Aquatic Plant Propagation in New Lakes and Ponds

In 2017, Bow Valley Habitat Development was given a task of making a newly created lake more productive for its first trout stocking. This would be achieved by enriching the lake with aquatic invertebrates and plants. The invertebrates would come naturally, if the lake was seeded with aquatic plant cuttings. The lake was man made, it was a little over 50 acres and at the deepest point 40 feet deep. As advised, the entire perimeter of the lake had been bordered with large gravel, to prevent shoreline erosion and turbid water, caused by wave action. This was beneficial, from a enhancement perspective, because the aggregate makes a perfect habitat for some types of aquatic invertebrates.

The lake was completly filled with water in 2017, so immediate action would bring the fastest results. The lake’s bed consisted of a well worked clay liner, so the nutrient levels for any new aquatic planting program were low, and this would make the job a challenging one. The clay, when covered with water, became a fine powdery muck. It would be difficult to get some new aquatic plants growing on the clay covered lakebed.

It was determined that the primary choice of aquatic weed for the lake would be chara, A.K.A Stonewort. Well know fly fisher, BC fisheries biologist, lake ecologist and writer, Brian Chan, once wrote: “The ideal trout lake would have white marl and Chara covered shoals.” Which I agree with totally. I have fly fished plenty of BC lakes with just such a weed covered bottom.

In the past, I have successfully used chara on similar clay lake or pond beds, so this was not experiment for me. Another thing I love about seeding chara, is that it is heavier than water and it sinks really fast. Other aquatic plants need to be anchored, because they are full of gases that make them float. The terminal end of some aquatic plants will sink slowly if you cut off just the very end. But the best way to plant those other plants is by attaching a small anchor stone, or place a stone over the plant cutting.

This photo shows what the lake bed looked like, prior to planting aquatic plants, in 2017. You can see how the gravel perimeter meets a powdery clay bottom that is consistant with a newly excavated pond or lake.

My goal for the lake was to plant approximately 97% chara, and the rest would be Coontail, AKA Hornwort (Ceratophyllum demersum L.), Richardson Pond weed (Potamogeton richardsonii) and Small-Leaf Pondweed (Potamogeton pusillus L.). The chara grows low to the lakebed, it grows in deep water and it is fast spreading, so this would be ideal. It is also great invertebrate habitat.

Some of the taller growing weeds will produce a root network from a cutting, so all that you have to do is make sure the cutting is anchored to the lakebed by a stone and very light steel wire (28 ga.). If the rocks are from a quarry or they have rough edges, it is easier to attach an anchor wire to the rock. When the cutting sinks to the bottom, it will develop an anchor root system in a week or two.

This is an example of what a cutting of Richardson’s Pond Weed looks like after 10 days of growth. Note, that the new roots are traveling out to find some type of anchorage, even soft soil. This is why using cuttings is the best approach to aquatic weed propagation. On the Coontail weed cuttings, I like to use a larger length, sometimes with the roots still attached.

On Harmony Lake, in the fall of 2017, the first weed planting program was completed by Bow Valley Habitat Development. In the following summer, I took some photos of the chara beds starting to form in the lake, along with other varieties that were starting to grow and spread.

The chara was really doing well by the summer of 2018, so this was the most important finding for the weed enrichment program. A few more small plantings would occur in 2018 and 2019, now that the initial planting had proved successful.

The other types of weeds were also doing well, so by 2019, the program was completed on Harmony Lake. As the plants spread, a marked increase in the invertebrate populations in the lake also happened. The bug life had increased subtantially.

This is Richardson’s Pond Weed one year after planting.

This is Coontail, two years after planting. You can also see the chara weed growing right next to the Coontail.



















Anchor Rocks For Sinking plant Cuttings

It is necessary to sink the weed cuttings, using small rocks for anchors. When the cutting is attached to the rock anchor, you can gently place the rock on to the surface, and let it sink to where you would like it. Littoral zones are where the plants would normally grow.

The rectangular and oblong shapes of small anchor rocks, with the attached wire, for the plant cuttings.

The rocks are natural, but the wire is not. No worries, the wire will rust into nothing, in a year. The weed cuttings are carefull wrapped onto the rock anchors for submergence. New roots from the cuttings will use the anchor rock for positive contact, on the clay covered bottom of the lake or pond.

The lake was ready for its first stocking, which took place in the spring of 2019. Now the the lake is stocked with small trout, the fish will need some hiding places. The taller growing aquatic plants will provide some well needed cover habitat for the newly stocked brown trout. This will help the trout hide, when the diving birds feed on Harmony Lake. It is estimated that the lake should be ready for another large stocking by the fall of 2019, or spring of 2020. There is certainly enought food in Harmony Lake, for the trout to feed on now!