In my experience, most so-called "dwarf" buddlejas are nothing of the kind. Both ‘Pixie Blue' and ‘Nanho Purple', which are supposed to be dwarf, have reached almost 1.8m/6ft in my garden so some genuinely dwarf varieties would be very welcome.
Step forward the new Buzz Series from Thompson and Morgan, the first two colours in the series have just been announced.
Created at T&M's own plant breeding station by their multi-talented breeder Charles Valin, ‘Buzz Lavender' is a strong lavender purple in colour, while ‘Buzz Magenta' is a vivid magenta shade. They'll reach just 1.2m/4ft in height in the garden and half that in a pot.
"The Buzz Buddlejas were developed after about 10 years of selecting for true dwarf habit, good branching and short internodes," breeder Charles Valin told me. "They are based on B. davidii and are perfect for growing in a pot in a patio or on the balcony. More colours are on the way."
You can order the Buzz buddlejas from Thompson & Morgan.
They sound excellent, but I have to point out one thing: T&M are announcing this series as "the world's first patio buddleja". Sorry folks, but ‘Blue Chip' from the USA has beaten you to it. Indeed it was a bit hit in last year's RHS trial of buddlejas at Wisley and was the second most popular buddleja in the visitor voting. In the garden it reaches 60-90cm/2-3ft but it's not yet available to British gardeners - so "Britain's first patio buddleja" would be fine!