There are hundreds of different species of Buddleia from around the World...some temperate and some tender. Although all will attract some butterflies...some species of Buddleia have an extraordinary attraction to butterflies which gives us all such pleasure.
Here is a list of species that may interest you with a brief description of it's habits that you might like to consider growing....Buddleias generally come from mountainous regions and do well in rocky dry conditions if they receive plenty of rainfall. Do try and pick some that will do well in your climate....the favourite, "Butterfly bush" are all varieties of Buddleia davidii, a wonderful plant for butterflies, but does not do so well in very hot dry climates. There are other species which are far better suited for these regions!
Comes from South Africa...evergreen and more likely to be suited to the Southern USA. Winter flowering species, fragrant. Hardy to -5C
Comes from China...Naturalised in South Eastern USA...flowers June/July..but only a few flowers at a time and not so attractive to butterflies as other species. Hardy to -10C
Comes from mountains in Afghanistan...needs a well drained soil. Flowers in the spring if left unpruned...or if pruned in the Spring, it flowers in summer to fall. Worth part pruning to get a long flowering time! Hardy to -5C
A favourite of mine..comes from the Himalayan mountains, does well in dry rocky places..flowers August/September. fast growing and more compact than B. davidii...but equally attractive to butterflies. Hardy to -10C
Hybrid between B.fallowiana & B. davidii, the benefits are a compact shrub ( like B. fallowiana) with increased hardiness. flowers August/September. Hardy to -15C
Comes from the Himalayan mountains, a narrow flower spike. tolerates dry conditions well. flowers July/August. Hardy to -15C
Comes from South American mountains. flowers in ball like panicles that are usually yellow. Not such an attraction to butterflies as the other Buddleia species. Hardy to -10
From China...a tender plant with quite large individual flowers that hang downwards. Dry well drained soil..Purple flowers June/July...not so attractive to butterflies as other species. Hardy to -5C
Comes from China..sunny dry soils with a long flowering period July/October Purple flowers in familiar hanging position. Very hardy...down to -20C
From China this has quite a different appearance to the other species. Small leaves and long drooping flower panicles in May/June. Good in dry conditions. Prune after flowering as next years flowers appear along previous years shoots! Hardy to -20
From China...quite a tender evergreen shrub..Pink flowers in the early spring February/March...likes a sunny position...does well in dry soils. Hardy to -5C
From China...flowers in mid-summer and does well on dry soils...very attractive to butterflies!...a sunny position to do well. Hardy to -10C
The favourite and most common species...there are so many color varieties to choose from, each of us have a preference...but I always think pale lilac is the best draw! Does not do so well in the warmer regions, most varieties flower August/September when pruned in the spring...staggered pruning does increase the flowering period...and some varieties flower for a longer period naturally...the best to my knowledge is a variety called "Beijing" Hardy to -15
Some observations on propagating Buddleias
Buddleia are so easy to root from cuttings and these can be taken at any time of the growing season...either stick them directly into the soil and keep watered...or place in any well drained soil in pots...bottom heat will help rooting but is not necessary. They also grow well from seed...but as this is a much slower process, don't bother unless you are trying to get a new species or variety going that is unavailable as a cutting.
Buddleia species grow very well in England...and we all tend to plant them directly in the ground or in pots. As they are mainly mountainous species it often amazes me when I see it growing so well half way up a wall, having germinated there from a wind blown seed...with it's roots in the cracks...but no obvious soil visible. These plants are nowhere so vigorous as soil planted plants but they flower really well! However Buddleia is often difficult to keep healthy in the hotter dryer areas of the USA. I was discussing this Problem with Dale McLung at the Orlando conference, and he said his problem was due to nematode worms in the soil that build up as the weather heats up. Obviously they need plenty of watering in these areas, but I think this problem can be overcome by observing the plants that grow in wall cracks here...the plant needs regular watering....but the roots do not like to be too wet all of the time. Try growing Buddleia in a pot with just gravel and only a couple of handfuls of potting compost mixed in. Try to protect the pot (Roots) from being cooked by the heat of the sun....and water regularly with a little tomato fertiliser...let the pot dry out completely between watering and see how this works! I bet this will overcome most of the problems!