FLOWER POWER! SEPTEMBER IN THE TUNNELHOUSE
October 1, 2024
Flower-power in the Tunnel House!
From September onwards, garden centres begin to to display a wide array of gorgeous flowering plants. Sadly, many of these plants are shipped in from regions much warmer than your own, and although it can be tempting to purchase one, chances are it will succumb to the elements in a less-than-favourable-summer, or fail to grow to its full potential even if the weather is warm. If your purchase does survive a cooler summer than it was intended to grow in, your first frost may well wipe it out.
However, if you have a tunnel house, you can enjoy flowering plants intended for a warmer climate than your own. That’s because undercover growing isn’t only about vegetables.
The beauty of bougainvillea
We most often notice bougainvillea when visiting Mediterranean parts of the world, yet these colourful climbers are actually native to South America, especially Brazil, Peru, and Argentina. The colour they deliver is not so much from their flowers, which are usually white or yellow, but from their bracts (modified leaves). These can be pink, red, white, orange, purple, and even peach in colour. Sadly, beautiful bougainvillea are not frost-tolerant, so if we want to enjoy them in a cooler part of the country, they will need to live out their life (at least during winter and early spring), under cover. Excited to give them a try? Then follow these easy-peasie steps!
Choose your pot!
While a bougainvillea can be grown directly into the ground of floor of your tunnel house, you will have little control over the spread of its roots, which may eventually invade the rest of your growing space. As well as this, the naturally rampant growth of the bougainvillea will have little to constrain it in this situation. That’s why we recommend growing a tunnel house bougainvillea in a pot, where it’s growth is more controllable.
A bougainvillea will appreciate a pot that is at least 500mm wide, and twice the depth of the bag it is being sold in. Terracotta pots are attractive, but they are also heavier than plastic pots. If you are happy to grow your bougainvillia in your tunnel house year round, go for terracotta (these pots tend to dry out the soil more quickly, but as bougainvillia are drought tolerant, that won’t be an issue). If, however, you have a sunny, sheltered outdoor spot for your bougainvillea to sit in during the summer, choose a light-weight plastic pot for ease of shifting (one with wheels attached is ideal).
The growing mix
Bougainvillia specialists choose a special mix for their plants. You can try making your own using growing medium by using the following recipe: 3 parts peat moss, 2 parts perlite, and 4 parts fine, rotted pine bark (usually available from garden centres). Alternatively, opt for a general potting mix.
Planting
If the plant you purchase doesn’t already come attached to a strong support, buy one for it at the same time as you purchase your plant, along with some ties. To plant your bougainvillea, half fill your pot with mix, ease the plant out of the bag, and tease out its roots a little with your fingers. If the bougainvillea isn’t already attached to a support, push the support you have purchased into the pot and firm around it. Plant your bourgianvillia close to the support, and fill the remainder of the pot with mix, keeping it back from the ‘trunk.’ Water the mix into the pot, and top it up if it settles. Gently tie the trunk to the support in several places. Don’t attempt any pruning at this stage (unless the variety of the Bougainvillia dictates you should – read the plant label), because the best time of year to prune most bougainvillia is autumn, after the flush of flowers is over.
Feeding
Despite bougainvillea appearing to thrive in the most inhospitable of settings, a container-grown tunnel house specimen will appreciate feeding. This should be done in spring, late summer, and autumn with high nitrogen/high potassium, slow-release fertiliser pellets. To do this, water the plant well, scratch the top centimetre of the mix around the plant to loosen the soil, and mix in the fertilizer pellets at the rate recommended on the container. Water again.
Maintenance
Bougainvillea are rambling climbers. They also have thorns. That’s why we recommend you prune your tunnel house bougainvillea into a manageable standard (a plant with a bare woody trunk and a compact, showy display of foliage and colour on top). To prune your bougainvillea, snip off, close to the trunk, all but the upper 5-6 ‘branches.’ Next, snip each of these ‘umbrella’ branches back to a length of 15-25cm. This will encourage growth to branch out to create the dense, compact canopy you are trying to achieve. With further prunings in following seasons, you can create an attractive ‘waterfall’ of flowering branches, or top your support with a topiary frame to create an interesting shape. If you’re after a multi coloured effect, consider planting two different coloured bougainvillea in one pot so that the flowering branches intertwine to put on a colour-rich show.
Bougainvillea don’t mind becoming pot-bound, so there’s no rush to repot yours unless it is showing signs of distress that cannot be explained in any other way (pot-bound distress can be indicated by wilting or discoloured leaves, sudden leaf or flower drop or a failure to flower).
Sun sense
Bougainvillea are sun lovers, but when growing undercover, they appreciate a little protection from direct sunlight over the hottest months of the year. This is easy to achiever when you drape a section of light-weight shade cloth across the ‘rafters of your tunnel house, directly above the bougainvillea (remember to remove it in autumn).
Tips
Display your bougainvillea to greatest effect by placing it at the end of the tunnel house pathway (but keep it back from the polythene skin).
Use your bougainvillea to draw in pollinating insects by placing it close to the door of your tunnel house.
When moving your potted bougainvillea, wear protective goggles and leather gloves, and watch out for the plant’s thorns. And always keep the plant well away from the skin of the tunnel house!