bulbs), but also gets CO2.  There the
plants are in pots, and the green horemanii are much smaller, but this may
be attributed to lower nutrient levels provided in that tank. This 70g also
has a red horemanii which is HUGE. The plant has been growing there for
several years, and is actually a family of horemanii. The rhizome is
probably 12 inches long. It has completely grown out of its 6" pot (placed
at the rear of the tank) has extend downward to the base of the tank (which
has 1 cm of sand just to cover the glass bottom), so the original plant is
now growing mashed up against the front glass and  APPEARS to be growing
directly out of the 1 cm substrate. From the trailing rhizome still in the
pot, several new horemanii have sprouted. These immature plants also reach
the water surface. [Note: rhizome division is a good way to reproduce this
plant.]  The leaves of the "mother" red horemanii are now over 2 feet (60cm)
in length. And as Karen indicated, many lie on the surface of the water and
dry out. Not the ideal situation. 

I believe this is a situation that can be controlled by reducing the light
intensity.  The tank has 4 fluorescent bulbs (2 tritons, 1 grolux, 1 grolux
WS). However,  I am lazy to replace my bulbs ( I leave them in place for 1-3
years, until they burn out!).  Around 6-8 months ago, before I changed 2 old
bulbs, I seem to recall that the leaves of the red horemanii just barely
reached the surface and did not bend over and dry out. And the plant looked
MUCH better. IMHO, once this plant (and plant tanks in general) mature to
the point where the leaves reach the surface, I suggest reducing the light
to control growth (e.g. reducing intensity,for at least parts of the
photoperiod). Depending on the desired effect, this can wait for the leaves
to reach the surface. 

I am sure many of you have noticed how plant growth seems to improve, if not
accelerate when the leaves of many plants start to approach and then lie
along the surface. I think that the average distance of the light to the
leaves is more important than the distance to the substrate.(Actually this
is a weighted average, with a lot more benefit from the leaves closer to the
surface). I also have a red horemanii in my 120g tank which is 2 inches (5
cm) taller than the 70g. It has only been growing there 6 months, but I
expect it could develop the same problems. Getting plants to grow slower or
smaller is one of the challenges to the experienced aquatic gardener. :-)