HOW TO MAKE WETLAND HABITATS

An Environmental Project for APRIL

WETLAND HABITATS are in continuous threat from drainage and pollution. As a result, some of our most colourful flowers are becoming rare. Among these are the marsh marigold, lady's smock, purple loosestrife and ragged robin. A mini-marsh will help to conserve them and will also attract plenty of wildlife. Bees, butterflies and hoverflies will find this habitat irresistible.

REQUIREMENTS

A roll of heavy-duty builder's polythene, plenty of good garden compost or leafmould, builder's sand, a bag of grit, marsh plants and a spade.

CONSTRUCTING A MARSH

1. Remove the sod from the designated area. (A partly shaded, partly sunny site is ideal).

2. Stack the sods, grassy sides downwards in a corner of the garden. The resulting mound could be used for making a wildflower bank.

3. Dig the area to a depth of between 50 to 60 cm. (The bigger the area, the better the marsh).

4. Keep the soil in a heap near the marsh for use later.

5. Make a ledge around the edge of the marsh, about 15cm wide and 7 cm deep, by digging under the sod and folding it backwards.

LAYING LINER IN A MARSH

Put a layer of builder's sand in the bottom of the dug out area, to protect the liner. Place the heavy-duty polythene on top of the sand and press it firmly into the sides. Leave an overlap of about 12 cm around the sides. (This can be trimmed later when the liner is firmly in place). Puncture two or three holes in the bottom and cover them with sand for drainage purposes. It is important that the holes don't become clogged and prevent seepage. A poorly drained marsh can become stagnant. Trim the polythene around the edge and tuck it under the sod, which was folded back.

Suitable plants:

1. Purple Loosestrife ( Lythrum salicaria)

2. Meadowsweet ( Filipendula ulmaria)

3. Ragged Robin ( Lychnis fios-cuculi)

4. Lady's Smock ( Cardamine praetensis)

5. Hemp Agrimony ( Eupatorium cannabinum)

6. Marsh Marigold ( Caltha palustris)

7. Bog Bean ( Menyanthes trifoliata)

8. Bugle (Ajuga reptans)

9. Yellow Flag ( Iris pseudacorus)

AFTERCARE OF A MARSH

1. Annual Irish rainfall is usually sufficient to keep a marsh area wet. However, if dry conditions prevail for an unusually long time, the marsh's water should be replenished either with a watering can or a slow trickle from a hosepipe. To be sure that it remains wet throughout the year water could be channelled from a downpipe to the marsh area.

2. Cut back the dead plant foliage in autumn and remove.

MAKING AN ADJACENT POND

Ponds are risky in school gardens, since they are quite prone to vandalism. If however, there is a good chance that a pond will survive, one should be constructed.

CONSTRUCTING A POND

Construction is similar to a marsh. However, a pond should be dug to a depth of at least 75 cm. It should also slope very gently to make it easy for frogs to enter and exit. A saucer-shaped profile is ideal. When the liner is installed it should be covered with a soil/ silver sand mixture to a depth of about 10 cm. A pond and marsh can be joined. The ridge between the two should be at pond level to allow excess water to spill into the marsh.

PLANTING A POND

Three types of plants are required: submerged plants to oxygenate the water; floating plants to provide shade; marginal plants for creature cover.

SUBMERGED PLANTS

Water Crowfoot (Ranunculus aquatilis), Water Starwort ( Callitriche stagnalis)

FLOATING PLANTS

Frogbit (Hydrocharis morsus-ranae), Broad Leaved Pondweed ( Potamogeton natans)

MARGINAL PLANTS

Marsh Marigold ( Caltha palustris), Brooklime (Veronica beccabunga)