Bougainvillea plants do not have invasive roots if the plant is watered regularly and the top stems are trimmed regularly. In drought conditions or in dry areas the roots can seek water from nearby pipes if they are leaking. While they are unlikely to break through plastic pipes, their roots may search out broken pipes if they lack water.
Bougainvillea plants will flower well when they have limited room to grow in pots. The plant and root system will stay smaller but the plant will flower vigorously.
Bougainvillea plants like to dry out slightly between watering. Watering them once or twice per week in summer will keep them happy. If you live in a tropical area, you may be able to rely on the summer rain to keep your plants happy.
Avoid adding too much nitrogen fertilizer which can cause excess green leaf growth and will slow down flower growth. The bright flowers on the end of bougainvillea stems are actually modified leaves with the tiny flowers hiding within these leaves.
Bougainvillea plants are climbers and so their roots do not need to grow deep into the ground to support their weight. Their long stems will grow up walls and garden screens being held up with the spikes on the bougainvillea stems.
Bougainvillea plants have shallow roots
Bougainvillea plants have relatively shallow roots compared to their size. Unlike large trees, these trailing vines do not need a deep tap root to stabilize the plant. They instead create a shallow matt of roots which help to hold the plant in the ground and feed it.
Avoid disturbing bougainvillea roots
Roots of the bougainvillea are sensitive to being disturbed. Take care when raking or adding more mulch as some of the roots grow close to the surface of the soil. The thin roots can be easily broken which can slow the plant’s growth.
Bougainvillea plants will flower with restricted roots
Bougainvillea plants will actually flower when they are getting limited fertilizer and their roots are restricted. They look great in pots as they start to fill the pot.
How to stop bougainvillea roots from becoming invasive
While bougainvillea plants do not have particularly invasive roots, there are some tips that can keep them contained and reduce the risk that they will venture into pipes nearby.
1. Keep the top of the tree trimmed
To keep the root system under control it is important to regularly trim the stems. Once the plant has finished flowering in summer, trim the stems back to remove the old flowers.
This will give you a chance to reshape the tree and remove any branches that are growing out of control. Limiting the size of the stems will reduce the size of the root system that the plant needs to grow to get the water and nutrients it needs.
2. Regularly water the plant
Bougainvillea plants that are getting regular water over summer will have less invasive roots. Plants that are left to dry out can seek water from a dripping tap nearby or a leaking pipe.
Old, clay pipes can crack over time, slowly leaking water. Bougainvillea plants growing nearby that are not getting enough water can seek out the water from the leaking pipe and may venture inside.
Avoid planting the bougainvillea near water pipes if you are concerned and keep the plant regularly watered. Allow the plant to dry out between watering to not cause root rot.
Watering bougainvillea once or twice per week in summer and once every 2-3 weeks in fall and
Bougainvillea plants will lose their leaves over winter in cold climates but will still need some water to keep them happy. When the warm weather returns in spring, the leaves will grow back and the flower will soon follow.
3. Plant bougainvillea in pots
If you are concerned about your bougainvillea roots invading nearby pipes, it is easy to grow them in pots. You can choose a dwarf or full size variety. Plant them in premium potting soil and keep them trimmed to the size you want.
You can even grow bougainvillea as bonsai. These hardy plants will survive a good prune
4. Choose a dwarf variety of bougainvillea to keep their roots compact
Dwarf varieties of bougainvillea are a great option if you have a small space and want to keep the roots contained. These varieties can be kept to a few feet high if you want to let them grow up a garden screen. These dwarf varieties will naturally have smaller root systems because they will be supporting less stems.
5. Use root barriers
Root barriers are a good option to keep bougainvillea roots contained if they are growing in the ground. These barrier pieces are dug in the ground and will stop the roots from spreading laterally. This will help to stop them from invading the space of your other plants or lifting pavers.
Are Bougainvillea Roots Invasive? | Summary
Bougainvillea roots are not particularly invasive but they will seek out nearby water if the plant is left to dry out. Plant bougainvillea plants in pots and allow them to climb up a nearby wall or screen. You can even trim them back to keep them small and easy to deal with.
Bougainvillea plants can grow huge. We had one growing at our old house that was over 30 feet tall but they can grow even taller. The traditional bougainvillea varieties will have large spines which can be dangerous for kids and pets.
Look out for new varieties that will grow without spikes. These still look beautiful are covered with colorful leaves in spring and summer. Bougainvillea plants will stay green all year round if you live in a mild climate.