19 March 2013
Verbena bonariensis (VB for short) is, for me, second only to the buddleia for attracting butterflies. It has two big advantages. One, that it flowers for weeks: looking back through my photos of VB, I’ve got it flowering from July through to the beginning of October, though not in the same year. Secondly, it attracts a wide range of butterfly species. Quite a lot of flowers attract some species but not all: lavender attracts the Whites and the Blues; marjoram is good for the Browns, whilst valerian (centranthus rubra – the one you see growing in walls) seems to mainly bring in Whites and the likes of Red Admirals and Small Tortoiseshells, etc.
If you look at the photos below you can see why the butterflies like it so much – the flowers are very similar to buddleia. Having multiple flowers on one flower-head presumably enables butterflies to get lots of food without having to expend much energy to do so, as would happen they had to fly from one flower to another.
Left: verbena bonariensis. Right: buddleia with Brimstone butterfly
In garden terms verbena bonariensis is a very obliging plant, fitting in more or less wherever you want it to go. Its leaves stay low, but the flowers come at the tops of long, slender, stalks, 3-4′ high (1m+), so even if it’s near the front, it just forms a very light screen – it can be useful to do this deliberately, to break up the planting heights and stop them being too boringly predictable. It is easily grown from seed, and any individual plant once established, is as tough as old boots – I believe it is a weed in its native South America. Whether it survives the winter seems very unpredictable: sometimes it does, sometimes it doesn’t, and I can’t identify any common factor to the failures.You may find it self-seeds, though sometimes only in the second year, so you may need to intoduce it twice. Some people treat it like an annual, and it will flower the first year, but you get a better plant the second year.
Left: Verbena Bonariensis with teasels. Right: verbena bonariensis with amaranthus ‘Marvel Bronze’.
You can start thinking about sowing seed indoors around now,as long as it’s not too cold. Some authorities say it germinates best if the seed is cold for a couple of weeks first, but I usually find it comes up well regardless. Cheapest seeds I’ve found are at www.seedaholic.com – £1.50 for 1,000 seeds: the butterflies will really love you if you grow that many!
Butterflies and Gardens 