Plant Doctor Archive

Watery woes

Question  I HAVE a water lily in my garden pond that appears to be unwell. It regularly produces new leaves, but each one only lasts for a few days before rotting. The pond is 40cm deep and has an area of 2sqm. It also has a small waterfall.

Answer  WATER lilies need plenty of sun to grow well, and rotting of new growth could be caused by lack of light. If the pond is shaded you may need to prune nearby shrubs to let more light through to the water surface.

At 40cm deep, the water is also too shallow for large-growing varieties of water lilies but should be fine for miniatures, so check the label to see what type you have.

To reach their full potential water lilies also need plenty of fertiliser. In nature they feed from the debris on the pond floor but in garden ponds you usually need to feed them with slow release fertilisers specially formulated for aquatic plants. Look for brands such as Pondtabbs distributed by Wright’s Water Gardens, Patumahoe, or Jobes Fertiliser Spikes for Aquatic Plants available at most garden centres.

Weekend Gardener, Issue 141, 2004, Page 22-23