As for being invasive,the leucadenron can get quite large, so it may have a extensive root system. Both need really good drainage as they're susceptible to root rot on occasions, especially the leucadendron.

How fast do Proteas grow?

In about a year the plant will grow to about 2.5 metres high and 2 metres wide, with many colourful bracts all over the bush. So if you thought you didn't have enough time to have magnificent flowering shrubs in your garden, think again, and think Proteas and Leucadendrons.

Which plants have invasive roots?