The only white-flowered, scented jasmine that is reliably hardy is the old-fashioned Jasminum officinale which is beginning to come out now and flowers through until the end of September. It is very vigorous and flowers best where it is given most room. Huge quantities of it were once grown round Grasse in France for the perfume industry, 7,000lb of blossom collected from each densely planted acre of jasmine. But I don't think that is the jasmine Ms Macpherson has in mind and it would be difficult to confine it to life in a 15in pot.
There are several other white-flowered scented species that survive outside in a Mediterranean climate. The best known of them is J polyanthum, which we more generally see as a pot plant, trained round a hoop of wire. Grown in this way, for a sheltered life in front of the television, it flowers through winter into early spring. Released into a more natural habitat outside, it flowers later, from April until June.
Ms Macpherson, down on the south coast, has at least a fighting chance of keeping this particular jasmine alive in winter. It thrives outside further down in the West country if it is given a sunny wall to play on. I think it would be worth the risk, because the smell is swoony. It is not particular about soil. A John Innes loam-based compost would be more sustaining than a soil-less one. John Innes No 2 would probably be best.
Rampaging in the Mediterranean over the tops of other shrubs or climbing into trees, this jasmine can reach almost 20ft, but in a pot, it is more likely to hover around three or four feet. It would need to be trained up and over a balloon or tripod of wire or bamboo, for its growth is very lax.
If you were growing this jasmine as a pot plant, you would expect to repot it every spring into fresh compost. This would be an unwieldy job in the size of pot Ms Macpherson has, so instead she could top-dress the compost each spring with Osmacote slow-release fertiliser or some similar product. She would need to keep the plant well watered.
Like J officinale, J polyanthum is evergreen, but slightly paler and brighter in leaf colour. It does not need much pruning. You train in as many growths as you want, then cut off anything you don't want after the plant has finished flowering.
Although J polyanthum is the most common of the white-flowered species found round the Mediterranean (yet its home is actually China), there are others such as J azoricum and J sambac, both of which are even more tender than J polyanthum. They do best in a greenhouse, kept just frost-free. J azoricum comes from Madeira, and has shiny evergreen foliage and very sweetly scented flowers. J sambac, an Indian species, is particularly resistant to drought, and flowers almost all the year round if the temperature is right.
However, neither of these are likely to help Ms Macpherson. If she doesn't want to risk losing a J polyanthum in its pot on her patio, or has nowhere to drag it under cover, what should she plant instead? Ideally, it needs to be a plant that would bake happily in summer, but could also canter through a frosty winter unscathed.
Would a mimosa survive the winter? It might. There used to be a wonderful great specimen growing on the west wall of a Georgian house in Wimborne Minster, not all that far from Southampton. I took the plunge earlier this season and put one against the west wall of our house. The foliage is a delight, whatever the time of year - fine, feathery and a strange shade of gun-metal blue. This is Acacia dealbata, the ordinary florist's mimosa, but it has grown at much too violent a rate to be suitable for life in a pot. A full- grown tree can be more than 45ft high.
A baileyana, the Cootamunda wattle, has the same flowering period - Christmas to April - but is a more manageable height and has foliageeven more feathery than A dealbata. You can cut plants back quite hard after flowering if you want to control their size. In the wild, they generally favour ground that is slightly acid, so in limey areas, you may need to give pot-grown plants an occasional dose of Sequestrene to keep them happy.
One of the smaller ceanothus, such as C azureus, would survive in a pot if well watered, and would enjoy being baked in summer. C azureus comes from Mexico, is deciduous and is covered with deep blue flowers from July through until autumn.
'Gloire de Versailles' is the only ceanothus with scented flowers - I would rate scent as quite an important attribute in a patio plant - but it grows bigger than C azureus. It is deciduous and carries big panicles of pale powder blue flowers all through late summer. You can keep it to the required size by pruning hard in spring. Shorten the shoots of the previous year's growth to within three inches of the old wood.
A Judas tree would sunbathe happily on Ms Macpherson's patio, but how would it cope with life in a pot? Given that the pot is quite large, it would probably not grumble too much. You see them more usually grown as small trees - mine was plastered with deep pink flowers this spring - but if you chose a multi- stemmed specimen rather than a single stemmed one, you could grow it as a rounded bush, pruning it to shape when necessary.
The foliage is very pleasing - wide fat hearts in a bright, fresh green - but the tree is not evergreen. It flowers in April or May. The older the tree, the earlier it flowers. The flowers themselves spring directly from the trunk and branches, without any stems. You can see the tiny buds colouring up like pimples during the winter. It is a wonderful sight in flower. Mine is the ordinary kind, but there is an elegant white-flowered form, Cercis siliquastrum 'Alba'. Judas trees hate being moved, so buy them when they are still small. In a pot, they would need regular feeding as well as watering.
Why "Judas tree"? Because there is a tradition that this is the tree on which Judas hanged himself. Don't let that put you off it. It is a beauty. So is its cousin, Cercis canadensis, especially the dark-leaved form 'Forest Pansy'. Mine grows well in shade, but it is supposed to prefer full sun, so it might also be a candidate for the hot pot. Shrubs to avoid in that situation would be woodlanders such as rhododendrons, hydrangeas, camellias and pieris.Reuse content