In some parts of the country frog spawn has been spotted already. We are still waiting here in Leicestershire.
The trigger for the amphibians to make the return journey to the water is temperature. It is the most obvious sign that the pond has woken up for a new year. In preparation, now is the time to prepare the pond water for the activity that will soon follow.
With the warming of the water in Spring often comes the fast growth of green algae commonly known as blanketweed. This is because the surface of the water is largely exposed to the sunshine as it has not much cover over it – the waterlily leaves do not reach the surface until May and your pond may have accumulated some nutrients due to vegetative breakdown of foliage left to decay over winter.
A good plant for early cover is the Water Hawthorn (Aponogeton distachyos). Its leaves are reaching the pond surface in the Nursery now and soon it will be flowering.