R2112 5.1 Aquatic Plants

Question 1

Name a marginal plant

Answer 1

• Iris pseudacorus*
• Caltha palustris*
• Butomus umbellatus*

<5cm and mud

Question 2

Name a bog plant

Answer 2

Lythrum salicaria ‘Feuerkerze’

• Primula bulleyana*
• Gunnera manicata*
• Osmunda regalis*

Question 3

Name a deep-water plant

Answer 3

• Nymphaea* ‘Marliacea Chromatella’
• Nymphaea* ‘Alba’
• Aponogeton distachyos*

Question 4

Name a floating plant

Answer 4

• Hydrocharis morsus-ranae*
• Ceratophyllum demersum (= oxygenator)*

Question 5

What is a marginal plant?

Answer 5

• Grow in shallow (5–15cm) water, with water over the crown of the plant.
• The roots are fully submerged and the foliage is above the level of the water.
• Marginal plants are planted on the first shelf of a pond.

Question 6

What is a bog plant?

Answer 6

• Bog plants thrive in rich soil that is constantly wet and most prefer sun, but a few are happy in shade
• Thrive around the edge of a pond or water feature, where the soil remains damp but not fully submerged.
• Add colour, height and interest to the border of a pond as well as creating shelter for its wildlife.
• Planted in situ, directly in the soil over the membrane.

Question 7

Growing medium for marginal plant?

Answer 7

• Heavy, loam based, low in organic matter and nutrients, especially nitrogen to avoid algal bloom.
• Garden soil could be used but must be free from fertiliser, pesticides, weeds and pests and diseases.
• The plants are either planted in containers or planted in soil in a natural pond.

Question 8

Name an invasive pond weed

Answer 8

Myriophyllum aquaticum

Question 9

Control of invasive pond weeds?

Answer 9

• Pull out by hand, ensuring that the weed is not broken up into small pieces and left at the side of the pool for 24 hours to allow pond life to re-enter the pool.
• Containers can be lifted or plants removed from the container to enable weed to be removed.
• Blanket weed can be removed with the use of a rake by winding it around the handle and leaving the weed at the side of the pool.
• Floating a bale of barley straw in a mesh bag in the pond is an effective method of controlling blanket weed. Approximately 50g of straw per m² of water surface area is ideal. The straw is added to the pond in spring and is removed after six months when it has turned black.

Question 10

Name an oxygenator

Answer 10

• Myriophyllum verticillatum*
• Myriophyllum spicatum*
• Ceratophyllum demersum*

(from https://www.theenglishgarden.co.uk/expert-advice/pond-plants/)

Question 11

Mix of plants for 4m² pond?

Answer 11

• 40 oxygenating plants
• 14 marginal plants
• 4 floating plants
• 2 water lilies
• 2 deep marginal plants

Question 12

Growing conditions for deep-water plants?

Answer 12

Grow in undisturbed water in full sun.

Question 13

How to plant deep-water plants?

Answer 13

• Plant in baskets in loamy soil with crowns just below soil surface and covered with pea shingle.
• Add a deep layer of stones at the bottom of the container for extra stability and to help anchor the plant in place. This is particularly useful when planting tall pond plants or when planting into flowing water.
• Planting depth: > 40cm (roots and crowns submerged in deep water)
• Planting: Water lilies and other such plants need time to adjust to deep water. When newly planted they will need a submerged temporary platform within the pond. Gradually lower them in stages until they reach their final positions - at each stage the foliage must have grown to reach the surface before they are submerged to the next depth.

Positioning: Thread some twine through the mesh sides of the container. With a friend, take one end of the twine each and gradually lower the plant into position, before gently tugging the twine from the container.

Question 14

How are pond plants propagated?

Answer 14

• Most can simply be divided; e.g. Nymphaea and marginals such as Butomus umbellatus and Caltha palustris; and pond-edge perennials and bog plants including Lythrum salicaria. In growing season.
• Submerged oxygenators and creeping marginals can be propagated by cuttings. Spring and summer. E.g. Ranunculus aquaticus
• Floating plants like Hydrocharis morsus-ranae naturally produce runners, plantlets or turions in the form of detachable swollen buds
• Some aquatics can also be raised from seed such as Aponogeton distachyos (collect summer/autumn)

Question 15

Controls for algae

Answer 15

Avoid nutrition via:

• Sun - make sure part of the pond (third) in shade
• Fertilisers leaching into the pond
• Sludge on pond floor
• Faeces from fish
• Rain water rather than tap
• Include water lilies - to take nutrition

Plant up at least one third of the surface with aquatic plants

Ensure there are also sufficient submerged oxygenators

Float a mesh bag of barley straw on the pond