Recent Questions
     Pond Plants

Q. Good morning!,

Question for you.  What causes water hyacinths to turn black
and not flourish?  They were extremely healthy looking when we put them in the pond but they are slowly dying.  Our pond is in full sun - perhaps they don't like that?  The same thing happened last year.  Our marginal plants are doing very well but the floating ones are not.  The water lilies are doing quite well too - some of the leaves die but I assume that's normal. There are lots of healthy leaves and lots of flowers.  The hyacinths have never flowered and have not looked happy all summer.  Any advice?

A. Hello Karen,

I am sorry to hear that your water hyacinths are not doing to well. There are a number of problems that can cause the leaves of your water hyacinth to turn black and rot away, so I am going to give you the list from most likely to least likely.

- Lack of nutrients: Our ponds are often too clean and/or there is too much competition for the hyacinths to gather enough food. This is probably the most common cause of black leaves. You can address this problem by scooping your hyacinths out of the pond and putting them in a container of water with some 20-20-20 fertilizer mixed in.

- Temperature shock: We tend to want to get our ponds going as soon as we can in the spring and end up adding our hyacinths to water that is too cold. It is also possible for temperatures to shift very quickly in small bodies of water shocking the root systems of the plants.

- High or Low pH: If the pH of the water is abnormally high or low it can impede the plant's ability to absorb nutrients from the water.

- Physical damage: Plants that have been battered around a lot may have small wounds in some of their cells that may lead to leaves dying back.

- Excess wind: The wind causes water to evaporate and can cause the natural moisture within the plant to be sucked out of the leaves causing them to die back.

- Insect Damage: It is very common for hyacinths to get attacked by aphids. The aphids bite in the plant causing little areas of damage that turn into little dark spots, the damage being wet all the time will eventually spread until the leaves are completely black.

- Root Rot: Occasionally hyacinths will contract a disease called root rot that will cause the roots to fall off of the plant. No roots = no food.

- Salt in the water: Hyacinths and other floating plants are very sensitive to salt, if salt is present in the pond it can cause the plants to slowly die back.

I hope this helps!

Sincerely,

Jessica

Q. Dear Pond Doctor,

I have a natural pond fed by seven under ground streams.  I have
installed a simple fountain purchased at a local Home Depot store.  Now after three years, I have unwanted plants growing in the water.  What can I do to get rid of them?

A. Hey Steve!

If you've ever left a pile of topsoil undisturbed for several weeks, you
probably noticed how quickly the weeds germinate and move in. The same goes for aquatic plants. They, like all living things, like competition. We once pulled a two year old native species water lily out of a backyard pond that weighed over 900lbs!

Depending on the size of your pond, you may want to manually remove them or chemically remove them. To discuss the later, call me, as local regulations may prevent or restrict this control approach.

Once the 'weeds' are gone, replace them with cultivated, non-invasive varieties. If you are close to the Ottawa area we can help you with this one, otherwise we would have to refer you on to another aquatic plant nursery.

In any pond, death and waste accumulates and creates ammonia, this ammonia is converted into nitrite by bacteria known as Nitrosomona. Since nitrite is toxic to plants and fish, Mother Nature converts nitrite into nitrate through nitrobacter bacteria. The nitrate is then used by plants (and algae) to grow. No plants in your pond - algae goes bananas. This is called the nitrification cycle. It is a highly complex system that must be allowed to run effectively in your pond otherwise Mother Nature will kick your butt. Your pond will be swampy, green and problematic.

Adding ornamental plants not only adds beauty to the water garden, but also helps draw out the nitrates at the end of the cycle, keeping the water clear and clean. They are, in effect, Mother Nature's filters. You can help the whole process by oxygenating the water with a bottom dual-membrane disc aerator. This encourages the nitrification cycle in the same way blowing on a campfire makes it burn hotter. The result is a cleaner, healthier pond, not to mention very happy fish.

If you need anything further give us a call.