Having problems with plant problems of specific plants?

Water lilies

Brown China Moth. Hydrocampa nymphaeata - Small brown and orange moth lays clusters of eggs on water lily leaves in summer. Larvae feed on the leaves and hide from view by sticking two pieces of leaf and lying between them.

Pick off affected leaves or submerge the whole leaf to be dealt with by the fish.

Crown Rot - Covers a number of fungal and bacterial diseases, like for instance Root Rot, this particularly affects the mottle leafed and yellow varieties of lily like Nymphaea moorei and Nymphaea chromatella.

Nymphaea chromatella one of the mottled leaved varieties of water lily most prone to root rot.

Symptoms generally include: leaves turning yellow and black and easily pull away from the centre crown. Eventually the crown begins to rot.

Solution: Remove the lily and cut away diseased tissue. Recovery may come from other growing points.

Alternatively, spray with systemic fungicide and quarantine until strong growth is visible.

This normally occurs on newly planted stock. To avoid the problem, don't plant new plants too deep and beware of sudden cold spells.

Leaf Spots - Cercosporae - Edges of the leaves become dry and crumbly.

Ovularia nymphaeum - Small spots that readily spread after which the leaves rot in patches. http://www.autoandbus.co.za/toyota_prado.php

Pick off affected leaves and burn. If heavily infested, the careful use of a systemic fungicide may be in order with the plant quarantined in a separate tank away from the main pool.

Water Lily Beetle. Galerucella nymphaea - Larvae and adults feed on the leaves and flowers.

Lily leaf eaten by the water lily beetle and probably snails.

Solution: Spray with a forceful jet of water. The fish will eat the dislodged pests. If there are no fish present some experts have recommended spraying very carefully with a systemic insecticide. These are harder to come by nowadays and their use is not likely to help the pool environment or even environment as a whole. Consider it only as a last resort for an expensive precious lily in the isolation of a separate tank.

An alternative suggestion is to spray with fish parasite solution at a dose rate suitable for the pool. See Aphid and Blackfly treatment above.

Marginals

Caltha palustris and related species Marsh marigold - all varieties are prone to mildew and fungal infections. Mildew seems to occur as a matter of course at the end of the flowering period. It can be treated in isolation with systemic fungicide but I find that is best to just cut back the infected foliage letting new fresh new growth emerge untainted.

Houttuynia cordata plena and H. cordata Chaemeleon are prone to scorching by late frosts. Leave to grow back. Generally this plants irrepressible vigour ensures its survival.

Houttynia cordata Chaemeleon, Juncus effuses var.spiralis, Lysimachia nummularia Aurea (creeping jenny), Menyanthes trifoliata (bog bean).

Myosotis scorpioides (subsp. palustris), Water Forget-me-not, can be affected by mildew at the end of the flowering season. Leave until it sets some seed and cut right back. The true species is a perennial, so it should send out newshoots from the base.

In general marginal plants suffer very few problems from fungus or viruses if they are robust healthy plants with good root systems when they are planted.

Water Forget-me-not, Myosotis palustris.)

Floating plants

Disappearance. Frogbit, Hydrocotyle ranae and Water Soldier, Stratiotes aloides will sink to the bottom of the pond as the water gets colder. They will also disappear in cool weather or after some major upheaval or disturbance.

Water Chestnut, Trapa natans is an annual and will only reappear again in spring, after it has died back in winter, if it has managed to set seed in the previous year. This does not occur very often in the UK. If it does set seed sow in pans of loam in water in April or May. Heat to around 18c-21c until germination occurs, then grow on in an unheated greenhouse.

Blackened foliage. From greenhouse to pool is a dangerous time for Water Hyacinth (Eichornia crassipes) or Water Lettuce (Pistia stratiotes). Even the slightest frost can spell doom.

Oxygenators

Brown or white crusty scale. This is a result of hard water or lime in the water. It is the same material deposit as inside a kettle.

Rub off, particularly at the growing tips. Do a pH test for a possible water change or buffer chemical to make the water less alkaline.

Disappearance. Snails or Carp - Blame the bloke you bought them off in the shop; he said they were a good idea.

If you havent got carp and you thought you didnt have any snails, you may not have bought any, but they probably came in as eggs deposited on new plants.