Water Garden Plants: Planting, Care, and Maintenance

• Marginal plants can be planted in regular plastic pots. Use only one type of plant per pot to prevent the stronger species from crowding out the weaker.
• You can use multiples of the same plant in one pot. This creates a denser planting with more visual appeal.
• Black or dark-coloured plastic pots are best, as they are not easily seen under water.
• Select an appropriately sized black plastic garden pot for your needs and line it with newspaper to prevent soil from falling out.
• Add soil halfway up the pot.
• Add some fertilizer suitable for water gardens into the soil at the bottom of the pot. This prevents it from leaching out into the water.
• Place the plants in the pot with the crown at the top and then add soil around the roots, leaving the crown uncovered.
• Add 1-2 cm of pea gravel or river pebbles to the top of the soil to hold it in place, leaving the plant’s crown uncovered.
• Sit the pot in your water garden or pond at the edge, creating a border.
• Place the pot at the correct height, so that there is 5-10 cm of water above the crown of the plant. Use bricks or pavers to adjust the height if necessary.

• Fertilizer tablets can be pushed into the soil when the plants are flowering.
• When required, you can unpot and divide the plants to thin them out, usually every 1-3 years.

• Water lilies grow from rhizomes, which is a horizontal underground stem of a plant from which new stems and roots grow. As rhizomes spread rapidly, they are usually planted in a container which resembles a colander, called an aquatic basket.
• Water lilies will often come in the correct aquatic basket at the time of purchase.
• Sit the basket at the bottom of your water garden or pond.
• Lilies can be placed in the pond or water garden from spring until early autumn.
• If potting the plant yourself, select the correct sized aquatic basket.
• Line the basket with newspaper to keep the soil intact.
• Fill the basket half full of soil.
• Position the lily in the basket with the crown at the top. Then add soil around the roots, leaving the crown uncovered.
• Add 1-2 cm of pea gravel or river pebbles to the soil surface to hold it in place, leaving the plant’s crown uncovered.
• Place the basket in the centre of your water garden or pond away from the edge, allowing room for the leaves to spread.
• Sit the basket at the correct height so that there is 15-45 cm of water above the crown of the plant. Use bricks or pavers to adjust the height if needed.
• Other types of rooted floating plants are planted the same way as water lilies but use regular plastic pots 15-20 cm (6-8”) wide in place of aquatic baskets.

Water Lily Varieties

• Almost Black (Slocum) – dark red flowers, almost black at the centre. Dark green leaves. Spreads 8-10 square feet. Depth 12-24”. Hardy to zone 4.
• Rembrandt (Marliac) – Garnet blooms with pink sepals, coppery green leaves, tolerates some shade. Spread 10-12 square feet, Depth 12-24”. Hardy to zone 4.
• Hollandia (Marliac) – large double pink flowers 6-8” across with large green leaves. Spread 10-12 square feet, Depth 10-20”. Hardy to zone 4.
• Marliac White (Marliac) – fragrant white flowers, an excellent bloomer with shiny, dark green leaves. Spread 8-10 Square feet, Depth 10-20”. Hardy to zone 4.

Hardy Shallow Rooted Plants

• Blue Water Iris (Iris Versicolor) – blue flowers in the early spring. Sword-shaped leaves. Height 24-36” Depth 0-6”. Hardy to zone 3.
• Cardinal Flower (Lobelia Cardinalis) – a native plant with brilliant red flowers. Attracts hummingbirds. Blooms from summer into the fall. Height 36-48”, Depth 0”. Hardy to zone 5.
• Variegated Sweet Flag (Acorus Calamus Variegatus) – sword-like green foliage striped with white. A striking foliage plant. Height 24-36”, Depth 0-6”. Hardy to zone 4. A solid green variety of Sweet Flag is also available.

• Water lilies are heavy feeders and should be fertilized every two months during the growing season.
• Waterlily fertilizer tablets or slow release granules can be placed in a folded piece of newspaper or brown paper and pushed between the soil and side of the basket or pot. Do not use bleached paper as it contains harmful chemicals.
• Remove any dead or dying leaves to reduce algae growth.
• Hardy water lilies can survive in cold areas and don’t need to be removed from the water, provided the water does not freeze down to the roots. If the water freezes completely, remove the plants before this happens.

• Submerged plants absorb their nutrients from the water. They require a lot less soil than other water plants and therefore can be potted in much smaller containers.
• They are often planted in a pot filled with gravel only, just to anchor the plants in the bottom of the water feature.
• Take 5-6 stems of the plant and bunch them together.
• Put the bottom end in a small plastic pot and fill it with gravel or river pebbles.
• Sit the pot in your water feature so that there is 15-40 cm of water above the leaves of the plant.

• Elodea (Elodea Canadensis) – a native plant, very hardy and vigorous. Hardy to zone 3.
• Hornwort (Ceratophyllum Demersum) – a fine-leaved hardy plant you only have to drop in the water. No planting required. Hardy to zone 5.

• Thin out submerged plants if they become overcrowded or overgrown.

• Floating plants simply float on the water’s surface, and their roots hang into the water. They do not need pots or soil. Place these plants on the water’s surface, and the will take care of themselves.

• Duckweed – a hardy floating plant with small green leaves. A favourite food of goldfish and koi. Spreads quickly but any fish or koi in the pond will keep it under control.
• Water Hyacinth – a floating plant that provides natural filtration and algae control. It creates shade and absorbs any excess nutrients through the root system. Occasional bloomer. Hardy to zone 9 and must be treated as tropical in our climate.

• Floating plants multiply quickly and can cover the water’s surface.
• No more than half the water’s surface should be covered between the free-floating and rooted floating plants.
• If the plants cover more than 50% of the surface area, scoop them out by hand or with a net.

• Never release aquatic plants into natural waterways. This helps to prevent the inadvertent release of invasive plant species such as yellow iris.
• There are many online suppliers of water plants who can provide you with native species for your water feature.