Koi fish ponds | Avoid poisonous plants and trees near your garden pond
My neighbour had a laburnum tree, which was growing over my pond. The leaves, blossom and seed pods all fell in the pond and my Koi ate the blossom as the skimmer couldn't remove it quickly enough. I lost two Koi in one week with strange symptoms, so I finally went round and asked if they would cut it down. I explained the problem and told them it was a poisonous tree and to my surprise they agreed. They cut it down last weekend and my Koi seem less shy and are feeding more than when the tree was there.
My neighbours want a new tree to replace the laburnum but I don't know what tree I can buy that will be safe for the fish. It will be in the same place and will eventually hang over the pond, I don't mind the falling leaves as long as it is not poisonous. Please can you suggest what I could buy them?
A It might seem a tall order to replace the spectacular display of the Laburnum with something as equally impressive, but really there are plenty of small trees that will flower and possibly fruit or give a stunning display of autumn colour without poisoning the inhabitants of a pool. Another prerequisite, I presume, is that it is a tree that will grow fairly quickly to maturity, whilst remaining relatively small.
Some of the Mountain Ash fit this bill. They don't cast too much shade and their root system stays compact and unintrusive. Sorbus aucuparia 'Asplenifolia' has elder type umbels of flower in spring followed by bright red berries in autumn when they are almost eclipsed by the stunning red foliage. Or there is the "Japanese Mountain Ash", Sorbus matsumurana with more large orangey/red berries.
Other small trees definitely to consider are the huge range of (and often forgotten) Crab apples such as Malus floribunda, "The Japanese Crab", or the stunning and scented Malus "Pink Perfection". Also there are the Hawthorns or Mays, particularly if you need something really tough and hardy. Craetagus oxycantha 'Coccinea Plena' often called 'Paul's double scarlet' is very popular or the Crataegus prunifolia for autumn colour. The fruit make great food for the birds.
If berries are a problem then go for a silver birch. Betula dalecarlica, 'the Swedish silver birch' is my favourite with its light foliage and gradually whitening bark.