The best buddleia for every garden

What could be more generous than a buddleia? With flower heads full of nectar and purple plumes crusted with peacock butterflies doing that slow-flap thing of theirs (looking for all the world like ecstasy), you have to give thanks for the “butterfly bush”.
I don’t suppose the peacocks know that buddleias have been in Britain for only 130 years. Since arriving from China and Japan they have made themselves at home on railway embankments and chimney stacks the length of Britain, and in gardens. As well as the common purple we plant fancier varieties — pinks, whites, mauves, blues, or varieties only 1m tall suitable for a pot.
However fancy the variety, their care mostly remains the same — chop them hard back in March to produce long shoots that flower the same year. It’s the best £6.99 that you will ever spend.
So good, in fact, that the word buddleia has become synonymous with the one species, Buddleja davidii. Yet there are lots of other good, easy buddleia species, as well as some glamorous but large and less hardy species that we’ll not bother with here.
How about the hybrid ‘Lochinch’? It’s dear old davidii crossed with the slightly more tender fallowiana, but the result is tough enough and it has the beautiful grey new leaves and stems of fallowiana. Fragrant, orange-eyed violet-blue flowers follow. It’s compact, medium sized and stands tall. An excellent choice.
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Not all buddleias have that long panicle of flower that we associate with the common butterfly bush. Some have bobbles instead. ‘Morning Mist’ (aka ‘Silver Anniversary’) has semi-evergreen, silver-white foliage (you could use it as a foliage shrub alone) and white, yellow-eyed and honey-scented flowers. You can prune it hard like B. davidii, but it does make the flowers very late to appear. For me, it’s sometimes October when they open.
The commonest and easiest of the bobble-type buddleias is B. globosa, the Chilean orange ball tree. The little candelabra of balls are held erect, like a pawnbroker’s sign, and they come in June, long before the common butterfly bush has got into gear.
It’s coarse too, like the butterfly bush, but none the worse for that. It’s a plant for tough, cold gardens and will never disappoint so long as you like orange on a plant 3-4m tall. It’s good for new gardens where there is space to be filled quickly. But what you must remember that the pruning is the opposite of davidii’s. It flowers on last year’s shoots, so you must not prune it in spring. You prune it lightly, in summer after flowering.
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Like davidii, it’s a plant that you can propagate simply by shoving a stick of it into the ground in October.
Despite flowering at different times, davidii and globosa have managed at some time to get it together and produce a hybrid, Buddleja x weyeriana, which share the qualities of both parents. Its bobbles are a softer orange, sometimes with a mauve tinge (sounds dreadful but they are rather nice), and it flowers on young wood, which means you can do that easy spring chop that you give to davidii’s. If you find bright orange too much, weyeriana may be the one for you. Or B. globosa ‘Lemon Ball’.
Then there is a species that fools everybody: Buddleja alternifolia and its silvery form ‘Argentea’. Never would you think this was a buddleia at first glance. It makes a large shrub or even occasionally a small tree of wispy branches that arch gracefully out and downwards, so much more attractively than any weeping willow. Along the stems are narrow green leaves and small, fragrant, lilac flowers, which appear in June. Like all “weeping” shrubs its base can look hollow, so it’s good to grow it with other shrubs or leaning over a wall.
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As with Buddleja globosa, the time to prune this species is in summer, as soon as it has finished flowering. The principle is to take out lots of the arching flowered shoots to let it make new ones for next year. All those long intermingled thin shoots can be a challenge to sort out and people tend to be too kind to it. Then the plant gets bigger and bigger until they complain, “Oh — it’s too big!” The answer, once it’s got to a decent size, is to be brave enough with your annual pruning.
Time to divide old clumps of water and woodland irises (Iris foetidissima, sibirica, chrysographes, ‘Gerald Darby’ etc). Whereas bearded border irises are divided into single fat rhizomes, these wirier rhizomes are better divided into small groups of half a dozen. Replant them fairly quickly, before the fine roots dry out. Sibiricas are exceptionally tough, so huge old clumps can be chopped into smaller chunks with their soil attached and moved in spring.
Nerines are one of autumn’s glories and are about to flower from the naked bulb. Clear away the dry spent remains of any foliage ready for the big event.
Time to be sowing grass seed, for new lawns or patch repairs. Prepare the surface well, breaking it down into a fine crumbly tilth without digging too deeply. Lightly roll the seedling grasses when they are 3cm high to firm them in. They will only need one or two light cuts before winter. Be aware that introducing high-vigour traffic-resistant grasses to repair an old lawn may show up permanently as a brighter green patch, even if it wears well.
With autumn planting in mind, it’s a good idea to have to hand a pack of mycorrhizal granules (rootgrow) to add to planting holes. It makes a world of difference to the establishment of most trees and shrubs by effectively extending their root system and is thereby helpful against the effects of drought in those early years.
Make rose cuttings over the next few weeks. Some are reluctant, but others root like weeds and it’s always worth having a go if you can beg a bit of one you like. Choose finger-thick 25cm firm young shoots, cut below a joint at the bottom and above a joint at the top. Push them two thirds into the ground somewhere shady and out of the way. Expect shoots late next spring.
Q. I have a mahonia in the corner of my walled garden which grows well but at 1.5m it’s quite leggy. I’ve tied the longer pieces to trellis but I don’t know if I should have cut it back to encourage bushier growth. It shares its space with a buddleia and a daphne. J Horton-Fawkes
A. Your mahonia is the common old Oregon grape, Mahonia aquifolium, which is a multi-stemmed suckering species and incredibly hardy. If you want it bushier, chop the longer stems down to 15cm in February and it will oblige. Mind you, it’s probably growing so tall because it’s smothered by its neighbours and you will probably have to repeat the operation every few years to keep it low.
Q. I have a border with a number of large camellia bushes along the centre. Is there anything you could suggest to plant at the back of the border to fill the gap between the fence and bushes? The soil is very heavy clay, which gets waterlogged in the winter and baked hard in the summer. J Turner
A. I’d hesitate to give your camellias much competition if the soil is so dry in summer. They are already doing well to thrive on heavy clay and summer drought can cause bud drop. A heavy inter- and under-planting could be counter-productive. Consider using a light planting in front of them (a skirt) of hellebores or Geranium macrorrhizum (you’d have to see what survived the waterlogging), and behind them a light screen of climbing hydrangea.
Q. Our last garden was horribly limey and there was so much we could not grow. I intend to test the soil in the next house we buy. What is the ideal pH? D Burns
A. A test kit costs only a few pounds — pH 5.1-6 is right for acid-loving ericaceous plants (rhododendrons etc) and pH 6.1-7 is ideal for most purposes.
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