Growing Water Lilies in Deep Ponds
One of the most frequent inquiries I receive is “What Water Lilies are suitable for deep water.”? The deepest water in larger ponds and lakes could be anywhere between 4 to 15 feet in depth or even deeper, but Water Lilies will not grow in waters of more than 5 ft deep and there are only a few Water Lily cultivars that will grow happily in water that is 5ft in depth. There are however, quite a lot of cultivars that will also grow happily in 3 to 4 ft of water if allowed time to establish.
There are two essential things that Water Lilies require in order to grow fast and colonise quickly, and these are warm water and light. All large growing Water Lily cultivars will grow twice or three times as fast when planted into shallow waters that are 12-18 inches deep. If a large growing Water Lily cultivar is planted into 3 to 5 ft of water, there will be less light and the water will be cooler and therefore, a large colony of Water Lily tubers/rhizomes will take a long time to establish. So, when you see a large patch of established Water Lilies growing in a village pond, they have probably been growing there for a long time or, they are growing in a purpose or natural raised/shallow area of clay/silt which is ideal.
Water Lilies always grow better when planted straight into natural clay and silt rather than in aquatic baskets as the rhizomes/tubers are not restricted. So, even in manmade concrete, lined or fibreglass ponds I would always recommend adding 6-8 inches of pond substrate into the bottom of the pond if possible ready for natural planting.
Aquatic Baskets and Water Depth Requirements
Adding a natural level of sediment/substrate to the bottom of a man made pond can be a costly procedure so, most of the time large Water Lily cultivars are planted into large 40 cm square aquatic baskets. To achieve impact and a more established look in the first season, you can plant multiple rhizomes (3 or 5) into one basket and this is always recommended if the basket is going to be positioned in deeper water (3-5 ft) but, if the basket is to be positioned in shallow water 12 to 18 inches, then you might want to plant just one or two rhizomes as they will grow three times as quickly, for the reasons as explained in the paragraph above.
One good thing about large aquatic baskets is they are spacious and 12 inches deep which means, that if your pond is 4ft deep and the baskets are going to be positioned at the bottom of the pond, you will be able to choose Water Lily cultivars with a water depth requirement of 3 ft as the water depth calculation will be the distance from the top of the aquatic basket to the water surface.
I have listed three large growing Water Lily cultivars below with links to photos, but there are plenty more listed on my website www.lilieswatergardens.co.uk that will grow in water that is 3-4 ft. The water depth requirements can be seen below the Water Lily cultivar images throughout the website.