Re-Potting Marginal Pond Plants
There are two types of marginal plants, shallow marginal plants and deep water marginal plants. Shallow marginal plants grow literally at the water edge and require no more than 4 cm of water depth. The different species and cultivars of deep water marginal plants require different water depths, but most will grow at the water edge like shallow marginal plants. Some of these will grow in water up to 20 cm in depth. Meanwhile others can grow in much deeper water that is up to 60 cm in depth.
Most shallow marginal pond plants are either creeping plants, or clump forming plants such as Rushes and Aquatic Grasses. In a natural pond, these plants have plenty of room to spread and establish, while Nature takes care of itself. In contrast, pond plants planted into Aquatic Baskets will only have a shelf life of 2 or 3 years before they need re-potting. This category of pond plants thrive best when growing in the centre of your Aquatic Baskets and here’s how. Simply take cuttings or split them into divisions and plant smaller segments back into your Aquatic Baskets when they require re-potting. I have listed the signs to look out for if your plants are pot-bound below.
- Plants have stopped producing flowers.
- Baskets have become distorted.
- Plant growth has become stunted and foliage colour is yellowish in colour.
Most deep water marginal pond plants in this category, grow from rhizomes and tubers. Pond plants with this type of root stock are often invasive, and some grow so fast they might even need re-potting every season. Re-pot your shallow and deep water pond plants any time between March and the end of July.
Correct Method Of Re-potting Deep Water Pond Plants That Have Rhizomes/Tubers
This is a very important paragraph. My method of planting (pictures below) might not seem obvious and/or even slightly strange to some people. When deep water plants need re-potting, you simply cut a few good growing tip segments and discard the rest of the old plant. Cut the growing tip segments to 2 or 3 inches in length,
The next bit is most important. Don’t replant the rhizomes/tubers back into the middle of the Aquatic Basket. Instead, plant them with the cut /sliced end of the new growing segment up tight against the edge of a round Aquatic Basket, or the corner of a square Aquatic Basket. This will appear as if you are planting into as little as one tenth of the space of the top area of the Aquatic Basket, but it makes sense as this will ensure that the newly potted plant will have plenty of space in which to grow.
It amazes me how often I see quite the opposite in some of the garden centres I have visited. I have seen rhizome/tuber root stock of marginal plants being advertised as ‘Pond Ready’. So often these are planted the wrong way round, pot bound, or crammed into 9 cm and 1 liter Aquatic Baskets that are just far too small for them. These plants will need re-potting straight away if they are to stand any chance of survival. Deep water marginal plants that grow from rhizomes and tubers should never be sold or re-potted into anything smaller than a round 23 cm Aquatic Planting Basket (3.5 liters).
I hope this article is useful. There are over 100 informative articles on all aspects of Water Gardening and the varieties of pond life who make their homes in the water, available to read on my retail online website, as well as over 750 pond plants and water garden plants available to buy online or from my retail nursery in Surrey.