Dragonflies & damselflies
Odonates
Role in the garden
Formidable predators: adults hunt midges, mosquitoes and other flying insects on the wing, up to butterflies; the aquatic larvae eat almost any prey smaller than themselves (British Dragonfly Society).
Activity period
May to October (adult flight); aquatic larvae all year
How to attract / manage it
Set up or preserve a water point (pond, basin, deep trough) with emergent plants on which the females can lay. Do not introduce goldfish into the pond, they devour dragonfly larvae and prevent the populations from establishing.
Practical guide
Where to find them
Near all still or slow-moving water: ponds, basins, pools, ditches. The adults patrol in full sun, often perching on the emergent stems of bank plants. Larvae present: under submerged leaves, in the silt, lying in wait for small aquatic prey.
Prevention
Not applicable, a beneficial to favour rather than prevent. To increase their presence: keep a diverse emergent vegetation around the pond, avoid any insecticide treatment in the garden.
Sources
- British Dragonfly Society : Frequently Asked Questions (british-dragonflies.org.uk)
Favourite plants / resources
Related plant entries
Mint
A very nectar-bearing herb. Its essential oils (menthol, menthone) have a repellent action shown in vitro on aphids, ants, and whiteflies.
Cattail (bulrush)
A pillar of the permaculture edible pond: four food harvests possible in the year (young shoots in spring, protein-rich pollen in early summer, the tender heart of the stem, autumn-winter rhizomes rich in starch). A phytopurification plant used to absorb heavy metals, hence its double value: food-bearing in clean water, purifying in water to be depolluted. Always to be planted in an openwork basket on a 10-30 cm underwater shelf.
Arrowhead (wapato)
An ancestral starchy tuber, the 'wapato' of the peoples of the Pacific Northwest and the Chinese 'cí gū', grown for millennia in Asia. Each plant produces in autumn 5 to 15 small tubers (1 to 4 cm) at the end of underground stolons, to be harvested in a controlled way by baskets, in winter, when the surface has withered. A little-invasive plant, an ideal complement to the cattail in the edible pond.
Yellow flag iris
A classic companion of the edible pond: dazzling yellow flowering in May-June (a major nectar plant of early summer), a refuge for dragonfly larvae and amphibians, roots that stabilise the banks. A native species (not listed as invasive in France), but vigorous: contain it in a basket in a small pond. A documented phytopurification plant (absorbs nitrates and moderate metals).