Frequently Asked Questions: Pond Plants

1. Are there any oxygenators that I should avoid?

Unfortunately, some of the plants used as oxygenators are rather rampant and will take over the whole pond if they are not kept under control. One of the worst offenders is Elodea Canadensis (Canadian pondweed), but it is one of the most reliable oxygenators and is also one of the most widely sold in aquatic centres. If you are prepared to pull out quantities of the weed once or twice every summer, either by hand or by dragging it out with a rake, leaving behind enough to continue oxygenating, you might find that t works for you. Remember to check through the weed you have pulled out to ensure that you have not pulled out any fish or other creatures.

2. How many oxygenators do I need?

A pond which has been created in a half-barrel will need no more than one or two plants, but if you have larger pond, introduce several species so that the planting density is at a rate of one bunch for every 30 x 30cm (1 x 1ft) or so of surface water, excluding marginal shelves.

3. Is it true that water lilies should not be planted under a fountain?

 Water lilies dislike water turbulence of any king, and it is true that they should not be planted immediately beneath a fountain or waterfall, where the leaves will be continually splashed by droplets. You should also try to protect water lilies from water turbulence caused by strong winds, perhaps by planting stands of rushes or sedges on the side of the pond from which the wind tends to blow most strongly.

4. Which water lilies are tender?

There are several lovely tender water lilies, some blooming during the day, others blooming at night. Many are very fragrant. The following day-blooming water lilies have blue flowers unless otherwise indicated: Nymphaea ‘Aviator Pring’ (yellow flowers); N. ‘Blue Beauty’ (fragrant); N. Caerulea (blue lotus); N. Capensis (Cape blue water lily);N.capensis ‘Rosea’(pink flowers);
N. x daubenyana; N. ‘General Pershing’(bluish-pink flowers); N. gigantea (Australian waterlily); N. ‘independence’ (rose-pink flowers);N. lotus (Egyptian water lily; pink-tinged white flowers, sometimes night blooming); N. Mexicana (yellow water lily; yellow flowers); and N. ‘St Louis’ (fragrant, yellow flowers). The following bloom at night : N. ‘Emily Grant Hutching’ (dark red flowers); N. ‘Sir Galahad’ (white flowers); and N. ‘Wood’s White Knight’ (white flowers).
         Gardeners who do not have the facilities to overwinter tender water lilies but who grow them for the fragrance or colour often treat them as annuals.

5. Can I apply chemical fertilizers and insecticides to the plants around my pond?

It is better not to apply chemicals of any kind in the vicinity of you pond; if there are fish the slightest contamination of the water will affect them. One of the causes of algal growth is raised nitrogen levels caused by run-off from garden fertilizers. No matter how carefully you plan the borders, it is almost inevitable that in periods of heavy rain some fertilizer will leach into the pond water. It is better to rely on garden compost and manure.