To grow a bougainvillea in a pot

Which bougainvillea species to grow in pots?

First of all, let’s be realistic: bougainvillea grows much better in open ground than in a pot! In fact, it is grown in a container for two specific reasons:

1. lack of space in the garden,
2. and/or because of harsh climate (if you live in a region where the climate is too cold for it to overwinter outdoors).

Indeed, hardiness of bougainvillea is quite limited. Native to Brazil, this plant needs plenty of sun and warmth to develop and flower.

To give yourself the best chance, start by choosing a variety of bougainvillea that will tolerate being grown in a pot. Consider in particular:

Varieties of bougainvillea ‘Violet de Mèze’, ‘Sanderiana’ and ‘Spectabilis White’

• the bougainvillea ‘Violet de Mèze’, a horticultural hybrid that will tolerate being grown in a pot wherever temperatures exceed -8°C;
• the bougainvillea glabra ‘Sanderiana’, one of the most popular species which has a more compact habit than other bougainvilleas, and which will quite happily be grown in a pot, even trained as a bonsai;
• the bougainvillea spectabilis (white, purplish-violet, red or even yellow), also capable of acclimatising to pot culture in less favourable regions.

Which pot to choose for bougainvillea?

Contrary to popular belief, bougainvillea does not flower better in a narrow pot, quite the contrary. Its substantial root system needs space to develop properly. Especially as this climbing plant can reach several metres in height. For an initial planting, opt for a pot 30 centimetres wide and deep. Choose a larger pot at each repotting.

©Dunk – Flickr

Preferably choose a terracotta pot pierced at the bottom. This material favours gas exchange. However, terracotta also favours faster evaporation.

Which substrate should be used for bougainvillea in a pot?

Bougainvillea needs a well-draining substrate to thrive. A thick layer of clay pebbles or gravel should therefore be placed at the bottom of the pot.

For the rest, make sure you choose a very high-quality potting compost mixed with horn meal and blood meal in small quantities, yellow sand for drainage, and garden soil.

When and how to plant a bougainvillea in a pot?

It is recommended to plant bougainvillea in a pot during summer. A period when the plant is outdoors and in flower.

1. Begin by moistening thoroughly the walls inside and outside of your pot
2. Prepare the growing medium by starting with a 3–4 cm layer of clay pebbles or gravel. Then mix ½ part potting compost with ¼ part yellow sand and ¼ part garden soil, and add the mixture to the pot
3. Moisten the root ball of the bougainvillea before removing it from its pot and placing it in the pot
4. Fill the planting hole and firm down lightly with your fingers around the edges of the pot
5. Install a trellis which can take the form of a bamboo tipi tied at the top, a wooden trellis or one in wrought iron
6. Finally, tie the woody climbing stems of the bougainvillea to the supports

Where should I place a bougainvillea pot during the growing season?

Bougainvillea grown in a pot can be placed outdoors from early May until mid-October.

©Paul Sullivan – Flickr

Place the pot indifferently on your balcony, patio or terrace. Most important is plant is exposed to full sun and kept sheltered from prevailing winds. Installing a windbreak can be considered to protect it.

What about watering and fertiliser?

Throughout summer, bougainvillea’s substrate must be kept moist. Make sure therefore to water it very regularly to prevent soil drying out completely between waterings.

Also apply fertiliser very regularly throughout the plant’s growth period. Carry out these fertiliser applications after watering if fertiliser is liquid, or scratch it into soil if it is blood meal.

Good to know: pruning bougainvillea in a pot is not necessary. On the contrary, severe pruning can slow flowering, which takes place on wood two years old. Simply remove any obstructive secondary shoots from time to time.

When should potted bougainvillea be brought indoors in autumn?

Bougainvillea is not very hardy and must be overwintered indoors in regions with cold winters. Bring pot indoors as soon as first frosts are forecast.

Shelter should then provide a temperature between 5 and 10°C so plant enters dormancy.

Make sure to space out watering from autumn (every 15 days to 3 weeks). During wintering period stop all fertiliser applications.

When and how to repot bougainvillea in a pot?

From March potted bougainvillea resumes growth. This is the best time to repot it. However, it is not necessary to repot your potted bougainvillea every year.

1. Start by putting on gardening gloves, as it is a thorny plant
2. Choose a new pot slightly larger in diameter than the previous one
3. Replace a layer of clay pebbles or gravel about 3 cm deep in the bottom of the pot
4. Add your potting compost mixed with garden soil and coarse sand
5. Soak the root ball of your potted bougainvillea before removing it from the old pot
6. Place the plant in its new pot, fill the hole and firm the soil before watering thoroughly
7. Install the trellis and tie the woody climbing stems to the stake
8. Place the plant in a bright spot and resume waterings gradually