Waterlilies repotted in April should have rooted through the mesh basket by now after being placed on a shallow shelf to start with. These can be placed a little deeper if the leaves can still reach the surface. Plenty of waterlily leaf 'pads' on the water surface will help prevent the water from warming up too much and turning green. You should aim for 50-60% water coverage in the first year.
Leave the waterlilies at that new depth until Autumn so they can establish easily in their first season. They can be moved to about halfway to the final depth listed on their ticket when Autumn comes and as they start to go dormant. Eventually they will be strong enough to go back to the base of the pond and rise in one journey to the water surface.
Waterlilies (Nymphaea) love still water (no splashing on their leaves) in good sunshine to flower best and a boost with a plant fertilizer tab during the growing and flowering season always helps. Push these tabs directly into the compost so that the roots can take up all the nutrients and gain the benefit.
The Water Hawthorn that has been flowering well will have begun to deteriorate in the recent sun - it is not dying but going dormant until the cooler water of Autumn returns.
Remember where it is when you come to do any maintenance or you may throw it out thinking that it is dead - if left alone it will return and flower again next year.
Many of you have been asking about the water surface plant Frogbit (Hydrocharis morsus ranae) - it should be available soon. We are just waiting for it to get stronger as it has only just reached the water surface after such an odd Spring.