Bougainvilleas are one of the great garden climbers and are popular around the world, anywhere that has a tropical or subtropical climate. Bougainvilleas come in many different colours apart from the usual purple, including pink, yellow and white; some have variegated leaves. Bougainvillea flowers are actually colourful papery bracts that surround the true pale yellow flower at the centre. Bougainvilleas are easy to look after once established.
Bougainvillea Have Weak Roots
Bougainvillea are often massive plants that sprawl into the tops of trees and over buildings. The plant grips onto other plants with its strong thorns. As the bougainvillea does not need to support it's own weight, as a free standing tree like an oak does, the bougainvillea does not have a strong root system. Bougainvillea roots tend to be long and brittle and they break easily if the ground they are growing in is disturbed in any way.
Bougainvillea Dislikes Root Disturbances
Young, unestablished bougainvillea can be fatally damaged if roots break when the ground is disturbed. If not killed then the plant will often go into a state of shock for many weeks, where it will not grow despite perfect conditions for doing so. Older plants are more tolerant and less likely to die outright by root damage but they are still sensitive, and care should be taken when digging in an area with bougainvillea.
Bougainvilleas are frequently grown in pots both to restrict their size and because they grow well as a bonsai. Bougainvillea bloom best in pots when their root system is restricted so repotting is kept to a minimum. If you do need to repot your bougainvillea, you should gently break the pot from around the roots if at all possible to avoid disturbance. If this is not possible, use a pallet knife to ease the roots from the sides of the pot as opposed to simply ripping the plant out.
Bougainvillea roots are also extremely sensitive to too much water. Roots that sit in water, even for a short period, often develop root or stem rot and plant death. When planting a new bougainvillea in the garden, resist the temptation to tease the root ball free in the hope that the roots will be encouraged to grow faster, as this will only result in more broken roots.
Preliminary experiments by the North Florida Research and Education Center show that using copper hydroxide impregnated pots helps bougainvillea cuttings to grow a more fibrous root system, which would makes the roots less susceptible to breakage. Bougainvillea roots require phosphorus for proper growth and development; feeding the plant a high phosphorus fertiliser will help to keep the roots as strong as possible.