Please see our Butterfly and Bee plant pdf here..
Verbena bonariensis A top
butterfly nectar plant. V.
bonariensis flowers continuously from
June till the first frosts and covers the main period of
garden butterfly emergence in late August and September.
Plant en masse for best effect.
Buddleja A butterfly magnet but has a tendency to flower before the main emergence of garden butterflies. Plant two bushes and cut one back in May so that it flowers in late summer. Alternatively, dead-head all flowers. The variety B. Lochinch responds well to dead-heading and will then flower through till November.
Mint Family The mint family is a prime butterfly-attracting family. Japanese hyssop Agastache rugosa is an excellent nectar plant. Plant in a sheltered place or treat as an annual. Other good plants are Marjoram Origanum vulgare; Betony Stachys; Bee-balm Monarda, Lavender Lavendula angustifolia/L. latifolia plus most other herbs.
Daisy Family Compositae Many plants in this family are excellent nectar plants. If you want hot colours that attract butterflies as well, this is the family to choose.
Others: Scabious flowers are attractive to butterflies. Use Devil’s Bit Scabious Sucissa pratesnsis in acid soils. Purple Loosestrife Lythrum salicaria is a showy native flower good in damp borders. Good spring nectar plants are Pussy Willow Salix caprea, Everlasting Wallflower Erysimum 'Bowles Purple' and even dandelions left to flower in a lawn. The ice plant Sedum spectabile provides useful late autumn nectar but it is best to avoid the modern hybrids.
Put fruit out, e.g. oranges, on a small table from August to November to attract Red Admirals, Commas and Peacock butterflies. Provide dark-coloured rocks for butterflies to bask on.