Often with greenhouse plants we find beautiful blooms such as Bougainvillea are not really flowers at all. These are spectacular displays of modified leaves termed bracts. These bracts form the visible ‘blooms’ and look wonderful for many weeks. Whereas the real floral parts are almost insignificant and not long lived. Anyway this technical difference matters not a jot when their display is so magnificent and lasts so long.
Bougainvilleas are tough thorny clambering climbers from South America named after a French Admiral. Introduced to Europe one was first flowered here in Norfolk at Holkham Hall in 1860.
This the original pinkish purple B. glabra is the ancestor of many differently coloured variations and hybrids. These are tender though becoming tougher once established. It’s claimed old plants survive in sheltered positions outdoors if their lower part and roots are well protected.
Bougainvilleas have a weakness though. Their roots are very susceptible to damage. Re-potting must be done carefully and gently. Sift in an open gritty mixture of leaf mould and loam based potting compost then water firm.
Use a large terracotta container, for weight and balance, and also because this won’t deform when moved. You can plant in the greenhouse border for a larger display. Either way you need wires, trellis or other plants to clamber up, to ten feet in a tub, twice that in the ground!
Feed regularly (high nitrogen) with each watering (rainwater is preferable). Both should be done generously from when growth resumes till it slows in autumn. Cut back on both during un-seasonally cold periods to prevent a premature check. In winter keep moist but avoid water-logging and particularly when it’s cold.
Now for maximum ‘flowers’ you need to be ruthless. In mid to late winter cut back the side shoots hard, remove any dead stuff and thin the main stems judiciously. The plants will respond with tremendous vigour then ‘bloom’ magnificently. You can even shear one over like a hedge or in early winter prune an old specimen almost to the ground. But left just untouched or insufficiently brutalised one will become un-productive.
Bougainvilleas suffer the usual greenhouse pests of spider mites, scale and mealy bugs, controlled with commercially available predators. Generally though this is not their problem.
There are eighteen species, numerous hybrids and the original purple has sported many dozens of times. This host of named varieties come in red, pink, green & pink, purple, white, cream, yellow, orange and bronze displays, some with bicoloured bracts and others with variegated leaves. Though their exact colours all change depending on soil, situation, feeding, weather and almost with the day of week.
The problem is there are so many gorgeous choices, and many are just so much miffier than the original. So get a selection, these will self select for the most suited to your conditions. Do include an ‘old purple’ such as ‘Elizabeth Angus’ for surest success.