Butterflies and caterpillars need more than a friendly plant or two in the garden, and just like us humans, they also have certain preferences.
In the case of butterflies, they like a spiral or three-dimensional garden bed with a variety of larval host plants. Such a bed is the ideal habitat for insects, according to the German Nature and Biodiversity Conservation Union (NABU).
A spiral bed winds its way upwards similar to an herb spiral, which becomes narrower towards the top and is bordered by large stones. The site should have room for a bed at least three metres in diameter, with the lower end facing south.
Mark out the base of the spiral with small stakes and some string. Dig the soil spade-deep. But dig only 40 centimetres deep towards the end section and leave room for a small pond there. Fill the base with 10 to 15 centimetres of gravel except for the pond area.
The spiral is built in layers and using the stones as a boundary. Fill half of it with gravel as the texture of the soil changes from the bottom to the top. You are creating a spiral that is suitable for plants with different needs.
This is followed by the actual filling. Equal amounts of soil and sand are mixed in the upper section which becomes a dry zone. Put a quarter each of sand and compost in the centre of the spiral. The lowest part is a moist zone. Half of the soil is mixed with one tenth sand and 40% humus. The soil should be calcareous, NABU says.
Lastly, position the pond at the start of the spiral on the lower end to close it. Seal it with either rubber pond liner or clay. Add some sand to plant the pond later.
Now, wait for a good downpour before putting the substrate mixtures in the spiral. You may need to top up a little later on. Then, you can begin planting.
Plants for the butterfly spiral:
- Upper third or dry zone: Yellow camomile (Cota tinctoria), dianthus carthusianorum or more commonly known as Carthusian pink and meadow clary or meadow sage (Salvia pratensis) like dry soil and are suitable for the upper part.
- In the middle or normal zone: This is ideal for common viper's bugloss (Echium vulgare), chives (Allium schoenoprasum) and yarrow (Achillea millefolium). The great burnet (Sanguisorba officinalis) and bugle or blue bugle (Ajuga reptans) like wetter soil.
- Lower third: Purple loosestrife (Lythrum salicaria) and cuckoo flower (Cardamine pratensis) prefer the lower end of the spiral. The marsh-marigold (Caltha palustris) should be at the very end near the pond as it likes moist soil.
