Water garden calendar, May

For those of you desperate for inspiration on the water garden design line check out the Royal Horticultural Society website at www.rhs.org.uk near the end of the month. The RHS organise all the biggest shows in the UK, starting the season off with the Malvern Spring Flower Show. The Malvern Spring Flower Show is in the first week of May, but the gem of gems of all flower shows in the world is the Chelsea Flower Show usually starting in the third week of May.

The Chelsea Flower Show in May is a flood of new ideas. In 2005 Andy Sturgeon designs a water garden for outside an extension to a house.

They will have all the major gardens on display on the website and some of them will be in 360degree-zoom-in- zoom-out mode. The Hampton Court Flower Show at the beginning of July is particularly inspirational for water gardeners because there is a special section for display gardens that are exclusively water gardens. As flower shows go, it is probably the biggest in the world.

Jobs for the month.

Keep a look out for herons. Herons are fast becoming more of a problem, as their numbers seem to be increasing. This is an illusion, as modern building developments on flood plains invade their natural habitats, so their only recourse is exploit new sources of food often ironically in areas where there natural habitat may once have been.

If your fish have disappeared from view and lurk shyly in the bottom of the pool and dont feed, suspect youve had a visit. Look into heron scarers. There are some effective devices on the market but they are not cheap. Then again if you charges are Koi carp worth 200 upwards then a reliable predator deterrent is a one off insurance premium.

Now you can go to town adding new plants to the pool. It is also a good time to plant lilies and or divide them now.

Check new plants for clusters of snails eggs. You dont want your plants to end up as fodder for these pests. If you are going to have snails, get the ramshorn shaped ones. There are much less voracious when it comes consuming your water hawthorn and oxygenators.

Watch for fish spawning. If the pool is highly populated, you could rescue some spawn and hatch it in a tank. It may be lying in amongst the oxygenators.

Now is the time that everything seems to be burgeoning and if you have algae, you should do something about it now. You may be able to push the balance of the pool ecosystem over to a position that is less favourable to the algae. Start with ecological solutions like eco-algicides, barley straw and extra plants before the heavy chemicals and the mechanical technology. However, if you live in a hot sunny part of the world then you will have had to resort to bio-filter technology as a routine.

The biological balance of the pool, plus all the details of biological filtration is something I will go into this a little later in the book. But part of the secret of this is to be patient, especially if you are just starting up. It can take anything up to 6 or 8 weeks to get that old nitrogen cycle rolling and once its rolling, if you make any changes in the biological set up it can take just as long to regain its balance, for good or bad.

Plants looking good are the Water Hawthorn (Aponogeton distachyos), Bog Bean (Menyanthes trifoliate); the foliage of Houttynia cordata in all its forms is fresh and striking.

Hostas out in the bog garden give an impressive display of foliage whilst the Globe Flower (Trollius europaeus) out-glows the marsh marigolds with enormous bright buttercup style flower from lemon yellow to startling oranges.

The species of plant that you can easily expect to see in the bog garden in May is finely demonstrated by Hall Farm Nurseries at the 2004 Malvern Spring Flower Show.

The double Marsh Marigold (Caltha palustris plena) is following in the wake of its cousin and there are lots more flowers in prospect by the end of the month including some of the Irises.