If you want your pond to look good, have healthy fish, and not be a maintenance nightmare; you must have, and promote the presence of, aquatic plants.
PLANTS! PLANTS! PLANTS! PLANTS! PLANTS! PLANTS! PLANTS! PLANTS! PLANTS!
That reminds me of an age old gardening axiom. You can't plant any flowers if you haven't Botany!
If you want a healthy pond, you need plants. Full stop. Plants are the hardest working organisms in the pond and are integral to the sequestration and mitigation of all soluble nutrients found in surface water. Stated a different way, plants tie up nutrients. Plants also can out-compete algae for nutrients because they are way more efficient at converting available food into plant material. So, the more plants that you allow to grow in and around your pond, the better your pond will look, smell, and function as an aesthetically pleasing ecosystem.
There are three types of plants that I will discuss here:
2. Floating leafed
1. Emergent Aquatic Plants:
These plants have parts above and below the waterline. These are shoreline plants like Cattails, Pickerel, Arrowhead, Bulrush, and Blue Flag Iris. Some of these plants can grow in 2-4ft of water (cattails ), others grow completely outside the water in saturated soils (Iris), and others grow in between those two extremes, but all are still deemed aquatic. These plants hold onto the bank with thick tuberous root systems which helps stabilize erosion issues. Also, they are fantastic filters in watergardens and aesthetic enhancements to any koi pond. These species are many and varied in form and color. Add these beautiful plants to compete for space and food against the algae blooms.
Location, Location, Location! Please be aware, it matters where you plant them. In order to find success, please read up on the species you like the most and plant them appropriately. If you have questions, please ask me where they should go, or if they would be right for your pond. Planting techniques for watergardens vary depending on species. Most of the time I plant them between rocks in a nest of pea gravel so the roots can take hold, arranging them along the waterline. Some plants like Arrowhead, and Pickerel, like to grow in about 3-6inches of water and need a bit more soil/media in order to thrive. I like filling a pot (like these) with pea gravel (and maybe some peat moss) and placing them on a planting shelf where they will burst from the water with cool foliage and blooms, attracting fish, insects, frogs, turtles, and people who will OOOO and AHHH all day at the wonderful oasis that you have created for yourselves.
Large ponds are super hard to plant. When planting, take the plant out of its pot and squish it into the soft soil at the appropriate depth for the plant. See.... super hard.... (wink wink). Remember, we want these plants to spread and multiply. In large ponds you may have to protect new plantings from herbivory. Geese, deer, muskrats, and many other such animals are jerks and are out to harvest/eat the very nutritious plants you just purchased and painstakingly placed in your pond. If you have critters frequenting your pond's edge (and most do), please protect the new plantings with chicken wire or other semi-rigid apparatus for 2-3 seasons. That way, the plants can develop hardy rootstocks that will be able to withstand the occasional munching from wildlife (jerks)......
2. Floating Leafed Plants:
For this discussion, I am focusing on water lilies and watershield. There are other floating plants, but they are mostly invasive or nuisance plants that will be discussed in a future post. Water lilies are great for creating habitat and shade for all species of fish and aquatic life likely to inhabit your pond. Goldfish, koi, bass, crappies and trout will use this cover to rest, hide or hunt for food. Each lily also develops a huge tuberous root which stores a ton of nutrients, serving as a filter as well. When planting these in watergardens, use a pot (like this) and use pea gravel as your planting media. The tuber will eventually escape the pot, but that's ok. We like big, beautiful waterlilies. In large ponds, either sink them in 2ft (or so) of water in the aforementioned pots, or just tie them to a brick and place them that way.
3. Submerged Plants:
In larger systems submerged plants are vital for the management of the pond. I DO NOT recommend these for watergardens as they grow out of control very fast in small environments. Contail, Sago Pondweed, Claspingleaf Pondweed, and Water Celery are common species from around here (upper Midwest). They provide cover, spawning habitat and nutrient mitigation for ponds, lakes, and streams and must be present if you are to have a productive fishery and good water quality. The more diverse the plant life becomes, the better off you will be in terms of wildlife potential and quality of your fishery. These plants can become nuisances if that diversity is not achieved, but their presence is still very important. If you kill off all of your plants, you open up the pond to colonization of species that are very difficult to control. You're also likely to have runaway algae blooms. A pond that looks like a fish bowl is unsustainable and inevitably, expensive to maintain.
This is a subject that is truly massive. I will be delving into each category of plants, giving specifics on individual species that are either great for the pond or decidedly bad for the system, so stay tuned.
As always, please ask questions or suggest topics for me to address. Take care out there, and plant something!