Mary’s Pond
The bucket of plants that we were given to start our pond spread like wild fire.  That’s how I learned that a pond can make anyone feel they have a green thumb.  Many plants that thrive in and around the pond are aggressive growers.  The competition is tough so the common plants grow, not so much by spreading by seed, but by sending roots (rhizomes) out to grow more plants in the same season.  
The list below are the more obvious, less well mannered, pond plants that will fill in a pond quickly then demand to be weeded out aggressively.  Many pond people control the growth by planting these plants in containers.
Elephant Ears, also known as Taro-  This plant grows over 5 feet tall at our pond edge.  Non native, tropical. The gigantic leaves are very attractive though the yellow flower is overlooked because it just looks like a rolled up leaf spike that is yellow.  It grows very aggressively and even sends new plants way out in the water.  Two ways to control it, do not allow it water or wait until the first frost.  One day you have a big beautiful plant, then there is a frost and you return to your pond to find all the leaves collapsed, and mushy.  I clean it up then, dig out areas that they have grown to far.  In April the plant tuber will send up new shoots and by July the plants are 4 feet tall.
Equisetum, also called Horsetail or Scouring Rush- Grows nearly world wide. This prehistoric plant is striking.  It multiplies by underground rhizomes.  As long as there is a water source it can survive.  In the San Joaquin Delta they survive a long way from water where there are whole fields of equisetum.  I suspect all these connected roots are still getting water from the waters edge many yards away. It was called Scouring Rush by pioneers.  There is silica in the plant and pioneers broke the plant up, bound it together like a brush, and scoured their pots with it.
Water Parsley- This plant is native to California.  Though the internet information says it can be aggressive that has not been my experience.  It is one of the few plants that was planted 5 years ago that I am not weeding out yearly.
Cattail- There are native and non-native cattails growing wild in California and I have not learned to tell the difference.  Our pond appears to have both the tall Cattail and the dwarf species.  The tall Cattail gets at least 9 feet tall, grows very aggressively and I spent MANY days, using all my strength, pulling out the rhizomes of Cattail last November.  I had not weeded it well the year before so last year it took over 1/3rd of the pond area.  The only reason it did not take over the entire area was that the water was to deep.  Cattail can only handle about 3 feet of water.  If one plants cattail control it by deep water and think about the sun and what will be shaded when the Cattails are 9 feet tall.  The Cattails leaves die during winter, which is unattractive but they can be cut down, better, pull them out,rhizomes and all.
Water Primrose-This plant dies back each winter
then in summer, by July, becomes aggressive and
begins to cover the pond.  That is when a pond
should  have much of it’s surface covered anyway.
It is easy to pull out if it gets to aggressive.  There is a
pretty yellow bloom to the plant.
Water Cress- This is not supposed to be a pond plant.  Books say it grows in moving water.  My husband brought some home from the grocery store for our salads.  I got tired of it and threw what was wilted into the pond out of curiosity.  That was 2 years ago, now Water Cress grows along 15 feet of the pond and grows out in the water about 3 feet.  It has white blooms in June.  The dragonflies and mosquito fish like it.
Canna- These flowers are easy to grow, multiply well but can be tough to dig out to thin.  The Chorus Frogs loved to hide in the leaves before the Bullfrogs took over the pond.  Canna reproduces by rhizomes and divides easily.  I got mine at a plant exchange.  Non native.
Yellow Iris; Non native  Grows aggressively by rhizome and needs to be weeded every couple years.  I will eventually take these out and replace them with the native Blue Flag Iris, which is shorter.
Yerba Mansa- Bought this native at the Sand Hill Crane Festival for $3 in 2003.  We were in the process of putting in the pond and this poor plant got stepped on, covered in dirt, submerged way to deep and left high and dry for long periods of time.  I do not think one can kill a Yerba Mansa.  Finally it had a proper place at the ponds edge and it thrived.  The parent plant sends out runners with small plants ready to root.  These new plants are easy to pull up or are great to allow to spread.  It took 2 years to see a flower on a plant but now they have a white interesting flower.
Mint-  Ah, we have Spearmint growing that is wonderful to brush by and smell.  It grows easily, not really aggressively.  If one does not water it, it will not spread.  The butterflies and bees love it.  Then we have a mint of unknown character that was given to me.  When someone gives you a plant beware of planting it if you do not think you will like it.  This mint is very aggressive.  It took over the overflow area (12x8 feet) and it has a foul odor.  It is going to be hard to get rid of and the bees and hummingbirds love the flowers so I left it. I just don’t like to smell it.
Water Lilies- I have two types of Hardy Water Lilies.  By the second year the lilies were crowded but I was not able to divide them until year four.  Last winter we let the pond nearly dry up so that I could spend the month digging out cattails and water lilies.  I was able to divide the water lilies and find homes for them.
The above list are my aggressive plants.  I did plant, then dispose of Umbrella Plant.  It just reminded me to much of nut grass and I was afraid it would be equally as aggressive.
We weed by the trailer full.  So many plants are invasive, thriving in the water.  
Friday, June 27, 2008
What to plant, What to watch out for