Hi Notty, buddlerii is verrygood for what you want the common name is butterfly bush , but I think even better is sedum,

Echinacea flowers later in the Summer and is covered on butterfles and bees.

Sedum Autumn Joy is a great favourite for Red Admirals, and the butterfly bush Cliffo refers to is, of course, Buddleia - plant it in a sunny spot, you get more butterflies if the flowers are in sun.

Buddleia is one of the best.
So too are Hebe, Lavender, Lilac.
Try these perennials too because they're fantastic - Scabiosa, Erigeron, Sedum, Thyme and Sage.

Plant these things in the sun because they attract the butterflies more than when the plant's in the shade.

to my resque agine Bamboo thanks love

Verbena bonariensis is a good choice too. I've also had butterflies on red valerian (the painted ladies were all over it earlier in the year) and oregano.

I counted 14 painted lady butterflies at one go on my sweet rocket, which is a short-lived perennial, about 3 years, but seeds itself. The other big hits in my garden have been the buddleia, verbena bonariensis and michaelmas daisies. I saw 2 painted ladies and a peacock on the verbena this morning, which was a surprise after yesterday's gales and rain!

Anything with large yellow daisies such as Inula magnifica are really good.

single flower forms are better rather than the showier double forms. the knapweeds are also worth having too.

Plant nectar-rich plants, herbs and wildflowers, Tropaeolum nasturtium, Thyme, Marjoram, Cornflower, French marigold, Honeysuckle and Asters are some.
Plant as many as possible in sunny areas with at least 1 Buddleia.
Because I wish to attract butterflies and other widllife I avoid the use of pesticides as much as I can.
Forgot oxeyed daisies.

Ideas for an arch are Clematis (so many varieties you can get of this plant), Climbing Roses,Honeysuckle, passion flower, sweet peas.
I hope these give you a few ideas

Blazing stars Liatris spicata blue which is a perennial. Butterflies and bees love it I have just bought 8 in the pound shop!!!

In my garden four things are certain to attract butterflies.
1. the buddlia (butterfly bush, mentioned earlier)
2. golden marjoram
3. mints. just leave a few stems grow and flower
4. fruit. I allow 1 or 2 of my pears to perish on the ground, the butterflies seem to be attracted to the natural sugars and moisture as the pear rots. This is much the same as you find in zoo's and butterfly house etc, where you will see that staff have placed some cut up banana, orange etc.

Arch; roses, grapes, passion flower, clematis are just a few to think about.