Today’s question comes from a gardener in North Yorkshire. Ernie Uplad of Richmond has just created a new garden pond in an open, sunny spot away from trees and wants some advice about planting:

‘I’m pleased with my new pond but need some help with deciding when to plant it up, the mix of plants to use and how to go about this- can you help, please?’

When to plant?

Well Ernie, you seem to have made a great start with the choice of a good location for your pond. As for planting  now (early spring to mid June) is the perfect time, as the weather is warming up. If you plant to put in some fish (I wouldn’t myself as they tend to eat much of the other wildlife that will inhabit your pond), then it’s important to plant up before you install them as they might go hungry unless you take the trouble to feed them yourself.

What to plant?

Some plants are essential for a pond (whether it’s for ornamental or wildlife value) – oxygenators. These are plants which live almost entirely underwater  and help to maintain an adequate level of oxygen for the other plants, fish and other animal life. They also help to reduce the level of algae, as do water lilies. The oxygenators include Canadian pondweed (Elodea canandensis), which is vigourous; Egeria densa (less vigourous); water Milfoil (Myriophyllum spicatum), with its delightful feathery foliage; and M. verticillatum, also with feathery foliage, and which also likes limy water.There are also plants you should avoid at all costs- the so called space invaders! Here’s a useful guide to these. 

You migth also like to consider ‘marginals’ – these are grown on the inside edge of the pond- here’s a guide to marginal plants. And, don’t forget plants that grow in permanently damp soil- in a bog garden you may have created next door to your pond. Here’s another useful guide to plants for a bog garden.

For planting actually in the pond here is a selection of plants to add height (they all grow up to around 45 cms (18ins) high) and will add other interest:

Water hawthorn (Aponogeton distachyus), with white flowers with dark spots throughout the year

Acorus gramineus ‘Variegatus’, for foliage colour in green and gold

Bog Arum (Calla palustris) with white flowers in summer

Calla palustris ‘Plena’ with double yellow flowers in March- April

Cotula coronopifolia with yellow ‘buttons’ in  July- August

Hydrocharis morsus-ranae, with white-flowered floaters all summer

Mimulus moschatus and M. ‘Whitecroft Scarlet’ with yellow and red flowers, respectively,  all summer

Golden Club (Orontium aticum) with yellow club flowers in May- June

All medium-sized lilies (Nymphaea) in red, white, pink and yellow shades throughout the summer.

Egeria densa close up

Acorus gramineus ‘Variegatus’ via RHS

Hydrocharis morsus – ranae, male flowers

How to plant?

Well, let’s take water lilies first.The crowns (rhizomes or tubers) should be planted in a medium to heavy loam with the crown tips exposed and upright- they must not be buried. all other container plants can be planted in the same type of soil and to the same depth as they were at the nursery or when you propagated them, but avoid over rich soils; you can buy special aquatic compost if you like, but by avoiding rich soils  you will minimise problems with algae and weed through raising the nutrient levels in the water. The oxygenators will need to be weighted if this has not already been done by the nursery. Clumps of 6-12 small pieces should be put on the floor of the pool and held in a group by a lead weight. This will keep them from floating to the surface. Natural floaters like Hydrocharis morsus-ranae are simply put on the surface.

How to propagate?

You might in due course want to propagate your own plants and for most water plants this is very simple. you just divide them in the spring after lifting out the containers any plants you  require. Division is achieved by driving in either two handforks (or two larger forks for larger plants) back to back, then pushing the forks apart to prise away the outermost plants in the clump. Do not use the centre crowns; these are the oldest parts of the plant and should be disposed of.

A pond is a fantastic resource for wildlife

Further information: RHS guide to aqauatic planting

Old School Gardener